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Kamikawa, Yutaka; Suzuki, Makoto; Agake, Toshiki; Murakami, Takahiko; Morita, Yusuke; Shiina, Hidenori; Fukushima, Manabu; Hirane, Nobuhiko; Ouchi, Yasuhiro
JAEA-Technology 2023-030, 57 Pages, 2024/03
JAEA-Technology-2023-030.pdf:1.93MB
Owing to the publication of the latest data about aircraft crashes by Nuclear Regulation Authority (NRA), it was necessary to re-evaluate the probabilities of aircraft crashes for Nuclear Science Research Institute (NSRI). By using of the assessment method provided in "Regulatory Guide of the Assessment Standard for Probability of Airplane Crash on a Nuclear Power Reactor Facility", we re-evaluated the probabilities of aircraft crashes against the nuclear facilities in NSRI. As a result of the evaluations, the sum of the probabilities of aircraft crashes against Waste Treatment Facilities (maximum probability among all nuclear facilities in NSRI) is 5.68
10
(times/(reactor 
year)) which is lower than 10
(times/(reactor year)) that is the assessment criterion whether aircraft crashes is considered to be "anticipated external human induced events" in design basis or not.
Sakai, Akihiro
Dekomisshoningu Giho, (64), p.24 - 33, 2023/05
Japan Atomic Energy Agency (JAEA) has proceeded with the project of near surface disposal of radioactive waste generated from research facilities, etc. as the implementing body. On the other hand, Nuclear Regulation Authority (NRA) has established the safety regulations and standards for the operation of the disposal facilities. This report outlines the disposal project of JAEA and the development of the regulations and standards for the disposal by NRA.
Planning and Co-ordination Office, Sector of Nuclear Safety Research and Emergency Preparedness
JAEA-Review 2021-019, 58 Pages, 2021/11
JAEA-Review-2021-019.pdf:2.26MB
In response to the directives of the 4th medium-to-long-term objectives, Japan Atomic Energy Agency will formulate the 4th medium-to-long-term plan and run its operation according to the plan from the fiscal year 2022. Consequently, the Sector of Nuclear Safety Research and Emergency Preparedness has reviewed the strategies of the safety research for contributing to the demand, "the continuous improvement of nuclear safety and the effectiveness of nuclear disaster prevention". It was also discussed how to proceed the safety research over the medium-to-long-term plan period based on the proposed new strategies. From the viewpoint of developing human resources and maintaining research capabilities in the sector, discussion was made on measures to pass on the knowledge and skills of senior and mid-career researchers to young researchers. The main elements of the proposed strategies are: (1) to efficiently and effectively develop both problem-solving research and advanced or leading research, considering the importance and needs on the nuclear safety and corresponding to regulatory trends and introduction of new technologies, (2) to produce research results of high quality for social implementation, including proactive proposal of measures for enhancing rationality of nuclear safety and regulation by utilizing risk information, and (3) to promote development of human resources and maintenance of technological base through challenging new research subjects. This report summarizes results of the discussion on the medium-to-long-term safety research strategies and the research plans based on the proposed strategies.
Takahashi, Fumiaki; Manabe, Kentaro; Sato, Kaoru
JAEA-Review 2020-068, 114 Pages, 2021/03
JAEA-Review-2020-068.pdf:2.61MB
Radiation safety regulations have been currently established based on the 1990Recommendation by the International Commission on Radiological Protection (ICRP) in Japan. Meanwhile, ICRP released the 2007 Recommendation that replaces the 1990 Recommendation. Thus, the Radiation Council, which is established under the Nuclear Regulation Authority (NRA), has made discussions to incorporate the purpose of the 2007 Recommendation into Japanese regulations for radiation safety. As ICRP also has published effective dose coefficients for internal exposure assessment in accordance with the 2007recommendation, the technical standards are to be revised for the internal exposure assessment method in Japan. Currently, not all of the effective doses have been published to revise concentration limits for internal exposure protections of workers and public. The published effective dose coefficients are applied to radionuclides which are important in radiation protection for internal exposure of a worker. Thus, we review new effective dose coefficients as well as basic dosimetry models and data based upon Occupational Intakes of Radionuclides (OIR) parts 2, 3 and 4 that have been published from 2016 to 2019 by ICRP. In addition, issues are sorted out to provide information for revision of the technical standards for internal exposure assessment based on the 2007 Recommendations in future.
