PLUTONIUM PRODUCTION STORY AT
THE HANFORD SITE: PROCESSES
AND
FACILITIES HISTORY
Michele Gerber, Ph.D.
June 1996
ABSTRACT
This document tells the history of the actual plutonium production
process at the Hanford Site. It
contains five major sections:
•
Fuel Fabrication Processes
•
Irradiation of Nuclear Fuel
•
Spent Fuel Handling
•
Radiochemical Reprocessing of Irradiated
Fuel
•
Plutonium Finishing Operations
Within each section, the story of the earliest operations is told,
along with changes over time until the end of operations.
Chemical and physical processes are described, along with the
facilities where these processes were carried out.
This document is a processes and facilities history.
It does not deal with the waste products of plutonium production.
TABLE OF CONTENTS
1.0
FUEL FABRICATION PROCESSES
58
1.1
SINGLE PASS REACTOR FUEL FABRICATION 58
1.1.1
Solid Uranium Metal Fuel Produced 58
1.1.2
The Overall Process
59
1.1.3
Canning 60
1.1.4
Canning Tests
61
1.1.5
Additional Chemical and Hazardous Components 62
1.1.6
Process Changes 62
1.1.7
313 Building Expansion Under Eisenhower/Switch to Lead-Dip Process
63
1.1.8
Projection Fuel Elements
64
1.1.9
End of Single-Pass Reactor Fuel Making
64
1.1.10
Other 313/314 Building Processes 65
1.2
N REACTOR FUEL FABRICATION
67
1.2.1
The 333 Fuels Manufacturing Building
67
1.2.2
Co-Extrusion Process
68
1.2.3
Other Processes in the 333 Building
69
1.2.4
The Waste Acid Treatment System (WATS) Process 69
2.0
IRRADIATION PROCESSING AT THE HANFORD SITE 71
2.1
HANFORD'S SINGLE PASS REACTORS
71
2.1.1
Historic Significance of B-Reactor
71
2.1.2
Single-Pass Reactor Buildings
71
2.1.3
Operation of the Single-Pass Reactors
73
2.1.4
Change and Experimentation in Production Process 73
2.1.5
Graphite Expansion Early Problem
74
2.1.6
Increased Power Levels/Production 74
2.1.7
Operating Challenges at Higher Power Levels 75
2.1.8
Reactor Upgrades for Increased Production 77
2.1.9
End of Single-Pass Operations
78
2.2
N REACTOR OPERATIONS 79
2.2.1
105 N Building and Reactor
80
2.2.2
N Reactor Operating Changes and Challenges 81
3.0
SPENT FUEL HANDLING AT THE HANFORD SITE
83
3.1
ORIGINAL LAG STORAGE PRACTICES
83
3.2
212 LAG STORAGE BUILDINGS CLOSE
83
3.3
CLOSURE/RE-OPENING OF FUEL STORAGE BASINS
84
4.0 RADIOCHEMICAL
SEPARATIONS PROCESSING
86
4.1
THE BISMUTH-PHOSPHATE PROCESS
86
4.1.1
Start-up of Radiochemical Processing at HEW 86
4.1.2
T, B, and U Process Groups
86
4.1.3
Original Separations Buildings
86
4.1.4
Galleries 87
4.1.5
Canyon 88
4.1.6
Processing Equipment 88
4.1.7
Stair Towers
89
4.1.8
224 Bulk Reduction Buildings
89
4.1.9
231 Isolation Building 90
4.1.10
The Bismuth-Phosphate Process
91
4.1.11
Dissolving
92
4.1.12
Extraction
92
4.1.13
Decontamination
92
4.1.14
224 Bulk Reduction Process
93
4.1.15
231 Isolation Process 93
4.1.16
Earliest Operations
93
4.1.17
Early Process Changes
94
THE PLUTONIUM PRODUCTION STORY AT THE
HANFORD SITE: PROCESSES AND
FACILITIES HISTORY
1.0 FUEL
FABRICATION PROCESSES
1.1 SINGLE
PASS REACTOR FUEL FABRICATION
1.1.1 Solid
Uranium Metal Fuel Produced
The nuclear fuel fabrication processes employed at the Hanford Site to
manufacture plutonium (Pu) for defense purposes essentially produced solid
uranium (U) metal fuel elements, jacketed in aluminum-silicon (later
Zircaloy-2)a
coats. Although some variations
were introduced, the solid metal fuel type was not replaced by powdered or
pelletized fuel forms, nor by mixed oxide (MOX) fuel blends for the production
of defense-grade Pu-239. Moreover,
the fuel-making processes used at the Hanford Site for defense production all
were unique and prototypical at the time they were initiated.
Thus, they qualify under criteria of the National Historic Preservation
Act (NHPA) as historic processes.
1.1.1.1 Original
Fuel-Making Buildings. The
original fuel-making process employed at the Hanford Engineer Works (HEW-
World War II name for the Hanford Site) was known as the
"triple-dip" process. It
took place in two buildings in HEW's 300 Area, known as the 313 Metal
Fabrication Building and the 314 Press Building (also known as the Metal
Extrusion Building). Both
buildings were constructed of structural steel framing, had concrete block
walls and concrete slab floors, and sat on reinforced concrete foundations.
The 313 Building had a precast concrete slab roof with tar and gravel
surface, and interior partitions made of concrete block and concrete brick.
The 314 Building had a corrugated asbestos roof with a 36‑inch
(91.44 centimeters) continuous roof ventilator extending nearly the
entire length of the building. Interior
walls consisted of concrete block with 3/16‑inch asbestos board on some
interior partitions.[i]
The original 313 Building, completed in the Autumn of 1943, was
rectangular in shape, with overall dimensions of 199.5 feet (60.8 meters)
by 65 feet (19.8 meters) by 20 feet (6.09 meters) (high).
However, eight subsequent additions made in late 1943 and in 1944
brought the overall dimensions to 199.5 feet (60.8 meters) by
182.5 feet (55.6 meters) by 20 feet (6.9 meters) (high),
with a total area of approximately 36,000 square feet
(3,344.4 square meters). The
continual early additions were caused by process improvements and changes in
the very new, untried, and unique uranium fuel fabrication activities being
carried out in the facility. According
to prime construction contractor DuPont Corporation: "In the construction of the 313 Building, the first
equipment to go into operation was known as the experimental line.
This line was set up specifically for experimental purposes...[and] was
dismantled and moved to other portions of the...Building."[ii]
The first 313 Building addition, on the east side, provided additional
space for furnaces and presses, and the second, on the west side, provided a
tool room and shop. The third
addition ran the entire east side of the building, and allowed space for
welding booths and jacket (can) washing.
The fourth addition, on the northwest corner, furnished an electrical
control room, and the fifth addition, along the west side, included a locker
room, women's rest room, and shower room.
(The locker and shower rooms later were eliminated in favor of a
storeroom.) The sixth addition was again on the northeast corner of the
facility, and provided more space for can washing. The seventh addition, on the southeast of the building,
allowed for a second canning process section and for "recovery"
(uranium scrap recycling) process equipment.
However, this latter equipment soon was moved to the nearby 314 Press
Building. The eighth and final
addition of WWII was on the northeast corner, and furnished space for a third
canning process section.[iii]
The 313 Building contained numerous electrical furnaces and metal
presses; three fuel canning areas; a welding area; a can cleaning area; a
control room; various supply tanks; a tool room and shop; and various offices,
storerooms, and sanitary rest rooms.
The 314 Press Building had original overall dimensions of 199.5
(60.8 meters) feet by 90.5 feet (27.58 meters) by 40 feet
(12.19 meters) (high) with an area of about 17,000 square feet (1579.35
square meters). It contained a
1,000‑ton extrusion press, electric furnaces, a rod-straightening
machine, a 7.5‑ton overhead crane, an autoclave area, a control
room, a shop and repair area, pumping units for the press, and various offices
and sanitary rest rooms. Outside,
there was a 12‑foot (3.66 meter) by 18‑foot (5.49 meters)
concrete and steel platform north of the building.
Gas cylinders were located outside along the north wall.[iv]
Hanford's original fuel-making processes can be summarized as follows:
It began in the 314 Building, where uranium that arrived as
billets was heated in a muffle‑type furnace with an interior, inert gas
atmosphere. (The helium or argon
atmosphere was used to reduce the oxidation of metal during heating.)
The uranium was then transferred through a closed passageway to
the extrusion press, which also operated in an inert atmosphere. After being extruded, the rods were outgassed, straightened,
and sent to the 313 Building for machining and jacketing.
In the 313 Building, U fuel rods were machined into fuel cores in
lengths of either 4 inches (10.16 centimeters) or 8 inches
(20.32 centimeters), with 1.3-inch (3.3 centimeters) inner diameters.
Known as "slugs," these cores were "canned" or
jacketed into finished elements, and then tested and inspected in this
building.
Details of the HEW fuel-making process provide valuable insights:
The earliest uranium for the fabrication of reactor fuel arrived
at the HEW in October 1943 as extruded rods.
The rods were delivered to the Riverland Yards.
The Riverland Yards were an official part of HEW and were located just
east of the Midway power substation (just west of the 100-B Reactor Area). Because railroad track had not yet been completed to the
300 Area, the rods were taken by rail to the Hanford Construction Camp
about 20 miles (32.19 kilometers) north of Richland, and then by
truck to the 300 Area. Once
railroad service to the 300 Area was connected in January 1944,
uranium was delivered to the fabrication area by rail.
Newly arrived U rods were unpacked and visually inspected (in sample
amounts) for cracks and for overall dimensions.
A random amount from each lot was taken to the 305 Test Pile
Building just west of the 313 Building, and irradiated at a low level to check
for warping, cracking, and embrittlement under irradiation.
If the sample withstood the process in good form, the entire lot was
accepted. Beginning in December
1943, the first uranium fabrication operation at HEW was machining, in
which bare uranium rods were lathed down to specific core dimensions in
the 313 Building. The
following month, operators began degreasing the machined cores before
inspection, using a commercial product that contained primarily
trichloroethylene, Detrexa,
a solvent degreaser. Core canning
operations actually began in the 313 Facility in March 1944.
In the 314 Building, autoclaves for fuel element testing started
to operate in July 1944. A scrap
recovery process began the following month.
Outgassing and straightening operations started in the
314 Building in September 1944, but HEW's uranium rods still were
being extruded offsite. Beginning
in November 1944, uranium was transported to HEW as billets, which were
stored until the extrusion process began to operate in the 314 Building
in January 1945. The press
testing phase lasted into mid‑spring, and then fuel operations
commenced. Greater confidence in
personnel performance ended shift work in the metal preparation buildings in
June 1945, and work proceeded on a straight, 6‑day-per-week schedule.
From that time until 1948, a complete cycle of metal preparation
occurred at HEW. The
uranium billets went to the 314 Building for extrusion, outgassing,
and straightening, then to the 313 Building for machining, canning, and
initial inspection, and then back to the 314 Building for autoclave and
radiograph testing.[v]
The original fuel canning process tried at HEW involved the use of an
electric heater press, known by workers as the "whiz‑bang," to
heat and bond the uranium fuel cores to their aluminum jackets. However, the heaters burned out frequently, did not heat the
elements and cans to consistent temperatures, and did not produce a uniform
bonding. This problem was serious
because nonuniform bonding caused thin places in the jacketing that, under
irradiation, heated up more than other places.
These "hot spots" could cause fuel element ruptures in the
reactors. By August 1944,
the uranium fuel cores were being jacketed in a triple‑dip method
that consisted of bathing them in molten bronze, tin, and then a molten
aluminum‑silicon mixture. The
bronze used in this process at HEW was relatively high in tin content
(53% tin and 47% copper), and the bronze bath itself had a flux cover
composed of barium chloride, potassium chloride, and sodium chloride.
As fuel cores were dipped into this mixture, they acquired trace
coverings of all of these substances.
Initially, the bare uranium cores were cleaned by passing them
through a trichloroethylene vapor degreaser, then through a nitric acid tank,
two rinse tanks, and a hot air dryer. The
nitric acid rinse was known as "pickling" the slugs.
Meanwhile, a steel "sleeve" that would surround each can
during the dipping process was cleaned in sodium hydroxide, and aluminum end
caps and cans were cleaned in a sodium dichromate solution followed by a
methanol rinse. The bare uranium
cores were dipped in a bronze bath to heat them to a uniform temperature
within the uranium beta phase (660 °C to 770 °C), and then placed in a tin bath to (1) cool them
into the uranium alpha phase (less than 660 °C) and (2) remove excess bronze. Next they were centrifuged to throw off excess tin.
Then the cores were immersed quickly in an aluminum-silicon brazing
bath (also in the uranium alpha phase), and water quenched.
The various heating and cooling procedures were done to randomize the
uranium grains, thus inhibiting the uranium "growth"
(expansion under irradiation) problem. After
water quenching, the steel sleeve was pulled away and cleaned with sodium
hydroxide and soap to remove any remaining aluminum-silicon.
The sleeve then could be reused many times.
The thickness of the residual end cap on the element was then measured
with a fluoroscope and marked with a punch to indicate the amount that needed
to be removed in subsequent end machining.
Identification numbers were stamped on the can base end, and the braze
line on the end cap was tungsten inert gas (TIG) welded to seal the
porous braze to the end cap and can. A
final etching in nitric acid completed the procedures.
Three tests followed the canning process.
The first, the frost test, consisted of spraying the can with
acenaphthene mixed with carbon tetrachloride (CCl4).
The canned element was then placed into an induction coil to heat its
surface. If there was a gas
bubble or a nonbonded spot, this spot would become shiny, and the element then
would be rejected and sent back through a recycling process. If the bond was good, the acenaphthene was removed with
trichloroethylene, and the element was inspected in one of several autoclaves
located in the 314 Building. In
that inspection, the canned element was placed into a steam autoclave, which
operated at about 100 pounds (45.36 kilograms) per square inch gauge
(psig) at 175 °C for more than 20 hours, to reveal any pinholes or
incomplete welds. Water from the
steam would be conducted through any such openings, and the uranium core
would expand rapidly, resulting from the formation of a uranium oxide (UO2)
compound known as U3O8, and split the aluminum can.
