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Appendix B
The DOE Nuclear Weapons Complex:
A Descriptive Overview
Nuclear weapons are produced in the United States by the Office of Defense
Programs (DP) of the Department of Energy (DOE). DP manages a large complex
of facilities, including 17 major plants in 12 states, to carry out its mission. Its
annual budget is about $10 billion, and DOE and its contractors employ about
80,000 people.
For the purpose of description, we organize the facilities in the complex into
three main types: the weapons laboratories, the materials production facilities,
and the weapons production facilities. The weapons labs design the weapons
providing the blueprints and technical specifi~cabons for their constructior~and
test them. The materials production facilities provide the raw nuclear materials
for fabrication into warheads. The weapons production facilities fabricate the
required nuclear components, supply the hundreds of non-nuclear components,
and assemble the warheads. In addition, DP manages He test facility and a waste
repository for the operation, which is currently the Waste Isolation Pilot Plant in
New Mexico.
Figure B.1 presents a snapshot of the current status of the complex, which,
over its Midyear history, has been configured in many different ways. It would be
impractical to indicate all the previous rounngs. It can be seen that the complex
has redundant capabilities for many processes, and in some cases, processes once
required for stockpiles have been discontinued.
WEAPONS LABORATORIES
The three weapons laboratories are the Los Alamos National Laboratory
(LANL) in Los Alamos, New Mexico; the Lawrence Liverrnore National
102
OCR for page 103
APPENDIX B
103
Laboratory (LLNL) in Livermore, California; and the Sandia National Laboratory
(SNL) in Albuquerque, New Mexico.
Los Alamos National Laboratory and NIL are both large multipurpose
complexes, and they both conduct many activities unrelated to nuclear weapons.
Within the context of nuclear weapons production, however, these two labs have
essentially the same missions: to design, develop, and test the nuclear components
of the weapons. Both labs are operated under contract with the University of
California Board of Regents. Between the two labs there is a vigorous competition,
which has undoubtedly been beneficial to weapons design. Each lab has provided
designs currently in the weapons stocl~ile, and each lab has several new designs
under development.
Sandia National Laboratory, like the other two labs, carries out many activities
not associated with nuclear weapons. Part of its mission in the nuclear weapons
complex is to design and engineer non-nuclear components associated with a
nuclear weapon. Such components include electrical systems, fusing and hiring,
neuron generators, tridum reservoirs, and delivery packages. SNL works closely
with LANL and LLNL to incorporate the nuclear components of a new design
into an operational.weapon. SNL also has responsibility for engineering
modifications and upgrades to weapons already deployed and for monitoring the
stockpile.
MATERIALS PRODUCTION FACILITIES
The materials production facilities include the gaseous diffusion plants at Oak
Ridge in Tennessee, Paducah in Kentucky, and Piketon in Ohio; Herald, Ashtabula,
Hanford; the Idaho Chemical Processing Plant, Y-12 at Oak Ridge, and the
Savannah River Site.
The mission of these facilities is to provide the nuclear materials used in
nuclear weapons, particularly uranium-235, uraraum-23S, plutonium-239, lithium-
6, tritium, and deutenum. The first three are among the heaviest of elements,
while the latter three are among the lightest Four of the six are produced by
separation from naturally occurring ores and water. The other two, plutonium and
tntium, are not available from natural sources but are produced in nuclear reactors
by transmutation of other elements.
Heavy Metal Production
Uranium as found in the ground is mostly uranium-238 with 0.7 percent
uranium-235 and 0.01 percent uranium-234. Uranium mills process the ores to
produce a concentrated uranium oxide, U3O~, which then is commercially converted
to gaseous uranium hexafluoride (UF: for enrichment processing in the gaseous
diffusion plants (GDPs). There are three GDPs: the Oak Ridge GDP (K-25 Plant)
in Tennessee, the Paducah GDP in Kentucky, and the Portsmouth GDP in Piketon,
Ohio. The Oak Ridge GDP has been on standby since 1985. The purpose of these
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104
_ F
SEU E
DU _ R
_ N
t D ·
_·1
Uranium ~ ~
.
~nput ~ _
Gaseous diffusion
Oak Ridge* _ .
Paducah. _ _
. ~
Pc~ncmc,' nh _
H
E
U.
Ingots
SEU
DU
DU
A
S
H
T
A
B
U
L
A.
