Alissa Tabirian
NS&D Monitor
8/28/2015
The National Nuclear Security Administration (NNSA) has called on its Los Alamos Field Office to create a working group that will solicit proposals for a “state-of-the-art seismic performance analysis” of the Los Alamos National Laboratory’s (LANL) Plutonium Facility (PF-4) as a step toward further strengthening the facility against earthquakes, according to an Aug. 18 letter to the Defense Nuclear Facilities Safety Board (DNFSB). The NNSA’s July 22 memorandum to the field office requests an updated plan “to address the remaining PF-4 seismic issues, considering the costs and benefits of additional design upgrades as well as addressing the schedule for a future safety basis update.” The plutonium processing facility is considered vulnerable to degradation or collapse in the event of large earthquakes, which would create a hazard for the public in the area through the possible release of radioactive material.
The memo emphasizes the need for “a working group to develop a request for proposal (RFP) for [NNSA’s Office of Safety, Infrastructure, and Operations] to solicit cost, scope, and schedule to conduct a dynamic, non-linear analysis of selected aspects of PF-4” as part of “a longer-term strategy to provide assurance of the acceptability of the final seismic system performance.” This analysis would follow “four seismic performance analyses accomplished during the last five years,” the memo says, and the results of the RFP solicitation would inform “a specific path forward for additional modelling of PF-4.”
A LANL seismic safety report issued last October said the facility was “designed to early 1970’s requirements and a less demanding earthquake” and notes that “there is little additional margin between an earthquake that initiates failures and a slightly larger one that induces collapse.” The report says a 2011 analysis “led to modifications” involving the roof structure and ceiling supports. Another analysis released in 2012 “indicated additional structural modifications were needed,” and a subsequent analysis raised concerns about “unreinforced capitals at top of basement columns,” the report says. It notes that a seismic expert panel was expected to “advise on path-forward” by February 2015. However, last December, the DNFSB informed Secretary of Energy Ernest Moniz that “NNSA’s current analysis does not adequately predict the likelihood of the seismic collapse scenario” and requested a “completed analysis” to identify the need for “structural modifications” at the facility.
The latest memo requests a revised plan that will include cost of benefit analyses of “column capital testing” options and roof girder upgrades, “given that an upgrade design exists and trained installation crews are currently available.”
