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Journal Articles

Research and development for safety and licensing of HTGR cogeneration system

Sato, Hiroyuki; Ohashi, Hirofumi; Yan, X.

Proceedings of 9th International Topical Meeting on High Temperature Reactor Technology (HTR 2018) (USB Flash Drive), 9 Pages, 2018/10

Japan Atomic Energy Agency has been conducting research and development with a central focus on the utilization of HTTR, the first HTGR in Japan, towards the realization of industrial use of nuclear heat. On the basis of licensing experience through the HTTR construction, JAEA initiated an activity to establish an international safety standard for licensing of commercial HTGR cogeneration systems fully taking into account safety features of HTGRs. This paper explains a roadmap towards licensing of commercial HTGR cogeneration systems. A test plan using the HTTR to support the establishment of safety standards and safety analysis methods is also presented.

Journal Articles

Development of waste acceptance criteria and current challenges relating to the disposal project of LLW generated in research, medical and industrial facilities

Nakata, Hisakazu; Amazawa, Hiroya; Izumo, Sari; Okada, Shota; Sakai, Akihiro

Dekomisshoningu Giho, (58), p.10 - 23, 2018/09

Low level radioactive wastes are generated in the research and development of the nuclear energy, medical and industrial use of radioisotope except NPP in Japan. The disposal of wastes arising from NPP has already been implemented while not the one for wastes from research institutes etc. Japan Atomic Energy Agency therefore has been assigned an implementing organization for the disposal legally in 2008 in order to promote the disposal program as quickly and firmly as possible. Since then, JAEA has conducted their activity relating to the disposal facility design on generic site conditions and developing Waste Acceptance Criteria for LLW from research institutes. This report summarizes the WAC and current challenges.

JAEA Reports

Waste Technical Standards Working Group annual report 2016

Waste Technical Standards Working Group

JAEA-Review 2017-017, 112 Pages, 2017/11

JAEA-Review-2017-017.pdf:2.87MB

In Japan Atomic Energy Agency, JAEA, a Waste Technical Standards Working Group has established since FY2015. The Working Group is composed of the members from waste management sections in each site in JAEA and from Radioactive Waste Management and Disposal Project Department. In this Working Group, we discussed quality management on conditioning waste packages, methodologies to evaluate the radioactivity concentration and measures for dismantling waste. This annual report summarizes the results of discussion in FY2016.

Journal Articles

Study of the calculation method for the elastic follow-up coefficient by inelastic analysis

Watanabe, Sota*; Kubo, Koji*; Okajima, Satoshi; Wakai, Takashi

Nippon Kikai Gakkai M&M 2017 Zairyo Rikigaku Kanfarensu Koen Rombunshu (Internet), p.581 - 585, 2017/10

no abstracts in English

Journal Articles

Prolonged stoppage of research reactors and critical assemblies affects human resource development

Uesaka, Mitsuru*; Mineo, Hideaki

Nippon Genshiryoku Gakkai-Shi, 58(8), p.468 - 473, 2016/08

All the research reactors and critical assemblies (hereinafter RRCAs) in Japan are stopped in order to fulfil the new regulatory requirements, which were reinforced after the accident at the Tokyo Electric Power Company's Fukushima Daiichi Nuclear Power Station. These RRCAs have played important roles in the areas of human resource development, academic research, medical and industrial application of nuclear technology. Prolonged stoppage of RRCAs affects adversely those activities. Atomic Energy Society of Japan set up a group to discuss this issue. The group has shown a proposal that the roles of the RRCAs, which are indispensable facilities to nuclear human resource development, should be placed positively in the energy policy and the science and technology policy of the country.

JAEA Reports

Selection of design basis event for modular high temperature gas-cooled reactor

Sato, Hiroyuki; Nakagawa, Shigeaki; Ohashi, Hirofumi

JAEA-Technology 2016-014, 64 Pages, 2016/06

JAEA-Technology-2016-014.pdf:4.21MB

In this study, we investigate a deterministic approach to select design basis events utilizing information obtained from probabilistic approach. In addition, selections of design basis events are conducted for commercial HTGR designed by JAEA. As a result, an approach for selecting design basis event considering multiple failures of safety systems is established which has not been considered as design basis in the safety guideline for existing nuclear facility. Furthermore, selection of design basis events for commercial HTGR has completed.

