Exploiting digital systems technology to improve nuclear safety

Nuclear plant designers in the 1990's have exceptional opportunities to exploit rapidly evolving computer and information system technology to make significant improvements in public safety. CANDU reactors have utilized extensive computer automation for reactor control for 20 years. A direct consequence is that the frequencies for forced outages and spurious protection system trips have been among the lowest for all reactor types. Historically, CANDU was among the first commercial power reactor to utilize computers to implement protection system. System functions with the PDC's (Programmable Digital Comparators) used in the CANDU 600 reactors. PDC's were used to implement the trip decision logic for the process trip parameters. The paper provides detail on safety benefits that have been realized from the use of digital automation for control and protection. The paper describes how accident risk reduction can be achieved in other ways with digital systems