New design of high power mercury target vessel of J-PARC

Wakui, Takashi; Wakai, Eiichi; Kogawa, Hiroyuki; Naoe, Takashi; Hanano, Kohei*; Haga, Katsuhiro; Shimada, Tsubasa*; Kanomata, Kenichi*

Materials Science Forum, 1024, p.145 - 150, 2021/03

https://doi.org/10.4028/www.scientific.net/MSF.1024.145

To realize a high beam power operation at the J-PARC, a mercury target vessel covered with water shroud was developed. In the first step, to realize an operation at 500 kW, the basic structure of the initial design was followed and the connection method between the mercury vessel and the water shroud was changed. Additionally, the operation at a beam power of 500 kW was realized in approximately eight months. In the second step, to realize the operation at 1 MW, the new structure in which only rear ends of vessels were connected was investigated. Cooling of the mercury vessel is used to reduce thermal stress and thick vessels of the water shroud are used to increase stiffness for the internal pressure; therefore, it was adopted. The stress in each vessel was lower than the allowable stress based on the pressure vessel code criteria prescribed in the Japan Industrial Standard, and confirmation was obtained that the operation with a beam power of 1 MW could be conducted.

Development of determination method of Mo content in metal waste generated at the Japan Power Demonstration Reactor

Shimada, Asako; Omori, Hiroyuki*; Kameo, Yutaka

Journal of Radioanalytical and Nuclear Chemistry, 314(2), p.1361 - 1365, 2017/11

AA2017-0285.pdf:0.49MB

https://doi.org/10.1007/s10967-017-5440-6

A separation method of Mo from Nb, Zr, and the matrix elements of rubble waste was modified to determine the content of Mo in metal waste. A separation scheme to treat 1 g of metal waste was established by optimizing the amount of ascorbic acid, the rinsing solution, and repeating of the procedure. A thin-layer source was prepared using direct drop deposition and evaporation to measure Mo content. Finally, Mo content in the metal waste generated at the Japan Power Demonstration Reactor was analyzed using the developed method.

Probabilistic risk assessment method development for high temperature gas-cooled reactors, 2; Development of accident sequence analysis methodology

Matsuda, Kosuke*; Muramatsu, Ken*; Muta, Hitoshi*; Sato, Hiroyuki; Nishida, Akemi; Ohashi, Hirofumi; Itoi, Tatsuya*; Takada, Tsuyoshi*; Hida, Takenori*; Tanabe, Masayuki*; et al.

Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 7 Pages, 2017/04

This paper proposes a set of procedures for accident sequence analysis in seismic PRAs of HTGRs that can consider the unique accident progression characteristics of HTGRs. Main features of our proposed procedure are as follows: (1) Systematic analysis techniques including Master Logic Diagrams are used to ensure reasonable completeness in identification of initiating events and classification of accident sequences, (2) Information on factors that govern the accident progression and source terms are effectively reflected to the construction of event trees for delineation of accident sequences, and (3) Frequency quantification of seismically-initiated accident sequence frequencies that involve multiplepipe ruptures are made with the use of the Direct Quantification of Fault Trees by Monte Carlo (DQFM) method by a computer code SECOM-DQFM.

Nitrogen K-edge X-ray absorption near edge structure of pyrimidine-containing nucleotides in aqueous solution

Shimada, Hiroyuki*; Minami, Hirotake*; Okuizumi, Naoto*; Sakuma, Ichiro*; Ukai, Masatoshi*; Fujii, Kentaro; Yokoya, Akinari; Fukuda, Yoshihiro*; Saito, Yuji

Journal of Chemical Physics, 142(17), p.175102_1 - 175102_9, 2015/05

AA2015-0073.pdf:1.15MB

https://doi.org/10.1063/1.4919744

Nitrogen K-edge X-ray absorption near edge structure (XANES) spectra of purine-containing nucleotides in aqueous solution

Shimada, Hiroyuki*; Fukao, Taishi*; Minami, Hirotake*; Ukai, Masatoshi*; Fujii, Kentaro; Yokoya, Akinari; Fukuda, Yoshihiro*; Saito, Yuji

Journal of Chemical Physics, 141(5), p.055102_1 - 055102_8, 2014/08

https://doi.org/10.1063/1.4891480

Mizunami Underground Research Laboratory Project, Plan for fiscal year 2013

Hama, Katsuhiro; Mikake, Shinichiro; Nishio, Kazuhisa; Sasao, Eiji; Iwatsuki, Teruki; Takeuchi, Ryuji; Matsuoka, Toshiyuki; Tanno, Takeo*; Onoe, Hironori; Ogata, Nobuhisa; et al.

JAEA-Review 2013-044, 37 Pages, 2014/01

JAEA-Review-2013-044.pdf:6.36MB

The Mizunami Underground Research Laboratory (MIU) project is being pursued by the Japan Atomic Energy Agency (JAEA) to enhance the reliability of relevant disposal technologies through investigations of the deep geological environment within the host crystalline rock at Mizunami City in Gifu, central Japan. The project consists of major research areas, "Geoscientific Research", and proceeds in three overlapping phases, "Phase I: Surface-based investigation Phase", "Phase II: Construction Phase" and "Phase III: Operation Phase". The present report summarizes the research and development activities planned for fiscal year 2013 based on the MIU Master Plan updated in 2010.

Mizunami Underground Research Laboratory Project, Annual report for fiscal year 2011

Kunimaru, Takanori; Mikake, Shinichiro; Nishio, Kazuhisa; Tsuruta, Tadahiko; Matsuoka, Toshiyuki; Ishibashi, Masayuki; Sasao, Eiji; Hikima, Ryoichi; Tanno, Takeo; Sanada, Hiroyuki; et al.

