BY MAIRE O’NEILL
Defense Nuclear Facilities Safety Board (DNFSB) Chair Joyce Connery has notified Secretary of Energy Jennifer Granholm that a probabilistic risk analysis of the Los Alamos National Laboratory Plutonium Facility (PF-4) has concluded that it can withstand seismic events.
Seismic safety of PF-4 has been discussed by the DNFSB and the Department of Energy since 2009 when LANL staff first identified elevated seismic hazards at the facility. The risk analysis by a LANL team concluded that the seismic safety risk of PF-4 is acceptable until LANL updates the site-specific probabilistic hazard analysis in 2025, Connery said in her August 15 letter to Granholm.
“The Board finds that the conclusions of the LANL project team were technically defensible and that the accompanying peer review process was robust. However, DOE would benefit from improving documentation of the effort. Currently, there is no single integrated report that comprehensively documents the probabilistic risk analysis effort and overall conclusions. Improving the formality of documentation would enhance transparency and facilitate better understanding and dissemination of the analysis,” Connery said.
She said the Board considers LANL’s approach in assessing the seismic risk for PF-4 as a best practice that DOE should consider applying at other defense nuclear facilities.
“LANL personnel followed a risk-informed approach like the one that the Nuclear Regulatory Commission adopted for the commercial nuclear industry. The risk analysis provided information on the likelihood of PF-4 failing to perform its credited safety function, considering all potential earthquake scenarios at the LANL site,” she said. “This was a commendable effort, representing a comprehensive application of such an approach for a defense nuclear facility.”
LANL Director Thom Mason on Monday congratulated the LANL PF-4 Seismic Risk Analysis Team for the commendation they received from Connery for their exemplary work in verifying the structure’s ability to tolerate seismic activity.
“PF-4 is America’s center of excellence for actinide research and technology, including world-class manufacturing capabilities for solving significant national security challenges,” Mason told Lab staff. “As such, it’s no surprise that keeping it safe and secure is one of our Laboratory’s most important jobs, which is why it was upgraded previously to withstand any credible seismic event.”
He added that as a result of the DNFSB’s findings, LANL’s confidence in PF-4’s ability to withstand earthquakes has been reinforced and also strengthened.
“The DNFSB is chartered with the responsibility of providing recommendations and advice to the President and the Secretary of Energy regarding public health and safety issues at Department of Energy defense nuclear facilities. Their positive assessment is an important win for our mission and institution,” Mason said.
He said it goes without saying that he is excited about the news, given the many years of effort that have been expended.
“I am incredibly proud of the team that worked incredibly hard to being these important results to bear,” Mason said. “In a time when national needs for our Laboratory’s unique capabilities are at an all-time high, this added assurance that our most crucial facility is up to the task of providing cutting-edge solution to our biggest national security problems could not have come at a better time for our workforce and our nation.”