OAK RIDGE Y-12
Retired I _,
wesponS ~ DU L~ _
DU scmp ~ r
Spent Naval I ~ ~ HEU
and research ! ~
Lithium bydroxide Li-6^
stockpile enrichment
stockpile
F etired weaponS=_|
~ Li~
_
D2O
~Not in operation at present
APPE:NDIX B
U03
Biliets
HANFORD
DU ~ N-Reactor.
LEU nitrate
~ ,
HEU nitrate
SAVANNAH RIVER
HEU
Fuel fabrication |
Water _ Heavy water plant.
r~ Heavy water rework ]! ,
Recycled D2O | D2O stockpile |
SRS. IDU targets
reactors |
LL' targets
FIGURF B.1 Plow of materials through the DOE Nuclear Weapons Complex. Diagram
byP.Rapp 1989.
OCR for page 105
APPENDIX B
l
U03 ~- ~
_ PUREX plant _
Plutonium Pu metal
Finishing
Plant
I_
i Pu metal
_ F-Canyon
i
Tritium facility :
Filled reservoirs 1 ~
To deployed
Tritium recycled weapons
from weapons
HEU 8 DU components
' Li~deuteride components
Hasten, Tennessee (Army) Bulk explosive
ROCKY
FLATS
Pu scrap
Fission
cores
T3 reservoirs
n ~ _ ~ ~
Kansas City Bendix Electronic, mechanical, plastic components
Pinellas, Florida Neutron generators
Retired
weapons
Mound, Ohio Actuators, igniters, detonators
105
PANTEX
Recycled materials /
V
Nuclear weapons ~
_ V
OCR for page 106
106
APPENDIX B
plants is to concentrate the uranium-235. The mechanism for concentration is
based on the fact that a UFO molecule containing uranium-235 is slightly lighter
than a UFO molecule containing uranium-238; consequently, the former has a
slightly higher thermal velocity. About two-thirds of the uranium-235 in the
natural ore is removed in the concentration process, so that there are two product
streams: enriched uranium and depleted uranium. Only the Portsmouth GDP is
now operated to provide concentrations higher than 4 percent ~arnum-235.
In general the enriched uranium may contain any percentage of uranium-235.
Uranium containing more than 20 percent uranium-235 is called highly enriched
uranium (HEU); enriched uranium with less than 20 percent uranium-235 is
known as low enriched uranium (LEU). HEU production for weapons ceased in
1964. Before that iune, the gaseous HEU was shipped from Piketon to the Y-12
Plant, where it was converted to metal and stockpiled. The HEU metal is
commonly known as "oralloy," where the first two letters indicate Oak Ridge.
LEU was used for the fuelltarget rods at the Hanford N-Reactor, which is now on
cold standby. For purposes of companson, the fuel in commercial power reactors
is about 3 percent uranium-235, the driver fuel for the production reactors at SRS
is typically 60 percent uranium-235, and naval reactor fuel is 97.3 percent uranium-
235. Depleted uranium (DU) is used both for SRS target rods and for components
in weapons.
There are two, almost independent' plutonium production streams. Bow
streams start with enriched and depleted uranium in the gaseous state, and both
streams provide plutonium metal to Rocky Flats. By far the largest effort in heavy
metal production is devoted to the creation and processing of plutonium. The first
stream to be described here flows through Fernald, Ashtabula, and Hanford. The
second goes through INEL, Oak Ridge, and Savannah River.
FernaldIAshtabula/~nford
The LEU and Do products, still in the gaseous state, are shipped to the Feed
Materials Production Center (FMPC) in Femald, Ohio. At the Fernald plant the
UFO iS reduced to the "green salt," IJF4, and mixed with green salt produced from
other inputs to the FMPC. The FMPC is a large and diverse facility containing 10
separate plants. Uranium input to the FbIPC enters in several forms, including
ore concentrates, metal scraps and residues, uranyl nitrate (UNH) from SRS, and
UO3 from Hanford. All these inputs are pr~ess~ ink uranium oxides, some of
which may be shipped to the GDPs for enrichment. Most of the input, however, is
processed into UO3 and hydrofluorinated into green salt, which is mixed with the
green salt from reduction of UFO. I he green salt is reduced to metal and cast into
ingots. Some of the DU is shipped to Y-12 for fabrication into weapons
components. The LEU ingots, and the rest of the DU ingots, are machined and
shipped to the `4shtabu~a Extrusion Plant in Ashtabula, Ohio. In Ashtabula the
ingots are extruded into tubes and billets for later fabrication into reactor rods.
