NNSA Says ‘Considerable Time’ Needed to Resolve TRU Facility Analyses
WC Monitor
4/10/2015
The National Nuclear Security Administration expects to take “considerable time” resolving issues with the documented safety analyses at Los Alamos National Laboratory’s facility for loading transuranic waste before allowing operations to restart, the agency said in a recent letter to the Defense Nuclear Facilities Safety Board. In early December, the DNFSB noted “significant flaws” in the hazard and accident analysis at LANL’s Radioassay and Nondestructive Testing (RANT) Shipping Facility, which is used to load the waste for shipment. On Dec. 17, M&O contractor Los Alamos National Security declared a potential inadequacy of the safety analysis, and on Dec. 18 NNSA’s Los Alamos manager rescinded approval of the RANT DSA, according to a March 25 letter from the NNSA to the Board. The NNSA previously reviewed the safety basis and came out with two conditions of approval and two directed actions in July 2014 before the DNFSB uncovered the additional issues.
Currently transuranic waste operations at Los Alamos are on hold after a batch of nitrate salt-bearing waste at the lab fell under scrutiny when it was linked to last year’s radiological release at the Waste Isolation Pilot Plant. “At the time the PISA was declared, the RANT facility was in Cold Standby Mode, which means there is no material-at-risk allowed at the facility,” the NNSA letter states. “The RANT facility will remain in Cold Standby Mode until a strategy for mitigating the seismic risk has been proposed and approved with compensatory measures as appropriate. Further, there may be other design bases accidents that are contained within the DSA that may have to be re-evaluated based on issues raised by the DNFSB letter.” It adds: “Resolving the individual RANT DSA issues identified in your letter may take a considerable amount of time.” The NNSA has committed to quarterly briefings starting May 1.
DNFSB Staff Report Notes ‘Significant Flaws’
The Board’s staff report, completed last September, notes “significant flaws in the hazard and accident analyses, resulting in inadequate identification and implementation of safety controls required by 10 CFR 830 and DOE Standard 3009.” The issues were not flagged during the Los Alamos Field Office’s July review, the report found. It also states: “The review revealed inadequate identification and implementation of safety controls to protect the public and worker.”
For example, the DNFSB staff reviewed “a hazard scenario with high offsite consequence that was mistakenly captured as moderate consequence and a scenario that was inappropriately identified as being bounded by a design basis accident included in the accident analysis,” the report states. That includes scenarios involving a crane failure and a seismic accident. Additionally, the documented safety analysis “includes non-conservative assumptions for multiple high consequence accident scenarios in both unmitigated and mitigated analyses,” according to the report.
