The Outline of investigation on integrity of JMTR concrete structures, cooling system and utility facilities

Ebisawa, Hiroyuki; Hanakawa, Hiroki; Asano, Norikazu; Kusunoki, Hidehiko; Yanai, Tomohiro; Sato, Shinichi; Miyauchi, Masaru; Oto, Tsutomu; Kimura, Tadashi; Kawamata, Takanori; et al.

JAEA-Technology 2009-030, 165 Pages, 2009/07

JAEA-Technology-2009-030.pdf:69.18MB

The condition of facilities and machinery used continuously were investigated before the renewal work of JMTR on FY 2007. The subjects of investigation were reactor building, primary cooling system tanks, secondary cooling system piping and tower, emergency generator and so on. As the result, it was confirmed that some facilities and machinery were necessary to repair and others were used continuously for long term by maintaining on the long-term maintenance plan. JMTR is planed to renew by the result of this investigation.

REIDAC; A Software package for retrospective dose assessment in internal contamination of radionuclides

Kurihara, Osamu; Hato, Shinji; Kanai, Katsuta; Takada, Chie; Takasaki, Koji; Ito, Kimio; Ikeda, Hiroshi*; Oeda, Mikihiro*; Kurosawa, Naohiro*; Fukutsu, Kumiko*; et al.

Journal of Nuclear Science and Technology, 44(10), p.1337 - 1346, 2007/10

https://doi.org/10.3327/jnst.44.1337

In the case of internal contamination of radionuclides, it is necessary to perform internal dose assessment for radiation protection. For this purpose, the ICRP has given the dose coefficients and the retention and excretion rates for various radionuclides. However, these dosimetric quantities are calculated only in typical conditions, therefore, are not necessarily covered enough in the case of dose assessment in which specific information on the incident or/and individual biokinetic characteristics should be taken into account retrospectively. This paper describes a developed PC-based package of software REIDAC to meet the needs in retrospective dose assessment. REIDAC was verified by comparisons with dosimetric quantities given on the ICRP publications and several examples of practical use were also shown.

Development of New Decladding System in the Reprocessing Process for FBR Fuel

Washiya, Tadahiro; Koizumi, Kenji; Koichi, Sugai,*; Takashi, Suganuma,; Aose, Shinichi

Saikuru Kiko Giho, (25), p.33 - 44, 2004/00

https://rdreview.jaea.go.jp/gihou/pdf3/n25-04.pdf

As a part of the feasibility study (FS) on commercialized fast reactor cycle systems, JNC has been developing the fuel decladding technology for the dry reprocessing process (oxide electrowinning process). In this process, the spent fuel should be reduced to powder for quick dissolution in the molten salt at electrolyzer. Therefore, JNC proposes new decladding system with innovative mechanical decradding devices. The decladding system consists of fuel crushing stage, hull separation stage and hull rinsing stage. In the fuel crushing stage, disassembled spent fuel pins are crushed and powdered by mechanical decladding device, then the following stage, the hull and the fuel powder are separated by magnetic separator. Only the fuel powder is fed to the electrolyzer. On the other side, the separated hull is melted by induction heating method, and the small amount of oxide included in the hull fragments is recovered at the hull rinsing stage. The recovered oxide fuel is fed back to the electrolyzer.

Study on radiation effects of commercial-off-the-shelf devices in space environment

Maeda, Takahiro*; Kakimi, Yukitaka*; Sasaki, Naoki*; Akashi, Kenji*; Oshima, Takeshi; Onoda, Shinobu

no journal, , 

no abstracts in English

Effect of particle properties on die filling behavior in nuclear oxide fuel pellet production

Akashi, Masatoshi; Nishina, Masahiro; Kato, Masato; Tanaka, Tatsuya*; Shimosaka, Atsuko*; Shirakawa, Yoshiyuki*; Hidaka, Jusuke*

no journal, , 

The Outline of fuel debris characterization; Large scale MCCI tests and MOX simulated fuel, etc.

Kitagaki, Toru; Ikeuchi, Hirotomo; Yano, Kimihiko; Hoshino, Takanori; Okamura, Nobuo; Hirooka, Shun; Akashi, Masatoshi; Watanabe, Masashi; Morimoto, Kyoichi; Ogino, Hideki; et al.

no journal, , 

no abstracts in English

Development of an apparatus for renitridation of TRU-Cd alloys aiming at engineering-scale tests with surrogates

Sato, Takumi; Akashi, Shin; Hayashi, Hirokazu

no journal, , 

no abstracts in English

Measurement of Gibbs free energy of formation of GdCd

Akashi, Shin; Shibata, Hiroki; Sato, Takumi; Hayashi, Hirokazu

no journal, , 

It is important to evaluate the thermodynamic stability of TRU-Cd intermetallic compounds to select the detailed conditions of the nitridation-distillation combined process. In this study, Gibbs free energy of formation of gadolinium (Gd)-Cd alloy which is used as a surrogate of the TRU-Cd alloy was measured. Gd-Cd alloy was prepared by heating Gd metal with Cd metal (atomic ratio=1:10) in a tungsten crucible sealed in an evacuated quartz tube at 773K for 4 hours. The prepared alloy was identified as the mixture of GdCd and Cd with X-ray diffraction measurement of the filed samples at room temperature. The potential of Gd-Cd alloy sample set in a tungsten crucible versus Ag/AgCl reference electrode was measured in (LiCl-KCl)-GdCl at 673-923 K. The electromotive force () of the cell (Gd (LiCl-KCl)-GdCl Gd-Cd) was calculated from the difference of the measured potential of Gd-Cd alloy sample and that of Gd metal. The latter was deposited on a tungsten electrode by potentiostatic electrolysis in (LiCl-KCl)-GdCl. Gibbs free energies of formation ( ) of GdCd calculated with the equation ( (GdCd)= -3 ) agree well with our data obtained by the electrochemical technique using the sample formed by co-deposition of Gd and Cd in a molten salt and the reported data obtained by Cd vapor pressure measurement. This result shows that method of this study is valid for the measurement of (GdCd).

Recent progress on development of pyroprocessing technology for minor actinide transmutation nitride fuels

Hayashi, Hirokazu; Sato, Takumi; Tateno, Haruka*; Akashi, Shin*; Shibata, Hiroki; Tsubata, Yasuhiro

no journal, , 

Japan Atomic Energy Agency (JAEA) has been developing the technology on transmutation of MA under the double strata fuel cycle concept. A combination of uranium-free Pu-MA-Zr nitride fuel and pyroprocessing has been chosen as the first candidate for MA transmutation fuel cycle using accelerator-driven system (ADS). This paper introduces the recent progress ondevelopment of pyroprocessing technology for MA transmutation nitride fuels. It contains a detailed design of the flowsheet on the electrorefining process of the spent fuels and the behavior of metal elements in renitridation process.

Remote control technology for monitoring inside RPV pedestal during retrieval of fuel debris; Prototype experiments

Matsuhira, Nobuto*; Komatsu, Ren*; Nakashima, Shinsuke*; Yamashita, Atsushi*; Fukui, Rui*; Takahashi, Hiroyuki*; Shimazoe, Kenji*; Woo, H.*; Tamura, Yusuke*; Takashi, Takayuki*; et al.

no journal, , 

This research aims to develop human resources in the field of remote technology for the decommissioning of the Fukushima Daiichi Nuclear Power Plant. We conduct research on a monitoring platform for fuel debris removal. Here, the developments on prototype experiments were described. We expect to develop research personnel through participation in projects, lectures, and facility tours.