Development of a Passive Residual Heat Removal System with an Air Cooling Component of the ATOM system

Development of a Small Modular Reactor (SMR) has been steadily paid attention over the past few decades for excellent siting flexibility, lower construction cost, or improved safety. Recently, a research team in Korea has focused on the development of a new SMR that aims at a naturally-safe and autonomous operation, called the Autonomous Transportable One-demand reactor Module (ATOM) project. A passive residual heat removal system (PRHRS) with an air cooling component is discussed using the MARS code, the one-dimensional (1D) system analysis code developed at KAERI in Korea. In this study, a feasibility assessment of the ATOM PRHRS with the air cooling component was discussed using the MARS code. Major outcomes of this study are summarized as follows: (1) The natural circulations were stably established in the PRHRS and DACS loops, removing the decay heat generated from the primary part. (2) the MARS simulation implies that the PRHRS with the air cooling system showed the improved cooling capability for 10 hrs as compared to the conventional PRHRS. For further study, to assess the feasibility of the overall ATOM safety systems, more extensive evaluations are essentially needed, including various accident scenarios.