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Koya, Toshio; Nozawa, Yukio; Hanada, Yasushi; Ono, Katsuto; Kanazawa, Hiroyuki; Nihei, Yasuo; Owada, Isao
Dekomisshoningu Giho, (42), p.41 - 48, 2010/09
The Research Hot Laboratory (RHL) in Japan Atomic Energy Agency (JAEA) had been contributed to R&D program for fuels and nuclear materials in or out of JAEA. However, the decommissioning work of RHL has been started on April 2003 as the rationalization program for decrepit facilities in former Tokai institute. This work will be progressing, dismantling the lead cells and decontamination of concrete caves then release in the regulation of controlled area. The partial area of RHL will be used for the central storage of un- irradiated fuel and for temporary storage of radioactive device generated by J-PARC. The 18 lead cells had been dismantled and the preparing work for remained 20 lead cells has been finished including the removal of the applause from the cells, survey of the contamination revel in the lead cells and prediction of radio active waste. The future plan of decommissioning work has been prepared to incarnate the basic vision and dismantling procedure.
Nozawa, Yukio; Koya, Toshio; Sekino, Hajime
JAEA-Technology 2007-019, 23 Pages, 2007/03
JAEA-Technology-2007-019.pdf:5.38MB
However, RHL is the one of target "A midterm decommissioning plan of Tokai Research Establishment" as the rationalization program for a decrepit facility in JAERI. This program has been taking over in JAEA. Therefore, all PIEs had been finished in March 2003 and the destruction works of hot cells have been started. The contents of these works are to remove out the apparatus from the hot cell and to transfer the irradiated samples and disposal of radioactive waste. The authorization work of the destruction program for regulation committee is in progress. The 18 lead cells had been destructed. The examinations performed in RHL will be succeeding to the RFEF and the WASTEF. The partial area of RHL facility will be used for the temporary storage of un- irradiated fuel samples used for our previous research works and radioactive device generated in proton accelerator facility (called J-PARC which is under constructing in Tokai site).
Umino, Akira; Saito, Mitsuo; Kanazawa, Hiroyuki; Koya, Toshio; Okamoto, Hisato; Sekino, Hajime*; Nishino, Yasuharu
Dekomisshoningu Giho, (32), p.2 - 12, 2005/09
The Research Hot Laboratory (RHL) in Japan Atomic Research Institute (JAERI) was constructed in 1961, as the first one in JAPAN, to perform the examinations of irradiated fuels and materials. RHL with two floors and a basement consists of 10 heavy concrete cells, and 38 lead cells (20 lead cells at present). The RHL had been contributed to research program in JAERI. However, RHL is the one of target 'A middle-range decommissioning plan for the facility in Tokai Research Establishment' as the rationalization program for decrepit facilities in JAERI. Therefore, all PIEs had been finished in March 2003 and the dismantling works of hot cells have been started. The 18 lead cells had been dismantled. The examinations performed in RHL will be succeeded to the RFEF and the WASTEF. The partial area of RHL facility will be used for the temporary storage of un-irradiated fuel samples used for our previous research works and radioactive device generated in proton accelerator facility (called J-PARC).
Nakano, Junichi; Miwa, Yukio; Koya, Toshio; Tsukada, Takashi
Journal of Nuclear Materials, 329-333(Part1), p.643 - 647, 2004/08
Times Cited Count：9 Percentile：48.81(Materials Science, Multidisciplinary)To study effects of minor elements on the irradiation assisted stress corrosion cracking (IASCC), high purity Type 304 and 316 stainless steels (SSs) were fabricated and added minor elements, Si or C. After neutron irradiation to 3.5
10
n/m
(E
1MeV), the slow strain rate tests (SSRT) for the irradiated specimens was conducted in oxygeneted high purity water at 561 K. Fracture surface of the specimens was examined using the scanning electron microscope (SEM) after the SSRT. Fraction of intergranular stress corrosion cracking (IGSCC) on the fracture surface after the SSRT increased with netron fluence. Suppression of irradiation hardening and increase of peiod to SCC fracture as benefitical effects of the additional elements, Si or Mo, were not observed obviously. In high purity SS added C, fraction of IGSCC was the smallest in the all SSs, although irraidiation hardening level was the largest in the all SSs. Addition of C suppressed the susceptibility to IGSCC.
