大型ナトリウム冷却高速炉(JSFR)の自然循環崩壊熱除去に関する試験研究

Experimental studies of natural circulation decay Heat removal in Japan Sodium Cooled Fast Reactor (JSFR)

上出 英樹 ; 宮越 博幸; 渡辺 収*; 江口 譲*; 古賀 智成*

Kamide, Hideki; Miyakoshi, Hiroyuki; Watanabe, Osamu*; Eguchi, Yuzuru*; Koga, Tomonari*

大型ナトリウム冷却高速炉の実用化を目指し、完全自然循環方式の崩壊熱除去システムについて、試験と解析を組合せた研究開発を進めている。試験では1次主冷却系の自然循環に関する縮尺水試験,崩壊熱除去系と中間熱交換器に挿入する崩壊熱除去用冷却器の自然循環と伝熱特性に関する部分モデルナトリウム試験を実施している。ナトリウム試験では、すべての系統が自然循環となる崩壊熱除去系の2次側ナトリウム系統、空気冷却器空気側の待機運転から起動時のスムーズな自然循環流量の立ち上がりを確認した。

Fully natural circulation system is adopted in a decay heat removal system (DHRS) of the designs of Japan Sodium Cooled Fast Reactor (JSFR). Several investigations of experiments and simulation methods on this DHRS are performed. Water experiments are carried out for the primary heat transportation system including a reactor vessel and heat exchangers of DHRS using a 1/10 model. As for the DHRS loop, sodium experiments were carried out, especially for a heat exchanger installed in an Intermediate Heat Exchanger (IHX). Here, several results of the sodium experiments were described. Transient characteristics during the start up in the air system of the air cooler, secondary loop of DHRS, and the primary loop were examined by the sodium experiments. Smooth increase of natural circulation flow rates in all systems of air and sodium was confirmed. Verifications of numerical simulation methods are planned based on the water and sodium experiments in this investigation plan.