If an element passed the autoclave test it then underwent a final
radiograph (X‑ray) test in the 314 Building, to detect porosity in the
end weld bead. Any porosity could
have become a pathway for water to contact the uranium fuel and cause the
element to rupture.[vi]
1.1.5 Additional
Chemical and Hazardous Components
In addition to the above‑mentioned chemicals, other hazardous
substances were used routinely in early HEW fuel fabrication processes. Aluminum cans and caps were cleaned using first
trichloroethylene, then Duponol-M-3a
(an industrial soap), phosphoric acid, and various rinses including methanol.
Steel sleeves were cleaned in sodium hydroxide and soap.
Caustic cleaners popular at HEW included Aluminux and Diversey‑415b,
both containing primarily sodium dichromate.
Sodium hydroxide and sodium nitrate were used to strip aluminum and
braze off the rejected uranium cores.
An intermetallic compound layer of uranium and copper (specifically UCu5)
on the rejected cores was removed by using hydrofluosilicic acid.
Acetone and methyl alcohol (methanol) were used as all‑purpose
cleaning and drying agents.
In 1948, the extrusion press in the 314 Building was excessed, and
HEW began receiving rolled uranium rods from an offsite commercial mill.
The rolling process seemed to offer metallurgical advantages, because
the uranium could be processed at lower temperatures, which induced less
oxidization and produced smaller and more random grains within the metal.
This type of grain within the uranium avoided the "pimpling and
dimpling" of fuel rods, a persistent problem in early fabrication
efforts. It was also a less
expensive process. From 1950 to
1951, a rolling mill was procured and installed in the 314 Building, to
save the costs of shipment to offsite mills.
However, this mill was relatively small, and the rolling operation was
transferred to a large facility constructed at the Feed Materials Production
Center (FMPC), an Atomic Energy Commission (AEC) site in Fernald, Ohio, in
1952. Thereafter, no extruding or
rolling operations were conducted at the Hanford Works (HW - the peacetime
name given to HEW in 1947 by the AEC) in connection with the fabrication of
fuel elements for single‑pass reactors.
The 314 Building process continued to operate for the purposes of
straightening uranium rods, providing autoclave and radiograph testing of
canned elements, and providing uranium scrap processing operations.[vii]
1.1.7 313
Building Expansion Under Eisenhower/Switch to Lead-Dip Process
In 1954, the 313 Building underwent a major remodeling and
expansion, reaching a total size of 182.5 feet (55.63 meters) by
486 feet (148.13 meters), with a total area of 76,633 square feet
(7119.44 square meters). At that
time, much contaminated equipment and other solid wastes from this building
and its immediate surrounding area and from the 303 fresh fuel warehouses
were buried. The remodeling
occurred at the time that fuel canning technology in the 313 Building
switched from the triple‑dip process to the new lead‑dip process.
Lead‑dip consisted of immersing the uranium fuel cores in a
duplex bath (molten lead covered with molten aluminum-silicon) to preheat the
cores in the uranium alpha phase. This
step formed an intermetallic compound of uranium and lead (UPb or UPb3)
on the core. It was followed by a
molten aluminum-silicon bath (also in the uranium alpha phase) to braze and
bond the cores to the aluminum cans and caps.
This process allowed the first canning bath to occur at a lower
temperature (lower than 660 °C) because the uranium cores already had been
beta heat treated in a molten salt bath at the FMPC.
However, the new method introduced a great deal more lead and other
heavy metals into 313 Building waste streams, because approximately
30,000 fuel elements were canned per week during the years of peak single‑pass
reactor operations at HW (1955‑1964). At about the same time that the lead‑dip process
replaced the triple‑dip method, an ultrasonic test replaced the frost
test, which eliminated the use of acenaphthene and CCl4.
Concurrently, the majority of testing autoclaves were removed from the
314 Building and placed in the north end of the 313 Building.
1.1.7.1 Hot
Die Size Process. In the early
1960's, just before the eight single‑pass reactors at HW began to close,
experiments were under way in the 304, 3716, and 313 Buildings with a new
canning procedure known as the Hot Die Size Process.
Also termed the "nickel‑plate" procedure, this
operation plated uranium fuel cores with nickel, using nickel sulfate,
nickel chloride, and boric acid. It
included standard fuel fabrication cleaning, degreasing, etching, and testing
chemicals and processes. Although
the Hot Die Size method was tested successfully, it was not implemented on a
large scale, because of the impending closures of HW's eight original
reactors.[viii]
1.1.7.2 Cored
and Internally and Externally Cooled (I&E) Fuel Elements.
In the 313 Building, additional fuel fabrication process changes
during the 1950's and early 1960's included the manufacture of cored fuel rods
beginning in 1954, internally and externally cooled (I&E) fuel rods
beginning in 1957, and projection fuel rods in the early 1960's.
The cored rods, hollow elements with an aluminum plug at either end,
bonded to the uranium with an aluminum-silicon braze, were designed to give
the uranium an inner space in which to expand during irradiation.
The early, solid fuel elements were experiencing a troublesome level of
distortion, and subsequent rupture, in HW's production reactors. However, the cored fuel elements frequently developed cracks
in both the uranium and the aluminum plug areas, and they were discontinued in
1957. The I&E fuel elements,
tried next, had a tubular hole down the middle, allowing cooling water to run
both around and through them in the reactors.
Projection fuel elements, with small fins protruding from their sides,
were of two types: the
bumper type had six short projections for use in ribbed process tubes, and the
self‑supporting type had eight projections for use in ribless process
tubes.
1.1.8 Projection
Fuel Elements
The switch to projection fuel rods represented yet another attempt to
solve the fuel element rupture problem then plaguing Hanford's eight single‑pass
reactors. Power and fuel exposure
level increases throughout the late 1950's and early 1960's had brought
reactor operating temperatures to a point that seriously augmented fuel rod
ruptures, with resultant increases in contamination released to the Columbia
River. Post‑irradiation
examinations of failed I&E fuel elements showed that only about
20% of the failures resulted from fuel element "quality
deficiency," while 80% resulted from longitudinal corrosion attack
caused by warp. Known as
"side hot‑spot" ruptures, these failures were caused by
positioning of the fuel rods in the process tubes.
The new projection fuel elements, first tested in 1961 in reactors at
HW, were manufactured in the 313 Building through the use of ultrasonic
welding. Canned fuel elements
first were dipped in a tank to deposit an Ivorya
soap film, useful in achieving a good weld.
After the projections were welded, the soap film would be rinsed off in
a three‑compartment rinse using standard fuel fabrication chemicals and
degreasers.[ix]
1.1.9 End
of Single-Pass Reactor Fuel Making
Fuel element preparation activities for the single-pass reactors ended
in the 313 and 314 Buildings in 1971, when the last of these reactors
closed. The 314 Building was
modified in the 1970's and was used for a variety of research projects and
crafts services. The majority of
the fabrication equipment for single-pass reactor fuel elements was removed
from the 313 Building between the mid‑1970's and the mid‑1980's.
However, the south end of the 313 Building continued to house
major functions in support of N Reactor fuel production.
Among these functions were the receiving and inspection of
uranium billets and other components used to make N Reactor fuel
elements and the chemical passivation of spacers from N Reactor, the
casting and machining of copper‑silicon preshape components used in
N Reactor fuel elements (beginning in 1973), and the neutralization
and handling of non‑uranium‑bearing acid wastes from
N Reactor fuel fabrication processes in the 333 Building.
Finished N Reactor fuels and fabrication components, tools, and
miscellaneous supplies were stored in the north end of the 313 Building
from 1971 to 1987, and an Engineering Development Laboratory, including
facilities for working with uranium, was established in the structure in
the 1970's. In 1983/1984, a
Suttonb
extrusion press was purchased and placed in the 313 Building as a backup
for the extrusion press operating in the 333 Building performing
N Reactor fabrication work. However,
the shutdown of N Reactor operations in December 1986 precluded use of the
Sutton press.
1.1.10 Other
313/314 Building Processes
Over the years, several other ancillary or off-shoot processes have
taken place in the 313 and 314 Buildings.
Among these have been U scrap recovery operations, experimental and/or
small-scale fuel making ventures, and waste treatment procedures.
From its earliest days, concern of the Manhattan Engineer District (MED
- earliest federal management agency over HEW) about the adequacy of
uranium supplies brought strict policies that mandated the reclamation of
all possible uranium scraps at federal atomic sites.
During the earliest fuel fabrication operations at HEW,
difficulties with early fuel canning techniques produced thousands of rejected
cores, lathe turnings, metal oxides that formed when canned slugs failed in
autoclave tests, and other scraps by mid-1944.
That June, Du Pont reported that "all available space"
around the 313 and 314 Buildings was filled with cans of scrap, and the
fabrication area fence had to be moved about 30 feet (9.14 meters)
east of fresh fuel storage building 303‑J to allow for more storage
space. Several can fires
occurred. Beginning with the
startup of extrusion press tests in January 1945, extrusion butt ends, oxides,
and container residues collected, along with acids from the slug pickling
process and from the slug recovery process.[x]
At first, the various types of scrap were shipped to offsite
reclamation processing centers. By
1946, however, the volume of uranium scraps accumulating and the expense
and fire and security hazards of shipment brought a change in policy at HEW.
A "chip recovery" operation began in the 314 Building.
It operated only a few days a month and involved collecting all chips
and turnings from machining operations, sorting them, breaking them into small
pieces, washing, drying, and then pressing them into briquettes. At first the briquettes themselves were shipped offsite.
In May, however, the MED ordered briquetting to be discontinued, due to
a number of uranium chip fires within the centrifuging step at other sites.
A "melt plant" was established in the 314 Building in late
1947. In that process,
"new" uranium could be made by combining
uranium tetrafluoride (UF4 or "green salt") and
either calcium chips or magnesium chips.
This mixture was placed in a dolomite-coated steel vessel, heated until
free molten uranium separated from magnesium fluoride or calcium
fluoride, and then allowed to cool. The
molten uranium settled into large buttons shaped like Derby hats (called
"Derbies" by HW workers). Slag
was jackhammered off the Derbies, which were mixed with the recycled
uranium scraps and briquettes, melted in a vacuum furnace, and cast into
ingots. These ingots were then
rolled into new uranium rods, either offsite or at Hanford, and used to
make additional fuel rods.
In the spring of 1946, an additional scrap recovery operation known as
the "oxide burner" began on the north side of the 314 Building.
All uranium‑bearing dust and particulate matter that could be
collected from the fuel fabrication facilities, as well as the tailings or
settlings from washes and quenches, was burned to convert it to oxide (powder)
form. The UO2 was then
collected in 5‑gallon (18.93 liters) buckets for compact shipment
offsite.[xi]
From the outset of chip recovery operations in 1946, HW's Health
Instruments (H.I.) Division detected serious radiological problems with this
process. Throughout 1946 and
1947, monitors reported that oxide burner operations were really spreading
metal dust and oxide around the 314 Building, producing airborne
contamination samples over tolerance.[xii]
In December 1947, the oxide burner operation moved to a separate
building north of the 314 Building.[xiii]
Both melt plant and oxide burner operations were phased out at HW
between 1952 and 1954. The
burnout of slag from used melt crucibles was completed, and the furnace was
excessed to the 300 Area Burial Grounds by late summer 1954.
Thereafter, solid uranium scraps at HW continued to be collected,
stored, and combined with solids collected from neutralized, uranium‑bearing
waste acids and processed through a press‑and‑frame filter press
in the south end of the 313 Building.
Together, all of these scraps were slurried into sodium diuranate,
stored in the 303 Buildings area, and shipped in barrels to the FMPC.[xiv]
From 1944 through the 1950s, bismuth fuel targets welded into nonbonded
aluminum cans, irradiated to make polonium‑210 in 100 Areas
production reactors, were fabricated in the 313 Building.
Polonium‑210 was the initiator in atomic (pre‑hydrogen and
non-hydrogen) weapons explosions. An
even larger number of lead-cadmium fuel rods, also welded into nonbonded
aluminum cans, were produced for use as "poison" elements in
the 100 Areas reactors and in the 305 Test Pile.
The term "poison" refers to the ability of these neutron
absorbing metals to slow down or even kill (control) nuclear chain reactions.
The production of lead‑cadmium fuel rods continued throughout the
years of single‑pass reactor operations (through 1971).
Additionally, lithium-aluminum alloy fuel targets, manufactured for the
P‑10 project at Hanford's 100‑B Area to produce tritium for
the world's first hydrogen weapons tests, were canned in nonbonded aluminum
cans in the 313 Building from 1949 to 1952.
During the early 1950s, a number of attempts were made to fabricate and
jacket metallic thorium fuel targets in the 313 Building to produce
uranium‑233. Many problems
connected with the rapid formation of a thick coat of oxide on the
thorium metal targets led to experiments with a variety of bonding
methods and coatings. Eventually,
thorium oxide (ThO2) powder and wafer fabrication was carried out
in the nearby 3722 and 3732 Buildings in the late 1960's.
Beginning in the late 1950s and continuing until 1971, a process
to electrolytically anodize the aluminum "spacers" (dummy fuel
elements) used in the single‑pass reactors (to create a protective
aluminum oxide [Al203] coating) was added in the
313 Building. The
passivation of N Reactor steel spacers to reduce rust formation also took
place in the 313 Building from the mid‑1960s through the mid‑1980s.[xv]
Also, highly enriched uranium-aluminum fuel cores, used as driver
elements in the early tritium production program and in a mid‑1960's
uranium‑233 production program in the N Reactor, were
manufactured and canned in nonbonded aluminum cans in the 313 Building.