The DU tubes are returned, first, to Femald for further machining, and then to
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APPENDIX B
107
SRS where they are usM as target rods for transmutation of uranium-238 into
plutonium. The LEU billets go to Hanford to make fueVtarget rods for He N-
Reactor, which is curmndy on cold standby. The DOE Modernization Report
anticipates that the FMPC will be permanency closed in the near future.
At the Fuel Fabrication Facility on the Hanford site, He LEU billets are
fabricated into reactor elements by extrusion into rods clad with zirconium.
These rods serve as both fuel and target in the N-Reactor. Neurons from
fissioning uranium-235 conven some of the urarnum-238 to various isotopes of
plutonium. The fissioning isotope, plumnium-239, is He one desired for both
reactor fuel and weapons. As the uranium-235 is used up, the amount of plutonium
increases, but the fraction of plutonium as plutonium-239 decreases as the relative
abundance of plutonium-240 increases. "Weapons-grade" plutonium contains
less than 7 percent plutonium-240, while '~fuel-grade" plutonium contains less
than 13 percent plutonium-240. Other isotopes, plutonium-241 and plutonium-
242, are also produced by subsequent neutron capture. Consequently, the limit to
the N-Reactor fuel cycle is determined not by the burn-up of uranium-235, but
rather by the desired abundance of isotopes in the produced plutonium. Chemical
processing of the irradiated reactor rods separates plutonium from the other
elements. Chemical processing cannot' however, separate plutonium isotopes.
Methods to do that are still under development.
Chemical processing of the irradiated rods begins in the PUREX (plutonium-
uranimn extraction) Plant on the Hanford site. The first step is the chemical
removal of the fuel cladding in the head-end dissolver. Subsequently, the fuel is
initially dissolved in an aqueous solution of nitric acid. An organic solvent is used
to separate the nitrates of uranium, plutonium, and neptunium from the fission
products. Further treatments with organic solvents and nitric acid solutions
isolate the uranium, plutonium, and neptunium. The three major outputs from the
PUREX Plant are IJNH, plutonium oxide (PuO2), and neptunium nitrate. The
neptunium is shipped to SRS; the other two products are processed further at
Hanford.
The uranyl nitrate goes to the Uranium Oxide ((JO3) Plant, where it is calcined
into uranium oxide powder. The powder is shipped either to the GDPs for
enrichment or to the Fernald Plant for processing into metal.
The plutonium oxide goes to the Plutonium Finishing Plant (PFP, or Z Plant).
There the plutonium is precipitated as the oxalate, convened to PuO2 and fluorinated
with gaseous hydrogen fluoride (HF). The resulting pink powder, PuF4, is
reduced to metal with calcium (see Appendix D). The plutonium is shipped to
Rocky Flats for fabrication into weapons components. PEP can also be used to
recycle scrap plutonium from Hanford and Rocky Flats.
- r -
ICPP/Y-12/Savannah River
The other heavy metal stream is somewhat newer, and it depends to some
extent on heavy elements previously produced. An important input to this stream
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108
APPENDIX B
is the spent naval fuel returned to the Idaho Chemical Processing Plant (ICPP),
located on the site of the Idaho National Engineering Laboratory KNELT. Other
inputs to ICPP include spent fuels from research and test reactors, both domestic
and foreign. The main mission of IFPP is the recovery of highly enriched
uranium for use in driver fuel in He SRS reactors. ICPP has extensive water-
f~led storage and staging facilities, allowing fuel to be moved into head-end
dissolution without exposure to air. The head-end facilities offer a variety of
dissolution processes to accommodate the venous fuels and claddings. Subsequent
processing is similar to He PUREX process, involving solvent extraction and
purification. ICPP is distinguished by its capability for handling and recovering
the highly enriched uranium of the returned naval fuels. Naval fuel returns are
expected to increase rapidly, perhaps tripling over the next 10 years. The output
product, powdered uranium oxide, is shipped to the Y-12 Plant at Oak Ridge for
processing into SRS fuel. A secondary mission of ICPP is the recovery of
krypton-85 from the spent fuels. The krypton-85 is shipped to Oak Ridge for
commercial sale, largely for use in the detection of leaks. ICPP is the only source
of krypton-85 outside the Soviet Union.
