Safety procedures that would prevent radiological injuries and fatalities must be implemented at the Savannah River Site’s tritium facilities, the Defense Nuclear Facilities Safety Board (DNFSB) said in a recent letter addressing unfinished revisions to SRS safety documents.
The safety watchdog laid out its concerns in a June 4 letter to Energy Secretary Rick Perry, signed by acting DNFSB Chairman Bruce Hamilton. It came as Savannah River Nuclear Solutions (SRNS), DOE’s management and operations contractor at the South Carolina site, makes revisions to the safety basis documents for tritium operations.
The Energy Department has held off on discussing the matter with the DNFSB until the safety basis documents are completed, according to the letter. That is not expected until later this year. “The board is concerned that its timely communication on critical safety matters must occur,” Hamilton wrote. “Therefore, we are communicating concerns regarding the revised tritium facilities safety basis and analyses identified thus far.”
The safety documents establish boundaries and hazard controls to ensure DOE facilities operate in a safe manner. They take a “worst-case scenario” approach, to cover any and all situations that could occur while work is being conducted. A DOE spokesperson said via email there are no major changes or issues at the SRS tritium facilities, but that federal law requires the safety documents to be updated annually.
Tritium gas, which the Savannah River Site produces for the Department of Defense, triggers the chain reaction in nuclear weapons. The site’s Tritium Extraction Facility (TEF) removes the material from tritium-producing burnable absorber rods that have been irradiated in commercial light-water reactors operated by the Tennessee Valley Authority (TVA). Beyond TEF, the tritium facilities include a processing building where the gas undergoes purification and a building that houses maintenance and support staff.
In March, DOE’s Savannah River Field Office found that an early version of the safety document – which had been revised but not yet approved – described “multiple credible events” that could cause contamination to two groups of workers: co-located workers, who are within 100 meters of a hazardous occurrence; and facility workers who are further away. The office called on the contractor to address those potential consequences.
The DNFSB letter does not give specific examples of such events, but says, in these instances, safety measures are needed “to prevent radiation-induced acute injury or fatality.”
The board noted other concerns with the draft safety documents. For example, workers are instructed to handle several urgent scenarios by evacuating the tritium facilities as quickly as possible. However, there are not sufficient details regarding scenarios in which a rapidly developing event requires workers to stay in place.
The letter adds that SRNS makes several potentially questionable assumptions about potentially hazardous scenarios. For example, the contractor stated that, in the case of a seismic event, flammable vapors would not accumulate because tritium gas would spread rather than gather in the same area. But the safety board said it has not seen the technical analysis supporting such a claim.
In another example, SRNS said there are multiple explosion incidents that could impact co-located workers. But because many of these potential events are highly unlikely to occur, SRNS appeared not to pay sufficient attention to them, according to the letter. “The Board is concerned that further evaluation of these events was omitted based on a low frequency of occurrence even though some are operational, and should be addressed as such,” the letter states.
A spokesperson for DOE’s semiautonomous National Nuclear Security Administration (NNSA), which oversees the Savannah River Site, said the agency is working with Savannah River and SRNS on updating the documents.