Beginning in 1954, waste acids containing recoverable amounts of
uranium from the 313 and 333 Buildings were routed to designated tanks in
the 313 Building, neutralized, routed to another tank, and passed through
a press-and-frame filter press. The
precipitate remaining on the filter press was known as "C‑6" sludge,
and was collected and placed in barrels for shipment to the FMPC. The centrifuging operation, along with waste acid storage
tanks, anodizing tanks, and the filter press used to separate sodium diuranate
from uranium‑bearing, neutralized wastes, was located in the south end
of the 313 Building. A process
to recover uranium cores from rejected, lead‑dip canned fuel elements
also began in the south end of the 313 Building in 1954. Boiling sodium hydroxide was used to remove the intermetallic
compound layer of lead and uranium from the elements. Beginning in 1975, the 313 Building played a key role in a
new Waste Acid Treatment System (WATS) process that was emplaced in connection
with the nearby 333, 334 and 334A Buildings.
The WATS process operated until 1987.
1.2 N
REACTOR FUEL FABRICATION
The fuel-making process for the New Production Reactor (N Reactor)
was very different from that used to make fuel for Hanford's single-pass
reactors. Soon after funding was
secured for N Reactor in 1958, a high pressure heat transfer apparatus
was emplaced in the 189/190-D Building, a converted World War II pumphouse in
the Hanford Site's 100-D Area. Its
purpose was to test a new, N Reactor fuel concept being developed in the
306 Metallurgical Pilot Plant, a 300 Area building dedicated to fuel
manufacturing experimentation. The
concept first tried for N Reactor fuel was a wire-wrapped, seven-element
cluster of long, thin fuel rods spaced together in a horizontal flow tube.
Each individual element was only 0.625 to 0.704 inches (1.59 to
1.79 centimeters) in diameter, and was 35 to 45 inches (88.9 to
114.3 centimeters) long. As such,
the heat transfer and flow properties of these elements were very different
from those of the solid U or I&E fuel elements previously used at Hanford.
An understanding of every characteristic of the new elements, including
subcooled and boiling burnout and pressure drop parameters, was essential if
they were to be recommended for N Reactor use, so trials continued
throughout 1959.[xvi]
However, attention soon turned to yet another new concept developed in
the 306 Building. This idea, of a co-extruded tube-in-tube fuel element design,
eventually was adopted for N Reactor.
A full-scale, experimental heat transfer test section that simulated
the downstream half of a tube-in-tube charge in N Reactor was built on
the mezzanine of the 189/190-D "flow laboratory."[xvii]
1.2.1 The
333 Fuels Manufacturing Building
In the meantime, construction of the new 333 Fuels Manufacturing
Building, to produce N Reactor fuel elements on a plant scale, was being
constructed just east of the 313 and 314 Buildings.
Building design itself did not depend on knowing exactly which
manufacturing process would be used, but once the co-extrusion process was
selected, the equipment eventually procured and constructed in the 333
Building was unique. The 333
Fuels Manufacturing Building itself was constructed of steel frame with double
metal insulated panel exterior walls and lightweight metal panels for interior
partitions. The foundation and
floors were poured concrete. The
roof consisted of insulated metal paneling covered with felt and roll tarpaper
and a tar and gravel surface. The
roof was refinished in 1962. The
structure was 300 feet (91.44 meters) by 140 feet
(42.67 meters), with a total area of 48,817 square feet
(4535.25 square meters). In 1980,
in response to anticipated increases in production, a small addition was
placed on the northwest corner of the 333 Building.
It consisted of two stories; the ground level an open bay shop and the
second story for offices. The
addition was 33 feet (10.06 meters) by 104 feet (31.70 meters), and
runs from the HVAC (heating, cooling and ventilating) supply units on the west
side of the building to the north exterior wall.
A majority of the 333 Building was a large, one story, open bay housing
large machinery for fuel-making, but the structure also contained two
mezzanines. The larger mezzanine
ran along the east wall and housed distribution equipment and offices.
The smaller central mezzanine housed ventilation equipment for the
chemical bay. Air conditioning
and heating of the building originally was accomplished with steam heat and
evaporation cooling forced air equipment located in a 30-foot
(9.14 meters) by 75‑foot (22.86 meter) enclosure adjoining the
west side of the building. During
1979-80, some energy conservation upgrades and cleanouts were made in this
system. New heat recovery systems
were installed. The 333 Building
has always been equipped with electrical fire detection mechanisms and an
automatic sprinkler system. The
co-extrusion process was carried out with various equipment pieces, but the
most prominent and unique of these was a Loewy Press that actually pressed all
of the fuel components (U core and all of the cladding components) together in
one unit. Each N Reactor fuel
element was 26 inches (66.04 centimeters) long, weighed approximately 52
pounds (23.59 kilograms), and had a tube-in-tube configuration with a
coolant channel running down the entire length of the element.
Projections also were welded onto each element, as the N Reactor
process tubes were smooth or "ribless."
The co-extrusion process provided a better, more uniform bond between
core and jacket that had been possible with older methods based on dipping. The new method was beneficial in smoothly cladding the inner
and outer tubes so that they would fit together without developing "hot
spots."
The co-extrusion process began with inspection and cleaning of copper
and copper-silicon pre-shapes and backing plates used in the process. The cleansing agents were nitric acid, nitric hydrofluoric,
and chromic nitric sulfuric acid. Next,
cladding components made from Zircaloy-2 were degreased, rinsed in nitric and
hydrofluoric acid, and dried with forced-air heating. In the meantime, U billets were degreased with
perchloroethylene, etch with nitric acid, rinsed, dried and inspected. Next, the copper, copper-silicon, Zircaloy‑2, and U
components were assembled and welded into a billet assembly.
This assembly was evacuated of air, leak tested, sealed preheated, and
then co-extruded (squeezed together) in the Loewy Press.
As the process specifications for this step emphasized:
"The quality of the extruded tube is dependent upon many things,
not the least of which is skill, care, effort,and precision that are put into
the co-extrusion operation."[xviii]
The process of cleaning, degreasing, etching and drying components,
then assembling and pressing them, was repeated for both the outer (larger)
and inner (smaller) tubes that made up the tube-in-tube configuration. The extruded tubes then exited the press to a roll-out table
where they were rolled continuously for at least six minutes to prevent tube
deformation and non-uniform cooling. Next
they were sectioned to the specified length, and the ends were machined to
create fuel sections or elements. Nitric
acid was used to remove copper silicon residues, and nitric sulfuric acid was
used to chemically mill (i.e., dissolve away) excess uranium on fuel element
ends. Elements then were etched
with nitric hydrofluoric and nitric acid, and brazed with an etched braze ring
material consisting of Zircaloy-2 alloyed with about five percent beryllium.
(This braze material previously had been degreased and etched.)
The brazed elements were heat-treated in a molten salt bath to
randomize the U grain structure to prevent preferential grain growth that
could rupture the elements in the reactor.
The next step in the process was to weld projections or supports onto
the fuel elements. Eight
lengthwise protrusions were attached to the outer surface of each fuel
element, evenly spaced around its diameter.
This configuration allowed cooling water to circulate optimally around
the elements, without creating hot spots where the sides of elements rested
too close to the inner walls of the process tubes.
After projections were welded onto the elements, the two tubes (inner
and outer) had to be attached together. Support
hardware was attached to the outer surface of the inner tube, and locking
hardware was affixed to the inner surface of the outer tube.
The two tubes then were given a final nitric hydrofluoric acid etc,
separately tested in autoclaves, inspected, assembled and interlocked, and
stored as finished fuel. The
coextrusion process was carried out continuously in the 333 Building from 1960
until December 1986, reaching a peak volume of approximately 250 finished fuel
elements per week in the mid-1980s.[xix]
1.2.3 Other
Processes in the 333 Building
From 1965 to 1967, the 333 Building performed autoclave testing,
final etching with nitric‑hydrofluoric acid, and inspection of special
lithium aluminate fuel targets made in the nearby 3722 Building for the
production of tritium. Highly
enriched (2.1% uranium‑235) uranium driver fuel elements for
tritium programs also were made in the 333 Building from 1965 to
1970.
1.2.4 The
Waste Acid Treatment System (WATS) Process
In 1971, a study of radioactive releases and special materials
accounting practices identified several areas of concern in 333 Building
operations. Among these concerns
were the amounts of contaminated gaseous, particulate and liquid discharges,
and the need for expansion of monitoring and sampling systems.
Partly in response to these concerns, the Waste Acids Treatment System
(WATS) process was developed, a new system to catch and neutralize waste acids
from the structure's fuel-making processes.
In 1973, the WATS began partial operations to treat waste acids
from 333 Building operations. It
operated for four months in 1973 and became fully operational in
January 1975. The
300 Area WATS process represented a method to prevent 333 Building
fuel fabrication bulk waste acids from discharging to the 300 Area
process sewer.
Tanks and control instruments for the WATS system were located in and
below the 334‑A Waste Acid Storage Facility, a small steel frame
structure that was moved in close to the 333 Building, from Hanford's 200
Area. The portion above grade was used for general storage of
products and absorbents, and the portion below grade contained three tanks
seated in a reinforced concrete pit 18.5 feet (5.64 meters) by
18.3 feet (5.58 meters) by 10 feet (3.05 meters) (deep).
Additional tanks and piping components for the WATS system were located
in the 313 Building, the 333 Building, the 334 Chemical Handling Facility next
door to the 333 Building, and in the nearby 311 Tank Farm.
The 303‑F Building, also nearby, served as the pumping
station for the various liquid and slurry waste transfers in the WATS process.
During most of the years of WATS operation (1975 to 1988) the tanks in
the 334‑A Building received approximately 210,000 gallons
(794 936.492 liters) of waste acids per year.[xx]
The waste acids treated in the WATS operation included nitric,
sulfuric, hydrofluoric, and chromic‑nitric‑sulfuric acids bearing
uranium, Zircaloy‑2 components, copper, beryllium, and other fuel
fabrication materials. Waste
acids were collected in the 334‑A Building tanks and then pumped to
the 313 Building for neutralization with sodium hydroxide.
Wastes containing recoverable amounts of uranium were routed
directly from the 333 Building to the 313 Building and were not
treated as part of the WATS process. Waste
acids containing nonrecoverable amounts of uranium were pumped to the
313 Building for neutralization and, beginning in 1985, were centrifuged
to remove solids. Solids from the
centrifuge were placed in drums and transferred to the 303‑K Radioactive
Mixed Waste Storage Facility or to the Central Waste Complex in Hanford's 200
West Area for eventual disposal. Filter
press effluent and centrifuge effluent from 313 Building operations then
was pumped to the 311 Tank Farm for storage and transported to Hanford's
100-H Area for evaporation. Beginning
in 1985, some neutralized waste effluents from the 333 Building were shipped
from to Hanford's 340 Retention and Neutralization Complex for
transshipment to the 200 Areas or offsite for disposal.[xxi]
2.0 IRRADIATION
PROCESSING AT THE HANFORD SITE
2.1 HANFORD'S
SINGLE PASS REACTORS
Nine plutonium production reactors, now closed and silent, cluster
along a 14-mile (22.53 kilometers) stretch of the Hanford shoreline of
the Columbia River. Eight of
these reactors, all except the N Reactor, are known as
"single-pass" reactors due to the once-through nature of their light
water cooling systems. Known as
"piles" in the 1940s, these machines drew cooling water from the
river, and pumped it through a series of filtration, chemical treatment, and
storage buildings and tanks. The
water then was passed directly through long, horizontal tubes in the reactors,
where the solid, Al-Si-jacketed uranium fuel rods underwent active neutron
bombardment. From there, the water was pumped out the back of the piles,
left for a brief time (30 minutes to 6 hours) in retention basins to allow for
short-term radioactive decay, and then returned to the Columbia River.[xxii]
2.1.1 Historic
Significance of B-Reactor
Hanford's original reactor, B, was the first such full-scale nuclear
facility to operate in world history. Built
by the Army Corps of Engineers and the DuPont Corporation in just 11 months
between October 1943 and September 1944, it now is listed on the National
Register of Historic Places. B
Reactor also has received special awards from the American Society of
Mechanical Engineers and the American Society of Civil Engineers.
2.1.2 Single-Pass
Reactor Buildings
The next seven reactors, D, F, H, DR, C, KE, and KW (in order of
construction) were similar in most features.
Built between 1943 and 1955, and shut down between 1964 and 1971, they
had an average life span of just 21 years.
The construction and general specifications of B, D and F Piles (the
original three reactors built in World War II) were similar to those of most
of Hanford's other single-pass reactors, although C, KE and KW were slightly
larger and contained some special features.
All of the piles rested on thick concrete foundations topped with cast
iron blocks. The reactor
buildings themselves were reinforced concrete structures shaped like tiered
wedding cakes with no containment domes.
They sat near the centers of five separate reactor areas of
approximately 700 acres (283.28 ha) each.
The core of each reactor was a series of graphite blocks that fitted
together. In the oldest
six reactors, the cores each measured 28 feet (8.53 meters)
from front to rear, 36 feet (10.97 meters) from side to side, and
36 feet (10.97 meters) from top to bottom.
In the K-Reactors, the cores each were 33 feet (10.06 meters) from
front to rear, 40 feet from side to side, and 40 feet (12.19 meters) from
top to bottom. The graphite
served as the "moderator" to slow and absorb extraneous neutrons
from the basic nuclear chain reaction. Each
stack was pierced front to rear by aluminum process channels that held the
fuel elements. The first six
Hanford reactors each contained 2,004 process channels, and the KE and KW
Reactors each contained 3,220. The
"lattice," or pattern of process channel configuration was a simple
rectangle, with only the corners of the core bearing no penetrations. Each
reactor's graphite core was surrounded by thick thermal and biological
shields. The core and shields
formed the reactor "block," and each block was enclosed in a welded
steel box that functioned to confine a gas atmosphere. The atmosphere of the earliest reactors was composed of
helium, an inert gas selected for its high heat removal capacity.[xxiii]
At the front and rear of each process channel, a carbon steel exit and
entry sleeve known as a "gunbarrel" penetrated the pile shields. The ends of each process tube flared into flanges to
facilitate a close fit and interface against the gunbarrels. Asbestos gaskets lay between the flanges and the stainless
steel nozzles that projected from the front and rear of each process tube.
