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Meeting Spotlight
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
Standards Program
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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Latest News
The U.S. Million Person Study of Low-Dose-Rate Health Effects
There is a critical knowledge gap regarding the health consequences of exposure to radiation received gradually over time. While there is a plethora of studies on the risks of adverse outcomes from both acute and high-dose exposures, including the landmark study of atomic bomb survivors, these are not characteristic of the chronic exposure to low-dose radiation encountered in occupational and public settings. In addition, smaller cohorts have limited numbers leading to reduced statistical power.
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.