Present status of HTTR and its operational experience

Iyoku, Tatsuo; Nojiri, Naoki; Tochio, Daisuke; Mizushima, Toshihiko; Tachibana, Yukio; Fujimoto, Nozomu

Proceedings of 15th International Conference on Nuclear Engineering (ICONE-15) (CD-ROM), 8 Pages, 2007/04

A HTGR is particularly attractive because of its capability of producing high temperature helium gas and its inherent safety characteristics. Hence, the HTTR wasconstructed at the Oarai Research Establishment of the Japan Atomic Energy Agency. The HTTR achieved the full power of 30MW and reactor outlet coolant temperature of about 850C on December 7, 2001. After several operation cycles, the HTTR achieved the reactor outlet coolant temperature of 950C on April 19, 2004. It is the highest coolant temperature outside reactor pressure vessel in the world. Extensive tests are planned in the HTTR and a process heat application system will be coupled to the HTTR, where hydrogen will be produced directly from the nuclear energy.

Report of investigation on malfunction of reserved shutdown system in HTTR

Hamamoto, Shimpei; Iigaki, Kazuhiko; Shimizu, Atsushi; Sawahata, Hiroaki; Kondo, Makoto; Oyama, Sunao; Kawano, Shuichi; Kobayashi, Shoichi; Kawamoto, Taiki; Suzuki, Hisashi; et al.

JAEA-Technology 2006-030, 58 Pages, 2006/03

JAEA-Technology-2006-030.pdf:10.69MB

During normal operation of High Temperature engineering Test Reactor (HTTR) in Japan Atomic Energy Agency (JAEA), the reactivity is controlled by the Control Rods (CRs) system which consists of 32 CRs (16 pairs) and 16 Control Rod Drive Mechanisms (CRDMs). The CR system is located in stand-pipes accompanied by the Reserved Shutdown System (RSS). In the unlikely event that the CRs fail to be inserted, the RSS is provided to insert BC/C pellets into the core. The RSS shall be designed so that the reactor should be held subcriticality from any operation condition by dropping in the pellets. The RSS consists of BC/C pellets, hoppers which contain the pellets, electric plug, driving mechanisms, guide tubes and so on. In accidents when the CRs cannot be inserted, an electric plug is pulled out by a motor and the absorber pellets fall into the core by gravity. A trouble, malfunction of one RSS out of sixteen, occurred during a series of the pre-start up checks of HTTR on February 21, 2005. We investigated the cause of the RSS trouble and took countermeasures to prevent the issue. As the result of investigation, the cause of the trouble was attributed to the following reason: In the motor inside, The Oil of grease of the multiplying gear flowed down from a gap of the oil seal which has been deformed and was mixed with abrasion powder of brake disk. Therefore the adhesive mixture prevented a motor from rotating.

Investigation of automatic shutdown of HTTR on May 21st, 2003

Hirato, Yoji; Saito, Kenji; Kondo, Makoto; Sawahata, Hiroaki; Motegi, Toshihiro; Tsuchiyama, Masaru*; Ando, Toshio*; Mizushima, Toshihiko; Nakazawa, Toshio

JAERI-Tech 2004-037, 33 Pages, 2004/04

JAERI-Tech-2004-037.pdf:4.08MB

HTTR (High Temperature Engineering Test Reactor) was operated from May 6th, 2003 to June 18th, 2003 to obtain operation data in parallel loaded operation mode and in safety demonstration tests. Operated with the reactor power at 60% of the rated power on May 21st, HTTR was automatically scrammed by a signalof "Primary coolant flow rate of the Primary Pressurized Water Cooler (PPWC): Low". The cause of the shutdown was the primary gas circulator (A) automatically stopped. The primary coolant flow rate of the PPWC decresed and reached the scram set value due to the gas circulator stop. As a result of investigation, it became clear that the cause of the gas circulator stop was malfunction of an auxiliary relay which monitored electric power of a circuit breaker in power line of the gas circulator. The cause of malfunction was deterioration of the relay under high temperature condition because the relay was installed beside an electric part which was heated up by electricity.

The Present condition of a tandetron AMS in JAERI-Mutsu

Kitamura, Toshikatsu; Aramaki, Takafumi; Mizutani, Yoshihiko*; Togawa, Orihiko; Mizushima, Toshihiko; Kabuto, Shoji*; Sudo, Kazuhiko*

JAERI-Conf 2000-019, p.26 - 29, 2001/02

https://jopss.jaea.go.jp/pdfdata/JAERI-Conf-2000-019.pdf

no abstracts in English

The AMS facility at the Japan Atomic Energy Research Institute (JAERI)

Aramaki, Takafumi; Mizushima, Toshihiko; Mizutani, Yoshihiko*; Yamamoto, Tadatoshi; Togawa, Orihiko; Kabuto, Shoji*; Kuji, Tomoyuki*; Gottdang, A.*; Klein, M.*; Mous, D. J. W.*

Nuclear Instruments and Methods in Physics Research B, 172(1-4), p.18 - 23, 2000/10

https://doi.org/10.1016/S0168-583X(00)00335-9

no abstracts in English

Investigation on marine radioactivity in radioactive waste dumping areas in the northwest pacific ocean and its marginal seas; JAERI's activities in the 2nd Japanese-Korean-Russian joint expedition 1995

Togawa, Orihiko; ; Mizushima, Toshihiko; Yabuuchi, Noriaki; Kobayashi, Takuya

JAERI-Research 98-062, 50 Pages, 1998/10

JAERI-Research-98-062.pdf:3.49MB

no abstracts in English

Effects of ships vibration and motion on plant parameters; Report on sea trials of nuclear ship MUTSU made first in Japan

Kakuta, Tsunemi; Kitamura, Toshikatsu; Mizushima, Toshihiko; ; ; ; ; ;

JAERI-M 92-034, 82 Pages, 1992/03

JAERI-M-92-034.pdf:2.36MB

no abstracts in English

Gamma irradiation tests of part of connector for nuclear instrumentation of nuclear ship Mutsu

; Mizushima, Toshihiko; Kakuta, Tsunemi; Nakazawa, Toshio

DEI-91-136, p.59 - 68, 1991/12

no abstracts in English

Operation of the High-Temperature Engineering Test Reactor

Fujimoto, Nozomu; Nojiri, Naoki; Tachibana, Yukio; Mizushima, Toshihiko

no journal, , 

A High Temperature Gas-cooled Reactor (HTGR) is particularly attractive because of its capability of producing high temperature helium gas and its inherent safety characteristics. Hence, the High Temperature Engineering Test Reactor (HTTR) was successfully constructed at the Oarai Research Establishment of the Japan Atomic Energy Agency. The HTTR achieved the reactor outlet coolant temperature of 950C on April 19, 2004. It is the highest coolant temperature outside reactor pressure vessel in the world. This is one of the major milestones in HTGR development of high temperature nuclear process heat application. Extensive tests are planned in the HTTR and a process heat application system will be coupled to the HTTR, where hydrogen will be produced directly from the nuclear energy. This paper gives an overview of the HTTR Project focusing on the latest results from the HTTR test and the future test plan using the HTTR.