The nozzles connected to coiled lengths of aluminum tubing known as
"pigtails" (originally one-half inch (1.27 centimeters) in
diameter but later larger), which in turn connected to stainless steel
crossheaders. Devices known as
"Parker fittings"a
connected the pigtails to the crossheaders.
The crossheaders [originally 39 sections of four-inch- (10.16‑centimeter‑)
diameter pipes] served to break down the huge water supply entering the
reactor building's valve pit via two 36-inch- (91.44‑centimeters‑)
diameter headers, then two 36-inch (91.44 centimeters) risers.[xxiv]
Test holes extended from the right side of each Hanford pile for the
irradiation of experiments and special samples.
Horizontal channels for control rods (HCRs) entered from the left side
of each reactor, and vertical channels for safety rods (VSRs) entered from the
top. The control and safety
systems functioned simply to absorb neutrons, thus slowing and eventually
stopping the controlled chain reaction of neutron exchange between the uranium
fuel elements.
The early Hanford reactors also were equipped with various safety and
control instruments that measured temperature, pressure, moisture, neutron
fluxb
and (radio)activity levels in the byproducts of the fission reaction.
Because no one instrument had enough range to measure neutron flux all
the way from shutdown (background) levels to the approximately
1,000,000,000,000 (1 trillion) times background levels experienced during
operations, each reactor was fitted with sub-critical, mid-range and full
power flux instrumentation.[xxv]
2.1.3 Operation
of the Single-Pass Reactors
During actual operations, raw water was pumped from the Columbia River
by pumphouses (known as 181 Buildings) located at and partially in the river.
From there, water for the earliest reactors was pumped to the 182
Buildings, which routed much of the water to the 183 Buildings for chemical
treatment, settling, flocculation and filtration.
A small portion of the water proceeded directly from the 182 Buildings
through large concrete pipes to the Hanford's 200 Areas [located 6 to 8 miles
(9.66 to 12.87 kilometers) away] for treatment and use there in chemical
separations and other operations. From
the 183 Buildings, Hanford's reactor process water was pumped to the 190
Buildings and stored in huge "clearwells" ready for pile use.
In the 190 buildings, sodium dichromate was added to the water to
prevent corrosion of pile process tubes.
The 190 Buildings then supplied the reactors themselves as needed.
Some of the earliest HEW reactor influent systems also contained 185
Buildings for dearation, and 186 Buildings for refrigeration of coolant water.
However, these functions were found to be unnecessary and the 185 and
186 Buildings were diverted to other uses.
At HEW's earliest reactors, each process tube usually was charged with
32 U fuel elements, along with a few dummy slugs in various configurations
(either solid or perforated and hollow) at each end of the process channel.
Many fuel configurations could be used to achieve various desired flux
patterns across the reactor lattice.
2.1.4 Change
and Experimentation in Production Process
The history of Hanford's single-pass reactor operations is one of
constant change and experimentation. Many
questions puzzled and intrigued early Hanford scientists.
For example, they worried about the possibility of "slug
failures," or the accidental penetration by cooling water of the aluminum
jackets surrounding the fuel elements. They
knew that such penetration would cause the uranium to swell, thus blocking the
coolant flow within the process tube. This condition would necessitate tube removal and
replacement, and could melt the fuel elements in that tube.
Also, fuel ruptures would allow the escape of radioactive fission
products in larger than average amounts.[xxvi]
Another topic that intrigued the early operators of Hanford's reactors
was that of temperature and neutron flux distribution.
At first, "poisons" (neutron absorbing materials) were
distributed in a uniform pattern throughout the reactor core during operation.
This method of control produced a flux pattern that resembled a cosine
(or bell) curve, front to rear within the pile.
Such a curve meant that while uranium elements in the center of the
reactor achieved maximum or optimum irradiation, many of the fuel elements
located in the rest of the reactor achieved sub-optimal irradiation, due to
lower neutron flux. This
situation not only was inefficient in terms of utilization of the uranium
supply, it also contributed to temperature gradients that caused expansion in
the graphite in the central portions of the pile.
Shortly after World War II, Hanford scientists tested several new
poison patterns, with the goal of "flattening" the pronounced cosine
curve, thus evening out the distribution of neutron activity and enlarging the
area of maximum flux and temperature within the reactor.
Quickly, they learned that many alterations in poison distribution
(control rod positions) would achieve higher and lower temperatures and
exposures in various reactor zones. They
dubbed all of these manipulations "dimpling" the reactor.[xxvii]
2.1.5 Graphite
Expansion Early Problem
Of all the operational questions and issues that were pioneered in the
Hanford reactors, almost none proved more compelling than those involving the
graphite. Swelling (expansion) of
the graphite, along with embrittlement, was a side-effect of irradiation. By late 1945, graphite expansion was causing the process
tubes to bow, "binding" them too tightly with their fittings and
other components, and straining the seals at the top and side corners of the
reactor shields.
As a result, a Graphite Expansion Committee was formed at Hanford in
early 1946.[xxviii]
Ultimately, concern over the graphite expansion problem and its
intrinsic threat to pile "life" led to the decision on March 15,
1946, to shut down B Reactor.[xxix]
However, in mid-1947, convinced by positive developments in graphite
study, site managers made the decision to restart the reactor the following
year.[xxx]
By 1950, further experiments had made it clear that the addition of
carbon dioxide (CO2) to the helium in reactor gas atmospheres could
alleviate much of the graphite swelling problem.
The CO2, because it had a lower heat removal capacity than
the helium, allowed the carbon atoms in the graphite crystal, displaced by
irradiation, to heat up, become active, and hence realign themselves.
By 1954, the CO2 additions were working so well the oldest
reactors operated with a gas atmosphere composed of 40% helium and 60% CO2,
and tests were being planned to try even higher proportions of CO2.[xxxi]
2.1.6 Increased
Power Levels/Production
Beyond even the graphite puzzle however, no early (and ongoing)
operational issue was more important to the Hanford Works than that of
increasing the power levels. B Reactor,
along with D, F, and DR, was designed to operate at 250 megawatts (MW -
thermal), while H, built five years later, was designed for 400 MW.
C Reactor, built during 1951-52, was designed for 650 MW, but the
learning curve in pile operations took such a leap that the twin K Reactors
(KE and KW) were built during 1953-55 designed for 1,800 MW each.[xxxii]
Questions concerning how to achieve higher power levels, with
consequent increases in plutonium production, had intrigued Hanford scientists
since World War II. In April
1949, an incremental test program that would take D‑Reactor to
330 MW was undertaken. By
January 1950, this experiment was so successful that DR-Reactor was being
operated at 400 MW.[xxxiii]
With the acceleration of the Cold War, increased power levels in the
Hanford reactors became even more important to perceived national defense
needs. From the late 1940s
through the closure of the last single-pass reactor in 1971, pile history at
Hanford was dominated by constant efforts to achieve increased power levels.
By late 1956, under President Eisenhower's policy of "massive
retaliation" and the boisterous challenges of Soviet Premier Kruschchev,
the World War II power levels at the three oldest reactors had more than
tripled, and stood at 800 MW. At
that time, a thorough set of modifications designed to allow increased coolant
flow was completed at these reactors. Similar
modifications were made at the other single-pass reactors through the early
1960s, spurred by the threat of Soviet technical superiority as demonstrated
by Sputnik. As a result of these
changes, and of fuel and tube design improvements, power level increases in
the World War II reactors reached the 2,200 - 2,400 MW range by the mid-1960s,
just after the Cuban "missile crisis" had once again boosted
American desired for a strong nuclear defense.
The mid-1960s operating figures in the HW reactors were nearly 10 times
the original design levels. At
the KE and KW Reactors, final operating levels in 1970 and 1971 stood at
approximately 4,100 MW each.[xxxiv]
Higher power levels themselves were easy to achieve, simply by adding
enriched uranium fuel elements (those containing higher percentages of U-235).
However, increased power levels presented many puzzling operational
challenges in the effects they imposed on reactor systems and components.[xxxv]
By mid-1951, Hanford scientists knew that the higher temperatures
associated with increased power levels could produce substantially higher fuel
jacketing and tube corrosion rates (and failure rates).[xxxvi]
However, their main concerns centered around how to deliver additional
cooling water to, through, and out of the reactors.
Such water would be needed to offset "boiling disease," the
Hanford term for a situation wherein steam might form in a process tube.
If this happened at higher power levels, greater water pressures would
be needed to sweep the steam from the tube (and thus to prevent a localized
meltdown).[xxxvii]
2.1.7 Operating
Challenges at Higher Power Levels
By mid-1953, effluent removal piping at the oldest reactors, already
operating at 20% to 50% above design capacity, was under intense
study.[xxxviii]
At the same time, operators realized that the filtration capacity for
intake water would have to be increased well beyond the original capacity of
approximately 35,000 gallons (132 489.42 liters) per minute (gpm) per
reactor. More important, however,
was the need to increase the intake pumping capacity.[xxxix]
In the meantime, as power levels crept upward in the oldest reactors
during the late 1940's and early 1950's, fuel element ruptures became a
reality. The first rupture
occurred at F Reactor in May 1948, and two others occurred later that year at
B Reactor.[xl]
The number of fuel element rupture incidents increased slowly during
1949-1950, but expanded dramatically in 1951 when Hanford Works experienced
115 fuel failures.[xli]
This number continued to climb throughout the early 1950s, bringing
further focus to fuel fabrication improvement studies.
Along with fuel element failures, higher power levels and higher
temperatures brought increasing levels of corrosion and failure of process
tubes. By 1953, each Hanford
reactor needed an average of 200 tube replacements per year.[xlii]
In order to reduce the ruinous corrosion, a special "Flow
Laboratory" was built in late 1951 in a modified WWII refrigeration
building. It functioned to study
corrosion and heat transfer within process tube "mock-ups"
(simulations).[xliii]
At the same time, the Hanford Works began an intense review of intake
water treatments.[xliv]
Sodium dichromate, a key corrosion inhibitor that had been added to
reactor water since World War II, was evaluated closely.
Because sodium dichromate was known to have detrimental effects on the
fish of the Columbia River, much experimentation with other corrosion blockers
was undertaken.[xlv]
However, due to dramatic rises in tube and fuel element corrosion when
the sodium dichromate was withdrawn, site scientists decided to continue using
it.[xlvi]
The drive to higher and higher power levels in Hanford's reactors
throughout the late 1940's and mid-1950's was accompanied by the need for
several changes to enhance operating safety.
The "last ditch" safety system in the five oldest reactors
was replaced with tiny, neutron-absorbing, nickel-plated carbon steel balls.
These balls were poised in hoppers at the top of the piles, ready to
pour in and tamp down the fission reaction if necessary.[xlvii]
Physical braces and supports, and many additional instruments also were
added.[xlviii]
Other changes in reactor operations shortened the time required to
perform routine operating chores. Since
World War II, charge-discharge ("C-D") operations (loading and
unloading the fuel elements from a reactor) were performed while a reactor was
shut down. However, by 1950
experiments were underway to perform C-D operations while a reactor was
running.[xlix]
During the early and mid-1950s, such a system was tested successfully.
It operated remotely, and worked by flushing fuel elements down the
process tubes via high pressure water.[l]
Due to cost, this system were not installed at the oldest five
reactors, but it was emplaced in the other, newer reactors.
Another change aimed at saving shutdown time in the Hanford reactors
concerned "purging" or cleansing the process tubes. Minerals, elements and suspended solids in the Columbia
River's water routinely built up a film on the process tube surfaces.
This situation caused heat build-up within the reactors.[li]
Since World War II, operators had "purged" (scrubbed) the
film from the tubes on a monthly basis, while the reactors were shut down.[lii]
However, by the early 1950's the Hanford Works was trying to conduct
"hot" purges -- so called because they occurred while the reactors
were running. Such operations
were very effective in removing reactor films, but greatly increased the
levels of pollution entering the Columbia River.[liii]
To help ameliorate the high levels of radioactivity, restrictions were
placed on the frequency of purges that could be conducted during autumn
periods of low river flow. Also,
a series of experiments was initiated to find ways to protect the river.[liv]
2.1.8 Reactor
Upgrades for Increased Production
Beginning in 1954 and continuing into the early 1960s, a series of
major modification projects designed to strengthen the reactor systems
necessary to support power level increases were emplaced at the eight
single-pass Hanford piles. Designated
"Reactor Plant Modifications for Increased Production," these
projects substantially increased intake pumping, filtration, and chemical
treatment and storage capacities.[lv]
Effluent systems likewise were strengthened and enlarged dramatically.[lvi]
Instrumentation with higher range capacity was emplaced.[lvii]
Electrical upgrades and many other miscellaneous changes were made
within reactor systems. One such
modification was the removal of aluminum liners (known as "thimbles"
by Hanford workers) in some of the process channels, because higher operating
temperatures would cause these liners to melt.[lviii]
Ironically, just as these projects were underway, significant changes
in fuel elements and process tube designs and materials took place at the
Hanford Works. These developments
allowed dramatic increases in reactor power levels, once again straining the
newly upgraded support systems. Much
of the increase in power level was made possible by the use of the I&E
fuel elements, which were first tested on a production basis in 1958.[lix]
Other operating efficiencies that came quickly in the late 1950's and
early 1960's resulted from the gradual replacement of aluminum process tubes
with tubes made of Zircaloy-2. Also,
self-supported (projection, bumper or ribbed) fuel elements were developed at
Hanford. Such fuel elements allowed greater passage of cooling water,
again allowing higher power levels to be sought within a margin of safety.[lx]
2.1.8.1 Maintenance
and Safety Issues at Single-Pass Reactors.
The higher power levels permitted by the development of internally and
externally cooled fuel elements, ribbed fuel elements, and new process tubes,
brought multiple operating challenges to the support systems of the Hanford
reactors. Pumps and pipes
developed destabilizing leaks, while electrical capacities proved inadequate.
Much of the reactor instrumentation also was rendered obsolete.