JAEA Reports

Replacement of the glove box panel in the nuclear fuel reprocessing facility

Yamamoto, Masahiko; Shirozu, Hidetomo; Mori, Eito; Surugaya, Naoki

JAEA-Technology 2016-009, 58 Pages, 2016/05

JAEA-Technology-2016-009.pdf:3.95MB

The panels of glove box installed at Tokai Reprocessing Plant have been deteriorated and transparencies have been decreased due to the long-term use. Therefore, the panels have been replaced from the view point of preventive maintenance. In the new regulation formulated since the Fukushima Daiichi Nuclear Power Plant accident, it is demanded that the glove box consists of incombustible or inflammable materials. In this replacement, new panels have been manufactured with polycarbonate which satisfied the UL94 V-0 incombustible class. The inside of glove box has been contaminated with radioactive materials. Thus, the contamination and operator's exposure have been investigated. Then radiation protection equipment have been selected. Also, it is necessary to maintain the glove box enclosure during the replacement. The replacement has been conducted by covering the opening parts with vinyl sheets. The enclosure function has been verified by the inspection of the new panels and glove box.

JAEA Reports

Impact assessment of the forest fires on Oarai Research and Development Center Waste Treatment Facility

Shimomura, Yusuke; Hanari, Akira*; Sato, Isamu*; Kitamura, Ryoichi

JAEA-Technology 2015-062, 47 Pages, 2016/03

JAEA-Technology-2015-062.pdf:1.85MB

In response to new standards for regulating waste management facilities, it was carried out impact assessment of forest fires on the waste management facilities existed in Oarai Research and Development Center of Japan Atomic Energy Agency. At first, a fire spread scenario of forest fires was assumed. The intensity of forest fires was evaluated from field surveys, forest fire evaluation models and so on. As models of forest fire intensity evaluation, Rothermel Model and Canadian Forest Fire Behavior Prediction (FBP) System were used. Impact assessment of radiant heat to the facilities was carried out, and temperature change of outer walls for the assumed forest fires was estimated. The outer wall temperature of facilities was estimated around 160$$^{circ}$$C at the maximum, it was revealed that it doesn't reach allowable temperature limit. Consequently, it doesn't influence the strength of concrete. In addition, a probability of fire breach was estimated to be about 20%. This report illustrates an example of evaluation of forest fires for the new regulatory standards through impact assessment of the forest fires on the waste management facilities.

Journal Articles

Status of JRR-3 after Great East Japan Earthquake

Arai, Masaji; Wada, Shigeru; Murayama, Yoji

Proceedings of International Topical Meeting on Research Reactor Fuel Management and Meeting of the International Group on Reactor Research (RRFM/IGORR 2016) (Internet), p.403 - 408, 2016/03

In response to the accident at Fukushima Daiichi NPS, the new safety standards for research and test reactor facilities came into force on December 18, 2013. The evaluation of natural disasters and prevention of spread of accidents beyond design basis mainly were enhanced in the standards. We have completed the necessary checks and assessments, and submitted an application for reviewing if JRR-3 complies with the new standards to the Nuclear Regulation Authority on September 26, 2014.

Journal Articles

Review on conformance to technical criteria for near surface disposal

Tezuka, Masashi; Koda, Yuya; Fujita, Yoshihiko*; Endo, Nobuyuki*; Kume, Kyo*

Heisei-26-Nendo Koeki Zaidan Hojin Wakasawan Enerugi Kenkyu Senta kenkyu Nempo, 17, P. 78, 2015/10

In FUGEN, asphalt solidified body which was solidified the concentrated liquid waste is, some of them might also be present which do not meet the criteria (buried technical standards) according to the buried disposal of waste Therefore, these can not be buried disposal remain status quo. Therefore, it is assumed that that may not conform to the above criteria, "Asphalt solid material" is to conform to the reference to "re-processing", in addition to the desk study on specific measures, and also to preliminary tests I went.

Journal Articles

Accident measures of serious accidents

Tamaki, Hitoshi

Tekisuto "Kakunenryo Saikuru" (Internet), 3 Pages, 2014/12

Revised regulatory rule of nuclear facilities in Japan defines "Serious accident", and require accident measures for them to not only power reactors, but also fuel reprocessing and fabrication facilities. This document describes the basis of accident measures for Serious accident at nuclear fuel reprocessing and fabrication facilities, as a part of "Text of Nuclear Fuel Cycle".

