In OE Weekly Summary 94-50, NFS reported on an event at the Hanford Plutonium Finishing Plant (PFP) where two workers inhaled airborne plutonium when two bags surrounding a contaminated plastic bottle tore as the package was removed from a seismic overpack. On February 13, 1995, the facility manager issued the final report on the event. Following is a summary of the findings and lessons learned from the report. (ORPS Final Reports RL--WHC-PFP-1994-0056 and RL--WHC-PFP-1994-0057)
On December 12, 1994, operators removed and double-bagged four one-half-liter plastic bottles, called "polyjars", from a glovebox in a room in the PFP. The operators moved the polyjars to a second room to be used as feed for plutonium sludge stabilization operations, but found the glovebox in that room filled with other items. They stored the polyjars in seismic overpacks, which are seismically-qualified storage containers, until they could be moved into the glovebox the next day. They locked the room to prevent routine access until the next day-shift. Two of the overpacks were too small and the operators were unable to fully close them.
On December 13, an operator removing one of the polyjars stored in a small overpack noticed a hole in the bag surrounding the polyjar. Three minutes later a continuous air monitor alarmed. Five workers left the area and submitted nasal smears to radiological control technicians. The two operators who handled the polyjar had positive nasal smears in the range of 59 to 124 disintegrations per minute (dpm) alpha and contamination on their protective clothing from 500 to 2,000 dpm. The other three workers had no detectable contamination. Several rooms had smearable alpha contamination in the range of 1,000 to 25,000 dpm/100cm2. The workers were placed on urinalysis and fecal sampling to provide definitive dose estimates.
On December 29, 1994, preliminary assessments for four of the workers indicated that their 50-year Committed Effective Dose Equivalent will be less than 100 millirem, well below the DOE limit of 5 rem. Analysis is still underway for the operator whose nasal smears indicated higher levels of contamination. However, his dose is not expected to be appreciably higher.
Facility managers appointed a team to investigate the causes of the event and to recommend corrective actions. The team determined that the direct cause was the inappropriate use of force by personnel resulting in tearing the bags surrounding the polyjar. Contributing causes included inattention to detail in handling the polyjars; violations of operating procedures and administrative requirements; less than adequate communications in operational turnover, pre-job briefings, and proper use of overpacks; less than adequate training of operations personnel in sludge stabilization activities and procedures; and an inadequate seal-out procedure. The root cause was inadequate management expectations and enforcement of policies associated with work organization, planning, and supervision of operational activities.
Facility managers implemented extensive corrective actions in the areas of personnel training and qualifications, and management involvement in day-to-day activities including pre- job briefings and ongoing work. Various procedures have been revised including those that now require use of respirators when handling plutonium bearing packages outside of gloveboxes. Labels on equipment now indicate applicable procedures. Facility managers developed lessons learned in the areas of criticality prevention, communications, handling of fissile materials, training, procedures, and senior management's routine presence in the plant. Senior plant managers met with plant personnel to discuss their expectations concerning conduct of operations, resumption of thermal stabilization activities, and future performance. They have also added the occurrence report to the required reading program for operations personnel.
NFS personnel reviewed the ORPS database for similar internal contamination events and determined that in 39 percent of the events the root cause was a management problem and 7 percent of the events were caused by policies not being adequately defined, disseminated, or enforced.
This event is significant because it resulted in the exposure of five workers to plutonium contamination, the spread of contamination in several rooms, and suspension of plutonium sludge stabilization activities for 21 days. It illustrates the importance of aggressive management action when responding to significant events. In this event, managers suspended operations, conducted a thorough investigation, and implemented extensive corrective actions to prevent recurrence.
Particularly noteworthy in this event are the corrective actions in the area of increased management involvement in the daily activities in the plant to provide routine oversight, directly assess conduct of operations, and provide mentoring in the areas requiring improvements. DOE facility personnel with responsibilities for compliance with conduct of operations principles should review their work processes to ensure that they provide for an adequate level of management involvement in pre-job briefings, ongoing work, and routine oversight of daily activities.