July-August 2019 NPJ

Nuclear Plant Journal, July-August 2019 NuclearPlantJournal.com 31 time online monitoring of an SSC may provide for greater long-term reliability and assurance of safe operations for a particular SSC. Further, the use of traditional ISI examination methods such as ultrasonic testing (UT), liquid penetrant (LP) testing, etc., may need to be replaced with more appropriate monitoring or surveillance techniques, such as online acoustic monitoring or periodic surveillance specimen testing (e.g., evaluate the onset of creep damage that may be applicable to some designs). These examples are departures from the historic approaches to ISI and are important to recognize. In particular, they are essential for plant personnel, regulators and authorized inspection agency personnel to internalize, since many inservice inspections or monitoring functions in Division 2 may cause a significant paradigm shift with the day- to-day responsibilities carried out in present ISI programs. Further, since each unique reactor design will likely be expected to have its own unique RIM parameters, ISI activities at one facility that has one specific design, may be different from RIM criteria at a facility with a different design reactor system. There are a significant number of countries outside the US that are pursing the use of a RIM approach for their commercial nuclear plants. For example, the Canada Nuclear Safety Commission (CNSC), updated in August 2017, REGDOC-2.6.1, Reliability Programs for Nuclear Power Plants. This document captures the existing requirements previously found in RD/ GD-98, Reliability Programs for Nuclear Power Plants, and replaces the latter document. This regulatory document describes the essential elements of a reliability program, including reliability assessment, modelling, evaluations, and monitoring. Canada adopts and implements several of the ASME RIM provisions into their programs. Another country that strongly embraces the RIM approach is Japan. Section XI has an ASME/Japan Society of Mechanical Engineers (JSME) Joint Working Group on RIM Processes and System Based Code. Their charter is to develop, review, and maintain, for publication in Section XI RIM (Division 2) of the Boiler and Pressure Vessel Code, requirements for the development of the RIM Process, establishing parameters for the formulation of Reliability Targets, PRA criteria, RIM reporting requirements and RIM specific Repair Replacement Activities. The Working Group may also develop System Based Code requirements, coordinating the requirements for construction and RIM. Other countries that use the ASME Section XI Code are also evaluating the use of Division 2 for their current and future plants. Conclusion The future of advance nuclear reactors with their varied designs will require a substantial shift in the performance and approach to ISI and monitoring activities. While the industry is making these advances, including the development of new codes and standards, it is expected that the RIM process will also be paramount to the future success of any new reactor designs that are deployed. This first edition of RIM will no doubt evolve over time as operating experience is gained. However, RIM’s technical foundation and its adaptability to establish meaningful ISI criteria that can rationally be applied to any future reactor design while continuing to assure that plant safety is maintained is a major step forward in advancing the future of safe and reliable power generation through the world. References 1. “Application of the System Based Code Concept to the Determination of In-Service Inspection Requirements:” Authors - Shigeru Takaya and Tai Asayama - Japan Atomic Energy Agency – January 2015 - Journal of Nuclear Engineering and Radiation Science JANUARY 2015, Vol. 1 / 011004-9. 2. “Elaboration of the System Based Code Concept – Activities In JSME and ASME – Overview:”– Authors – Tai Asayama, Takayuki Miyagawa, Koji Dozaki, Yoshio Kamishima, Masaaki Hayashi and Hideo Machida. Proceedings of the 2014 22nd International Conference on Nuclear Engineering ICONE22 July 7-11, 2014, Prague, Czech Republic. Contact: A. Thomas Roberts, POMO18 Consult LLC, 2 Wilderness Way, Chadds Ford, PA 19317; telephone: (609) 560-1778, email: pomo18consult@ gmail.com. Figure 1 (Flow Chart from ASME XI Division 2 Appendix IV).