Activities on the leakage of radioactive substances from buried pipe with cracking

Kameyama, Yasuhiko; Yanai, Tomohiro; Kurosawa, Akihiko; Asano, Norikazu; Hiyama, Kazuhisa; Kusunoki, Hidehiko ; Fukasaku, Akitomi

The Japan Materials Testing Reactor (JMTR) is a testing reactor dedicated to the irradiation tests of materials and fuels. The JMTR has been in a shutdown period since 2006 for its refurbishment, and will restart in 2011. Water analysis and so on are carried out in the hot experimental room, and sample preparation and measurement for the radiation management are carried out in the radiation control room. The waste fluid such as hand-wash water, sample water, washing water generated in these rooms is transferred to the waste tank in the hot machine room through the buried pipe. The crack was found at the flange of the buried pipe when sewerage works were carried out. The flange is located in a non-controlled area. A small amount of radionuclide (cesium 137 and cobalt 60) was detected as a result of radioactivity measurement from the surrounding soil. In this report, the cause of the leakage from the buried pipe, the countermeasure and the prevention measure are summarized.