[Federal Register Volume 64, Number 166 (Friday, August 27, 1999)]
[Notices]
[Pages 46894-46896]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-22278]
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DEFENSE NUCLEAR FACILITIES SAFETY BOARD
[Recommendation 99-1]
Safe Storage of Fissionable Material Called ``Pits''
AGENCY: Defense Nuclear Facilities Safety Board.
ACTION: Notice, recommendation.
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SUMMARY: The Defense Nuclear Facilities Safety Board has made a
recommendation to the Secretary of Energy pursuant to 42 U.S.C.
2286a(a)(5) concerning safe storage of fissionable material called
``pits.''
DATES: Comments, data, views, or arguments concerning this
recommendation are due on or before September 27, 1999.
ADDRESSES: Send comments, data, views, or arguments concerning this
recommendation to: Defense Nuclear Facilities Safety Board, 625 Indiana
Avenue, NW, Suite 700, Washington, DC 20004-2901.
FOR FURTHER INFORMATION CONTACT: Kenneth M. Pusateri or Andrew L.
Thibadeau at the address above or telephone (202) 694-7000.
Dated: August 23, 1999.
John T. Conway,
Chairman.
[Recommendation 99-1]
Safe Storage of Fissionable Material Called ``Pits''
Dated: August 11, 1999.
Fissionable components are at the heart of all nuclear weapons, and
have therefore been of central importance to that part of the nation's
defense posture that relies on nuclear deterrence. Most of the defense
nuclear programs of DOE and its predecessor agencies have been devoted
to production of the fissionable material for these components and the
working of this material into weapons parts. Most fissionable material
in nuclear weapons is in components called ``pits,'' which are the
primary parts of the weapons, and which have geometrical forms,
dimensions, and other features which are highly classified. Pits are
predominantly made of plutonium metal which by itself would corrode in
an air atmosphere, causing a possibility of dispersion of this
hazardous material. Therefore, pits normally have a corrosion-resistant
cladding, and where possible they are kept in an inert atmosphere. The
design purpose of pits and their constituent material leads them to
have singular importance, both from the standpoint of national security
and that of safety. In particular, when pits are stored by themselves,
not incorporated in a nuclear weapon (``stand-alone'' pits), special
attention is required to avoid any undue risk.
Most plutonium pits in this country were formerly made at the Rocky
Flats Plant of the Department of Energy, situated between Boulder and
Golden, Colorado. When manufacture of new pits was ended in 1989, a
number of previously made but still unused pits existed outside of
completed weapons, along with some others that had been manufactured
but that required rework. Also, when weapons are dismantled, their pits
are stored as stand-alone pits. In the following, the term ``pits''
will be reserved to those components not incorporated in nuclear
weapons.
The number of stand-alone pits continues to grow as more nuclear
weapons are dismantled in accordance with international agreements and
national policy, and it is now in excess of 10,000. Most of the
nation's pits are stored at this time at the Pantex Plant of the
Department of Energy, near Amarillo, Texas, under conditions considered
to be secure and also safe for the time being.
Current plans envisage three principal destinies for pits stored at
Pantex. Some pits are to be retained in a strategic reserve, in case a
decision should be made to use them in nuclear weapons at a future
time. Other pits regarded as surplus to any conceivable future defense
mission are to be converted from metallic form to a plutonium oxide,
which is to be added to depleted uranium oxide. The combination is to
serve as the fissionable material in mixed oxide fuel in certain
commercial nuclear reactor plants. Plutonium from some surplus pits
that will be difficult to use in this way will be disposed of.
Numerous decisions must still be made to convert such tentative
plans to reality. The most basic ones would establish where certain
actions and processes are to take place. They are:
1. Where is the strategic stockpile of pits to be stored?
2. Where is the conversion of metallic plutonium to plutonium oxide
to take place?
3. Where is the manufacture of mixed oxide fuel to occur?
4. Where will surplus pits awaiting disposition be stored?
Current actions of DOE are consistent with storage of pits for the
strategic stockpile at the Pantex Plant. Pits destined for conversion
to plutonium oxide and subsequent incorporation in mixed oxide fuel
must be processed into feedstock prior to fuel manufacture. DOE has
announced in its Record of Decision following an Environmental Impact
Statement that Savannah River is the preferred site for this conversion
to feedstock. For this to take place, pits in the latter category must
be shipped to the Savannah River Site from their present location at
the Pantex Plant at Amarillo, Texas.
