Application of nontransfer type plasma heating technology for core-material-relocation tests in boiling water reactor severe accident conditions

BWR型軽水炉シビアアクシデント挙動における炉心物質移行挙動(CMR)模擬のための非移行型プラズマ加熱試験技術開発

阿部 雄太  ; 佐藤 一憲 ; 中桐 俊男  ; 石見 明洋 ; 永江 勇二 

Abe, Yuta; Sato, Ikken; Nakagiri, Toshio; Ishimi, Akihiro; Nagae, Yuji

原子力機構では非移行型プラズマ加熱を用いたBWR体系での炉心物質の下部プレナムへの移行挙動(CMR)に着目した試験を検討している。この技術の適用性を確認するために、我々は小規模試験体(107mm107mm222mm (height))を用いたプラズマ加熱の予備実験を行った。これらの予備実験の結果から、SA(シビアアクシデント)研究への非移行型プラズマ加熱の優れた適用性が確認できた。また我々は、中規模の模擬燃料集合体(燃料ピン50ロッド規模)を準備し、まだ技術的な適用性が確認できていない制御ブレードやCMR事体に関する試験を実施予定である。

A new experimental program using non-transfer type plasma heating is under consideration in JAEA to clarify the uncertainty on core-material relocation (CMR) behavior of BWR. In order to confirm the applicability of this new technology, authors performed preparatory plasma heating tests using small-scale test pieces (107 mm 107 mm 222 mm (height)). An excellent perspective in terms of applicability of the non-transfer plasma heating to melting high melting-temperature materials such as ZrO has been obtained. In addition, molten pool was formed at the middle height of the test piece indicating its capability to simulate the initial phase of core degradation behavior consistent with the real UO fuel Phebus-FPT tests. Furthermore, application of EPMA, SEM/EDX and X-ray CT led to a conclusion that the pool formed consisted mainly of Zr with some concentration of oxygen which tended to be enhanced at the upper surface region of the pool. Based on these results, an excellent perspective in terms of applicability of the non-transfer plasma heating technology to the Severe Accident (SA) experimental study was obtained.