JAEA-Review 2013-018, 169 Pages, 2013/09

JAEA-Review-2013-018.pdf:15.71MB

Japan Atomic Energy Agency (JAEA) at Tono Geoscience Center (TGC) is pursuing a geoscientific research and development project namely the Mizunami Underground Research Laboratory (MIU) Project in crystalline rock environment in order to construct scientific and technological basis for geological disposal of High-level Radioactive Waste (HLW). The MIU Project has three overlapping phases: Surface-based Investigation phase (Phase I), Construction phase (Phase II), and Operation phase (Phase III). The MIU Project has been ongoing the Phase II and the Phase III in 2011 fiscal year. This report shows the results of the investigation, construction and collaboration studies in fiscal year 2011, as a part of the Phase II and Phase III based on the MIU Master Plan updated in 2010.

Mizunami Underground Research Laboratory Project, Plan for fiscal year 2012

Kunimaru, Takanori; Mikake, Shinichiro; Nishio, Kazuhisa; Tsuruta, Tadahiko; Matsuoka, Toshiyuki; Ishibashi, Masayuki; Kuboshima, Koji; Takeuchi, Ryuji; Mizuno, Takashi; Sato, Toshinori; et al.

JAEA-Review 2012-028, 31 Pages, 2012/08

JAEA-Review-2012-028.pdf:3.86MB

Japan Atomic Energy Agency (JAEA) at Tono Geoscience Center (TGC) is pursuing a geoscientific research and development project namely the Mizunami Underground Research Laboratory (MIU) project in crystalline rock environment in order to construct scientific and technological basis for geological disposal of High-level Radioactive Waste (HLW). The MIU project is planned in three overlapping phases; Surface-based Investigation Phase (Phase I), Construction Phase (Phase II) and Operation Phase (Phase III). Currently, the project is under the Construction Phase and the Operation Phase. This document introduces the research and development activities planned for 2012 fiscal year based on the MIU Master Plan updated in 2010, construction plan and research collaboration plan, etc.

Interdisciplinary approach to improve and systematize the investigation and evaluation techniques on geological environment in relation to radioactive waste repository; Japanese fiscal year, 2010 (Contract research)

Kojima, Keiji*; Onishi, Yuzo*; Watanabe, Kunio*; Nishigaki, Makoto*; Tosaka, Hiroyuki*; Shimada, Jun*; Aoki, Kenji*; Tochiyama, Osamu*; Yoshida, Hidekazu*; Ogata, Nobuhisa; et al.

JAEA-Research 2011-033, 126 Pages, 2012/02

JAEA-Research-2011-033.pdf:31.33MB

The next advancements for the research of radioactive waste repository was started to improve and systematize the investigation and evaluation techniques on geological environment in consideration of intra-field of science and technology. Intra-field means the various fields among each study area of (a) geological environment, (b) design and engineering, (c) safety evaluation for radioactive waste repository, here. The following items were studied and discussed this year. (1) To Reconstruct Near Field (NF) Concept in consideration of coupled phenomena on geological environment. (2) To develop systematic investigation techniques on the geological environment in consideration of intra-field among each study area above mentioned (a), (b) and (c). Regarding (1), examination of NF concept focused on the realistic crystalline rock was carried out. Also through the overall discussion in the committee, comments from the all commissioners in relation to the intra-field of their study area were made to reflect on reconstruction of NF concept. Regarding (2), the research and development in consideration of NF and intra-field among each study area were conducted.

Development of groundwater treatment method using radiation-induced graft polymerization adsorbent at the Mizunami Underground Research Laboratory; Annual report for 2008 fiscal year (Joint research)

Iyatomi, Yosuke; Hoshina, Hiroyuki; Seko, Noriaki; Shimada, Akiomi; Ogata, Nobuhisa; Sugihara, Kozo; Kasai, Noboru; Ueki, Yuji; Tamada, Masao

JAEA-Technology 2010-045, 10 Pages, 2011/02

JAEA-Technology-2010-045.pdf:1.16MB

The concentrations of fluorine (7.2-10 mg/L) and boron (0.8-1.5 mg/L) dissolved in groundwater pumped from the shafts during excavation of the Mizunami Underground Research Laboratory (MIU), Tono Geoscience Centre, must be reduced to the levels below the environmental standards for fluorine: 0.8mg/L and boron: 1 mg/L. As well, collaborative research on groundwater treatment to remove fluorine and boron started in 2006 between the Environmental and Industrial Materials Research Division, Quantum Beam Science Directorate and the Tono Geoscientific Research Unit, Geological Isolation Research and Development Directorate. This is because the Quantum Beam Science Directorate has synthesized fibrous adsorbents with radiation-induced graft polymerization and applied adsorbents to collect rare metals dissolved in hot springs and sea water. The results of previous testing indicate that the adsorbent was able to remove more than 95% of the boron and fluorine and that performance of adsorbent for boron removal was better than the performance using ion-exchange resin. It was also apparent that the pH of groundwater had an influence on the performance of the adsorbent with respect to boron removal. Therefore we reran the recycling test using groundwater from the neutralization tank at the groundwater treatment facility. The results indicated that the performance of the adsorbent using neutral groundwater for boron removal was higher than using uncontrolled groundwater. However the bed volume (BV) with recycled adsorbent decreased compared to first use. It is thought that sulfur added at the groundwater treatment facility was retained by the adsorbent despite elution, and affected the performance such that repeat usage resulted in decreased efficiency. In addition, it is considered that the goals established in the first year compared to the results obtained to date, including the status of waste water treatment at the MIU, and summarized the results in this development.