高速実験炉「常陽」における炉内補修技術の開発と実践 - MARICO-2 試料部の回収-
Development of repair techniques in the reactor vessel of the experimental fast reactor Joyo . Retrieval of the MARICO-2 test subassembly .
皆藤 泰昭 Yasuaki KAITO 芦田 貴志 Takashi ASHIDA 今泉 和幸 Kazuyuki IMAIZUMI 伊澤 修 Osamu IZAWA 内藤 裕之 Hiroyuki NAITO
FBR In-vessel repair technique Joyo MARICO-2 retrieval SFR
In the experimental fast reactor “Joyo”, it was confirmed that the top of the irradiation test sub-assembly (S/A) of “MARICO-2” (material testing rig with temperature control) had been bent onto the in-vessel storage rack as an obstacle, and the MARICO-2 S/A had been stuck in the transfer pot owing to its deformation. Since the MARICO-2 S/A cannot be retrieved with the existing handling equipment, special handling equipment was developed while considering the anomalous conditions. Emphasis had been placed on (1) how to precisely control the gripper position in the reactor vessel, and (2) how to retrieve the MARICO-2 S/A together with transfer pot with high reliability in the design and development of equipment. The equipment was designed based on the past experience, then verified in ex-vessel partial/full mock-up test and in-vessel partial test. The MARICO-2 S/A was retrieved successfully together with transfer pot in 2014. This paper describes the in-vessel repair techniques developed for MARICO-2 S/A retrieval.