DEFENSE NUCLEAR FACILITIES SAFETY BOARD

August 9, 1994
 
MEMORANDUM FOR:         G. W. Cunningham

COPIES:                 Board Members

FROM:                   William Von Holle

SUBJECT:                Trip Report for Visit to Lawrence Livermore National
                        Laboratory

1.  Purpose:  This report contains the highlights of the visit of staff member
    William Von Holle on July 13-14, 1994, to attend a review at Lawrence
    Livermore National Laboratory (LLNL) of Defense Nuclear Agency (DNA)
    Propellant Sensitivity Program, discuss the Plutonium Immobilization Program
    and plutonium residue treatment research, and obtain an update on a recent
    plutonium storage can bulging incident.  Staff members, Andrew De La Paz and
    Charles Martin, and outside expert Joseph Leary, visited LLNL separately on
    July 18-21, 1994, to perform a general safety analysis and review the
    storage of nuclear materials. 

2.  Summary: 

    a.   LLNL is developing promising techniques for plutonium residue treatment,
         but Department of Energy (DOE) has stopped all funding for such activity
         pending outcome of the EIS for plutonium disposition.

    b.   The recent bulging can incident at LLNL is still undergoing
         investigation, but they believe they have identified the causes at this
         time.
    
    c.   LLNL has taken the lead role in the Plutonium Immobilization Project
         (ultimate disposition).  Vitrification is the leading candidate, thus
         far, with the final recommendation to be made following completion of
         the project in 1995.

3.  Background:

    LLNL has a relatively small plutonium inventory and a small research and
    development program for processing plutonium.  The Livermore plutonium
    facility had not been formally reviewed by the DNFSB staff when other larger
    facilities were reviewed in preparation for the Plutonium Storage report,
    DNFSB/TECH-1.

    The recent bulging plutonium storage can and the Board's interest in
    National laboratory leadership in plutonium technology, including the need
    for background information for the R&D requirement for Board Recommendation
    94-1, sparked renewed interest in the LLNL storage practices and research
    program.

3.  Discussion:

    a.   Processing Plutonium for Stable Interim Storage:

         Several workers in plutonium chemistry briefed the staff member on their
         activities in treatment options for unstable plutonium residues. The
         staff member contacted Dr. Mark Bronson, Ms. Karen Dodson, and Dr. John
         Wilder.

         Livermore has several promising candidates for processing unstable
         plutonium residues to stable metal or oxide.  Among those are the
         following:

         1.   Advanced Salt Scrub Reactor:  This could be made into a semi-
              continuous operation to reduce the plutonium in pyrosalts to metal
              with high efficiency.  The advantage this may have over oxygen
              sparge is the coincident removal of americium, which LLNL claims
              does not happen in oxygen sparge. 

         2.   Pressure Cycled Calcination:  This method pulses air into the
              calcination oven alternately with a vacuum to expose fresh surfaces
              for calcination.  The pulsing increases the efficiency of the
              operation and minimizes the need for worker intrusion. This
              minimizes worker exposure and area contamination.  According to LLNL
              personnel, it is quite simple and elegant and adaptable to most
              existing furnaces in the DOE complex.

         3.   Molten Salt Destruction:  This technique converts most waste
              material including rubber into clean gases by oxidation in molten
              K,NaCO3 plus O2.  It would be done in two stages for plutonium
              contaminated wastes:  Pyrolysis and calcination at 700C, followed by
              organic destruction at 950C.  Plutonium oxide is recovered from the
              salt. This could be used for treatment of all the combustibles in
              the inventory.  LLNL has a demonstration plant working on non-
              radionuclide contaminated waste materials like rubber.

         A tour of the processing experimental area in the Plutonium Facility
         included observation of much of the apparatus for the above processes. 
         However, progress has been slow and is about to stop for lack of
         funding.  All funding for experimental work has been stopped until the
         EIS for plutonium disposition is completed.

    b.   The DOE Plutonium Disposition Project:

         The LLNL program manager for SNM Disposition, Dr. Jeffrey Kass, and the
         program manager for Plutonium Immobilization, Dr. Leonard Gray, provided
         a description of LLNL's role in these activities.  This project is to
         decide on the long-term form for storage (50 yrs.+) for plutonium as it
         comes from excess weapons and from process plants as oxide or metal. 
         The Immobilization Project is roughly a two-year, $9M, effort among the
         DOE facilities and some universities and institutes.  The plan is to
         screen out most of the alternatives by September 1994, concentrating on
         the remaining two or three most promising concepts.  The final choice
         will be made by September 1995.  Vitrification is the leading candidate,
         according to the project leader.  LLNL is scheduled to do a number of
         technical and economic assessments as paper studies.  Only very limited
         funds are available for experimental or testing work.

    c.   Bulging Plutonium Oxide Cans:

         During a tour of the LLNL Plutonium facility, the staff member observed
         two bulging Pu cans written up in a recent occurrence report, Report #
         SAN--LLNL-LLNL-1994-0040.  A more recent radiographic examination of 15
         cans found two with inner bulging cans.  The cans contained impure oxide
         with 4% to 20% plutonium by weight; it consisted of a mixture of chem
         wipes, residues from the analytical laboratories and plutonium oxalate
         from solution recovery.  It was reported to have been heat treated to
         650 C, but not stabilized.  Apparently this treatment was not sufficient
         to prevent subsequent radiolytic reactions, and the contents pressurized
         its sealed container.  The bulging of the outer container would follow
         the leak or rupture of the inner can.  All similar cans are scheduled to
         be opened and repackaged with material calcined at 800 C.  It is
         interesting to note that this material was repackaged approximately one
         year ago. 

         Dr. Ralph Condit, investigator for the recent plutonium oxide bulging
         storage cans, updated the staff member on plans for the continuing
         investigation.  LLNL personnel are planning to sample the pressurizing
         gases while opening the bulged cans as well as characterize the impure
         oxide material in order to establish the source of the gas.

    d.   LLNL Safety Surveillance Program:

         Outside expert Joseph Leary joined DNFSB Staff members Andrew De La Paz
         and Charles Martin for a safety review visit the week following the
         first DNFSB Staff visit. 

         LLNL personnel perform nuclear material surveillance consistent with
         material control and accountability requirements.  This includes bi-
         monthly inspections of all outer containers and selections of a small
         sample for nuclear material type and mass verification.  However, it was
         not evident to the DNFSB Staff that weight measurement data and
         packaging details (if an item was repackaged) were being provided to the
         appropriate LLNL personnel as part of a safety surveillance program.

    e.   The DNA Propellant Sensitivity Program Meeting:

         The trip included a day-long review of DNA's Propellant Sensitivity
         Program, which has begun to systematically investigate various rocket
         propellant hazards for their ongoing weapon safety investigation . The
         DNFSB Staff member attended the review as an observer.

4.       Future Activities:

    The DNFSB Staff will continue to follow the progress of the bulging cans
    incident.  Another visit is planned soon to discuss this and the Pu
    materials storage safety and accountability.  The Staff will continue to
    monitor the interim stabilization and long-term disposition projects for
    application to Recommendation 94-1.