Almost as basic are decisions still awaited regarding the
structures in which both medium-term and long-term storage will take
place, and the nature of the storage itself including the containers
that will be used for shipping and storage. For most of the pits now in
storage at Pantex, the outer metallic cladding is the only reliable
containment. Although the cladding of pits has rarely failed or been
breached, most pits have been protected throughout their existence by
the sealed atmosphere within a nuclear weapon, limiting their exposure
to incompatible or corrosion-producing materials. However, most pits at
Pantex are now in AL-R8 containers with a normal atmosphere, along with
celotex packing material that is a potential source of moisture and
chlorides. The containers are not tightly sealed, and they are kept in
magazines with an atmosphere that communicates with the outside air
through a normal ventilation system. The AL-R8 container is used for
storage, but not for shipping pits. It is regarded as noncertifiable
for shipping.
Furthermore, inspection, cleaning, and other operations associated
with dismantlement of nuclear weapons makes use of chemicals that could
conceivably initiate corrosion or otherwise damage a pit in the long
term. The condition of pits following dismantlement is not well
documented, and some long-term modes of possible degradation are not
well understood. Some types of pits must be kept cool.
In 1992, as the forthcoming size of the inventory of pits came to
be realized, DOE began to plan for measures to better protect them. A
surveillance program was instituted. A plan was developed to place pits
in sealed stainless steel containers called AT-400A, each having a
sealed stainless steel insert holding a pit in an inert atmosphere. The
AT-400A would have fully protected its enclosed pit, and would have
been certifiable as a shipping container. As plans developed,
repackaging of pits was to start in 1995 and was to have been completed
in five years. However, this repackaging never became a reality. The
Pantex contractor found the final weld seal on the AT-400A's insert to
be very difficult, and the cost of the AT-400A was concluded to be too
high. Use of the AL-R8 continued.
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The design laboratories have stated in letters to DOE and to Pantex
in 1995 and 1997 that pits, when in AL-R8 containers for an extended
period, face a possibility of corrosion. They recommended that no pits
should be stored an appreciable period of time in these containers.
Further, they stated that if pits are to be stored in AL-R8s for more
than five years, aggressive surveillance should be applied and humidity
control should be used.
DOE has since pursued a course intermediate between continued use
of the AL-R8 alone and introduction of a totally new container such as
the AT-400A, and has developed a design of a stainless steel pit
container with a bolted, flanged closure, to be an insert for the AL-
R8. Some materials compatibility problems have been attached to the
design, but these seem surmountable.
The Board has been actively following the development of plans for
pit storage, and has discussed the issues with DOE and the Pantex
contractor on numerous occasions during the years since 1992. On
December 31, 1997, the Board sent to the Assistant Secretary for
Defense Programs a comprehensive review of the matter, defining a
number of steps believed to be necessary for conduct of an adequate
program, and stating that it may be prudent to assign overall
responsibility for the endeavor to a senior line manager within DOE to
ensure success. No formal reply to the letter was made, although the
issue was pursued during briefings of the Board, including some at
Pantex. The next written communication on the matter occurred in a
letter from the Deputy Assistant Secretary for Military Application and
Stockpile Management, DOE, on October 14, 1998. The letter informed the
Board that proposed use of the AT-400A container had been abandoned in
favor of the AL-R8 with a sealed insert.
On November 6, 1998, a letter from the same source transmitted a
copy of an Integrated Pit Storage Program Plan (IPSPP) which included
up-to-date plans for interim storage of all Pantex pits (an earlier
version of the IPSPP had been furnished the Board in January 1998, but
that had been withdrawn). The Board responded on March 12, 1999,
finding that the IPSPP did not adequately address the concerns stated
in its letter of December 31, 1997. The IPSPP continued to be focused
on short-term goals and did not take into account the need for informed
decisions to be made regarding critical elements of the pit management
system, such as the selection of pit packaging and storage facilities
and preparation for eventual shipment to disposition facilities.
On April 15, 1999, the Assistant Secretary for Defense Programs
responded in a letter agreeing that the IPSPP does not fully address
all pit life-cycle issues. He stated that the Plan was intended to
ensure safe storage in the near-term. He also promised to form a multi-
disciplinary team in the summer of 1999 to identify appropriate issues
and develop the desired end-states, to assign, subject to higher
approval, the responsibilities for their achievement, and to identify
the resources. The IPSPP would be modified accordingly.
