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Conference Spotlight
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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The Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
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Deep Space: The new frontier of radiation controls
In commercial nuclear power, there has always been a deliberate tension between the regulator and the utility owner. The regulator fundamentally exists to protect the worker, and the utility, to make a profit. It is a win-win balance.
From the U.S. nuclear industry has emerged a brilliantly successful occupational nuclear safety record—largely the result of an ALARA (as low as reasonably achievable) process that has driven exposure rates down to what only a decade ago would have been considered unthinkable. In the U.S. nuclear industry, the system has accomplished an excellent, nearly seamless process that succeeds to the benefit of both employee and utility owner.
Dong Hoon Kim, Gwang Seop Son, Choul Woong Son, Dong Young Lee
Nuclear Technology | Volume 189 | Number 1 | January 2015 | Pages 87-102
Technical Paper | Nuclear Plant Operations and Control | doi.org/10.13182/NT13-142
Articles are hosted by Taylor and Francis Online.
This paper presents the architecture of the reactor protection system (RPS) in a nuclear integrated safety system (NISS) and describes the evaluation and analysis of reliability for NISS-RPS using the Markov model. NISS-RPS has four-channel redundancy like existing digital RPSs. However, a channel is configured based on triple modular redundancy and can be reconfigured on detecting faults. To analyze and evaluate the reliability of NISS-RPS, the Markov model for NISS-RPS and RPSs that are in operation or under construction in Korea were developed. Their reliability was evaluated and analyzed using the models. From the reliability analyses for NISS-RPS, it was observed that the failure rate of each module in NISS-RPS should be <2 × 10−5/hour, and the mean time to failure (MTTF) is ∼20 000 hours, which is two times better than the MTTF requirement of 10 000 hours. The MTTF average increase rate, which depends on the fault coverage factor (FCF) increment, ΔMTTF/ΔFCF, is 1850 hours/0.1. The results of comparison with other RPSs show that the reliability of NISS-RPS is at least 1.5 times better than that of the other three types of RPS architecture, and the MTTF is at least 14 months longer than that of the other types.
