Software quality assurance in the 1996 performance assessment for the Waste Isolation Pilot Plant

The US Department of Energy (DOE) Waste Isolation Pilot Plant (WIPP), located in southeast New Mexico, is a deep geologic repository for the permanent disposal of transuranic waste generated by DOE defense-related activities. Sandia National Laboratories (SNL), in its role as scientific advisor to the DOE, is responsible for evaluating the long-term performance of the WIPP. This risk-based Performance Assessment (PA) is accomplished in part through the use of numerous scientific modeling codes, which rely for some of their inputs on data gathered during characterization of the site. The PA is subject to formal requirements set forth in federal regulations. In particular, the components of the calculation fall under the configuration management and software quality assurance aegis of the American Society of Mechanical Engineers (ASME) Nuclear Quality Assurance (NQA) requirements. This paper describes SNLʹs implementation of the NQA requirements regarding software quality assurance (SQA). The description of the implementation of SQA for a PA calculation addresses not only the interpretation of the NQA requirements, it also discusses roles, deliverables, and the resources necessary for effective implementation. Finally, examples are given which illustrate the effectiveness of SNLʹs SQA program, followed by a detailed discussion of lessons learned.