Thermal-hydraulic design concerning reactor upper plenum and large diameter piping for the innovative sodium-cooled fast reactor

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藤井 正; 此村 守; 上出 英樹 ; 山口 彰; 戸田 幹雄*

Fujii, Tadashi; Konomura, Mamoru; Kamide, Hideki; Yamaguchi, Akira; Toda, Mikio*

実用化戦略調査研究で検討中のナトリウム冷却炉では、建設コスト低減のためにコンパクトな冷却系を採用している。しかし、炉上部プレナムや1次冷却系配管でのナトリウム流速が従来設計よりも増大するため、炉上部プレナムの流動適正化と配管系の流動励起振動に対する健全性が熱流動上の課題となっていた。これらの課題に取り組むために、いくつかの水流動試験を実施し、その結果を実機設計に反映している。

An innovative sodium-cooled fast reactor (JSFR) has been investigated on the Feasibility Study on Commercialized Fast Reactor (FR) Cycle Systems. In order to reduce plant construction cost, JSFR adopts compacted reactor vessel and reduction of loop number. According to adoption of compacted cooling system, sodium flow velocities in the reactor upper plenum and the pipings of the cooling system exceed to those of conventional design, therefore, flow optimization in the reactor upper plenum and structural integrity of the piping system to flow-induced vibration (FIV) have been actualized as thermal-hydraulic issues. To solve above issues, some water experiments have been performed. The thermal-hydraulic design of the primary cooling system including the reactor vessel has been advanced reflecting these experimental results.