Operation, test, research and development of the High Temperature Engineering Test Reactor (HTTR) (FY2021)

Department of HTTR

JAEA-Review 2023-016, 82 Pages, 2023/09

JAEA-Review-2023-016.pdf:2.31MB

The High Temperature Engineering Test Reactor (HTTR) is the first Japanese High Temperature Gas-cooled Reactor (HTGR) with 30MW in thermal power and 950C of maximum outlet coolant temperature that is constructed by the Japan Atomic Energy Agency located at Oarai-machi, Higashiibaraki-gun, Ibaraki-ken, Japan. The purpose of the HTTR is establishment of basic HTGR technologies, demonstration of HTGR safety characteristics and so on. The HTTR has had a lot of experience of HTGRs' operation and maintenance throughout rated power operations, safety demonstration tests, long-term high temperature operations and demonstration tests relevant to HTGRs' R&Ds. In the fiscal year 2021, as the HTTR completed activities to conform to the New Regulatory Requirements of Nuclear Regulation Authority, The HTTR restarted since the 2011 off the Pacific coast of Tohoku Earthquake and carried out the Loss-of-forced cooling test without Vessel Cooling System (VCS) operational at 9MW (Three gas circulators trip and VCS is stopped.) as the safety demonstration test. This report summarizes the activities carried out in the fiscal year 2021, which were the situation of the New Regulatory Requirements screening of the HTTR, the operation and maintenance of the HTTR, R&Ds relevant to commercial-scale HTGRs, the international cooperation on HTGRs and so on.

Maintenance management of HTTR (Characteristics and achievements of maintenance management)

Shimazaki, Yosuke; Yamazaki, Kazunori; Iigaki, Kazuhiko

Hozengaku, 18(1), p.16 - 20, 2019/04

no abstracts in English

Approach for the treatment and disposal of dismantling waste (Research reactor)

Sakamoto, Yoshiaki

Genshiryoku Bakkuendo Kenkyu (CD-ROM), 24(2), p.141 - 146, 2017/12

https://nuce.aesj.or.jp/jnuce/vol24/Jnuce-Vol24-2-p141-146.pdf

Some research reactors are under decommissioning or preparation for application of decommissioning license for regulation authority in our country. The reasonable treatment and disposal of dismantling waste is important for decommissioning of research reactors. Therefore, in this paper, JAEA's approach of the treatment and disposal of dismantling waste was introduced from the point of view of disposal of low level radioactive waste arising from research, industrial and medical facilities.

A Sensitivity analysis for construction of the seismic response analysis model of a nuclear reactor building by using a three-dimensional finite element model

Choi, B.; Nishida, Akemi; Nakajima, Norihiro

Kozo Kogaku Rombunshu, B, 63B, p.325 - 333, 2017/03

The Japan Atomic Energy Agency promotes research and development of three-dimensional vibration simulation technologies for nuclear facilities. In this paper, we report a seismic response analysis of the Tohoku Pacific Coast Earthquake using three-dimensional models of the High-Temperature Engineering Test Reactor (HTTR) building. We conducted a sensitivity study using input parameters with uncertainty. Furthermore, we examined the variation of the seismic response results against the input parameters.

A Parametric study for the seismic response analysis of a nuclear reactor building by using a three-dimensional finite element model

Choi, B.; Nishida, Akemi; Nakajima, Norihiro

Proceedings of 24th International Conference on Nuclear Engineering (ICONE-24) (DVD-ROM), 7 Pages, 2016/06

https://doi.org/10.1115/ICONE24-61128

Research and development of three-dimensional vibration simulation technologies for nuclear facilities have been promoted in the Center for Computational Science and e-Systems of the Japan Atomic Energy Agency (JAEA). A seismic intensity of upper 5 was observed in the area of High-Temperature Engineering Test Reactor (HTTR) at the Oarai Research and Development Center of the JAEA during the 2011 Tohoku earthquake. In this paper, we report a parametric study of seismic response analyses of this earthquake using three-dimensional finite element models of the HTTR building with various uncertainty parameters (e.g. soil-structure interaction effects, soil properties). By examining the variation of the response result against the uncertainty parameters, we obtained a knowledge, which is essential for constructing a valid three-dimensional finite element model.

Development of transportation container for the neutron startup source of High Temperature engineering Test Reactor (HTTR)

Shimazaki, Yosuke; Ono, Masato; Tochio, Daisuke; Takada, Shoji; Sawahata, Hiroaki; Kawamoto, Taiki; Hamamoto, Shimpei; Shinohara, Masanori

Proceedings of International Topical Meeting on Research Reactor Fuel Management and Meeting of the International Group on Reactor Research (RRFM/IGORR 2016) (Internet), p.1034 - 1042, 2016/03