The Y-12 Plant at Oak Ridge is a large multi-purpose facility with several
different missions, both in materials production and in weapons production. One
mission is to produce uranium metal of about 60 percent enrichment for use as
SRS driver fuel. Because the several inputs to this metal production have varying
enrichments, the process streams are carefully blended to produce the required
enrichment. One input is the ICPP oxide, which may have originated with naval
fuel or with reactor fuels. The other input is highly enriched uranyl nitrate from
processing of spent fuels at SRS. To blend the product to the required enrichment'
oralloy from the Y-12 stockpile is added to the mix, and the final uranium metal
product is shipped to Savannah River.
Unlike the Hanford N-Reactor, which uses reactor rods functioning
simultaneously as fuel and target, the SRS reactors use independent fuel and
target rods, made of different materials. At the SRS Fuel Fabrication Facility, the
uranium metal from Y-12 is alloyed with aluminum and ex~uded into fuel rods
with aluminum cladding. At the SRS Target Fabrication Facility, the hollow
tubes of depleted uranium from Fernald are electroplated with nickel and bonded
into aluminum cans to serve as target rods for transmutation into plutonium. The
Target Fabrication Facility also assembles the lithium target rods for tritium
production (see Light Element Production below).
There are five production reactors at SRS, designated C, K, L, P. R. They were
all designed with heavy water, D2O, as coolant and moderator, allowing great
flexibility in the use of the reactors for production of various nuclear materials,
including trivium and plutonium. The P. K, and L reactors are currently shut down
because of safety concerns; the C-Reactor is being cannibalized, and the R-
Reactor is permanently closed. Currently there is no plutonium production
planned, at least in the near term, at SRS; the focus is on tritiurn production.
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Representative terms from entire chapter:
heavy water
APPENDIX B
109
After the rods are removed from a reactor, they are processed in different
chemical separations facilities called '~canyons," because Hey are 30 feet wide by
60 feet high, and almost 900 feet long, heavily shielded in concrete and steel. Too
radioactive for human occupation, the canyons are operated entirely by remote
control. The PUREX Plant at Hanford is a similar canyon facility. At SRS, the H-
canyon processes the discharged fuel rods to r~over the enriched uranium, while
the F-canyon processes the irradiated DU target rods to recover the plutonium.
Tritium is recovered from the lithium Beget rods in a separate Tritium Facility,
where remote handling is not required (see Light Element Production below).
The H canyon uses a modified PUREX process of dissolution and solvent
extraction to recover He enriched uranium from the fuel rods. Highly enriched
UNH is shipped to the Y-12 Plant to be recycled and blended back into new SRS
driver fuel. LEU, also in the forth of UNH, is shipped to the Fernald Plant.
The F
110
APPEND[X B
contains more than 200 tons of it. To maintain its Purina, the D2O is periodically
processed Trough the SRS Heavy Water Rework Unit and returned to the large
SRS stocl$,ile. Supplies for weapons production are shipped from the SRS
stockpile to Oak Ridge in the form of liquid heavy water.
Li6 and Li6D Production at Y-12
At the Y-12 Plant the heavy water is processed together with metallic Li6 to
produce lithium-6 deutende (Li6D). The Li6D is formed into weapons components
and shipped to Pantex (see Weapons Production Facilities below). Li6, like heavy
water, was extracted in large quantides at one time, but it is now drawn from
existing stockpiles. Li6 is a stable isotope that makes up about 7.4 percent of
natural lithium ores. Lithium itself is one of the most abundant elements. Dunng
the l950s, thousands of tons of lithium hydroxide were purchased for the weapons
program. Enrichment of Li6 was the mission of several large plants at Y-12. The
basis of the enrichment process is the differential preference of li~ium-7 for
mercury. With the introduction of mercury into aqueous lithium hydroxide, the
lithium-7 will concentrate in the amalgam phase. Enrichment of Li6 required the
use of very large amounts of mercury at Y-12. Production of Li6 stopped in 1963,
after the accumulation of a large stockpile. Li6 components from retired weapons
are resumed to Y-12 for recycling.
In addition to its use in Li6D components, Li6 is also used for production of
tritium in the SRS Factors. Enriched Li6 from Y-12 is shipped to the SRS Target
Fabrication Facility, where it is alloyed with aluminum and canned as target rods
for the reactors. Li6 is also used for control rods in the reactor cores, as well as for
shielding around the core. The irradiated lithium is processed ire the SRS Tritium
.,.
. Any.