Journal Articles

Authorization of new elements

Nagame, Yuichiro; Nakahara, Hiromichi*

Nippon Butsuri Gakkai-Shi, 60(9), p.707 - 709, 2005/09

no abstracts in English

Journal Articles

Shape optimization using adjoint variable method for reducing pressure drag and its application to ITBL

Shinohara, Kazunori; Okuda, Hiroshi*; Ito, Satoshi*; Nakajima, Norihiro; Ida, Masato

Keisan Kogaku Koenkai Rombunshu, 10(2), p.629 - 632, 2005/05

To obtain optimal designed shape effectively, a parallel computing method of determining Armijo's line-search step size of the adjoint variable method is proposed. The adjoint valiable method is based on the Lagrange multiplier method (a conditional variational principle), and consists of the state equation, the adjoint equation and the sensitivity equation. The equations for decreasing the fluid drag of shaped surface under a constant volume condition are formulated. To solve the equations effectively by the steepest descent method, the parallel algorithm that finds the Armijo's line-search step size is implemented by using ITBL (the grid system of Japan's shared super computers attached to the network). Using this parallel method, the calculation cost can be reduced.

Journal Articles

RF and timing reference distribution system for J-PARC linac

Kobayashi, Tetsuya; Chishiro, Etsuji; Anami, Shozo*; Yamaguchi, Seiya*; Michizono, Shinichiro*

Proceedings of 1st Annual Meeting of Particle Accelerator Society of Japan and 29th Linear Accelerator Meeting in Japan, p.320 - 322, 2004/08

J-PARC (Japan Proton Accelerator Complex) linac, which is 300 m long, consists of 324 MHz accelerating section of the upstream and 972 MHz section (as future plan) of the downstream. In the klystron gallery, totally about 60 RF source control stations will stand for the klystrons and solid-state amplifiers. The error of the accelerating field must be within $$pm$$ 1 degree in phase and $$pm$$ 1% in amplitude. Thus, the high phase stability is required to the RF reference for all of the low-level RF control systems and the beam monitor systems. This paper presents a final design and the summary of the performance evaluation of the RF reference distribution system including the timing control signal distribution for this linac.

Journal Articles

Revision of JIS Z 4511 and the present and future status of calibration of practical radiation protection instruments, 1

Murakami, Hiroyuki; Minami, Kentaro*

Radioisotopes, 53(3), p.197 - 205, 2004/03

no abstracts in English

JAEA Reports

A Consideration about major business control system for independent administrative institution

Abe, Shinya*; Nakata, Yutaka; Iitsuka, Tomoaki; Yamagishi, Kojiro*

JAERI-Tech 2003-077, 233 Pages, 2003/10

JAERI-Tech-2003-077.pdf:15.07MB

Japanese government is carrying out the administrative reform aiming to promote decentralization of authority, to magnify the field of private sectors, etc. in order to correspond appropriately to matured economy, internationalized market, etc. As one of the reforms, Japanese government decided that JAERI and JNC would unite into an independent administrative agency. The aims of the independent administrative agency institution include realization of effective and transparent system and management. The aim of the present investigation is to be useful for the new agency to develop a major business control system, which manages financial affairs and accounts not only efficiently but also in correspondence with open information to the public and promoting research activities effectively.

Journal Articles

RF reference distribution system for the J-PARC linac

Kobayashi, Tetsuya; Chishiro, Etsuji; Anami, Shozo*; Yamaguchi, Seiya*; Michizono, Shinichiro*

Proceedings of 28th Linear Accelerator Meeting in Japan, p.366 - 368, 2003/08

For the J-PARC linac, a 12-MHz RF reference is distributed to 60 low-level RF control systems of klystron stations through optical links. The error of the accelerating field must be within +/- 1 degree in phase and +/ 1% in amplitude. Thus, a very high phase stability (within +/- 0.3 degree in phase) is required to the reference distribution system. New optimized optical components for this linac were developed and the performance of them was tested. The results will be reported. In adition, the timing control signal distribution system for the linac will be illustlated.

Journal Articles

Electric length stabilization of RF reference distribution cable

Nagai, Ryoji; Sawamura, Masaru; Kikuzawa, Nobuhiro; Hajima, Ryoichi; Nishimori, Nobuyuki; Minehara, Eisuke

Proceedings of 28th Linear Accelerator Meeting in Japan, p.315 - 317, 2003/08

no abstracts in English

Journal Articles

Ready to construct ITER

Hada, Kazuhiko

Nippon Kikai Gakkai Doryoku Enerugi Shisutemu Bumon Nyusu Reta, (25), p.2 - 3, 2002/10

no abstracts in English

201 (Records 1-20 displayed on this page)