Progress of design and related researches of sodium-cooled fast reactor in Japan

日本におけるナトリウム冷却高速炉の設計と研究開発の進展

上出 英樹 ; 阪本 善彦 ; 久保 重信 ; 大木 繁夫 ; 大島 宏之; 神山 健司  

Kamide, Hideki; Sakamoto, Yoshihiko; Kubo, Shigenobu; Oki, Shigeo; Ohshima, Hiroyuki; Kamiyama, Kenji

東日本大震災以降、日本におけるナトリウム冷却高速炉の開発において安全性の強化、特にシビアアクシデント対策が重要な視点となっている。本論文ではこれらの点での設計ならびに研究開発の進捗を報告する。崩壊熱除去系の強化では炉心損傷事故時の対応を含む多様性、信頼性の向上、熱流動評価手法にかかる研究が行われている。炉心損傷事故時の溶融燃料の挙動について、国際協力を含む炉内試験、炉外試験、基盤的研究が行われ、シビアアクシデントの発生防止の観点での炉心設計改良が進んでいる。

Development of a sodium-cooled fast reactor has been implemented in Japan from the viewpoint of severe accident countermeasures in order to strengthen safety of a fast reactor since the Great East Japan Earthquake. This paper describes the progress of design study and research and development related to safety enhancement and the severe accident countermeasures. For the purpose of strengthening of decay heat removal function, several researches have been carried out on the decay heat removal in a core disruptive accident (CDA), diversity and applicability of decay heat removal systems, and thermal hydraulic evaluation methods. In order to elucidate the behavior of molten fuel during CDA, some in-pile and out-of-pile tests has been performed by international collaboration including basic experiments. Core design was also improved from the viewpoint of preventing the occurrence of severe accident.