In-operando distribution measurement of internal temperature and stress in lithium-ion battery

Hirano, Tatsumi*; Maeda, Takehiro*; Murata, Tetsuyuki*; Yamamoto, Takahiro*; Matsubara, Eiichiro*; Shobu, Takahisa; Shiro, Ayumi*; Yasuda, Ryo*; Takamatsu, Daiko*

SPring-8/SACLA Riyo Kenkyu Seikashu (Internet), 11(5), p.345 - 353, 2023/10

https://doi.org/10.18957/rr.11.5.345

no abstracts in English

Decommissioning state of Plutonium Fuel Fabrication Facility; Dismantling the glove box W-9 and equipment interior, and a part of tunnel F1

Nagai, Yuya; Shuji, Yoshiyuki; Kawasaki, Takeshi; Aita, Takahiro; Kimura, Yasuhisa; Nemoto, Yasunori*; Onuma, Takeshi*; Tomiyama, Noboru*; Hirano, Koji*; Usui, Yasuhiro*; et al.

JAEA-Technology 2022-039, 117 Pages, 2023/06

JAEA-Technology-2022-039.pdf:11.96MB

Japan Atomic Energy Agency (JAEA) manages wide range of nuclear facilities. Many of these facilities are required to be performed adjustment with the aging and complement with the new regulatory standards and the earthquake resistant, since the Great East Japan Earthquake and the Fukushima Daiichi Nuclear Power Station accident. It is therefore desirable to promote decommissioning of facilities that have reached the end of their productive life in order to reduce risk and maintenance costs. However, the progress of facility decommissioning require large amount of money and radioactive waste storage space. In order to address these issues, JAEA has formulated a "The Medium/Long-Term Management Plan of JAEA Facilities" with three pillars: (1) consolidation and prioritization of facilities, (2) assurance of facility safety, and (3) back-end countermeasures. In this plan, Plutonium Fuel Fabrication Facility has been selected as primary decommissioned facility, and dismantling of equipment in the facilities have been underway. In this report, size reduction activities of the glove box W-9 and a part of tunnel F-1, which was connected to W-9, are presented, and the obtained findings are highlighted. The glovebox W-9 had oxidation & reduction furnace, and pellet crushing machine as equipment interior. The duration of activity took six years from February 2014 to February 2020, including suspended period of 4 years due to the enhanced authorization approval process

Consideration of a quick exit from plastic tents in an event of emergency while working with air-fed suits: Evaluation of applicability of plastic enclosure tents for body decontamination

Asakawa, Jun; Hirano, Hiroshi*; Nagai, Yuya; Aita, Takahiro; Shibanuma, Tomohiro; Kimura, Yasuhisa

Hoken Butsuri (Internet), 57(2), p.93 - 101, 2022/09

https://doi.org/10.5453/jhps.57.93

In the dismantling work of glove boxes (GBs) contaminated with radioactive materials at the nuclear fuel facilities, plastic tents are constructed around the entire GBs, and workers putting on air-fed suits (AFS) (hereinafter referred to as AFS worker) dismantle the GBs and interior equipment by using cutting tools. If an AFS worker suddenly feels sick during the work and the worker is unable to move independently, it will be necessary to exit in the shortest time from the viewpoint of respecting human life. In this case, a lot of radioactive materials may be brought into the contamination control room, thus the room and the equipment of the workers may be contaminated. Consequently, until the decontamination work is completed, the other AFS workers will have to put on AFS and wait for long time, which puts a strain on the workers. In this report, the plastic enclosure tents for body decontamination developed in JAEA were used as a new contamination control room replaced the contaminated one, and the procedure to quickly exit the remaining AFS workers was proposed. As a result, we confirmed that it was possible to greatly reduce the waiting time of the other AFS workers who is forced to wait in the dismantling area.

Present status of J-PARC linac

Oguri, Hidetomo; Hasegawa, Kazuo; Ito, Takashi; Chishiro, Etsuji; Hirano, Koichiro; Morishita, Takatoshi; Shinozaki, Shinichi; Ao, Hiroyuki; Okoshi, Kiyonori; Kondo, Yasuhiro; et al.

Proceedings of 11th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.389 - 393, 2014/10

http://www.pasj.jp/web_publish/pasj2014/proceedings/PDF/FSP0/FSP021.pdf

no abstracts in English

Conservative evaluation of remaining radioactivity on decommissioned nuclear power plant sites

Tanaka, Tadao; Shimada, Taro; Ito, Takeshi*; Hirano, Takahiro*; Sukegawa, Takenori

Progress in Nuclear Science and Technology (Internet), 1, p.408 - 411, 2011/02

https://doi.org/10.15669/pnst.1.408

Nuclear power plant sites are allowed to be released from nuclear safety regulations after the plants are decommissioned in Japan. The regulatory compliance will require confirming that there is no significant radioactivity remaining on the sites for the site release. In the present study, we propose an evaluation method of Cs-137 remaining on sites of decommissioned nuclear power plants. The method is time-efficient and gives a conservative result. In the evaluation method concept, all of the Cs-137, which is in reality distributed across the area of interest, is assumed to be the single point source located at the furthest position on the surface of the area from a detector. For such a configuration, the counting time that the Cs-137 point source is detectable is predicted using Monte Carlo calculations. If radiation from the Cs-137 point source is not detected for longer than the predicted counting time, it can be proven that the radioactivity remaining on the surface of the area is lower than the radioactivity corresponding to the assumed Cs-137 point source. A Cs-137 radiation source was placed at a fixed distance from the Ge detector, and the peak counting rate of Cs-137 were measured. The detectable time predicted by Monte Carlo calculations was approximately equal to the actual measurement time by the Ge detector, which means that the proposed evaluation method was reasonable for the conservative evaluation of remaining radioactivity.

