Increasing demands for Reliability, Availability, Maintainability, and Safety (RAMS) are fostering design innovations in modern nuclear facilities. High Temperature Gas-cooled Reactor (HTGR) is an advanced technology characterized by inherent safety features, where significant core degradation can be practically eliminated through the robust ceramic-coated fuel particles, high-temperature resistant graphite matrix, inert helium coolant, and passive heat removal. The novel technological concepts and first-of-a-kind engineering solutions introduce, however, methodological challenges in conducting RAMS assessments for HTGRs and collocated facilities. This article opens a series of works derived from the original results of the RAMS analyses performed for the newly designed high-temperature reactor HTGR-POLA (POLish Atomic). Initiated at an early stage of the reactor's design, these studies have yielded broadly applicable outcomes relevant to the field of reliability engineering and system safety. This work introduces an integrated framework for the Reliability-Centered Design (RCD) process, incorporating digital twin modeling, lifetime simulations of the RAMS parameters, Monte Carlo-based uncertainty assessment, and Sobol’s index-driven quantification of sensitivity measures. This approach, preceded by traditional methods such as Failure Modes and Effects Analysis (FMEA) and Fault Tree Analysis (FTA), aims at optimizing the design of HTGR-POLA in terms of RAMS while minimizing its complexity. The findings of this work highlight the effectiveness of the new RCD framework in balancing competing design objectives, as shown by the example of the electrical power system, where the design complexity and Forced Outage Rate (FOR) were jointly considered.
Kowal et al. (Mon,) studied this question.