Human factors issues associated with advanced instrumentation and controls technologies in nuclear plants

A survey of advanced instrumentation and controls (I ampersand C) technologies and associated human factors issues in the US and Canadian nuclear industries was carried out by a team from Oak Ridge national laboratory to provide background for the development of regulatory policy, criteria, and guides for review of advanced I ampersand C systems as well as human engineering guidelines for evaluating these systems. The survey found those components of the US nuclear industry surveyed to be quite interested in advanced I ampersand C, but very cautious in implementing such systems in nuclear facilities and power plants. The trend in the facilities surveyed is to experiment cautiously when there is an intuitive advantage or short-term payoff. In the control room, the usual practice is direct substitution of digital and microprocessor-based instruments or systems that are functionally identical to the analog instruments or systems being replaced. The most advanced I ampersand C systems were found in the Canadian CANDU plants, where the newest plant has digital system in almost 100% of its control systems and in over 70% of its plant protection system. The hypothesis that properly ''introducing digital systems increases safety'' is supported by the Canadian experience. The performance of these digital systems was achieved using an appropriate quality assurance program for the software development. The ability of digital systems to detect impending failures and initiate a fail-safe action, is a significant safety issue that should be of special interest to every US utility as well as to the US Nuclear Regulatory Commission. 12 refs. 5 tabs