Tritium Production at SRS
The Tritium Facility is a"chemical separation facility," but the irradiated Li
rods do not require remote-handling canyons for processing. The mission is T
separation, p~f~cation, and loading. One input is the irradiated lithium-aluminum
target rods. The targets are heated under vacuum, and the liberated gases include
hydrogen, D, T. helium-3, and helium4. Palladium diffusion and cryogenic
distillation are used to separate and purify He tritium. Another input to the
Tritium Facility is the T recovered from deployed weapons which is contaminated
with helium-3. ReseIvoirs filled with tritium are shipped from SRS to Pantex and
to military installations. A new facility at SRS, the Replacement Tritium Facility,
is almost complete and should begin to operate in 1990. The new facility is
underground, and it uses new hydride technology that greatly reduces the amount
of tritium in the filling plumbing, and is expected to reduce greatly the releases of
T to the atmosphere. This facility will replace the gas handling and processing
that is conducted in the existing tritium facility.
APPENDIX B
111
WEAPONS PRODUCTION FACILITIES
Production of Weapons Components
Of the six weapons production facilities—Kansas City, Mound, Pinellas, Y-
12, Rocky Flats, Pantex three are involved only with nonnuclear components.
The Kansas City Bendix Plant supplies various electrical, mechanical, and plastic
components; the Mound Facility manufactures igniters, detonators, and other
small-scale pyrotechnic components; and the Pinellas General Electric Plant
produces neutron generators and neutron detectors.
The Y-12 Plant and the Rocky Flats Plant contain specialized machine shops
that process raw nuclear materials into the finished components required by the
warhead designs. The Y- 12 Plant bakes and machines Li6D into ceramic weapons
components for shipment to Pantex. It also fabricates uranium components, from
both enriched and depleted uranium. These components are shipped to Rocky
Flats, where they are assembled, together with plutonium and beryllium
components, into "pits," i.e., the shells of fissionable materials inside the high
explosive of the weapons. The plutonium and beryllium components are fabricated
at the Rocky Flats Plant. Many other metal components, including the stainless
steel tritium reservoirs, are fabricated in the extensive metal-working facilities at
Rocky Flats.
The plutonium input comes pardy from Hanford and SRS, and partly from the
retirement and scrap recycling operations at Rocky Flats itself. In line with its
mission of pit assembly, Rocky Flats also has the mission of disassembling the
pits from retired weapons. The recovered plutonium is chemically processed to
remove americium, which is purified and shipped to Oak Ridge. Americium is
removed either by molten-salt extraction or by dissolution in nitric acid, followed
by ion exchange, peroxide precipitation, fluorination, and calcium reduction to
metal. This process is also used for plutonium scrap recovery. Building 371 at
Rocky Flats was added to the complex in 1981 to modernize and integram these
operations, but it was closed after a short operational run because of design faults.
Assembly and Disassembly of Weapons
Finally, all the components are brought together for assembly at the Pantex
Plant in Amarillo, Texas, and Mom there the devices are delivered to the Department
of Defense. The Pantex Plant itself fabricates the chemical high explosives,
which are assembled around the pits fabricated at Rocky Flats. Much of the
recent work uses modern insensitive explosives, which come in bulk quantities
from the Arrny facility in Holsten, Tennessee. At Pantex the high explosive (HE)
is pressed into rough billets and machined to final shape. The HE components are
prepared and assembled in special "bays," made of thick concrete and designed to
vent an accidental explosion through the earth-covered r ~of. The bays are spaced
to avoid sympathetic explosions.
112
APPENDIX B
The find assembly of nuclear weapons takes pace in special assembly cells
known as "Grave! Genies." Components going into the final assembly include
the high explosives, the pits from Rocky Flats, He Li6D pans from Y-12, the
Olled T reservoirs from SRS, and the many nonnuclear components from other
facilities Scheduling and staging the shipment and inventor of these components
is an indicate business. The completed warheads are staged oasis at Pantex
before shipment to military installations.
As a corollary ~ its mission of warhead assembly, Pantex is ~SQ responsible
for disassembling rewed weapons. The nuclear components are returned to the
plants that produce them for processing and recycling. Pantex is Be only Cecilia
with He capability to disassemble nuclear weapons It is therefore the swing
point for any maintenance or modification of weapons, excel for the replenishment
of the trivium resenro~s. Pan tex also conducts quality assurance testing on
components of deployed weapons.