Detailed analyses of specific phenomena in core disruptive accidents of sodium-cooled fast reactors by the COMPASS code

Morita, Koji*; Zhang, S.*; Arima, Tatsumi*; Koshizuka, Seiichi*; Tobita, Yoshiharu; Yamano, Hidemasa; Ito, Takahiro*; Shirakawa, Noriyuki*; Inoue, Fusao*; Yugo, Hiroaki*; et al.

Proceedings of 18th International Conference on Nuclear Engineering (ICONE-18) (CD-ROM), 9 Pages, 2010/05

https://doi.org/10.1115/ICONE18-29886

A five-year research project has been initiated in 2005 to develop a code based on the MPS (Moving Particle Semi-implicit) method for detailed analysis of specific phenomena in core disruptive accidents (CDAs) of sodium-cooled fast reactors (SFRs). The code is named COMPASS (Computer Code with Moving Particle Semi-implicit for Reactor Safety Analysis). The specific phenomena include (1) fuel pin failure and disruption, (2) molten pool boiling, (3) melt freezing and blockage formation, (4) duct wall failure, (5) low-energy disruptive core motion, (6) debris-bed coolability, and (7) metal-fuel pin failure. Validation study of COMPASS is progressing for these key phenomena. In this paper, recent COMPASS results of detailed analyses for the several specific phenomena are summarized.

Neoclassical tearing mode control using electron cyclotron current drive and magnetic island evolution in JT-60U

Isayama, Akihiko; Matsunaga, Go; Kobayashi, Takayuki; Moriyama, Shinichi; Oyama, Naoyuki; Sakamoto, Yoshiteru; Suzuki, Takahiro; Urano, Hajime; Hayashi, Nobuhiko; Kamada, Yutaka; et al.

Nuclear Fusion, 49(5), p.055006_1 - 055006_9, 2009/05

https://doi.org/10.1088/0029-5515/49/5/055006

no abstracts in English

Clearance assessment for building concrete through bulk in-situ -spectrometry (Contract research)

Maeda, Shingo*; Hirano, Takahiro*; Shimada, Taro; Nakayama, Shinichi

JAEA-Technology 2008-066, 35 Pages, 2008/10

JAEA-Technology-2008-066.pdf:4.83MB

Bulk in-situ -spectroscopy is effective for a slightly and uniformly contaminated surface such as a room surrounded by concrete walls. The time-consuming scoping scanning survey for the entire surface is essential to ensure the slight and uniform contamination prior to the bulk in-situ measurement. However, the scoping scanning survey is omissible if the conservative procedure is acceptable. The count rate, cps, for the material of interest can be obtained by in-situ Ge detector will be converted to the radioactivity using conversion factor, Bq/cps, which depends on the distance from the detector to the furthest point. The radioactive concentration, Bq/g, is evaluated by dividing the radioactivity by the "measurement unit" of 100 kg. This procedure could certainly produce a conservative value. If the value obtained by this procedure is lower than the regulated clearance level, the material of interest can be cleared without the prior scoping scanning survey.

Code development for core disruptive accidents in sodium-cooled fast reactors

Koshizuka, Seiichi*; Liu, J.*; Morita, Koji*; Arima, Tatsumi*; Zhang, S.*; Tobita, Yoshiharu; Yamano, Hidemasa; Ito, Takahiro*; Naito, Masanori*; Shirakawa, Noriyuki*; et al.

Proceedings of IAEA Topical Meeting on Advanced Safety Assessment Methods for Nuclear Reactors (CD-ROM), 9 Pages, 2007/10

A computer code, named COMPASS (Computer Code with Moving Particle Semi-implicit for Reactor Safety Analysis), is being developed for various complex phenomena of core disruptive accidents (CDAs) in sodium-cooled fast reactors (SFRs). Theoretical studies are performed about a unified algorithm for compressible and incompressible flows, fluid flow with solid debris, and algorithm improvement for free surface flows. Code verification and validation procedures are established by exploiting the past experiences in those of SIMMER-III code. COMPASS will be used for separated phenomena in CDAs, while the whole core will be analyzed by SIMMER-III. COMPASS is expected to clarify the detailed process in duct wall failure and fuel discharge to avoid re-criticality during CDAs in large size SFRs.

R&D of the next generation safety analysis methods for fast reactors with new computational science and technology, 8; Status of R&D in FY2006

Koshizuka, Seiichi*; Liu, J.*; Morita, Koji*; Arima, Tatsumi*; Zhang, S.*; Tobita, Yoshiharu; Yamano, Hidemasa; Ito, Takahiro*; Naito, Masanori*; Shirakawa, Noriyuki*; et al.

no journal, , 

A computer code is developed based on a particle method technology in order to simulate in detail various phenomana in core disruptive accidents in fast reactors. This report is a summary of progress during FY2006 in a five-year project of the code development.