Preliminary study of the conceptual design of the Atom Safety System

Abstract

A new research project has begun in Korea for the conceptual development of a further advanced SMR that pursues a naturally-safe and autonomous operation called Autonomous Transportable On-demand reactor Module (ATOM). Major design goals of the ATOM system are focused on the boron-free primary coolant system that enables the automatic load follow operation. Moreover, the air-cooled condensate system is selected as a final heat sink. In this study, the conceptual development of ATOM safety system was preliminarily discussed. To design and select the safety system, the design features of currently developed SMRs were reviewed. Most SMRs employ passive safety systems to enhance the safety and reliability. The NuScale design adopts entire passive features, but the reactor power is limited relatively lower. In this regard, one major design goal of the ATOM system is to set the optimum passive systems. Several safety systems are currently considered for ATOM including the passive residual heat removal system (PRHRS), the passive containment cooling system (PCCS), and the dry/wet cooling system (DWCS). The air cooling part as the ultimate heat sink in DWCS is important because it could eventually response to extreme regions lacking enough cooling water. Moreover, another concept with a natural draft cooling tower is suggested for the PRHRS and PCCS, which might be expected to provide indefinite grace time during accident environments. In the For further study, in order to assess the feasibility of the suggested safety systems and cycle analysis, quantitative evaluations are essentially required, especially including accident scenarios.