[3D12-13] Research Reactor Upgrading

3:20 PM - 3:35 PM JST(6:20 AM - 6:35 AM UTC)

[3D12] Study on closed-loop hydrogen thermosiphon flow for JRR-3 cold neutron source

*Sho Tokunaga¹, Takemi Nakamura¹ (1. JAEA)

Keywords:

Cold neutron source,CNS,Liquid Hydrogen,thermosiphon

In JAEA JRR-3 cold neutron source (CNS), the moderator cell is currently under detailed design for upgrading its material and structure. For this design, it is necessary to evaluate the flow stability and the void fraction variation in the cell for the closed-loop hydrogen thermosiphon in the entire CNS system with the new cell applied. The previous presentation showed RELAP5/MOD3.2 can be used for evaluation. In this presentation, we analyzed with more detailed models and summarized the flow state of the existing CNS system. Its validity was evaluated based on the results of previous studies. As a result, we were able to quantitatively evaluate the mechanism of the closed-loop thermosiphon.