Sono, Hiroki; Sukegawa, Kazuhiro; Nomura, Norio; Okuda, Eiichi; Study Team on Safety and Maintenance; Study Team on Quality Management; Task Force on New Nuclear Regulatory Inspection Systems
JAEA-Technology 2020-013, 460 Pages, 2020/11
JAEA-Technology-2020-013.pdf:13.46MB
Japan Atomic Energy Agency (JAEA) has completed the introduction of a new frame work of safety, maintenance and quality management activities under the new acts on the Regulation of nuclear source material, nuclear fuel material and reactors since April 2020, in consideration of variety, specialty and similarity of nuclear facilities of JAEA (Power reactor in the research and development stage, Reprocessing facility, Fabrication facility, Waste treatment facility, Waste burial facility, Research reactor and Nuclear fuel material usage facility). The JAEA task forces on new nuclear regulatory inspection systems prepared new guidelines on (1) Safety and maintenance, (2) Independent inspection, (3) Welding inspection, (4) Free-access response, (5) Performance indicators and (6) Corrective action program for the JAEA's nuclear facilities. New Quality management systems and new Safety regulations were also prepared as a typical pattern of these facilities. JAEA will steadily improve these guidelines, quality management systems and safety regulations, reviewing the official activities under the new regulatory inspection system together with the Nuclear Regulation Authority and other nuclear operators.
Motome, Yuiko; Akiyama, Yoshiya; Murao, Hiroyuki
Journal of Nuclear Engineering and Radiation Science, 6(2), p.021115_1 - 021115_11, 2020/04
The nuclear safety research reactor (NSRR) is a research reactor of training research isotopes general atomics -annular core pulse reactor type. The NSRR facility has been utilized for fuel irradiation experiments to study the behaviors of nuclear fuels under reactivity-initiated accident conditions. Under the new regulation standards, which was established after the Fukushima Daiichi accident, research reactors are regulated based on the risk of the facilities. To apply the graded approach, the radiation effects on residents living around the NSRR under the external hazards were evaluated, and the level of the risk of the NSRR facility was investigated. This paper summarizes the result of the evaluation in the case where the safety functions are lost due to a tornado, an earthquake followed by a tsunami. All in all, the risk is confirmed to be relatively low, since the effective dose on the residents is found to be below 5 mSv per event due to the loss of the safety functions.
Motome, Yuiko; Akiyama, Yoshiya; Murao, Hiroyuki
Proceedings of 26th International Conference on Nuclear Engineering (ICONE-26) (Internet), 8 Pages, 2018/07
The NSRR is a research reactor of TRIGA-ACPR type, located in the Nuclear Science Research Institute. The NSRR facility has been utilized for fuel irradiation experiments to study the behaviors of nuclear fuels under reactivity initiated accident conditions. Under the new regulation standards after the Fukushima Daiichi accident, the research reactors are being regulated according to the risk of the facility. Graded approach is introduced in the regulation. In order to apply the graded approach, the radiation effects of residents living around the NSRI under the external hazards were evaluated and the level of the risk of the NSRR facility was investigating. This report is summarized for the result of the evaluation in case the safety functions were lost by the tornado, earthquake and following tsunami. As the result, the risk is confirmed to be low, since the effective dose of the residents has been below 5 mSv per event due to the loss of the safety functions by the tornado, earthquake and following tsunami.