The rate of repackaging of Pantex pits is not well predictable, but
one estimate places corresponding completion of the task at no sooner
than the year 2008. The Pantex contractor is seeking a means to operate
two shifts within present budgets, which could mean a completion date
approximately in the year 2006. Startup of a second repackaging line
might speed the process by about two years. Since the original plan was
to repackage all pits in AT-400A containers by the year 2000, even the
most intensive of these possibilities would amount to a long delay
during which pits would reside in present AL-R8 containers in
conditions regarded by the design laboratories as undesirable.
There are some safety questions regarding the present design of the
AL-R8 system with the sealed insert. The celotex in the outer container
may constitute a chemical threat to the sealed insert because of
questions of moisture and chlorides. The principal question relates to
the carbon steel bolts used for the flanged closure of the sealed
insert because these bolts may be more subject to corrosion, and their
failure would expose the pit within to the conditions which had caused
bolts to fail. The Board considers these design questions to be readily
solvable.
Finally, the end product of the repackaging into the AL-R8 would be
placement of all pits in containers unsuitable for shipping, and pits
slated for conversion to mixed oxide for reactor fuel might not be
available for repackaging in containers that could be certified for
shipping until well into the 21st century. To conduct the necessary
repackaging into shipping containers not yet even designed would
subject personnel to additional radiation exposure. There are no
present plans to avoid this situation.
Apart from possible effects of readily avoidable design problems of
sealed inserts for AL-R8 containers, the Board regards the use of these
sealed inserts for repackaging of pits stored at Pantex to be the basis
for acceptable solution during the near term. Repackaging pits into the
improved AL-R8 should adequately solve the problems that the design
laboratories identified as attached to the existing system of storage.
Inspection over time will tell how long such storage can be relied on.
On the other hand, the length of time foreseen for arriving at
repackaging of pits into this acceptable state is not compatible with
avoidance of safety problems identified by the design laboratories. The
Board is also concerned regarding these potential problems. They are a
legacy of past manufacture of nuclear weapons and are among the
questions raised by the Board's Recommendation 94-1, which addressed
the need for safe interim storage of these legacy materials.
Pits in the strategic reserve at Pantex have great value to
national defense. These pits, manufactured at great cost and great
effort by the Department of Energy and its forebears, are probably only
second in importance to nuclear weapons in the military stockpile. In
the nuclear weapons defense system, they are effectively irreplaceable.
Their assured safe protection should be a vital component of national
defense.
Furthermore, DOE's program plan for materials disposition is in
peril regarding recycling excess pits into mixed oxide fuel, because
there is no container suitable for shipping the pits from the Pantex
Plant to the Savannah River Site, and no plans exist for development of
such a container.
To further the safety of pits at the Pantex Plant, the Board
recommends that:
1. The remaining questions of materials compatibility affecting the
possibility of chemical attack on closure of sealed inserts for AL-R8
containers be settled expeditiously;
2. Action be taken to accelerate the repackaging of pits into
containers suited to safe storage for the near term;
3. A system of statistical sampling for continued integrity of
containers and their sealed inserts for repackaged pits be put into
effect suited to forecasting the horizon for need for further
repackaging; and
4. The importance of the above measures be emphasized by defining
them as the specific responsibility of a designated individual of the
stature, position, and technical knowledge necessary for their
accomplishment, and
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who is given the authority and resources required.
John T. Conway,
Chairman.
APPENDIX--Transmittal Letter to the Secretary of Energy
DEFENSE NUCLEAR FACILITIES SAFETY BOARD
625 Indiana Avenue, NW, Suite 700, Washington, D.C. 20004-2901,
(202) 694-7000
August 11, 1999.
The Honorable Bill Richardson,
Secretary of Energy 1000 Independence Avenue, SW, Washington, DC
20585-1000.
Dear Secretary Richardson: On August 11, 1999, the Defense
Nuclear Facilities Safety Board (Board), in accordance with 42
U.S.C. 2286a(5), unanimously approved Recommendation 99-1, which is
enclosed for your consideration. Recommendation 99-1 deals with the
safe storage of fissionable material called ``pits.''
41 U.S.C. 2286d(a) requires that after your receipt of this
recommendation, the Board promptly make it available to the public
in DOE's regional public reading rooms. The Board believes the
recommendation contains no information that is classified or
otherwise restricted. To the extent this recommendation does not
include information restricted by DOE under the Atomic Energy Act of
1954, 42 U.S.C. 2161-68, as amended, please arrange to have it
promptly placed on file in your regional public reading rooms.
The Board will also publish this recommendation in the Federal
Register.
Sincerely,
John T. Conway,
Chairman.
Enclosure
c: Mr. Mark B. Whitaker, Jr.
[FR Doc. 99-22278 Filed 8-26-99; 8:45 am]
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