Developing human performance measures

Through the reactor oversight process (ROP), the U.S. Nuclear Regulatory Commission (NRC) monitors the performance of utilities licensed to operate nuclear power plants. The process is designed to assure public health and safety by providing reasonable assurance that licensees are meeting the cornerstones of safety and designated crosscutting elements. The reactor inspection program, together with performance indicators (PIs), and enforcement activities form the basis for the NRC's risk-informed, performance based regulatory framework. While human performance is a key component in the safe operation of nuclear power plants and is a designated cross-cutting element of the ROP, there is currently no direct inspection or performance indicator for assessing human performance. Rather, when human performance is identified as a substantive cross cutting element in any 1 of 3 categories (resources, organizational or personnel), it is then evaluated for common themes to determine if follow-up actions are warranted. However, variability in human performance occurs from day to day, across activities that vary in complexity, and workgroups, contributing to the uncertainty in the outcomes of performance. While some variability in human performance may be random, much of the variability may be attributed to factors that are not currently assessed. There is a need to identify and assess aspects of human performance that relate to plant safety and to develop measures that can be used to successfully assure licensee performance and indicate when additional investigation may be required. This paper presents research that establishes a technical basis for developing human performance measures. In particular, we discuss: 1) how historical data already gives some indication of connection between human performance and overall plant performance, 2) how industry led efforts to measure and model human performance and organizational factors could serve as a data source and basis for a framework, 3) how our use of modeling and simulation techniques could be used to develop and validate measures of human performance, and 4) what the possible outcomes are from this research as the modeling and simulation efforts generate results.