Lifetime reliability and availability simulation for the electrical system of HTTR coupled to the electricity-hydrogen cogeneration plant

Abstract

The lifetime reliability and availability for the Electrical Facility of the High Temperature Engineering Test Reactor (HTTR) have been evaluated. The impact of the electrical malfunctions on the Forced Outage Rate (FOR) of the HTTR-based electricity-hydrogen cogeneration has been determined. Normal operation and emergency conditions have been considered for the standard system design and its modified configuration of higher redundancy. The Monte Carlo method has been applied for the uncertainty assessment followed by the Fussell-Vesely importance evaluation. A novel methodological concept has been proposed for the integration of reliability and availability simulations of alternative models corresponding to several options of the system's design considered under various analytical assumptions. It provides a computational framework suitable for the incorporation of the alternative models into one simulation case driven by the common set of reliability data at each iteration step. This enables efficient comparison of the models in terms of reliability, availability, and uncertainty. The results of this work are of high practical importance for the safety and reliability of the HTTR-based cogeneration plant. The former was confirmed by the high availability of safety-related electrical loads, while the latter needs optimization to meet the industry standards concerning FOR.