Manufacture of substitutive assemblies for MONJU reactor decommissioning

Sakakibara, Hiroshi; Aoki, Nobuhiro; Muto, Masahiro; Otabe, Jun; Takahashi, Kenji*; Fujita, Naoyuki*; Hiyama, Kazuhiko*; Suzuki, Hirokazu*; Kamogawa, Toshiyuki*; Yokosuka, Toru*; et al.

JAEA-Technology 2020-020, 73 Pages, 2021/03

JAEA-Technology-2020-020.pdf:8.26MB

The decommissioning is currently in progress at the prototype fast breeder reactor Monju. Fuel assemblies will be taken out of its core for the first step of the great task. Fuel assemblies stand on their own spike plugged into a socket on the core support plate and support with adjacent assemblies through their housing pads each other, resulting in steady core structure. For this reason, some substitutive assemblies are necessary for the purpose of discharging the fuel assemblies of the core. Monju side commissioned, therefore, Plutonium Fuel Development Center to manufacture the substitutive assemblies and the Center accepted it. This report gives descriptions of design, manufacture, and shipment in regard to the substitutive assemblies.

Sensitivity analysis for the scenarios on deterioration or loss of safety functions expected in disposal system due to human error on application of engineering technology

Takeda, Seiji; Inoue, Yoshihisa; Kimura, Hideo

Materials Research Society Symposium Proceedings, Vol.1518, p.237 - 242, 2013/10

https://doi.org/10.1557/opl.2013.89

The sensitive analysis of radionuclide migration for the scenarios on deterioration or loss of safety functions expected in HLW disposal system due to the human error (initial defective scenarios) is performed in this study. Release rates for Cs-135 and Se-79 are estimated from Monte Carlo-based analysis. Maximum release rates of radionuclides for initial defective scenarios, buffer (colloidal transport case) and sealing plugs (pathway of short-circuit), are about one or two order magnitude higher than that normal scenario. From a viewpoint of future safety review, these results especially indicate the need to understand the feasibility on two types of initial defective scenario for the buffer and sealing plugs, leading to the loss of restraint of colloidal migration in the buffer and the loss of restraint with the plugs from migration through dominant pathway in tunnels and their vicinity.

Sorption distribution coefficients of selenium on a sandy mudstone under reducing conditions of underground

Iida, Yoshihisa; Kimura, Yuichiro*; Yamaguchi, Tetsuji; Ueda, Masato*; Tanaka, Tadao; Nakayama, Shinichi

Genshiryoku Bakkuendo Kenkyu, 15(2), p.57 - 67, 2009/03

https://doi.org/10.3327/jnuce.15.57

Sorption of radionuclides on rocks is an important factor for safety assessments of geologic disposal of radioactive wastes. Batch sorption tests were conducted to investigate effects of concentrations of NaNO and NaCl on sorption distribution coefficients(Kd) of selenium(Se) on a sandy mudstone under reducing environment of underground. The rock and groundwater used in the tests were sampled from depths of 129-156 m with special care minimizing contact with air. Se was spiked as HSe or Se to the test solutions and kept as HSe throughout the test periods by keeping reducing conditions (Eh, pH) of the solutions. Obtained Kd values were in a range of 0.015-0.037 m kg, which were as high as those for a typical sorbing element, Cs.

New method to measure the rise time of a fast pulse slicer for laser ion acceleration research

Mori, Michiaki; Yogo, Akifumi; Kiriyama, Hiromitsu; Nishiuchi, Mamiko; Ogura, Koichi; Orimo, Satoshi; Ma, J.*; Sagisaka, Akito; Kanazawa, Shuhei; Kondo, Shuji; et al.

IEEE Transactions on Plasma Science, 36(4), p.1872 - 1877, 2008/08

https://doi.org/10.1109/TPS.2008.2000886

A dependence of cut-off proton kinetic energy on laser prepulse duration has been observed. ASE pedestal duration is controlled by a fast electro-optic pulse slicer where the risetime is estimated to be 130 ps. We demonstrate a new correlated spectral technique for determining this risetime using a stretched, frequency chirped pulse.

