On June 22, 1994, personnel at Lawrence Livermore National Laboratory reported that a worker performing general housekeeping and relocating storage cans in the interim storage vault noticed that a crimp-sealed (food-pack), double-canned, plutonium bearing storage can was bulging on both ends. Using prescribed transfer procedures, facility personnel moved the can to a fume hood in the recovery laboratory and surveyed the outer surface for contamination. They detected no contamination. They performed a visual inspection of the other cans in the storage vault and found another one of the same configuration with bulging ends. (ORPS Report SAN--LLNL-LLNL-1994-0040)
Facility personnel reported that material in the can was packaged during the recent Inventory Reduction Program. The program packaging configuration specified crimp-sealed cans for storing plutonium bearing material. These cans were then placed in individual, sealed glovebox bagout bags and placed in individual crimp-sealed outer cans suitable for interim vault storage.
After transferring the first bulged container to a fume hood, a laboratory recovery operator dressed in protective clothing opened the outer can and observed that gas vented from the can when the crimped-seal was broken. The inner can, still in the bagout bag was transferred to a glovebox located in the room. Facility personnel removed the second bulging container from the vault and bagged it directly into a second glovebox in the recovery laboratory. Both containers will remain in the gloveboxes until a plan is developed to determine what caused the pressurization.
Facility personnel, along with outside support help, continued to investigate the event to determine a path forward. They are also developing procedures to place all cans in the interim storage vault that are known to contain similar materials in plastic bags to minimize the potential for spread of contamination. Weekly visual inspections for bulging cans are also planned. NS will provide a Weekly Summary update as more information on the cause for the bulging cans becomes available.
NS has reported similar occurrences involving pressurized or deformed storage containers in the Operating Experience Weekly Summary. Numerous publications are also available to DOE and contractor personnel that describe safety problems associated with plutonium storage containers. Because of the potential for additional occurrences at DOE facilities, the Office of Defense Programs issued Safety Information Letter (SIL) 93-05, Potential Worker Contamination from Failed Plutonium Storage Containers, in December 1993. SIL 93-05 included descriptions of recent occurrences at Los Alamos and the United Kingdom. A detailed discussion of the processes that lead to plutonium oxidation and subsequent failure of storage vessels plus recommended remedial actions for certain plutonium storage configurations are also included. In January 1994, Office of Defense Programs issued DOE/DP-0123T, Assessment of Plutonium Storage Safety Issues at Department of Energy Facilities. Personnel at DOE facilities where plutonium is stored should consider reviewing these documents and their recommendations for applicability to their facilities. NS is developing a Safety Notice on the storage of plutonium metals and oxides that will be issued later this year.
Dr. Raymond Cooperstein (DP-31) informed NS that the Office of Defense Programs issued draft
standard, U. S. Department of Energy Criteria for Storage of Plutonium Metals and Oxides, for
review and comment in April 1994. Dr. Cooperstein stated that, "individuals who have not
previously submitted comments on the draft should submit their comments as soon as possible for
resolution. When the comments have been resolved the document will be approved as a fully
coordinated DOE Standard and listed in the DOE Standards Index. It is anticipated that the
document will be approved during the last quarter of 1994.
Dr. Cooperstein can be contacted at (301) 903-5353.