High Integrity Digital Systems And Nuclear Safety

This paper discusses the status of NRC in setting acceptance criteria for high integrity digital systems and the research to support the development of these criteria. Design and evaluation of high integrity digital systems must include consideration of hardware, software, and human factors as they relate to safety. Two of the NRC sponsored research projects are discussed. The first project is "Risk Impact of New Technologies", which has two objectives which are: (1) to demonstrate the feasibility of techniques for assessing how digital technology in instrumentation and control is expected to change human actions and error rates, system unavailability, and core damage frequency; and ( 2 ) to improve methods for analyzing this human performance in PRA's. The second project is "Integration of Research to Develop the Technical Basis for Software Regulatory Positions" which is to provide the technical basis for developing software acceptance criteria and identify areas where further research is required.