Development of laser driven proton sources and their applications

Daido, Hiroyuki; Sagisaka, Akito; Ogura, Koichi; Orimo, Satoshi; Nishiuchi, Mamiko; Mori, Michiaki; Ma, J.-L.; Pirozhkov, A. S.; Kiriyama, Hiromitsu; Kanazawa, Shuhei; et al.

Proceedings of 7th Pacific Rim Conference on Lasers and Electro-Optics (CLEO-PR 2007) (CD-ROM), p.77 - 79, 2007/00

http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=4391143

We are developing a proton accelerator using an intense lasers with a focused intensity of 10 W/cm. To monitor proton energy spectra as well as plasma parameters at each laser shot, we are using real time detectors. The proton energy of MeV is stably obtained for applications.

Determination of distribution coefficients on rocks under maintained reducing conditions of underground, 1; Considerations on reducing conditions of underground

Yamaguchi, Tetsuji; Kimura, Yuichiro; Iida, Yoshihisa; Tanaka, Tadao; Nakayama, Shinichi; Ueda, Masato*; Araki, Kunio*

no journal, , 

no abstracts in English

Experimental research for long term evaluation on radioactive waste disposal; Progress in 2006

Tanaka, Tadao; Yamaguchi, Tetsuji; Iida, Yoshihisa; Kimura, Yuichiro; Taki, Hiroshi; Fujiwara, Takeshi; Ueda, Masato*; Mukai, Masayuki; Yamada, Fumika; Mizuno, Tsuyoshi; et al.

no journal, , 

no abstracts in English

Energetic proton beam generation driven by J-KAREN laser

Mori, Michiaki; Yogo, Akifumi; Orimo, Satoshi; Ogura, Koichi; Sagisaka, Akito; Nakamura, Shu*; Shirai, Toshiyuki*; Iwashita, Yoshihisa*; Noda, Akira*; Oishi, Yuji*; et al.

no journal, , 

no abstracts in English

Improvement of the JAEA J-KAREN laser and its applications to high field science, 4; Phase rotation technique of the intense and short pulse laser driven proton beam by synchronous RF field

Nishiuchi, Mamiko; Daido, Hiroyuki; Yogo, Akifumi; Mori, Michiaki; Kiriyama, Hiromitsu; Kanazawa, Shuhei; Sagisaka, Akito; Ogura, Koichi; Orimo, Satoshi; Kondo, Shuji; et al.

no journal, , 

By applying the RF filed to the high intensity short pulse laser-driven MeV proton beam, we have demonstrated the generation of the quasi-monoenegetic proton spectra and modification of the spatial distribution of proton beams. We used J-KAREN laser system at the JAEA. We focused it to Polyimide target. The intensity was 410Wcm. We produced repetetively the proton beams with the maximum energy of 2.2 MeV. We guided this proton beam to the cabvity of the RF field. We observed significant energy peaks in the proton energy spectra. The resultant energy concentration was 11 % (FWHM) out of 100 %. At the same time, we could change the divergence of the beam with the RF field. According to the Monte-Carlo simulation, the spatially converging proton beam has energy spectra with the energy spread of 100 %, on the contrary the spatially diverging beam has mono-energetic energy spectra. This method is very useful because it can apply to repetitivelly produced proton beams to control the energy as well as spatial distributions.

Energetic ion beam generation driven by J-KAREN laser

Mori, Michiaki; Yogo, Akifumi; Kiriyama, Hiromitsu; Sagisaka, Akito; Ma, J.-L.; Ogura, Koichi; Orimo, Satoshi; Nishiuchi, Mamiko; Pirozhkov, A. S.; Okada, Hajime; et al.

no journal, , 

no abstracts in English