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Togawa, Orihiko; Okura, Takehisa; Kimura, Masanori
JAEA-Review 2022-049, 76 Pages, 2023/01
JAEA-Review-2022-049.pdf:3.74MB
Before construction and after operation of nuclear facilities, environmental consequence assessments are conducted for normal operation and an emergency. These assessments mainly aim at confirming safety for the public around the facilities and producing relief for them. Environmental consequence assessments are carried out using observations/ measurements by environmental monitoring and/or model predictions by calculation models, sometimes using either of which and at other times using both them, according to the situations and necessities. First, this report investigates methods, roles, merits/demerits and relationship between observations/measurements and model predictions which are used for environmental consequence assessments of nuclear facilities, especially holding up a spent nuclear fuel reprocessing plant at Rokkasho, Aomori as an example. Next, it explains representative examples of utilization of data on observations/measurements and results on model predictions, and considers points of attention at using them. Finally, the report describes future direction, for example, improvements of observations/measurements and model predictions, and fusion of both them.
Maekawa, Fujio
JAEA-Conf 2022-001, p.7 - 13, 2022/11
The partitioning and transmutation (P-T) technology has promising potential for volume reduction and mitigation of degree of harmfulness of high-level radioactive waste. JAEA is developing the P-T technology combined with accelerator driven systems (ADS). One of critical issues affecting the feasibility of ADS is the proton beam window (PBW) which functions as a boundary between the accelerator and the sub-critical reactor core. The PBW is damaged by a high-intensity proton beam and spallation neutrons produced in the target, and also by flowing high-temperature liquid lead bismuth eutectic alloy which is corrosive to steel materials. To study the materials damage under the ADS environment, J-PARC is proposing a plan of proton irradiation facility which equips with a liquid lead-bismuth spallation target bombarded by a 400 MeV - 250 kW proton beam. The facility is also open for versatile purposes such as soft error testing of semi-conductor devises, RI production, materials irradiation for fission and fusion reactors, and so on. Application to nuclear data research with using the proton beam and spallation neutrons is also one of such versatile purposes, and we welcome unique ideas from the nuclear data community.
Task Force on Maintenance Optimization of Nuclear Facilities
JAEA-Technology 2022-006, 80 Pages, 2022/06
JAEA-Technology-2022-006.pdf:4.24MB
The Task force on maintenance optimization of nuclear facilities was organized in the Nuclear Science Research Institute (NSRI) of Japan Atomic Energy Agency (JAEA) since November 2020, in order to adequately respond to "the New nuclear regulatory inspection system since FY 2020" and to continuously improve the facility maintenance activities. In 2021, the task force has studied (1) optimization of the importance classification on maintenance and inspection of nuclear facilities, and (2) improvement in setting and evaluation of the performance indicators on safety, maintenance and quality management activities, considering "the Graded approach" that is one of the basic methodologies in the new nuclear regulatory inspection system. Each nuclear facility (research reactors, nuclear fuel material usage facilities, others) in the NSRI will steadily improve their respective safety, maintenance and quality management activities, referring the review results suggested by the task force.
Yonomoto, Taisuke; Nakashima, Hiroshi*; Sono, Hiroki; Kishimoto, Katsumi; Izawa, Kazuhiko; Kinase, Masami; Osa, Akihiko; Ogawa, Kazuhiko; Horiguchi, Hironori; Inoi, Hiroyuki; et al.
JAEA-Review 2020-056, 51 Pages, 2021/03
JAEA-Review-2020-056.pdf:3.26MB
A group named as "The group for investigation of reasonable safety assurance based on graded approach", which consists of about 10 staffs from Sector of Nuclear Science Research, Safety and Nuclear Security Administration Department, departments for management of nuclear facility, Sector of Nuclear Safety Research and Emergency Preparedness, aims to realize effective graded approach (GA) about management of facilities and regulatory compliance of JAEA. The group started its activities in September, 2019 and has had discussions through 10 meetings and email communications. In the meetings, basic ideas of GA, status of compliance with new regulatory standards at each facility, new inspection system, etc were discussed, while individual investigation at each facility were shared among the members. This report is compiled with expectation that it will help promote rational and effective safety management based on GA by sharing contents of the activity widely inside and outside JAEA.
