Current post irradiation examination techniques at the JMTR Hot laboratory

Shibata, Akira; Kato, Yoshiaki; Oishi, Makoto; Taguchi, Taketoshi; Ito, Masayasu; Yonekawa, Minoru; Kawamata, Kazuo

KAERI/GP-418/2015, p.151 - 165, 2015/05

The JMTR stopped its operation in 2006 for refurbishment. The reactor facilities have been refurbished from 2007. After refurbishment, JMTR Hot laboratory is expected to perform various post irradiation examinations. In this report, installations of experimental apparatuses and recent experimental method are introduced. (1) A nano-indenter with radius spherical indenter. Inverse analysis using FEM could presume material constants from load-depth curve of indentation. Mechanical properties of oxide layer of zirconium alloy and irradiated stainless steel will be analyzed. (2) Transmission Electron Microscope (TEM). TEM is capable of imaging at a significantly higher resolution than light microscopes or normal SEM. JAEA installed a TEM apparatus (JEOL JEM-2800) in JMTR Hot laboratory. The maximum magnification is 150,000,000 times. It can be operated from a remote location using a computer network. This contributes to the convenience of remote researchers and reducing the amount of exposure.

Neutron shielding reinforcement in the JMTR Hot Laboratory

Ito, Masayasu; Kawamata, Kazuo; Tayama, Yoshinobu; Kanazawa, Yoshiharu; Yonekawa, Minoru; Nakagawa, Tetsuya; Omi, Masao; Iwamatsu, Shigemi

JAEA-Technology 2011-022, 44 Pages, 2011/07

JAEA-Technology-2011-022.pdf:3.29MB

Hot laboratory are facilities that execute the post irradiation examination of sample irradiated in material testing reactors etc. The handling of high burn-up fuel is scheduled in the JMTR (Japan Materials Testing Reactor) Hot Laboratory with JMTR re-operate in FY 2011. This report describes evaluation, production and installation of shielding of the hot cells in the JMTR Hot Laboratory.

Study of optimum composition of extra high purity Nb-W alloys for reprocessing condition with nitric acid

Ioka, Ikuo; Yonekawa, Kazuo; Maruyama, Nobutoshi*; Kiuchi, Kiyoshi; Nakayama, Jumpei

no journal, , 

Nb-W binary alloy which is superior to current zirconium for corrosion and cracking in severer environment is developed for advanced reprocessing plants. Ductility of Nb-W binary alloy is improved by an application of extra high purity (EHP) refining technology, but mechanical strength deteriorates. A ductile-brittle transition temperature (DBTT) of Nb-W binary alloy rises, though the increase in W improves mechanical strength. DBTT of the weld tends to be high in comparison with the base metal, and a rise of DBTT by increase in W becomes the problem. Nb-W EHP alloys with different content of W were manufactured to choose an optimum composition range. Tensile, corrosion and Charpy impact tests were carried out to examine the optimum composition range of Nb-W EHP alloy.

Development of advanced equipments for PIEs in JMTR-HL

Ito, Masayasu; Taguchi, Taketoshi; Yonekawa, Minoru; Kurosawa, Makoto; Kawamata, Kazuo; Sozawa, Shizuo; Ishihara, Masahiro

no journal, , 

JMTR-HL has been promoting the advancement of PIE meets future needs of irradiation, and has been constructing the position of basic research of nuclear energy for the purpose of realizing a research environment to support "Green Innovation " and "Life Innovation" such as measures for prolonged LWR that is a subject for study worldwide, development of Next Generation LWR, the development of radioisotopes manufacturing technology for medical use, and has been promoting the development of post-irradiation test facility that is selected by the Ministry of Education as "Cutting-Edge Research Infrastructure Projects" toward the achievement of a base for international R&D. This development has done TEM, FIB and XPS, etc. and have enabled the processing and the sample observation of irradiated material specimen of 30 MBq amount of radioactivity (in terms of cobalt).

Current status and developments of post irradiation examination techniques in JMTR Hot laboratory

Shibata, Akira; Taguchi, Taketoshi; Aoyagi, Tatsuhiko; Ito, Masayasu; Kato, Yoshiaki; Yonekawa, Minoru; Kawamata, Kazuo

no journal, , 

Cs Adsorption behavior evaluation on the surface of nuclear reactor structure materials under high temperature and high pressure steam

Sumita, Takehiro*; Yonekawa, Kazuo*; Sekio, Yoshihiro; Sato, Isamu*; Kobayashi, Yoshinao*; Osaka, Masahiko; Maeda, Koji; Akasaka, Naoaki

no journal, , 

During Fukushima Daiichi Nuclear Power Plant (1F) accident, high radionuclides such as Cs and I were mainly released as fission products (FPs) due to fuel melting in units 1 to 3, and it increased radiation dose in reactor buildings. With the aim of 1F decommissioning, it is necessary to establish methods to retrieve fuel and an adequate access route, which requires knowledge of Cs adsorption behavior on the surface of structural materials during Severe Accidents (SA). However, there are no Cs adsorption behavior evaluations under the simulated SA condition with high pressure in the previous studies. In this study, CsI adsorption behavior on SUS304L under the condition was evaluated using newly designed apparatus which can control temperature, pressure, moisture and gas atmosphere. The findings from microstructural observation and elemental analysis after the adsorption test suggested that the adsorption of CsI was influenced by especially pressure.