Even the graphite swelling problem increased, as the levels of neutron
flux and bombardment rose exponentially.[lxi]
Safety reviews called for a mounting list of improvement projects.[lxii]
From that time forward, the story of the Hanford single-pass reactors
became one of how to design and fund all of the support systems upgrades that
were needed. One project that was
accomplished at all of these reactors during 1960-62 was the construction of a
large exhaust gas confinement system. It
was comprised of a below-ground filter building, duct work that routed gases
from the reactor through these filters and then back into the exhaust stack,
and sampling equipment. Another
part of this project provided a rear face fog spray system for each reactor,
and a front face fog spray system at C, KE and KW Reactors.[lxiii]
Additionally, the Ball-3X systems at most of the reactors were upgraded
in the early 1960s, as part of an overall "exposure reduction
program" undertaken by Hanford's Irradiation Processing Department.[lxiv]
Several instrumentation improvements and replacements also were
approved for many of the reactors, based on safety and control considerations.[lxv]
2.1.9 End
of Single-Pass Operations
In January 1964, President Lyndon Johnson announced that, due to a
decreased need for special nuclear material (SNM), Hanford's reactors would be
shut down in a phased sequence beginning in December 1964.[lxvi]
At the same time, Columbia River pollution from reactor effluent was
becoming an increasingly important factor in regional and national
considerations. Hanford
scientists, as well as health officials in Washington, Oregon and the U.S.
Public Health Service became more and more concerned with the effects of
reactor effluent in the huge river. By
1960, the total volume flow from the Hanford reactors had increased
approximately ten-fold over that of the World War II period, shortening
the practical retention time to only about 30 minutes and making
diversion of unusual effluents to "cribs" (percolating areas dug
into the earth) or other holding areas virtually impossible. Furthermore, the total amount of radioactivity reaching the
Columbia River stood at nearly 14,000 curies per day.[lxvii]
Within this effluent flow, the main isotopes of concern were phosphorus
32 (P-32), zinc 65 (Zn-65), chromium 51 (Cr-51), iron 59 (Fe-59), and arsenic
76 (As-76). It had been known
since the late 1940s that these isotopes
concentrated within aquatic plants and animals to vastly higher levels
than were found in the river water itself.
Multiple studies pointed to the fact that the Columbia's water could be
at or below permissible levels for various radionuclides, and still present a
hazard to consumers of river fish, ducks and other wildlife.[lxviii]
Throughout the late 1950s and early 1960s, virtually every aspect of
the bioaquatic and potential downstream health consequences of reactor
effluent was examined, including the effects of temperature, operating purges,
various purge agents and filtration aids, fuel element ruptures, sodium
dichromate, and the radionuclides themselves.[lxix]
Various solutions were proposed and tested.
Salient among these was the concept of passing reactor effluent through
beds of aluminum shavings, in order to entrap various radionuclides.[lxx]
Laboratory tests seemed promising, but a production-size bed installed
in 1960 at the D Reactor retention basin demonstrated so many shortcomings
that the idea of decontamination of reactor effluent via aluminum test beds
was effectively abandoned in 1961.[lxxi]
Another concept that was explored thoroughly at Hanford was that of
varying the intake water treatments. However,
mixed results, combined with undesirable side effects, resulted in very little
practical improvements.[lxxii]
In the early 1960s, an idea that had been explored in the 1950s for
reducing radionuclide releases to the Columbia River was revived.
This "Inland Lake" concept proposed routing reactor effluent
through trenches to artificial, inland lakes dug in the center of the site
where the distance between land surface and the underground water table was
significantly greater than it was near the reactor retention basins.
Proponents of the idea pointed to the longer time period for
radioactive decay and thermal cooling of effluent, before the wastes finally
would reach the river. However,
studies conducted in the 1950s had demonstrated undesirable effects, including
the wind entrainment of radioactive mists that could spread contamination over
wide areas extending even to offsite. Furthermore,
problematic underground mounds in the water table, caused by disposal of
low-level liquids wastes from chemical processing plants near the center of
the site would be worsened by the addition of reactor effluent.[lxxiii]
As the reactor shutdowns began at Hanford in the mid-1960's, operators
and scientists struggled to extend the viability of the remaining piles by
developing environmentally acceptable means of effluent disposal.
In the spring of 1967, with five single-pass reactors operating, a
Hanford summary report on alternate methods of reactor effluent treatment and
disposal listed several additional options.
Conversion to recirculating cooling systems was listed as economically
prohibitive, since it would involve providing 400,000 gallons (1 514
164.75 liters) per minute of additional cooling (pumping) capacity per
reactor, with all attendant piping modifications.
Other related equipment also would be needed for each reactor, for a
total conversion cost of $32 million per reactor.
Other potential solutions also were expensive and posed awkward siting
problems between the reactors and the Columbia River.
Still other, less expensive proposals each came with physical or
acceptability barriers.[lxxiv]
The eight single pass reactors at the Hanford Site all closed
permanently between December 1964 and January 1971.
The Hanford Site's ninth defense production facility, N Reactor,
operated from early 1964 to December 1986.
Like Hanford's single-pass reactors, N Reactor was tied in umbilical
fashion to the Columbia River, and it was light water cooled, graphite
moderated, and fueled with bored metal uranium.
Also, none of the defense production reactors at the Hanford Site were
equipped with containment domes. Nevertheless,
there were major differences between N Reactor and the older Hanford piles.
N Reactor recirculated its primary coolant water, instead of returning
it to the river, thus releasing significantly less radioactive effluent (waste
water) on an everyday basis. Additionally,
the light water coolant circulated under pressure, allowing for much higher
operating temperatures, and the water was demineralized so that less film was
deposited inside the process channels.
Another major difference between N Reactor and the older Hanford piles
was that N Reactor had a negative-void coefficient design, while the
single pass reactors had a positive-void coefficient design. The negative-void factor was a crucial safety feature because
it meant that when a steam bubble or void developed in a process tube, the
effect tended to shut down N Reactor. This
factor prevailed because, at N Reactor, there was a low ratio of graphite
moderator to U fuel. The cooling
water provided a significant portion of the moderating effect.
Thus, loss of coolant had the effect of reducing reactivity.
In the single pass reactors, a steam bubble or void tended to increases
the neutron flux logarithmically, thus enhancing the chances for a nuclear
accident. Lastly, in 1966, the
steam generated from the heat of the nuclear chain reaction was captured at N
Reactor to produce electricity for the domestic power needs of the Pacific
Northwest. Today, N Reactor
remains as the only U.S. defense reactor that served a "dual
purpose."[lxxv]
2.2.1 105
N Building and Reactor
The 105-N (N Reactor) Building was a reinforced concrete structure
sitting atop a thick slab of reinforced concrete.
The reactor core itself was 39 feet (11.89 meters), 5 inches
(12.70 centimeters) high, 33 feet (10.06 meters) wide, and 33
feet (10.06 meters), 4.5 inches (11.43 centimeters) tall.
It consisted of 1,800 tons of nuclear grade graphite blocks notched,
interlaid and pierced by 1.004 process channels. The lattice was arranged in a rectangle 32 feet
(9.75 meters) high by 34 feet (10.36 meters) wide, with 21 channels
omitted from each corner. Eighty
seven HCRs entered the N Reactor core, 41 from the left side and 46 from
the right side. One hundred and
eight vertical safety channels existed to receive ceramic "3X" balls
to shut down the reactor in case of need.
A small number of other channels pierced the core to hold experiments,
and to position traverses to measure graphite distortion over time, graphite
temperature, and flux. Graphite
bowing over time was both expected and feared by the designers of N Reactor.
The original reactor manual stated that "there is as yet no
determination of the maximum extent to which contraction of nuclear graphite
can be induced by irradiation." An
8.3-inch (21.08 centimeters) depression at the top center of the graphite
moderator was chosen as the original design basis, corresponding to about a
three percent contraction, while 12 inches (30.48 centimeters) was
"estimated to be tolerable for the reactor as built."
The design lifetime of the reactor was 25 years.[lxxvi]
The N Reactor core was surrounded special layers of reflector graphite,
then by water cooled thermal shields constructed of boron steel and cast iron,
and then surrounded again by a primary shield of high density concrete. Helium gas formed the pile atmosphere. A fog spray system at both the front and rear reactor faces
was provided for contamination control and cooling in case of a loss of
contaminated steam from the core. The
water influent system began at the 181-N River Pump House, proceeded to the
182‑N High Lift Pump House where raw river water was treated and
where demineralized and deoxygenated water was injected into the makeup and
cooling water, the 183‑N flocculation and filter plant, and to the
183-NA Pump House that sent coolant water into the reactor.
Extra supplies of treated water were held in the 183-NB clearwell.
N Reactor's primary coolant system used from 100 to 1,500 gallons
(378.54 to 5 678.12 liters) per minute of fresh, treated water, a
vast decrease from the 35,000 to 105,000 gallons (132 489.42 to 397
468.25 liters) per minute consumed by Hanford's single pass reactors.[lxxvii]
2.2.2 N
Reactor Operating Changes and Challenges
Over its years of operation, many changes took place at N Reactor.
From 1965-67, a "co‑product" demonstration campaign
took place, in which tritium was produced in the reactor from special lithium
aluminate fuel elements. Beginning
in 1966, N Reactor steam for electrical production was harnessed at the
Hanford Generation Plant (HGP) constructed just west of the pile by the
Washington Public Power Supply System (WPPSS).
In 1971, N Reactor was ordered closed due to a diminished national need
for defense plutonium production. An
agreement was reached to keep the reactor running primarily for electrical
production. During the 1970s, a
time when the entire Hanford Site undertook modifications to achieve more
desirable interfaces with the environment, a number of upgrades to N Reactor's
waste treatment systems were emplaced. Trenches
were dug to receive reactor effluent, thus allowing a longer percolation time
through the soils just inland from the reactor, for radioactive decay to occur
before effluents reached the Columbia River.
Monitoring instrumentation for waste products was added, secondary and
shield coolant loops were converted from single-pass to recirculating systems,
and a special containment tank was constructed to hold the pile purge effluent
for transfer to Hanford's high level waste storage tanks.
Release of this purge material to the Columbia River was discontinued.[lxxviii]
Beginning in the early 1980s, a large defense build-up was ordered by
President Ronald Reagan. At the
same time, N Reactor arrived at 20 years old and began to experience system
failures of many types. One
fundamental problem was the distortion of the graphite stack, where built-in
slip joints could not accommodate all of the local distortion, some block
cleavage, and actual separation of blocks that had occurred within the central
core. Such distortions produced "significant changing
problems" by 1982. Additionally,
the 1982 summer outage revealed center transverse contraction resulting in a
total sag of about three inches, and tube elongation to the extent that many
connector clearances were rated as "minimal."
As N Reactor struggled to remain a crucial piece of America's defense
arsenal, many system upgrades were undertaken.
In the 189/190‑D Thermal Hydraulics Laboratory, a complete
mock-up of N Reactor's core, in it's actual distorted and curved
condition, was built, in order to study remediation concepts.
An N Reactor Loop Components Test Facility, a high temperature,
pressurized, recirculating demineralized water test loop also was constructed
to model and evaluate leaks in the primary flush lines of the core, various
valves, and alternative ideas for operations.
Another model was built to test inspection and removal equipment for
the graphite cooling tubes, and to demonstrate a process tube drying system.
In April 1986, an accident at the Chernobyl nuclear plant in Soviet
Russia brought about a stand down for safety evaluations at N Reactor. The reactor never re-opened.
It was ordered to cold standby by the DOE in February 1988, and a large
D&D project leading to final disposition began in 1994.[lxxix]
3.0 SPENT
FUEL HANDLING AT THE HANFORD SITE
3.1 ORIGINAL
LAG STORAGE PRACTICES
After irradiation in a reactor, nuclear fuel is known as "spent
fuel." In defense production
at the Hanford Site, this fuel has always placed under water, allowed to
undergo a period of radioactive decay, and then chemically dissolved and
"re-processed" to separate the Pu product from associated fission
products and other elements. In
HEW jargon, the solid U fuel elements were known as "lags" as soon
as they became spent fuel. B‑Reactor
and HEW's other earliest reactors were constructed with spent fuel basins just
below the rear faces. The fuel
was literally pushed out the rear face of each reactor by charging fresh fuel
into the front. Spent fuel basins
at the earliest Hanford reactors each were 81 feet (24.69 meters) by 68
feet (20.73 meters), and were divided into two sections each.
The basins were 20 feet (6.10 m) deep, although the water was
maintained at about 16 feet (4.88 m) deep. Each basin was served by submerged buckets that were
suspended from a monorail via 25‑foot (7.62‑meter) yokes.
Long rakes and tongs were used to load each bucket with one-half ton of
fuel elements.
Viewing of the discharge area was accomplished with two main
periscopes, located on the ceiling of the discharge area and on the wall
opposite the rear face of the pile. Additionally,
the latter location contained a "Fly-eye" viewer that consisted of
four wide-angle lenses. A shielded
cab, which could be attached to the 50,000‑pound
(22 679.62 kilograms), 8 to 10 feet (2.44 to 3.05 meters) wide
"D" elevator, also had its own periscope.
One last periscope was located in the labyrinth that led to the
discharge area balconies, but its view often was blocked by the
"D" elevator (which had to be raised to the top of the
reactor's rear face during discharge operations).
Thermocouples were placed at the inlet and outlet of the storage basin,
and water temperature levels as indicators of radiation intensity were
monitored carefully.
The earliest spent fuel handling practice at the Hanford Site was to
keep the lags in the basins at the reactor rear faces for a very short period
of time (several hours to one day). The
irradiated fuel rods then were loaded into shielded rail cask cars and taken
to the 200‑North Area for storage in the 212 Lag Storage Buildings. Within any one of these three buildings, the rods were stored
for periods of time ranging from a few weeks up to perhaps as long as 50 days,
to allow for isotope decay, before they were taken to either T‑Plant or
B‑Plant for chemical separation.[lxxx]
3.2 212
LAG STORAGE BUILDINGS CLOSE
As the needs of the Cold War rapidly increased Pu-239 production at
Hanford, difficulties developed with the 212 Buildings.
