Brian Bradley
WC Monitor
10/23/2015
A recent Defense Nuclear Facilities Safety Board staff report indicated several areas for improvement within the Savannah River Site’s L Area Complex safety basis, although the Energy Department’s Savannah River Operations Office did not break any DOE requirements. DNFSB Chairwoman Joyce Connery referenced those findings in an Oct. 20 letter to Assistant Energy Secretary for Environmental Management Monica Regalbuto, and enclosed the board’s report with the letter. One issue the DNFSB cited was that the L-Area safety basis credited certain programs for risk reductions, but did not identify “specific administrative controls.” Specific administrative controls, or SACs, are administrative controls selected to prevent or mitigate specific potential accident scenarios, and which also have safety importance equivalent to engineered controls that would be classified as “safety significant”—which the Nuclear Regulatory Commission defines as a term that identifies an object as having an impact on safety, whether determined through risk analysis or other means, that exceeds a predetermined significance criterion—or as “safety class,” which refers to a three-leveled scale officials use to classify structures, systems, and components according to the severity of consequences of their potential failures. According to the board, SRS’ safety basis also included “inappropriate initial conditions and assumptions used in the unmitigated safety analysis, legacy assumptions in the DSA [L-Area Documented Safety Analysis], and deficient implementation of compensatory measures specified in a waiver associated with a safety system.” DOE does not require its SRS Operations Office to periodically complete a full review of the safety basis, according to the report.
The L Area stores nuclear materials, principally spent nuclear fuel in the water basin and neutron moderator in tanks and drums. More specifically, the facility’s current mission is to provide for the safe receipt, storage, handling, and shipping of spent nuclear fuel, other special nuclear materials, and neutron moderator. The DSA was established in 2002, and is derived from the former L Area Basis for Interim Operation (BIO). The DSA and primary safety controls have had “minimal revision” since the BIO-to-DSA conversion, but SRS contractor Savannah River Nuclear Solutions has annually updated SRS’ safety basis “as required to support new missions,” mainly receipt of new fuel types, according to the DNFSB report. “DOE-SR Safety Evaluation Reports over this time only reviewed DSA changes,” the report states. “DOE-SR has not recently reviewed the full scope of the L-Area safety basis. There are no DOE requirements for DOE-SR to periodically complete a full review of the safety basis.”
Union of Concerned Scientists Global Security Program senior scientist Edwin Lyman said while DOE should do a better job of characterizing its fuel, stabilization options are limited, in part, because the spent fuel is zircaloy-cladded. “Given that the material could not be reprocessed in H Canyon without modifications anyway … and there is only a relatively small amount of material, I think pursuing options for stabilizing it for dry storage makes more sense and would be less risky,” Lyman said.
During the DNSB’s review and in post-review discussions with DOE, department staff members agreed that addressing the board’s suggested areas for improvement would strengthen the safety basis, Connery’s letter states. “The Department of Energy is committed to continuing safe operations of the L-Area,” a DOE spokesperson said in an email. “DOE values the safety and technical insights of the Board and Board staff, and is reviewing the Board letter and Staff Issue Report, and will take appropriate action based on that review.”