Nakano, Junichi; Tsukada, Takashi; Tsuji, Hirokazu; Terakado, Shogo; Koya, Toshio; Endo, Shinya
JAERI-Tech 2003-092, 54 Pages, 2004/01
JAERI-Tech-2003-092.pdf:14.05MB
Irradiation assisted stress corrosion cracking (IASCC) is a degradation phenomenon caused by synergy of neutron radiation, aqueous environment and stress on in-core materials, and it is an important issue in accordance with increase of aged light water reactors. Isolating crack initiation stage from crack growth stage is very useful for the evaluation of the IASCC behavior. Hence facility for in-situ observation during slow strain rate test (SSRT) for irradiated material was developed. As performance demonstrations of the facility, tensile test with in-situ observation and SSRT without observation were carried out using unirradiated type 304 stainless steel in 561 K water at 9 MPa. The following were confirmed from the results. (1) Handling, observation and recording of specimen can be operated using manipulators in the hot cell. (2) In-situ observation can be performed in pressurized high temperature water and flat sheet type specimen is suitable for the in-situ observation. (3) Test condition can be kept constantly and data can be obtained automatically for long test period.
Motooka, Takafumi; Terakado, Shogo; Koya, Toshio; Kiuchi, Kiyoshi
JAERI-Tech 2001-089, 52 Pages, 2002/01
JAERI-Tech-2001-089.pdf:5.05MB
The safety for corrosion of various metals applied to spent fuel dissolvers has been evaluated by the mock-up tests using small scaled equipment and the reference tests in laboratories with small specimens. These tests have been conducted under un-radioactive environments. The environment in practical reprocessing plants has many radioactive species. Therefore, the effect of irradiation on corrosion should be evaluated in detail.In this study, the corrosion testing equipment employed to simulate environments in a dissolver has been developed. This report describes the specification of corrosion testing equipment and the results of primary and reference and hot tests.Corrosion test using the equipment under heat transfer and irradiation conditions have been carried out for 1000 hours in safety. As a result, it has been indicated that zirconium has excellent corrosion resistance in fuel dissolved solution. It is expectable that useful corrosion test data in radioactive environment are accumulated with this equipment in future.
Sawa, Kazuhiro; Sumita, Junya; Ueta, Shohei; Suzuki, Shuichi*; Tobita, Tsutomu*; Saito, Takashi; Minato, Kazuo; Koya, Toshio; Sekino, Hajime
Journal of Nuclear Science and Technology, 38(6), p.403 - 410, 2001/06
Times Cited Count：7 Percentile：48.68(Nuclear Science & Technology)no abstracts in English
Motooka, Takafumi; Terakado, Shogo; Koya, Toshio; Hamada, Shozo; Kiuchi, Kiyoshi
JAERI-Tech 2001-023, 29 Pages, 2001/03
JAERI-Tech-2001-023.pdf:2.21MB
no abstracts in English
Minato, Kazuo; Sawa, Kazuhiro; Koya, Toshio; Tomita, Takeshi; Ishikawa, Akiyoshi; Baldwin, C. A.*; Gabbard, W. A.*; Malone, C. M.*
Nuclear Technology, 131(1), p.36 - 47, 2000/07
Times Cited Count：57 Percentile：94.74(Nuclear Science & Technology)no abstracts in English
Minato, Kazuo; Ogawa, Toru; Koya, Toshio; Sekino, Hajime; Tomita, Takeshi
Journal of Nuclear Materials, 279(2-3), p.181 - 188, 2000/06
Times Cited Count：34 Percentile：87.87(Materials Science, Multidisciplinary)no abstracts in English
Minato, Kazuo; Ogawa, Toru; Sawa, Kazuhiro; Sekino, Hajime; Koya, Toshio; Kitagawa, Isamu; Ishikawa, Akiyoshi; Tomita, Takeshi;
Proc. of the Int. Conf. on Future Nuclear Systems (GLOBAL'99)(CD-ROM), 8 Pages, 1999/00
no abstracts in English
Shiina, Hidenori; Nozawa, Yukio; Ono, Katsuto; Nishi, Masahiro; Koya, Toshio; Ishikawa, Akiyoshi
no journal, ,