In High Temperature Engineering Test Reactor (HTTR), three neutron holders containing Cf with 3.7 GBq for each are loaded in the graphite blocks and inserted into the reactor core as a neutron startup source which is changed at the interval of approximately ten years. These neutron holders containing the neutron sources are transported from the dealer's hot cell to HTTR using the transportation container. The holders loading to the graphite block are carried out in the fuel handling machine maintenance pit of HTTR. There were two technical issues for the safety handling work of the neutron holder. The one is the radiation exposure caused by significant movement of the container due to an earthquake, because the conventional transportation container was so large (1240 mm, h1855 mm) that it can not be fixed on the top floor of maintenance pit by bolts. The other is the falling of the neutron holder caused by the difficult remote handling work, because the neutron holder capsule was also so long (155 mm, h1285 mm) that it can not be pulled into the adequate working space in the maintenance pit. Therefore, a new and low cost transportation container, which can solve the issues, was developed. To avoid the neutron and ray exposure, smaller transportation container (820mm, h1150 mm) which can be fixed on the top floor of maintenance pit by bolts was developed. In addition, to avoid the falling of the neutron holder, smaller neutron holder capsule (75 mm, h135 mm) with simple handling mechanism which can be treated easily by manipulator was also developed. As the result of development, the neutron holder handling work was safely accomplished. Moreover, a cost reduction for manufacturing was also achieved by simplifying the mechanism of neutron holder capsule and downsizing.

JRR-2 decommissioning activity, 2

Suzuki, Takeshi; Nakano, Masahiro; Okawa, Hiroshi; Terunuma, Akihiro; Kishimoto, Katsumi; Yano, Masaaki

JAERI-Tech 2005-018, 84 Pages, 2005/03

JAERI-Tech-2005-018.pdf:27.52MB

no abstracts in English

Present status of JRR-2 decommissioning

Nakano, Masahiro; Okawa, Hiroshi; Suzuki, Takeshi; Kishimoto, Katsumi; Terunuma, Akihiro; Yano, Masaaki

Dekomisshoningu Giho, (30), p.11 - 24, 2004/09

http://www.randec.or.jp/publish/documents/gihou/Decommissioning%20gihou_30.pdf

Japan Research Reactor No.2(JRR-2), heavy water moderated and cooled tank type research reactor with maximum thermal power of 10MW,was operated for over 36 years, and was permanently shut down in December, 1996. In 1997, decommissioning plan was submitted to the STA, and dismantling was begun. Decommissioning program of JRR-2 is divided into 4 phases. Phase 1, 2 had already been completely finished without any trouble. Furthermore, the phase 3 was also finished in February, 2004 as planned. On exposure of worker in phase 1, 2 and 3, it was achieved to control lower than the estimate. On exposure of worker in phase 1, 2 and 3, it was achieved to control lower than the estimate. Reactor will be removed in phase 4 by one piece removal technique. The reactor building is planned to use effectively as a hot experimental facilities after decommissioning. The decommissioning plan was changed that the reactor would be kept in safety storage.

Selection of important nuclides from the viewpoint of safety assessment for disposal of radioactive waste arising from research institutes, 2; Analytical scheme for nuclide composition in radwastes arising from research and testing reactor and post-irradiation examination facilities

Asai, Shiho; Sakai, Akihiro; Yoshimori, Michiro; Kihara, Shinji

JAERI-Tech 2003-071, 46 Pages, 2003/08

JAERI-Tech-2003-071.pdf:4.31MB

As part of survey concerning radioactive inventory of radwastes arising from research institutes, an analytical scheme has been studied for verifying their nuclide composition based on calculation analysis and record, in consideration of the its characteristics. In this study, radwastes are used as samples, which arise from research and testing reactors and post-irradiation examination facilities (PIE facilities). Though separation procedures are simplified and rationalized, quantifiable values could be obtained with relative errors under 10% for almost all the samples containing nuclides like Ni and U which concentrations are low, and recoveries were high on the whole. These show that the analytical scheme is useful for chemical separation of radwastes arising from research and testing reactors and PIE facilities.

General description and operational experience of a dry storage facility for JRR-3 spent fuels in JAERI

Kusunoki, Tsuyoshi; Koda, Nobuyuki; Uchiyama, Junzo*

Dai-24-Kai Kaku Busshitsu Kanri Gakkai Nihon Shibu Nenji Taikai Rombunshu, p.149 - 156, 2003/00

A dry storage facility (DSF) was constructed in March 1982 to store the JRR-3 metallic natural uranium spent fuel elements those had been stayed under water in a core or a spent fuel pool for a long period (Maximum : about 20 years). The facility consists of a storage, an air circulation system, an auxiliary system and a control room. The storage is composed of the concrete shielding and 100 dry-wells. In each dry-well, a stainless steel made canister with the spent fuels is stored. The air circulation system has an air-inlet and outlet pipes, headers and air circulation blowers to circulate air in the system and maintain the pressure inside the dry-well below the atmosphere. This system also performs the role as radiation monitoring system. The facility is designed to satisfy safety requirements as a nuclear fuel facility, such as criticality safety, radiation shielding and earthquake performance. JAERI has successfully experienced the dry storage of 1798 spent fuel elements about for 20 years.