Reliability assessment of the thermal hydraulic phenomena related to a CAREM-like passive RHR system

In this paper, RMPS methodology is used for estimating the reliability of the safety function associated to the Passive Residual Heat Removal System of a CAREM-like advanced reactor. The passive system assessment is made on a basis of a Loss of Heat Sink transient. Given this scenario, the safety function is to remove the core decay heat after the actuation of the shut-down system, thus reducing the primary system pressure and leading the plant to a safe condition. In order to accomplish the evaluation of the functional reliability, the following RMPS steps were followed: system identification: system modeling; characterization of TH phenomena; direct Monte Carlo simulation; sensitivity analysis and quantitative reliability estimation. As main outcome, an estimate of the functional reliability was achieved by Monte Carlo simulations based on a response surface