Conceptual design of reactor system for hybrid micro modular reactor (H-MMR) using potassium heat pipe

Hybrid micro modular reactor (H-MMR) combining MMR with renewable energy and energy storage systems (ESS) is designed using heat pipe. H-MMR could produce 10 MW of electric power more flexibly and efficiently through load following. LOCA accident is precluded in advance as there is no primary coolant due to the use of potassium heat pipe. Reactor solid core consist of hexa-annulus UN fuel with a heat pipe inserted, which connects a sodium pool of intermediate heat exchanger (IHX). The annular gap wick heat pipe (ACHP) using potassium is optimized to maximize the heat transport performance. Reactor core configuration is designed through core analysis and thermal analysis using 1D lumped finite differential method. Reactor core of H-MMR make 18 MW of thermal power for 56 years without refueling when diameter of heat pipe is 22 mm. The feasibility of heat pipe safety system and sodium pool is evaluated in normal operation. Reactor vessel auxiliary cooling system (RVACS) is designed to cool down decay heat within safety margin using implicit transient analysis.