Seki, Masakazu; Maekawa, Tomoyuki; Izawa, Kazuhiko; Sono, Hiroki
JAEA-Technology 2017-038, 52 Pages, 2018/03
JAEA-Technology-2017-038.pdf:4.6MB
The Japan Atomic Energy Agency is conducting a reactor modification project of the Static Experiment Critical Facility (STACY). In the modification, STACY is to be converted from a thermal reactor using solution fuel into that using fuel rods and light water moderator. Reactivity of the modified STACY core is controlled by the water level fed in the core tank as well as the present STACY. In order to verify the basic design of the water feed and drain system of the modified STACY, we constructed a mockup test apparatus with almost the same structure and specifications as the modified STACY. In the mockup test, performance checks were pursued regarding limitation of maximum flow of water feeding, adjustment of the flow rate of water feeding, stop of water feeding and others. This report describes the outline and results of the mock-up test of the water feed and drain system of the modified STACY.
Yoshikawa, Hideki
Enerugi Rebyu, 37(10), p.13 - 14, 2017/10
We introduce the R&D activities of Japan Atomic Energy Agency immediately after the accident at Fukushima Daiichi Nuclear Power Station and some facilities established in Fukushima Prefecture.
Iwamoto, Hiroki; Meigo, Shinichiro
EPJ Web of Conferences, 153, p.01016_1 - 01016_9, 2017/09
Times Cited Count：3 Percentile：76.20(Nuclear Science & Technology)Amano, Yuki; Watanabe, Koji; Masaki, Tomoo; Tashiro, Shinsuke; Abe, Hitoshi
JAEA-Technology 2016-012, 21 Pages, 2016/06
JAEA-Technology-2016-012.pdf:1.81MB
To contribute to safety evaluation of fire accident in fuel reprocessing plants, solvent extraction behavior of ruthenium, which could form volatile species, was investigated. Distribution ratios of ruthenium at fire accident conditions were obtained by extraction experiments with several solvent composition at different temperature as parameters. In order to investigate release behavior of ruthenium and europium at fire accident, release ratios of ruthenium and europium were also obtained by solvent combustion experiments.
Okumura, Keisuke; Kojima, Kensuke; Tanaka, Kenichi*
JAEA-Conf 2015-003, p.43 - 47, 2016/03
In the safety assessment concerning disposal of radioactive wastes generated in the decommissioning of nuclear facilities, it is necessary to evaluate the radionuclide inventory produced by the activation of structured materials. For this purpose, we have to pay much attention to the activation of many impurities irradiated in various neutron spectra depending on their positions and materials. Therefore, accurate activation cross-section data are necessary for many nuclides and reactions. A new multi-group neutron activation cross-section library (MAXS) was developed based on the recent nuclear data JENDL-4.0 and JEFF-3.0/A to apply it to the activation calculations for the decommissioning of nuclear facilities. The library contains cross-sections and isomeric ratios for many reactions such as (n,
), (n,f), (n,2n), (n,3n), (n,p), (n,
), (n,d), (n,t), (n,n), (n,np), and so on, for 779 nuclides, in the 199-energy group structure of VITAMIN-B6.
Mascari, F.*; Nakamura, Hideo; Umminger, K.*; De Rosa, F.*; D'Auria, F.*
Proceedings of 16th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-16) (USB Flash Drive), p.4921 - 4934, 2015/08
Abe, Hitoshi; Masaki, Tomoo; Amano, Yuki; Uchiyama, Gunzo
JAEA-Research 2014-022, 12 Pages, 2014/11
JAEA-Research-2014-022.pdf:1.03MB
To contribute safety evaluation of boiling and drying accident of high active liquid waste (HALW) in fuel reprocessing plant, release behavior of Ru, which was considered as an important nuclide for evaluating public dose from the volatile viewpoint, has been investigated. It has been reported that release of Ru becomes conspicuously after HALW is dried up. In this work, to grasp the release behavior of Ru, release ratio of Ru with thermal decomposition of Ru nitrate, which would be in the dried HALW, was measured and release rate constant of Ru from the nitrate was estimated. It was found that the calculation result of release rate of Ru from the nitrate with rise of temperature by using the constant could well simulate the result acquired from the beaker-scale experiment.
Oigawa, Hiroyuki; Sasa, Toshinobu; Kikuchi, Kenji; Nishihara, Kenji; Kurata, Yuji; Umeno, Makoto*; Tsujimoto, Kazufumi; Saito, Shigeru; Futakawa, Masatoshi; Mizumoto, Motoharu; et al.
