On November 16, 1994, personnel at Savannah River Separations Equipment Development (SED) facility reported that initial results of trap assays indicated significantly less plutonium than expected. Facility managers investigated the event and initiated actions to assure safe conduct of operations. The SED is an equipment development facility that has not operated since the 1970s, is known to have a significant quantity of plutonium within the process equipment, and has been identified as one of the first facilities for Decontamination and Decommissioning (D&D). There was no impact on the health and safety of personnel and no damage to equipment as a result of this event. (ORPS Report SR--WSRC-LTA-1994-0128)
SED was shut down in 1979 and its process control equipment, including valves, gages and process monitors, were removed. The inventory of plutonium expected to be in the facility is based on a review of data contained in researchers' notes and mass balances from the time when the facility was in operation. The Savannah River Technical Center (SRTC) was selected to characterize the material in the facility in preparation for D&D. In early October 1994, SRTC personnel, using a state-of-the-art assay methodology developed for this project, began to characterize material contained in the process equipment. Initial results of the assays of the traps indicated significantly less plutonium than anticipated. Traps are components in the process system known to contain plutonium. Due to lack of precise inventory data from the time the facility was in operation, there are significant levels of uncertainty concerning the exact location and quantities of material in the process and these uncertainties have been taken into account for all safety analyses and work planning.
Facility managers investigated the event and have taken the following actions to resolve the inventory uncertainties and to assure safe conduct of operations: They initiated a thorough search of all accountability records to verify the quantities of material that were brought in and removed from SED. They initiated a criticality investigation and analysis to ensure that the current safety analysis is bounding for the now known conditions. They also engaged the criticality technology group to review and approve ongoing activities and to develop procedures for the assay of additional components.
They are investigating oral reports from personnel involved with the facility in the 1970s that some of the components from this process were buried at that time, to evaluate environmental and criticality implications for the burial ground.
They have established a joint DOE/ Westinghouse Savannah River Company team to manage the review activities.
This event is significant in that it illustrates the information uncertainties that can occur when D&D activities are undertaken at a DOE facility that has been shut down for a long period of time. The rules, analytical methods, facility inventory records, and operations were less formalized than they are at DOE facilities today. This can result in significant uncertainties that require resolution, including performance of bounding analyses related to environmental effects and potential criticality, and incorporation of formalized multi-disciplinary technical and management reviews in the work plans to assure safe, environmentally acceptable, and orderly conduct of D&D projects.
Facility personnel can obtain additional information about this event by calling Joe Cohen, DOE Facility Representative at (803) 725-7722 or Terry Spears, DOE Deputy Director of Quality Programs Division, at (803) 725-2534.