By 1950, Site planners realized that additional capacity for lag
storage was needed. One key
factor was the AEC's decision to store spent fuel from 90-125 days before
re-processing, in order to reduce the emissions of iodine 131 (I-131) and
other gaseous fission products into the regional environs.
Other crucial factors included the increased amounts of fuel being
produced and handled once the H and DR reactors came on line in 1949 and 1950
respectively, and the anticipation that various forms of E-metal would be
tried in order to push production even higher.
In 1951, with C-Reactor under construction, as well as the desire to
save the transportation costs to and from the 212 Buildings and to reduce
radiation exposure to workers from fuel transfers, the 212 Buildings closed.
From that time forward, spent fuel at Hanford was stored only in the
fuel basins at the rear faces of the reactors.[lxxxi]
The reactor fuel storage basins, as had the 212 Buildings, operated
within certain fundamental parameters. All
cooling was accomplished using either once-through or feed-and-bleed
principles. Filtered water was
routinely added to the basins and water was discharged either via overflow
weirs or floor drains. The
discharged water was routed to cribs for soil filtration.
As a result of this routine water addition, the fuel storage basins at
Hanford were relatively clean radiologically.
Additionally, fuel was always stored in open containers.
This facilitated heat removal after discharge from the reactor.
Corrosion products were not an issue because following a relatively
short storage time, fuel was processed. The
fuel storage basins at the KE and KW reactors operated in the same manner,
although they were larger. At
these piles, the rectangular, reinforced concrete basins each were 125 feet
(38.10 meters) long, 67 feet (20.42 meters) wide, 21 feet
(6.40 meters) deep, and were divided into three sections.
By the early 1960, lag storage time at HW had increased to an average
of 200-250 days.[lxxxii]
3.3 CLOSURE/RE-OPENING
OF FUEL STORAGE BASINS
As each HW reactor closed between 1964 and 1970, its spent fuel basin
likewise closed. In some cases,
fuel storage basins at a given reactor would remain open a number of months
after the pile itself had shut down, in order to accommodate fuel from another
reactor. However, all lag storage
basins except for the N Reactor basin closed by 1971.
In 1972, the last radiochemical processing plant at the Hanford Site,
the PUREX (plutonium uranium extraction) Plant entered a long shutdown period
(although it later re-opened). The
N Reactor, because of its dual-purpose design, was kept operational to support
Pacific Northwest electrical power needs.
N Reactor was operated in this mode throughout the decade, and
continued to produce spent fuel. The
N Reactor fuel storage basin was not sized to support the resultant fuel
inventories. As a result, the
decision was made to use the K Reactor spent fuel basins for additional
storage space for N Reactor lags.
The K East basin was the first to be modified to store N Reactor fuel. It received only superficial cleaning, and the bare concrete
walls of the basin were left uncoated. All
drains and overflow weirs were blocked off and a water recirculation system
was installed. The recirculation
system consisted of two pumps, two underwater cartridge filters for
particulate removal, and two water-to-water heat exchangers for basin cooling.
Storage racks were installed on the basin floor to support single tier
storage of N Reactor fuel. Filtered
water was used to supply the basin water make-up needs.
A barrier was installed across the entrance to the North Loadout Pit to
isolate it from the basin proper. The
actual construction activities were completed and the facility began accepting
N Reactor fuel in 1975. N
Reactor fuel was shipped and stored in open containers.
The containers (canisters) were specifically designed for this purpose.
These canisters remained unchanged from the design used to support
earlier N Reactor operational needs.
The fuel inventory quickly grew in the K East basin and along with it,
radiological problems. With the
basin sealed and with no ability to add clean water and discharge contaminated
water, fuel corrosion products were captive in the facility. Radioactive contamination and radiation exposure levels
increased. Steps were taken to
mitigate this situation included the addition of a skimmer system along with a
sand filter, and later, an ion exchange system.
As the PUREX Plant remained closed and N Reactor continued to operate,
plans were initiated to modify the K West basin to accommodate the extra fuel.[lxxxiii]
The K West modification was designed to prevent a recurrence of the K
East Basin experience. The K West
Basin was drained and the walls and floor were cleaned and sealed with an
epoxy material. The drains and
overflow weirs were blocked off. All
of the basin clean-up systems in operation at K East were installed in the K
West Basin. These included a
basin recirculation system with cartridge filters and heat exchangers, a
skimmer system with a sand filter, and an ion exchange system.
The decision was also made to fill the basin and maintain water level
using demineralized water. A lid design was developed for the existing fuel storage
canisters which allowed them to be closed.
The design allowed the canisters to vent if there was any gas
generation. Fuel shipments to the
K West Basin began in 1981, with all fuel shipped to and stored in closed
canisters.[lxxxiv]
In 1983, when the PUREX plant was getting ready to resume reprocessing
of spent fuel to recover plutonium and uranium, the fuel in the K East basin
was sorted to separate the weapons-related fuel from that used to generate
electricity. The fuel was dumped
from the canisters, sorted and placed back in the open canisters.
A proposal to place the K East fuel in sealed canisters, like those
used in K West, was rejected. Today,
the K East Basin holds the nation's largest single concentration of stored
spent fuel. The existing fuel
inventories include 3600+ open canisters of spent fuel stored in the K East
Basin and 3800+ closed canisters of spent fuel stored in the K West Basin.
This inventory totals ~2100 MTUs.
4.0
RADIOCHEMICAL SEPARATIONS PROCESSING
AT THE HANFORD SITE
4.1
THE BISMUTH-PHOSPHATE PROCESS
4.1.1
Start-up of Radiochemical Processing at HEW
The earliest radiochemical processing operations at the Hanford
Engineer Works using "hot" (irradiated uranium) feed began at the
221-T Cell Building, also known as T‑Plant or T-Canyon, on December 26,
1944. This event was historic
because T-Plant was the first full-size radiochemical processing plant in the
world. The only previous
radiochemical processing of irradiated uranium fuel elements had been done on
an experimental scale at a facility known as the Clinton Semi-Works (or SMX),
located at the Clinton Engineer Works in Oak Ridge, TN.[lxxxv]
4.1.2
T, B, and U Process Groups
The original separations process used at HEW was the bismuth-phosphate
(BiPO4) process. It was
based on the principle that bismuth phosphate is similar in crystal structure
to plutonium phosphate. The
entire operation was a batch, precipitation process that achieved separation
by varying the valent state of plutonium 239 (Pu-239), and then by repeatedly
dissolving and centrifuging plutonium-bearing solutions.
The steps of the bismuth-phosphate process were carried out first in T‑Plant,
then in the 224-T Bulk Reduction Building, and then in the 231-Z Isolation
Building. A second and third
set of facilities for both the first and second phases of the BiPO4 process
also were built at HEW, but the final steps always took place in the 231-Z
Building. The second set of
facilities was known as the B Process Group, and consisted of the 221-B
(B-Plant) and 224‑B Buildings and their associated support
structures. B-Plant began
processing irradiated U at Hanford on April 13, 1945.
The third set of facilities was known as the U Process Group, and
consisted of the 221-I (U-Plant) and 224-U Buildings and their associated
support facilities. The U Process
Group never handled irradiated uranium, but served as a training facility
until another use for the buildings was developed in 1952.[lxxxvi]
4.1.3
Original Separations Buildings
The 221-T Cell Building originally was 85 feet (25.91 meters) wide
by 875.5 feet (266.85 meters) long by 102 feet high. It was a dense, thick, reinforced concrete, rectangular mass,
approximately one-quarter below grade, with no windows.
At the time that T-Plant was built, its design and construction was
described by the DuPont Corporation builders as "extremely unusual...due
to process requirements. In other
words, once the equipment in any of the cells is placed in operation, it will
not be possible to approach it for maintenance or to manually remove or fit up
piping." Remote operational
requirements, as well as radiation shielding requirements, resulted in the 221‑T Building
being unique, and a first-of-a-kind structure in the world, when it was built.
The 221‑B Building was virtually identical to T-Plant,
except that it had 65 feet (19.81 meters) less length and did not contain
a special head-end testing laboratory that was included in T‑Plant.
The foundation of each canyon building structure was a reinforced
concrete pad varying from six to eight feet (1.83 to 2.44 meters) in thickness
with a spread footing. Outside
building walls were likewise reinforced concrete three to five feet
(0.91 to 1.52 meters) thick. The
barricade wall between the cells and canyon and the galleries was seven feet
(2.13 meters) thick. Each
building had a suspended flat concrete roof varying from three to four feet
(0.91 to 1.22 meters) in thickness. Construction
joints were provided between each building section and expansion joints at
frequent intervals. The inside
surfaces of the cells and pipe trench, removable cover blocks, the deck floor
level in each canyon, and each second floor control gallery were painted with
"Amercoat,"a
an epoxy-based contamination fixant sealant, to reduce the porosity of the
concrete surfaces.
Each 221 Building structure was separated into two main portions -
Galleries and Canyon, with the inside of the building being divided into 22
sections (for T-Plant) and 20 sections (for B-Plant).
Each section encompassed two cells.
Sections were 40 feet (12.19 meters) long with the exception of
Sections 1, 2, and 20, which were 44 feet (13.41 meters), 43 feet
(13.11 meters), and 43.5 feet (13.26 meters) respectively.
Inside the head-end of T-Plant, were two developmental equipment cells,
A and B, having the same length as cells 1, 2, 3, and 4 [a total of 65 feet
(19.81 meters) in length]. The
essential difference between this testing laboratory and a standard T-Plant
section was that each testing laboratory cell contained the equipment
corresponding to that in two standard cell sections. The head-end laboratory section also included a continuation
of the basement, first and second floor galleries that ran the length of
T-Plant. However, these galleries
turned at the head-end and continued across to the rear wall of the building.
The HEW canyon buildings were so designed that the control panel
boards, chemical and service distribution, were located in three galleries,
one above the other along the "front" side of the building; the west
side in the case of T-Plant and the north side in the case of B-Plant. The first gallery, at the basement level, was used
principally for electrical distribution and control cabinets. The first floor gallery consisted of a piping loft containing
steam, water, air, and chemical headers as well as piping connections between
the panel boards and weigh tanks on the second floor and through-wall cell
piping. The second floor gallery
was the control center for the cell equipment, and was known as the operating
gallery. Each 40-foot building
section constituted a separate unit, and were controlled by separate gauge
boards in the operating gallery. The
gauge board panels were installed in a row along the barricade wall between
the canyon and the galleries, with weigh tanks along both front and back walls
of the gallery.
The lower portion of the canyon below the "deck" (ground)
level contained 40 individual concrete cells having removable concrete
cell-block covers. The cell
covers were constructed with overlapping, step-wise edges, to contain the
radiation within the cells. A
10-foot (3.05‑meter), 6‑inch (15.24‑centimeter) square
exhaust duct ran along the back wall of the building paralleling the bottom of
the cells and was connected by an underground concrete duct to the
291 Exhauster Buildings and Stacks for the removal of cell fumes.
Immediately above this duct was a pipe trench which also paralleled the
cells, containing inter-connecting cell piping.
The pipe trench was also covered with removable, sectional concrete
block covers.
The construction of the cells was standardized as much as possible, to
ease the maintenance problems as much as possible.
The sections having standard designs were 4, and 6 through 20.
Section 1 differed in that it was a large cell with two long openings
for the immediate storage of partially precessed material.
Section 2 contained two long openings of the same size, one of which
centered over the railroad track where irradiated fuel elements were brought
into the building, and the other which housed initial cell equipment.
A reinforced concrete railroad tunnel, extending 150 feet from the
front sides of the buildings provided rail service to this section. Section 3 differed in that the pipe trench ended opposite
cell #5. Section 5 differed in
that cell #10 was much deeper, because it served as a collection point for
drainage to the sewer section. At
T-Plant, the head-end sections differed in that the pipe trench terminated in
a manner that would allow for future extension of the building if desired.
(Such extension did not happen.)
The equipment installed in the cells consisted mainly of centrifuges
and vessels with and without agitators, and connecting piping between cell
walls and equipment. Around the
periphery of each cell were 42 flanged piping connections serving the cell
equipment. Special piping
connectors were used allowing pipes, conduits, and instrument leads to be
connected by tightening a single nut. Vertical
connectors were used for electrical connections only, and horizontal
connectors were used for piping and instruments only.
The canyon portion of each Cell Buildings was served by an overhead
bridge crane equipped with 75-ton and 10-ton hooks as well as four independent
monorail hoists of one and one/half-ton capacities.
The crane cab was designed to contain special controls, observation and
communication facilities in order to remove cell blocks, cell equipment and
cell piping by remote control. The
canyons also each contained a second overhead bridge crane, 10-ton capacity
for maintenance use only, when the building was completely shut down.
Four-story reinforced concrete stair towers were constructed along the
front side of each 221‑T Building (eight in T-Plant and seven in
B-Plant) to provide access to the three gallery levels and the crane-cab
runway. These stair towers also
housed heating and ventilating equipment and rest rooms for the galleries.
Reinforced concrete labyrinthed stair towers were built along the rear
sides (east side in the case of T-Plant and south side in the case of
B-Plant), to provide access to the canyon portion of each building at the deck
level. T-Plant had ten such rear
stair towers and B-Plant had nine.[lxxxvii]
4.1.8
224 Bulk Reduction Buildings
The 224 Buildings were constructed of reinforced concrete.
Each was a three-story frame structure with concrete and concrete block
exterior and interior walls. The
front of each 224 Building was placed precisely 150 feet from the back of its
corresponding 221 Building, and in line with the front of its process
group's 222 Control Laboratory. Each
224 Building contained a total of 21 rooms not including two stair towers, one
closet, one janitor's closet, and an elevator "penthouse."
The overall dimensions were 60 feet (18.29 meters)
1 inch (2.54 centimeters) by 197 feet (60.05 meters) long, with
a total area of 11,982 square feet (1 113.16 square meters).
Each building was 40 feet (12.19 meters) high for the majority of
its length, but reached higher elevations over two stair towers and over the
small penthouse area.
