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Apr 19 – 22, 2022
Vienna, Austria
Europe/Vienna timezone
FR22 starts in Vienna 19 - 22 April 2022 Online Stream:

Conceptual design of ultra-long life hybrid micro modular reactor cooled by potassium heat pipe

Apr 20, 2022, 3:04 PM
Vienna, Austria

Vienna, Austria

ORAL Track 1. Innovative Fast Reactor Designs 1.2 Innovative Design Advances


Mr Seongdong Jang (Korea Advanced Institute of Science and Technology (KAIST))


As part of achieving sustainable development, a concept of the hybrid micro modular reactor (H-MMR) has been proposed by integrating the MMR design developed by KAIST with renewable energy and energy storage systems (ESS). The reactor power is designed to be 18MWth, and it is aimed for an ultra-long core lifetime for more than 20 years without refueling. The H-MMR core consists of 18 hexagonal fuel assemblies (FAs) with a potassium heat pipe cooling system. The hexa-annulus types of UN fuel, including potassium heat pipes, are assembled into the oxide dispersion-strengthened steel (ODS) hexagonal duct. These heat pipes are connected to a sodium pool that is set up above the reactor core as an intermediate heat exchanger. The PbO and ODS reflectors are designed with a B4C shielding layer. The primary reactivity control system is placed in the radial-reflector as a drum-type, and a conventional secondary reactivity control device is located in the center of the core. The neutronic analyses were performed by Monte Carlo code, Serpent 2, with ENDF/B-VII.1 data library. The results showed that the H-MMR achieves ultra-long life of 56 years without refueling and the discharge burnup is 37.12 MWD/kgHM, while the reactivity swing over the whole lifetime is less than 0.45 dollar. The results suggest that the ultra-long life micro module type fast reactor design that guarantees the improvement of the inherent safety via the use of potassium heat pipes can be realized.

Country/Int. organization Korea, Republic of
Speaker's email address
Speaker's title Mr
Affiliation/Organization Korea Advanced Institute of Science and Technology

Primary author

Mr Seongdong Jang (Korea Advanced Institute of Science and Technology (KAIST))


Yonghee Kim (Korea Advanced Institute of Science and Technology)

Presentation materials

Peer reviewing