Regulatory and technological insights from the US industry severe accident program and NRC interactions on severe accident issues

The technical foundation and process developed by the US nuclear industry to identify and resolve severe accident issues has the potential to greatly influence the certification of advanced light water reactors (ALWRs). Many of the insights gained from the Industry Degraded Core Rulemaking (IDCOR) Program are relevant and are an important part of the experience base that is being utilized in the design of advanced light water through the DOE sponsored Advanced Reactor Severe Accident Program (ARSAP). Key elements of the IDCOR Program are being extended by ARSAP. In particular, the improvements to the accident analysis code, MAAP, are being directed toward the few remaining issues that were not completely resolved by the US Nuclear Regulatory Commission (NRC) and IDCOR. In addition, insights from the development of system analysis methods and individual plant examinations are identifying plant vulnerabilities in existing plant designs. These improvements are reflected in severe accident requirements which ARSAP has provided to the Electric Power Research Institute (EPRI) ALWR Requirements Document. As a result, improvements in plant designs and operating procedures are being made in advanced light water reactor designs. 22 refs., 1 fig.