The foundation of each 224 Building was comprised of reinforced
concrete walls with spread footings, reinforced concrete piers and beams, and
concrete pads. Each floor slab
was reinforced concrete 4 to 12 inches (10.16 to 30.48 centimeters)
thick. Each roof consisted of flat reinforced concrete 5 to 12
inches (12.70 to 30.48 centimeters) thick, covered with built-up felt,
gravel surfaced roofing, and containing 8 wood frame ventilators with meters.
The roof slabs were removable, so as to allow the movement of large
equipment pieces in and out.
Each 224 Building was essentially divided into two main sections:
the process cell section, and the office and operating gallery section.
The back side of the main structure contained the process cells and had
one foot thick concrete walls with a balcony running around three sides.
The 27-foot (8.23‑meter) by 197-foot (60.05‑meter) process
cell area contained five cells known as Cells A to E inclusive.
These cells were served by a hand-operated overhead crane.
Cells A through D measured 27 feet (8.23 meters) by 28 feet
(8.53 meters). Cell F
measured 25 feet (7.92 meters) by 51 feet (15.54 meters), was L‑shaped,
and had an office in one corner of it. A
glass enclosure was located in the cell against this office wall, where the
partially finished product was collected for transfer to the 231-Z Isolation
Building. In Cell C, the
right-hand portion was a pit which connected with an underground pipe tunnel
that ran from the center line of Sections 13 and 14 in the corresponding 221
Building to each 224 Building.
The floors in the cells were sloped to a trench along the wall, for
gravity delivery to waste collection tanks.
The walls and floors in Cells A through E, and walls, floors, and
ceilings in F Cells and its office were painted with Amercoat. A mezzanine floor extended across the side facing the
corresponding 221 Building. Gauge
boards and weigh tanks used in connection with Cell F were mounted on this
mezzanine.
One-foot (0.30‑meter) thick interior walls divided the process
cell section of each 224 Buildings from the office and gallery section.
The "front" (offices and gallery) side of the main structure
was reinforced concrete frame with 8-inch (20.32‑centimeter) concrete
block panels and 8-inch (20.32‑centimeter) and 4-inch (10.16‑centimeter)
concrete block partitions. An
elevator was installed adjacent to the No. 1 stair tower and was provided with
an outside concrete loading platform to facilitate the movement of chemicals
to and from trucks. The first
floor contained offices, a chemical storage room, and other service rooms.
The second floor was principally a pipe loft containing five concrete
vestibules opposite each centrifuge platform.
All chemical and service lines entered the building on this level.
The third floor was an operating gallery that contained gauge boards,
tanks, and instruments.[lxxxviii]
The 231-Z Building was located in the western portion of the 200-West
Area of the Hanford Site, midway between T-Plant and U-Plant. Originally, this structure was a two-story, flat roofed,
reinforced concrete, frame building with 8‑inch concrete block panels
and 4‑inch (10.16‑centimeter) and 8‑inch
(20.32 centimeter) concrete block partitions.
Overall dimensions were 147 feet (44.8 meters) by
189 feet (57.61 meters) 10‑inch (25.40 centimeters) by
24 feet (7.32 meters) 6‑inch (15.24 centimeters)
tall, with a total of 27,964 square feet (2597.94 square meters).
A one-story ventilation and equipment room ran along the west end of
the building. The 231-Z facility
had no windows.
In World War II, the 231-Z Facility contained a total of 57 rooms
including 20 laboratories, several process and chemical receiving and
storage rooms, offices, change room facilities designed to accommodate 190
employees, air conditioning equipment, a distilled water system, ventilation
and exhaust systems, and a compressed air system.
Six of the laboratories were known as "cell laboratories,"
and served as the major centers where the actual Pu isolation process was
carried out. All of the rooms
except for one rest room were located on the first floor, with the second
floor serving as a pipe and service loft containing duct work and filters for
the ventilation and exhaust systems.
The interior of the 231-Z Building was configured with two 8 foot
(2.44‑meter) wide, north and south corridors, A and B; one on each side
of the (6) cell laboratories with emergency exits to the outside of the
building. Corridors C and D ran
east and west, connecting with corridor B.
Corridors E and F ran north and south separating laboratories and
intersect corridors C and D. Two
concrete stairways led to the second floor, and below-grade piping led to a
waste disposal system. This
piping was modified in 1948 to achieve additional control of 231-Z process
wastes.
The 231-Z Building foundations consisted of reinforced concrete piers
with spread footings and concrete walls with spread footings. Floors were reinforced concrete varying from 4‑inches
(10.16‑centimeters) to 12‑inches (30.48 centimeters) in
thickness. The walls and ceilings
of the cell laboratories and Vaults A and B were reinforced concrete
1 foot thick. The roof was
likewise reinforced concrete 4‑inches thick and was covered with
built-up felt, gravel surface roofing containing numerous openings for intake
and exhaust ducts. The walls,
floors, ceilings, and equipment in rooms 1 to 6, 8, 27, 31 to 45, Vaults A and
B, and corridors A, B, C, D, E, and F were painted with "Amercoat"
to obtain non-porous surfaces.[lxxxix]
4.1.10
The Bismuth-Phosphate Process
The bismuth phosphate essentially dissolved the jackets off of
irradiated U fuel elements, then dissolved the fuel itself, and then carried
out a series of precipitations followed by centrifugation and re-dissolving of
the precipitate cake. The valent
state of the Pu-239 (known as "product" at this stage) was
manipulated so that it would stay with, or separate from, the various
solutions and precipitate cakes produced in the operations.
In the +4 (tetravalent) state, the Pu-239 would carry with the bismuth
phosphate-based solutions. In the
+6 valent state (hexavalent), the Pu-239 would not carry with the bismuth
phosphate, and a by-product precipitation could be achieved.
The plutonium was reduced (taken to the tetravalent state) by adding
oxalic acid or ferrous ions, and oxidized (taken to the hexavalent state) by
adding sodium bismuthate (when bismuth phosphate was the carrier), or
potassium permanganate (when lanthanum fluoride was the carrier).
Actually, lanthanum fluoride was known to be a better carrier of
plutonium, in that it could carry with a smaller bulk or volume and could
carry away the stronger lanthanides such as Cs, Sr and La. However, it was/is very corrosive, and for that reason it was
rejected for the main phase of the Hanford separations process.
The first step in the separations process carried out at HEW was
dissolving, a process that removed the aluminum fuel jackets from the uranium
elements. It was carried out in
the dissolvers and metal solution storage tanks located in Sections 3 and 4
(Cells 5, 6 and 7) of the canyon buildings (T- and B-Plants).
The irradiated, jacketed fuel rods first were placed in boiling sodium
hydroxide, to which sodium nitrate slowly was added (reduce the formation of
hydrogen). This step produced
"coating removal waste." Next,
three metric tons of declad metal were charged into a dissolver.
Nitric acid was added in three increments, enough to dissolve one ton
in each increment. In order to
keep the time cycle as short as possible, "a substantial metal heel"
was lef[xc]t
in the dissolver between charges. New
material was charged on top of this heel.
The second step in the process was the extraction step. This operation separated the product (Pu-239) from most of
the uranium. It also removed
about 90% of the fission products into what was called the metal waste
solution. The extraction step
reduced the gamma radiation activity level by a factor of 10.
In the first extraction step, plutonium was kept in the +4 (reduced)
valent state. Bismuth nitrate and
phosphoric acid were added to the solution that contained the dissolved fuel
elements, causing the formation of bismuth phosphate. A product precipitation (one that carried the Pu with it)
then occurred. The precipitate
was centrifuged to separate the solid portion from the liquid.
The liquid portion was jetted away as waste.
The solid portion ("precipitate cake"), which contained the
Pu, was placed in another tank and dissolved with nitric acid.
Sodium bismuthate or potassium permanganate were added to the
plutonium-bearing solution to oxidize the Pu to the +6 state, and then sodium
dichromate was added as a holding agent to keep the Pu steadily fixed in this
state. The BiPO4 then
precipitated as a byproduct, leaving the Pu in solution.
The third step, decontamination, essentially was a repetition of the
extraction process. The
final decontamination cycle reduced the gamma activity level by a factor of
10,000, giving an overall process "decontamination factor" of
100,000 below that of the original uranium solution.
The plutonium-bearing solution from the extraction step was reduced
with the addition of ferrous ammonium sulfate.
Then, bismuth nitrate and phosphoric acid again were added, a product
precipitation occurred, and the precipitate was centrifuged.
The solid portion, containing the Pu, was liquified with nitric acid,
oxidized, and the remaining BiPO4 precipitated away as waste.[xci]
4.1.14
224 Bulk Reduction Process
Plutonium-bearing solution was transferred from the "tail"
ends of the canyon buildings to the 224 Buildings via underground piping.
The starting batch size in the latter facility was 330 gallons.
Here, the Pu solution from the 221 buildings was oxidized with sodium
bismuthate. Phosphoric acid then
was added to produce a byproduct precipitation, leaving the Pu in solution.
Centrifuging then separated the solution and precipitate.
Nitric acid was added to dissolve the byproduct cake, and it became
waste. Next, the
plutonium-bearing solution was oxidized with potassium permanganate (KMnO4).
Hydrogen fluoride and lanthanum salts were added, in what was known as
the "crossover" step. A lanthanum fluoride precipitate was produced, leaving
hexavalent Pu in solution.
Impurities were precipitated in a byproduct cake, as the fission
products were carried with the lanthanum.
This byproduct cake contained all of the lanthanides (cerium,
strontium, lanthanum, etc.) that the BiPO4 could not carry out of the stream.
The cake was dissolved in nitric acid, neutralized with sodium
hydroxide, and sent to tanks for settling.
The plutonium solution then was reduced to +4 state by adding oxalic
acid. Lanthanum salts and
hydrogen fluoride again were added, thus precipitating lanthanum fluoride that
contained the Pu. The precipitate
was separated by centrifugation, and potassium hydroxide was added to
metathesize the Pu lanthanum fluoride, forming a solid Pu lanthanum oxide.
(Metathesis is a chemical process to convert a solid to another solid.)
Any liquid was removed by centrifugation, and the solid Pu lanthanum
oxide was then dissolved in nitric acid to form Pu nitrate.
By this time, the original 330-gallon batch that had entered the 224‑T Building
had been concentrated to eight gallons (volume).[xcii]
Lastly, the plutonium nitrate from the 224 facilities was sent to the
231-Z Building for the final processing that could be done at the Hanford
Engineer Works. Hydrogen
peroxide, sulfates, and ammonium nitrate were added to the plutonium-bearing
solution. The hexavalent Pu
precipitated as plutonium peroxide. Nitric
acid then was added to dissolve this precipitate.
The Pu nitrate then was placed in small shipping cans and boiled right
in these cans, using hot air. It
was reduced to a wet nitrate paste. In
this form, the Pu was stored in the 213-J and K vaults in the southeast end of
Gable Mountain, and then shipped to the secret Los Alamos Site.
Each shipping can held about one kilogram (kg) of Pu.[xciii]
Operating experiences during the initial months of canyon operations
were described by DuPont as unusually satisfactory."[xciv]
No serious mechanical problems developed, except that the bowl of the
centrifuge in Section 16 of T-Plant jammed against some dip tubes when it was
run backwards on January 5, 1945. The
centrifuge was replaced via remote operations, partially decontaminated in a
spare cell, and then buried in 1954 when it was determined that it could not
be repaired. This and other miscellaneous remote tasks gave operators
confidence that "the Canyon Buildings can be operated remotely as planned
and with somewhat less loss of fabricated equipment than originally
anticipated."[xcv]
During the next six months of canyon operations, procedures were
standardized. Technical efforts
were directed towards reduced time cycles, as production sped for the special
nuclear materials needed to win the war.
By mid-1945, emphasis had shifted to "a review of process
technology and operating technique in an effort to improve efficiency and
reduce waste losses."[xcvi]
Free nitric acid concentration was reduced to obtain an increase in the
specific gravity of dissolver solutions.
The most significant improvement, however, came in the late summer,
with the installation of piping to allow for intermediate solution transfer
from storage to the precipitators in Section 6 (Cells 11 and 12).
This was a safety measure, as metal solution slightly in excess of
charge requirements then could be taken from storage, agitated, and sampled so
that the correct amount, based on critical mass limitations, could be
transferred to the extraction sections of the plant.
Further safety improvements included more rigorous efforts to empty and
decontaminate the precipitators used in the extraction and decontamination
cycles. These measures assured
the prevention of Pu-239 buildup on equipment.
The original HEW separations canyons were designed on the basis that
one plant would have the capacity to process the output from one pile
(reactor). With each HEW reactor
originally planned to produce one metric ton of metal (containing
approximately 250 grams of product - Pu-239) per day, the earliest standard
procedure for T-Plant involved starting a one metric-ton charge of metal into
the dissolvers about every 26 hours.
However, by the summer of 1945, production tests had shown that charge
size could safely be increased to 1.5 metric-tons of metal, "without
noticeable effect of yield or equipment performance."[xcvii]
By September 1, process modifications enabled the plant to complete the
processing of a charge in just 20 hours, with only a 10% allowance added onto
the average process cycle for equipment repairs.
Other very early changes included the elimination of potassium
carbonate from the separations process in February 1945, and one month later,
due to the unavailability of potassium hydroxide containing only 0.0005% iron
impurity, the relaxation of process specifications for this chemical to allow
for 0.005% iron impurity. Overall,
the first full-scale separations experiences at T-Plant and at the 224-T Bulk
Reduction Building and the 231-Z Isolation Building, led to large reductions
in many essential materials, per unit of production.
For example, the strength of the key dissolving agent nitric acid was
decreased from an average of 95% to an average of 69% (a 33% reduction).
By September 1, 1945, other chemical requirements were reduced by an
average of 41%, and potassium carbonate had been eliminated from the process
altogether.
