Analysis of Accident Scenarios in a Generic Natural Circulation Small Modular Reactor with the Astec Code in the Framework of the SASPAM-SA Project

Abstract

In response to the needs for safe and sustainable energy solutions, the emergence of Small Modular Reactors (SMRs) has increased significant interest. The HORIZON-EURATOM SASPAM-SA project, currently ongoing, addresses the transferability of knowledge from large Light Water Reactors (LWRs) to integral Pressurized Water Reactors (iPWRs) and analyses the behavior of generic SMR designs with passive mitigation strategies under accident conditions. In this framework, this study investigates the safety assessment of a generic natural circulation iPWR using the code ASTEC (Accident Source Term Evaluation Code) developed by the French Institute for Radiation Protection and Nuclear Safety (IRSN). The ASTEC code is able to simulate an entire accident sequence in a nuclear power plant, from the initial event to the potential release of radioactive elements outside the containment, involving the modelling of diverse thermal hydraulic and physico-chemical phenomena. This paper presents the outcomes derived from the analysis of hypothetical Design-Basis Accident (DBA) and Severe Accident (SA) scenarios, in one of the two generic iPWRs considered in the SASPAM-SA project, showing the code’s capability to adequately describe the key thermal hydraulic and core degradation phenomena.