Proceedings of 4th International Workshop on the Utilisation and Reliability of High Power Proton Accelerators, p.507 - 517, 2005/11
Under the framework of J-PARC, the Japan Atomic Energy Research Institute (JAERI) plans to construct the Transmutation Experimental Facility (TEF). The TEF consists of two facilities: the Transmutation Physics Experimental Facility (TEF-P) and the ADS Target Test Facility (TEF-T). The TEF-P is a critical facility which can accept a 600 MeV - 10 W proton beam. The TEF-T is a material irradiation facility using a 600 MeV - 200 kW proton beam, where a Pb-Bi target is installed, but neutron multiplication by nuclear fuel will not be attempted. This report describes the purposes of the facility, the present status of the conceptual design, and the expected experiments to be performed.
Hayashi, Koji; Inagaki, Yoshiyuki; Kato, Michio; Fujisaki, Katsuo*; Aita, Hideki; Takeda, Tetsuaki; Nishihara, Tetsuo; Inaba, Yoshitomo; Ohashi, Hirofumi; Katanishi, Shoji; et al.
JAERI-Tech 2005-032, 46 Pages, 2005/06
JAERI-Tech-2005-032.pdf:4.79MB
This is annual report on the experimental operation of the mock-up test facility with a full-scale reaction tube for the HTTR hydrogen production system in 2001 fiscal year. The first experimental operation was performed during two weeks from March 1, 2002 to March 13, 2002 to test on the thermal hydraulic performance of the steam reformer and also to train the operators. The thermal hydraulic performance test of the steam reformer was performed to evaluate the heat transfer characteristics between helium gas and process gas in the steam reformer. This report is summarized with an overview of the test, the results and its operation records.
Oka, Kiyoshi
JAERI-Research 2004-009, 225 Pages, 2004/07
JAERI-Research-2004-009.pdf:47.47MB
In the present paper, I describe the necessary approaches and elemental technologies to solve the issues on the system integration of the typical robot systems for maintenance in the nuclear fusion facility and rescue in the accident of the nuclear power plant facilities. These robots work under the intense radiation condition and restricted space in place of human. In particular, I propose a new approach to realize the system integration of the robot for actual use from the viewpoints of not only the environmental and working conditions but also the restructure and optimization of the required elemental technologies with a well balance in the robot system. Based on the above approach, I have a contribution to realize the robot systems working under the actual conditions for maintenance in the nuclear fusion facility and rescue in the accident of the nuclear power plant facilities.
Watanabe, Koji; Tashiro, Shinsuke; Abe, Hitoshi; Takada, Junichi; Morita, Yasuji
JAERI-Tech 2004-029, 48 Pages, 2004/03
JAERI-Tech-2004-029.pdf:3.19MB
In a part of building ventilating installation of a nuclear fuel facility, a reprocessing plant for example, the pre-filters are adopted as one of the ventilation filters. In a fire accident, it is supposed that, because of the pre-filter clogging by large smoke, its differential pressure (
p) is evolved up to the value at its breakage. Therefore, in regard to maintaining the confinement of radioactive materials, it is important to predict the time course of p of the pre-filter accurately. In the current study, it was assumed that the empirical equation for the DF of the pre-filter as function of smoke particle diameter (SPD), between 0.7-2 
m, could be applied to estimating its DF for SPD above 2 m. Under this assumption, the time corresponding to its p at its breakage, calculated by CELVA-1D, was agreed well with the experimental result.
Kiyanagi, Yoshiaki*; Nagamiya, Shoji*; Oyama, Yukio; Ikeda, Yujiro; Oigawa, Hiroyuki; Igashira, Masayuki*; Baba, Mamoru*; Iwasaki, Tomohiko*; Watanabe, Yukinobu*; Ishibashi, Kenji*
Nihon Genshiryoku Gakkai-Shi, 46(3), p.173 - 197, 2004/03
no abstracts in English
Kobayashi, Tadayoshi; Miyajima, Kazutoshi; Yanagihara, Satoshi
Keisoku Jido Seigyo Gakkai Dai-3-Kai Shisutemu Integureshon Bumon Koenkai (SI2002) Koen Rombunshu, 2, p.105 - 106, 2002/00
no abstracts in English
Ishii, Toshimitsu; Ooka, Norikazu; Naka, Michihiro; Kanaya, Kunio; Saito, Junichi; Okamoto, Yoshizo*
Proceedings of 6th Far-East Conference on Nondestructive Testing (FENDT '02), p.273 - 278, 2002/00
no abstracts in English
Shibanuma, Kiyoshi
Denki Kyokai-Ho, (925), p.20 - 23, 2001/11
no abstracts in English
Tachibana, Mitsuo; Hatakeyama, Mutsuo; Yanagihara, Satoshi
Nihon Genshiryoku Gakkai-Shi, 41(6), p.677 - 685, 1999/00
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)no abstracts in English