Additional and ongoing process improvement studies carried out during
the 1945-46 period were directed at: simplification
of operations to achieve reductions in process time, modification of the
process to increase canyon capacity per batch, reduction in waste volumes,
recovery of additional product from wastes, the establishment of better
understandings of process safety and safety limits,
a
Zircaloy-2 is an alloy composed chiefly of zirconium, blended with small
amounts of tin, iron, chromium and nickel.
It is not a trademark product name.
aDetrex
is a trademark of Detrex Chemical Industries.
aDuponol-M-3
is a trademark of the E.I. du Pont de Nemours & Company.
bAluminux
and Diversey-415 were both trademark products of the Diversey Chemical
Corporation.
aIvory
is a trademark of the Proctor and Gamble Co., Cincinnati, Ohio.
bSutton
is a trademark of the Sutton Engineering Corporation, Pittsburgh, PA.
a
Parker fittings were a trademark product of Parker Intangibles, Inc., of
Wilmington, DE.
b
Neutron flux is a measure of the level of neutron excitation, movement or
activity during the fission process. Flux
is measured in terms of the number of neutrons that strike one square
centimeter in one second.
a
Amercoat is a trademark product of the Ameron Protective Coatings Division,
Ameron, Inc., of Brea, California.
[vi].
Hanford Engineer Works, HW‑10475, Section A, pp. 1‑28;
DuPont, Operation, HAN‑73214, Book 10, pp. 2-139; Weakley, HW‑58115‑DEL;
Williams and Williamson, H‑3‑08393; Harlan and Williamson, H‑3‑8391;
Kratzer, HW‑21450.
[vii].
Harrington and Reuhle, eds., Uranium Production Technology,
pp. 5‑12, 383‑425; and Greninger, HW-14110, pp. 72-73; and
G.E. Hanford Co., HW-7504 pp. 49-50.
[viii].
Weakley, HW‑58115‑DEL; U.S. DOE, DOE/RL‑90-11; AEC‑GE
Study Group, GEH‑26434, p. 3.18; GE‑Bouillon and Griffith,
HWS‑4955.
[xi].
National Lead of Ohio, "Uranium Feed Materials..."
pp. 14‑15; Durum and Chamberlin, "300 Area Monthly
Reports" (March 1946 and June 1946); Kidder, HW‑7-4049.
[xiv].
Bixler, "300 Area Monthly Reports," December 1947, January
1948, April 1948; Bixler, Special Hazards Incident Investigations,"
Class I, #85 and 86 (1948)
and Class II, #9 (1948); Hervin, "Radiation Monitoring Coverage,"
July 1954; pp. 1‑2; U.S. DOE, DOE/RL‑90‑11,
Appendix A.
[xv].
Kent, HW‑25906, pp. 5‑6; Hochschild, HAN‑49157‑DEL;
Corlett, HW‑38332, pp. 1‑6; Yost, HW‑39945,
pp. 1‑4; Lane, HW‑47260, pp. 1‑4; Weakley, HW‑24494,
pp. 1‑4; Weakley, HW‑27321, pp. 1‑2; Weakley, HW‑27734,
pp. 2‑15, Brandt and Kraemer, HW‑28282, pp. 1‑4;
Brandt, HW‑29871, pp. 1‑3; and p. 352; U.S. DOE,
DOE/RL‑90‑11, p. A‑10; Harrington and Reuhle, eds., Uranium
Production Technology, p. 352.
[xvi].
Operation Managers, HW-59099, p. A-17; Operation Managers, HW-59463,
pp. A‑16-17; Operation Managers, HW-59717, p. A-22; Operation
Managers, HW‑60233-A, p. A-13; Operation Managers, HW-60505-A, p.
A-18; Operation Managers, HW-63303, p. A-19
[xvii].
Batch and Toyoda, HW-65722, pp. 3-6; Toyoda, HW-71389; Thorne, BNWL‑SA‑1770;
Operation Managers, HW-63740-A, pp. A-16-17; Operation Managers, HW-64108,
pp. A-15-16; Geering, HW-66267; Operation Managers, HW‑65459, p. A-18;
Operation Managers, HW-65854, p. A-19; Operation Managers, HW-66237, p.
A-14; Operation Managers, HW-67532, pp. A-16-17; Operation Managers,
HW-67954, p. A-17.
[xix].
Drumheller, HWS-6797; AEC/GE Study Group, GEH-26434, p. 3.36;
U.S. DOE, DOE/RL‑90‑11; Clemans, WHC‑CM‑5‑20;
Gill, HW‑69941.
[xxii].
Hanford Engineer Works, HW-10475-B; DuPont, Construction,
HAN-10970, Vol. III, pp. 719‑735; Wahlen, WHC-EP-0273; IPD,
"Maintenance Work Forecast, 1966;"
Russ, HW-30401, Vol. I.
[xxiii].
Hanford Engineer Works, HW-10475-B, pp. 1,105-1,210; DuPont, Construction,
HAN-10970, Vol. III, pp. 788-792, and 806-811; Russ, HW-30401, Vol. I.
[xxv].
"Hanford Technical Manual," HW-10475-B; DuPont, Construction,
Vol. III, pp. 788‑792; DuPont, Operation, Book 7, pp.
79-115; Jordan, HW‑3‑1121; Hanford Engineer Works, OUT-1462, pp.
13-14.
[xxvii].
Menegus, HW-7-2744; Hanford Engineer Works, HW-10475-B; pp.
1110-1125; DuPont, Operation, HAN-73214, Book 7, pp. 107-114; Wende,
HW-7-3486; Wende, HW-7-3834.
[xxxi].
Carbon and Fryar, HW-20425; Warekois and Reinker, HW-19281; Cole,
HW-21659; Reinker and Bupp, HW-33842; Curtiss, HW‑55819.
[xxxii].
DuPont, Operation, HAN-73214, Book 11, pp. 13-15; Handford
Engineer Works, OUT-1462, pp. 64-69; DeNeal, DUN-6888.
[xxxiv].
Reinker, HW-22110; Strand, HW-27778; Russ, HW‑30401,
Vol. 1; IPD, HW-74094, Vol. 3; DeNeal, DUN-6888, p. 49.
[xxxvi].
Carbon and Fryar, HW-20425; Warekois and Reinker, HW-19281; Cole,
HW-21659; Reinker and Bupp, HW-33842; Curtiss, HW‑55819.
[xlii].
Wells, HW-27318; Pitzer, HW-25656; Dalrymple, HW-26395; Lewis and
Rohrbacher, HW‑29132; Strege, HW-32960.
[xliv].
Ritchey, HW-12492; Conley, HW-15943; Conley, HW-20342; Woods,
HW-23163; Greninger, HW-25012.
[xlviii].
Paul and Stephens, HW-34467; Greager, HW-37033; Call and Rector,
HW-30863; DeNeal, DUN‑6888, pp. 53-55.
[l].
Schilling and Hess, HW-25082; Lovington, HW-36224; Young, HW-43343;
McCarthy, HW-43456; Carlson and Trumble, HW-62471.
[li].
Conley, HW-20342; Fox, HW-25345; Bupp, HW-28531; Pearl, HW-28739;
Bainard, HW-40694; Richman, HW-45070.
See also: Richman, HW-37694.
[lii].
DuPont, Operation, HAN-73214, Book 11, pp. 76-77, 110; Hanford
Eengineer Works, OUT-1492, p. 88; Kidder and Jordan, HW-3-2224.
[liii].
Parker, HW-20959; Healy, HW-24578.
(Note: For further
discussion of the problems associated with radionuclides and Columbia River
fish, see Gerber, On The Home Front, Chapter 5.)
[liv].
Starkebaum, HW-33698; Conley, HW-24055; deHalas and Gay, HW-34821;
Hardin, HW-36021; Hardin, HW-38808; Hardin, HW-40703; Matsumoto,
HW-43830; Koop, HW-50601. (Note:
For further discussion of Hanford policy regarding operating purges,
see Gerber, On the Home Front, Chapter 5.)
[lv].
Trumble, HW-44708, Vols. 1 and 2; Russ, HW-30401, Vol. 1; Young, HW‑56230-RD;
IPD, HW‑74094, Vol. 3; Stainken, HW-35589.
[lix].
Renn, HAN-65347; Dickeman, HW-65580; Trumble, HW-61580; DeNeal, DUN‑6888;
Quinn, HAN-73578; Reid, HW-57497. (Note:
For a complete discussion of fuel fabrication changes and improvements at
the Hanford Site, see Gerber, WHC‑MR-0388.)
[lxi].
Deichman, HW-67741-Del; Dickeman, HW-65580; Bainard, HW-49777; Travis
and Bloch, HAN-71403; Upson, HW-63562; CETO, HW‑61197 RD; Young,
HW-65760; Young, HW-66468; Curtiss, HW‑55819.
[lxii].
McLenegan, HW-62729; Corley, HW-61206; Watson, Fox, Harrison, Kempf,
and Reinig, HW-65269; Trumble, HW-67131; Kratzer, HW‑67491; Curtiss,
Fullmer, and Gilbert, HW-67491; Jones, HW‑62861; Robbins, HW-66363.
[lxiii].
Trumble, HW-67131; Heacock and Jones, HW-SA-2287; IPD,
"Acceptance of Completed Project...," November 8, 1961; Jessen,
"Physical Completion Notice...," December 15, 1961.
[lxiv].
IPD, "IPD Radiation Exposure Reduction Program," October
20, 1958; Walker, HW‑50351-Del; Faught, "Reevaluation of the
Justification...," February 13, 1958; Porter, "Request for
Mechanical Development...," November 17, 1958; DeNeal, DUN-6888.
[lxv].
IPD, "Project Proposal...Project CG-786," December 2, 1957;
Murray, "Construction Completion and Cost Closing Statement,"
February 13, 1959; G.E. Hanford Company, "Project Proposal, Revision
1...Project CG‑707," June 21, 1957; IPD, "Semi-Monthly
Project Report," November 1958; IPD, "Project No.
CGI-806...," June 15, 1961; Astley, "Pressure Monitor System
Repair and Modification," March 28, 1962; Copeland, HW-63298;
Greninger, "Improvements to Gamma Monitor System...," June
27, 1960; Greninger, "Transmittal Letter...," September 6, 1961;
IPD, "Acceptance of Completed Project," May 1, 1963; Corlett,
"Fuel Rupture Monitor System," July 1, 1964; Astley, "Project
CGI-904...," July 10, 1964; Simsen, IP64-15;
Hermann, HW-78840; Lyons, DUN-812; DUN, "Acceptance of Completed
Project CGI-143 (105-B)," September 30, 1966; Lyons, RL-REA-676;
Jessen, "Physical Completion Notice...," April 10, 1967.
[lxvii].
Hall and Jerman, HW-63653; Washington State Department of Health,
CIC-161754; Spies, CIC-161740; Spies, CIC-161731; Dworsky, CIC-161744;
Silker, HW-56366; McCormack and Schwendiman, HW-61325; Foster and
Junkins, HW-63654; Healy, HW‑60529; Geier, DUN-1906.
(Note: A curie is a
measure of radioactivity defined as the amount of radioactive material that
has an activity of 3.7 X 1010 disintegrations per second.
About 14 curies of radioactivity were released to the atmosphere in
the 1979 incident at Three Mile Island, Pennsylvania.
For a more complete discussion of the effects of radionuclides in the
Columbia River, see Gerber, On the Home Front, Chapter 5.)
[lxviii].
Herde, HW-3-5501; Coopey, HW-11662; Olson and Foster, HW-20055;
Schiffman, HW-72107; Parker, HW-32809.
(Note: This is a partial listing.
There are many similar studies.
For a complete discussion of the role of reactor effluent in the
Columbia River, see Gerber, On the Home Front, chapter 5.)
[lxix].
Foster, HW-49713; Foster, HW-54858; Junkins, HW-68096; Hall,
HW-65733-RD; Hall and Jerman, HW-64517; Hall and Jerman, HW-63653.
[lxxii].
HLO and IPD, HW-70526; Geier and VanWormer, HW-75609; Geier, HW‑75949;
Geier, HW-83775; Silker, BNWL‑CC‑1055; Geier, DUN-3935.[lxxii].22
[lxxv].
Hanford Atomic Products Operation, HW-69000, Vol. I, p. 2.0-6; Stapp
and Marceau, BHI-00627, Rev 0, p. 23.
[lxxvii].
Hanford Atomic Products Operation, HW-69000, Vol. I, pp. 3.6-2-8;
Stapp and Marceau, BHI-0627, Rev. 0, Appendix C.
[lxxix].
Erickson, UNI-1437, Rev. 2, pp. 5-6, 10, V-1; Scott, UNI-1960, pp.
1-3, 13-17; Newby and Marshall, UNI-2109; Lyon, UNI-2110; Nelson, UNI-3422;
Nelson, UNI‑3329; Zaloudek and Ruff, UNI-3653 (PNL-5924); Zaloudek and
Ruff, UNI-38994 (PNL-5930); Lee, UNI-4193; Nelson, UNI-4191 Rev. 1;
Alzheimer and Gonzalez, UNI‑4285; Martek, UNI-4263; Lyon, UNI-1986;
Cummings, UNI-2063; Rainey, UNI‑2182; Conn, UNI-2227 Rev. 1; DeMaria,
UNI-3481 Rev 1; Shoemaker and Fuller, UNI-21016; Reeves, UNI-610 Rev. 1;
Lechelt, UNI-2925; Lattin, UNI-3333; Rasmussen, UNI-3583; Stauch, UNI‑4210;
Linschooten, UNI-4148; Pope, UNI-4239; Smith, UNI-4253; Sullivan, UNI-4225.
[lxxx].
Hanford Engineer Works, HW‑10475‑B, pp. 910-919.
(Note: The exact fuel
storage times used in World War II are not known.
Following the war, storage times lengthened in order to allow for
additional decay (stabilization) of radioisotopes such as Iodine 131.)
[lxxxii]. Watson, Brendel and Shields,
WHC0EP-0477.
[xci].
Hanford Engineer Works, HW-10475-C; Stoller and Richards, Reactor
Handbook, 2nd ed. pp. 227-234.