While the cause of the radiological release at the Waste Isolation Pilot Plant (WIPP) in New Mexico is still being investigated, a preliminary report by the US Department of Energy (DoE) has already identified corrective actions that should be taken.
|The entrance to the WIPP facility (Image: DoE)
The WIPP plant disposes of US military origin transuranic waste in an underground salt formation. The facility is owned by the DoE and operated by Nuclear Waste Partnership LLC (NWP).
A monitor detected airborne radiation within the plant on 14 February. The release was directed through high-efficiency particulate air (HEPA) filter banks located in the surface exhaust building. However, "a measureable portion" bypassed the HEPA filters through two ventilation system dampers and discharged directly into the environment from an exhaust duct. Tests later showed that 21 workers at the surface received low level amounts of internal contamination.
An initial investigation by the DoE's Office of Environmental Management into the radiological release has now concluded that "a thorough and conservatively considered hazard analysis, coupled with a robust, tested and well maintained HEPA filter capable exhaust ventilation system could have prevented the unfiltered above-ground release."
The report noted that the direct cause for the failure of a waste container, leading to the radiological release, remains unknown. However, the root cause of the release was NWP's and DoE Carlsbad field office's "management failure to fully understand, characterize and control the radiological hazard." It added, "The cumulative effect of inadequacies in ventilation system design and operability compounded by degradation of key safety management programs and safety culture" led to the release and the "delayed/ineffective recognition and response" to it.
The HEPA filter bypass isolation dampers, the board concluded, are "not suitable as a containment boundary" and reduce the overall efficiency of the HEPA filter system.
Matt Moury of the DoE's Office of Environmental Management said, "The accident investigation board reviewed procedures related to safety, maintenance, and emergency management to better understand the aboveground events surrounding the radiological incident. The department believes this detailed report will lead WIPP recovery efforts as we work toward resuming disposal operations at the facility."
Locating the source
The waste at WIPP is placed in panels within the underground facility, each divided into seven rooms. Workers have now re-entered room 7 of panel 7, the suspected release location. The first waste had only recently been placed within this area. To avoid heat concerns due to the protective clothing they were wearing, the workers only spent a limited time in the room. However, they did not see any visible damage among the first few rows of waste containers there.
Commenting on the findings of the initial report, DoE Carlsbad field office manager Joe Franco said, "This report will serve as a guidance for the recovery team moving forward. We understand the importance of these findings, and the community's sense of urgency for WIPP to become operational in the future. We are fully committed to pursuing this objective."
A second report will be published once the source is pinpointed. This will focuseon the direct cause of the release and worker protection measures underground.
Researched and written
by World Nuclear News