DEFENSE NUCLEAR FACILITIES SAFETY BOARD

April 15, 2011 

MEMORANDUM FOR: T. J. Dwyer, Technical Director

FROM: B.P. Broderick and R.T. Davis 

SUBJECT: Los Alamos Report for Week Ending April 15, 2011 

Plutonium Facility – Seismic Safety: This week, LANL declared a Potential Inadequacy of the Safety 

Analysis (PISA) based on preliminary seismic evaluation results that indicate an increased likelihood of 

structural failure in some locations during postulated seismic events. In 2007, the Probabilistic Seismic 

Hazard Analysis for Los Alamos was updated and indicated increased seismic hazard for LANL 

facilities. A Justification for Continued Operations (JCO) for nuclear facilities was approved by the site 

office while the Seismic Analysis of Facilities and Evaluation of Risk (SAFER) project was initiated to 

evaluate the impact of the increased hazard. The SAFER evaluation of all LANL nuclear facilities 

except the Plutonium Facility was completed last year. The Plutonium Facility analysis has been 

ongoing and is now expected to be complete in May including independent peer review and resolution 

of comments. 

Currently, SAFER preliminary results have identified nine Plutonium Facility issues where the 

anticipated seismic demand may exceed the structural capacity during the design basis seismic event. 

The potential failures may invalidate safety basis assumptions related to the facility’s leak path factor in 

the 2008 Documented Safety Analysis (DSA), which is scheduled to be fully implemented within two 

months, and may impact assumptions in the yet to be approved 2010 DSA. As a part of the PISA 

declaration, LANL has identified a compensatory measure to develop and implement an emergency 

operating procedure to isolate the facility’s exhaust stacks during certain seismic accident conditions to 

eliminate a potential unfiltered material release path that could result from two of the newly identified 

failure modes. The PISA is expected to result in an unreviewed safety question and safety basis 

personnel are developing an evaluation of the safety of the situation. Plutonium Facility management 

noted that facility upgrades to resolve these issues are being evaluated. 

Weapons Engineering Tritium Facility (WETF): This week, the NNSA site office issued a letter to 

LANL senior management addressing WETF. In its letter, the site office notes numerous issues that 

have stemmed from WETF’s existing nine year old safety basis, identified deficiencies in key safety 

management programs, and the existence of a significant population of legacy tritium containment 

vessels that need to be dispositioned to address safety concerns. The site office asserts that despite 

WETF safely restarting and conducting limited operations to meet national security requirements last 

year, the laboratory infrastructure and support for WETF has not been commensurate with what is 

required to sustain safe nuclear operations over the long term. Given this, NNSA requests for LANL to 

provide the following within 30 days: • an accounting of anticipated mission and readiness activities; • a 

perspective on hazards for current operations and continued storage of legacy items until they can be 

dispositioned; and • a risk-prioritized path-forward to address known gaps in safety management 

programs and the means that LANL will use to ensure any new gaps are identified and addressed in a 

timely manner. 

As part of WETF’s planned risk reduction activities, WETF personnel are also poised to begin a 

campaign to overpack a large number of legacy tritium containment vessels that may present overpressurization hazards and lack the pedigree currently required for containing tritium. These legacy 

items will either be overpacked in credited tritium containment vessels or introduced into gloveboxes.