Tonoike, Kotaro; Yamane, Yuichi; Umeda, Miki; Izawa, Kazuhiko; Sono, Hiroki
Proceedings of International Conference on Nuclear Criticality Safety (ICNC 2015) (DVD-ROM), p.20 - 27, 2015/09
From the viewpoint of safety regulation, criticality control of the fuel debris in the Fukushima Daiichi Nuclear Power Station would be a risk-informed control to mitigate consequences of criticality events, instead of a deterministic control to prevent such events. The Nuclear Regulation Authority of Japan has set up a research and development program to tackle this challenge. The Nuclear Safety Research Center of Japan Atomic Energy Agency, commissioned by the authority, has launched activities such as computations of criticality characteristics of the fuel debris, development of criticality risk assessment method, and preparation of criticality experiments to support them.
Minehara, Eisuke
Proceedings of 2nd Annual Meeting of Particle Accelerator Society of Japan and 30th Linear Accelerator Meeting in Japan, p.200 - 201, 2005/07
As the fourth generation energy recovering super-conducting linac (ERL) driven light source is planned to develop and to build as the most advanced national light source facility in Japan, this is a conceptual design work and key components developmental programs including a 200MeV prototype construction. Our existing 4K zero-boil off refrigerator cryogenic and a huge 2K liquefier facility will be combined to make a new hybrid one. Because all cryogenic devices in Japan have been seriously and unnecessarily controlled and affected their safety, maintenance, operation and construction over these several tens years, we will therefore have to cut back excess safety regulation in Japanese domestic high pressure vessel code using a structure reform and special economic zone policy.
Okuno, Hiroshi; Akiyama, Hideo*; Mochizuki, Hiroki*
Journal of Nuclear Science and Technology, 40(1), p.57 - 60, 2003/01
Times Cited Count：1 Percentile：10.59(Nuclear Science & Technology)Low-level waste (LLW) drums are required to transport as fissile material if the current IAEA's Regulations for the Safe Transport of Radioactive Material are rigorously applied. This problem is a consequence that water contents of concrete in LLW drums contained deuterium (D) in quantities more than 0.1% of fissile material mass, therefore they are not excepted from packages containing fissile material. Consideration of differences in the absorption cross sections of light hydrogen and D shows that the relative increase in the neutron multiplication factor by a presence of D in natural water for hydrogen (H)-moderated systems is not larger than 0.015%. A numerical calculation confirms that the infinite multiplication factor of a mixture of 
U-metal and water in a U/H mass ratio of 5% increases proportionally to the D/H atomic ratio, and that its relative increase is less than 0.03% for the D/H atomic ratio of 0.015%. The limiting fissile-to-H mass ratio of 5% in the exception rule is concluded to be applicable to H-moderated systems including D in natural water.
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Proc. of PATRAM'98, 1, p.217 - 223, 1998/00
no abstracts in English
; Sugimoto, Jun
Nihon Genshiryoku Gakkai-Shi, 39(4), p.46 - 47, 1997/00
no abstracts in English
Okoshi, Minoru; Yoshimori, Michiro; Abe, Masayoshi
Planning and Operation of Low Level Waste Disposal Facilities IAEA-SM-341/70, 0(0), p.416 - 425, 1997/00
no abstracts in English
; Sobajima, Makoto
Nihon Genshiryoku Gakkai-Shi, 38(5), p.369 - 370, 1996/00
no abstracts in English
Yamamoto, Hideaki; J.A.Mackinney*
JAERI-Conf 95-015, 354 Pages, 1995/07
no abstracts in English
Okoshi, Minoru; Yoshimori, Michiro
Proc. of 3rd Japan-Russia Joint Symp. on Radiation Safety, 0, p.75 - 85, 1995/00
no abstracts in English
Soda, Kunihisa; Kukita, Yutaka; ; Sugimoto, Jun; Yamano, N.
Int. Conf. on New Trends in Nuclear System Thermohydraulics,Proc,Vol. II, 0, p.3 - 8, 1994/00
no abstracts in English
Murata, Mikio; ;
Fusion Technology, 21, p.673 - 677, 1992/03
no abstracts in English
Hoshi, Tatsuo
IAEA-SR-179, 15 Pages, 1992/00
no abstracts in English
Yamamoto, Hideaki;
EPA-520/1-90-013, p.193 - 196, 1990/00
no abstracts in English
