[en] In this study, we suggest a new concept design of GBS (Gravity Based Structure) type ONPP (Offshore Nuclear Power Plants) using the SMART (System integrated Modular Advanced Reactor) model, which is the most recent SMR (Small Modular Reactor) model in Korea. Because floating and submerged types of NPPs (Nuclear Power can easily be affected by severe ocean environments such as tsunamis and storms, a new GBS type ONPP using the APR1400 model, the largest NPP model in Korea, was proposed in our previous work. We expand this concept for the SMART model and suggest a new concept with design parameters, design requirements, and the new total GA (General Arrangement) based on modularization. We discuss its structural safety features. We believe that the proposed GBS type ONPP design concept based on the SMART model can be a robust alternative to the original land based SMART. (authors)

[en] In March 2011, Fukushima Nuclear Power Plant (NPP) accident occurred because of unprecedented earthquake and tsunami on east side of Japan. Decay heat removal system was dysfunctional due to loss of all power and eventually the reactor core was severely damaged which led to a large release of radioactive material to environment and public. From this accident, protection of NPPs from any natural disasters came to the fore. Moreover, development of passive safety systems which can protect NPPs when Station Blackout (SBO) occurred was emphasized. In recent years, KAIST research team is developing a concept of ocean NPPs which can meet both aforementioned goals in safety while potentially increasing economy and enhancing public acceptance. Furthermore, another passive safety system, which is being developed by KAIST research team namely Integrated Passive Safety System (IPSS) can be successfully coupled to the ocean nuclear system to augment passive safety. In this paper, as a reference system for ocean NPP, recently developed Korean small reactor, SMART is chosen to demonstrate the ocean NPP concept with IPSS. The paper will quickly review the potential improvement of Ocean SMART safety as well as the plant layout. This will be followed by a simple analysis to size required additional component for IPSS and illustrate how IPSS and ocean environment can have synergy effect on NPP safety. (authors)

[en] Highlights: • We suggested the concept of coupling the SMART to the GBS, and we made suggested improvements. • We describe the design concepts and GA of SMART ONPP. • We analyzed seismic feature of SMART ONPP preliminarily. • We suggested the concept of coupling the IPSS to the SMART ONPP, and we made suggested improvements. - Abstract: From the Fukushima accident, protection of NPPs from any imaginable natural disasters became very important. In this study, the authors suggest a new concept of ocean nuclear power plant (ONPP) by using SMART as a reference reactor, which is the most recent Small Modular Reactor (SMR) developed by Korea, to demonstrate that the proposed concept can improve the safety of NPP from earthquake and tsunami. The proposed concept utilizes Gravity Based Structure (GBS), which is a widely spread construction technique of offshore plants. Because, floating type or submerged type NPPs can be easily affected by severe ocean environments such as tsunamis and storms, additional safety features have to be added to the existing land based plant. In contrast, the newly proposed GBS-type ONPP does not require going through significant design modifications due to inherent characteristics of the construction method. The authors have demonstrated this concept can be applied to the large nuclear power plant in the previous work and will expand this concept for SMRs in this paper. The authors discuss the new concept by presenting design parameters, design requirements, and the new total general arrangement. Furthermore, due to the unique configuration of ONPP SMART, innovative passive safety features can be added to the existing SMART design. The performance of proposed concept to resist earthquake as well as newly added passive safety feature will be discussed by presenting simplified analysis results