DNFSB pushes seismic safety issue

-A A +A

LANL > Recent analysis shows facility vulnerable to structural collapse

By John Severance

The Defense Nuclear Facilities Safety Board continues to have the Plutonium Facility at Los Alamos National Lab in its crosshairs.

In a Jan. 3 letter addressed to Energy Secretary Steven Chu, board chair Peter Winokur wrote, “The board remains deeply concerned with the seismic safety posture of PF-4 at Los Alamos.”

Winokur cited a recent analysis performed by a LANL contractor which demonstrated that PF-4 was vulnerable to structural collapse.

“The large plutonium inventory of PF-4, coupled, with the facility’s proximity to the public, creates the potential for very high offsite dose consequences if the building were to collapse. Structural upgrades necessary to fix the PF-4 vulnerabilities are currently projected to take several years to complete. In the interim, the potential for very high dose consequences remains.”

NNSA spokesman Josh McConaha said in a statement, “NNSA acknowledges receipt of the DNFSB letter submitted to the Secretary of Energy on Jan. 3, 2013, regarding the seismic safety posture of the Plutonium Facility (PF-4) at Los Alamos National Laboratory, and is working with LANL to respond to the actions requested by the Chairman. 

“NNSA has been steadily improving the safety of PF-4 and has been in close communication with the DNFSB to address their concerns. The NNSA considers the safety of the public our highest priority. 

“Based on the results of ongoing analysis, we will take any additional actions that are necessary to ensure public safety at PF-4, and continue ongoing physical improvements to reduce the probability of a seismic collapse and increase the overall safety posture of the facility.

“The risk to the public from a major seismic event at PF-4 is very small even before planned improvements; the facility is operating well within the safety objectives established by DOE safety policy, and public safety is adequately protected.”

In 2009, the DNFSB issued a recommendation to focus DOE and NNSA management attention on the need to improve the safety posture of PF-4. And in Winokur’s letter, the board acknowledges that seismic remediation has taken place at PF-4.

Those existing measures would be largely defeated by a collapse of the PF-4 structure, Winokur wrote.

The Deputy Energy secretary, in a letter dated July 19, 2012, established guidance for evaluating these types of situations where new information indicates the existing control strategy of a facility is no longer viable to keep postulated offsite consequences from exceeding the DOE Evaluation Guideline of 25 rem Total Effective Dose Equivalent.

NNSA’s contractor has submitted, and DOE headquarters personnel are reviewing an addendum to the PF-4 Documented Safety Analysis that provides the information required by the deputy secretary.

Winokur said the board “strongly urges DOE to implement additional near-term measures to reduce the potential consequences of a seismically-induced collapse.”

Winokur suggested the DOE look at the possibility of accelerating the disposition of plutonium already designated as waste or surplus material, robust containerization of dispersible plutonium forms and strengthen emergency planning and preparedness protocols and measures.

The DNFSB requested a report be done by DOE in the next two months that provides the senior leadership assessment of the current state of public and worker protection for PF-4 seismic accident scenarios and the risk reduction measures to be applied to mitigate near-term seismic risks.

On Dec. 24, Winokur submitted a report to Congress on the status of significant unresolved issues with the DOE’s Design and Construction Projects.

And on top of that list was the status of PF-4.