Ground improvement work for deployment place of accident response equipment at Tokai Reprocessing Plant

Asada, Naoki; Sasaki, Shunichi; Rachi, Reona; Komori, Tsuyoshi; Suzuki, Hisanori; Takeuchi, Kenji; Uchida, Naoki

Nihon Hozen Gakkai Dai-20-Kai Gakujutsu Koenkai Yoshishu, p.5 - 8, 2024/08

no abstracts in English

Development of a method of periodic safety review to cope with the aging degradation of hot laboratories

Tamaoki, Yuichi; Omori, Tsuyoshi; Fujishima, Tadatsune; Mizukoshi, Yasutaka; Sakamoto, Naoki

Proceedings of 53rd Annual Meeting of Hot Laboratories and Remote Handling Working Group (HOTLAB 2016) (Internet), 6 Pages, 2016/11

Post irradiation examinations are conducted in hot laboratories in Oarai Research and Development Center of the Japan Atomic Energy Agency in order to develop fuels and materials for fast reactors. These facilities, the majority of which were constructed in the 1970s, have accumulated operating experience over a period of more than 40 years. Continuous operational safety requires the maintenance of important equipment such as electronic devices, manipulators, in-cell cranes, as well as air conditioning and ventilation systems. A method for the periodic safety review for hot laboratories based on the periodic safety review method employed for preventive maintenance at commercialized power reactors in Japan has been developed. In this paper, the status of implementation of the periodic safety review for hot laboratories using the safety review method are introduced.

Development of safety review method to cope with an aging degradation for the facilities using nuclear material

Fujishima, Tadatsune; Mizukoshi, Yasutaka; Sakamoto, Naoki; Omori, Tsuyoshi

Hozengaku, 13(2), p.115 - 125, 2014/07

http://ci.nii.ac.jp/naid/40020160893

In order to develop fuels and materials for fast reactors, five hot laboratories as a facility using nuclear materials for post irradiation examination (PIE) are now in operation at the Oarai Research and Development Centre of Japan Atomic Energy Agency. More than 30 years have passed since the first hot run of these facilities was started, and it has been indispensable to maintain the principal equipment for continuous safe operation. For application to preventive maintenance and the safe operation, a new safety review method that could be applied for these facilities was developed by modification of periodic safety review tools using for Japanese commercialized power reactors. Effective repair or replacement of equipment before malfunction have been performed and the priority for preventive maintenance could be appropriately determined for stable management of hot facility operations by the developed method.

Fabrication of U-Pu-Zr metallic fuel elements for the irradiation test at experimental fast test reactor Joyo

Nakamura, Kinya*; Ogata, Takanari*; Kikuchi, Hironobu; Iwai, Takashi; Nakajima, Kunihisa; Kato, Tetsuya*; Arai, Yasuo; Uozumi, Koichi*; Hijikata, Takatoshi*; Koyama, Tadafumi*; et al.

Nihon Genshiryoku Gakkai Wabun Rombunshi, 10(4), p.245 - 256, 2011/12

https://doi.org/10.3327/taesj.J10.038

Sodium-bonded metallic fuel elements were fabricated for the first time in Japan for the irradiation test in the experimental fast test reactor JOYO. U-20Pu-10Zr fuel slugs of 200 mm in length and approximately 5 mm in diameter were fabricated in a small-scale injection casting furnace. Each fuel slug was loaded into the ferritic martenstic stainless steel (PNC-FMS) cladding tube with the sodium thermal bond, thermal insulator and reflector in a helium gas atmosphere glove box. After top-end plug welding to the cladding tube and heat treatment of the welding area, each fuel element was subjected to the sodium bonding process. After the inspection such as element length, gas plenum length and helium-leak tightness, six metallic fuel elements are transported to the JOYO site for the coming irradiation test.

Longitudinal particle simulation for J-PARC RCS

Yamamoto, Masanobu; Anami, Shozo*; Ezura, Eiji*; Hasegawa, Katsushi; Hara, Keigo*; Horino, Mitsuyoshi*; Nomura, Masahiro; Omori, Chihiro*; Schnase, A.; Shimada, Taihei; et al.

Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.358 - 360, 2008/00

The beam commissioning has been started at the J-PARC RCS in October 2007, and the beam acceleration and the extraction at 3 GeV has been succeeded. Some longitudinal bunch gymnastics has been tested toward the high intensity operation, one of the issues is arriviating the space charge effect at the injeciton. Since the multi-turn injection scheme is employed at the RCS, the electric charge density of the bunch near the center of the RF bucket tends to be high with only normal fundamental RF capture. Some schemes such as adding 2nd higher harmonic RF, the momentum offset and the phase offset of the 2nd one are simulated by longitudinal particle tracking code to make the bunching factor low. The comparison between the beam test result and the particle tracking simulation is described.

Evaluation on rapid heating rupture behavior in heavily irradiated PNC316 fuel claddings

Yoshitake, Tsunemitsu; Omori, Tsuyoshi; Sakamoto, Naoki; Ukai, Shigeharu

PNC TN9410 96-281, 81 Pages, 1996/09

PNC-TN9410-96-281.pdf:6.48MB

The estimation of the life of fuel claddings at thermal transient event is important for evaluating of the fuel claddings validity under the loss of coolant flow (LOF) accident. In order to estimate the life time of the fuel claddings corresponding to any temperature rising condition, the instrumental technique was first improved in the post-irradiation examination and the temperature-transient-to-burst tests were extensively conducted on PNC316 claddings which were irradiated in JOYO as a fuel test assembly PFC030M and a driver fuel assembly PFD304. The life time evaluation of the irradiated PNC316 fuel claddings was carried out, based on these test results. The results obtained in this work are as follows; (1) As a result of the improvement in the temperature-transient-to-burst testing, the diametral change data and higher hoop stress data were obtained. And the highly accurate measurement of rupture temperature was also achieved. (2) The temperature-transient-to-burst test results showed that the rupture temperature of the irradiated PNC316 cladding was equal to that of unirradiated one up to present neutron fluence in LOF stress condition. It was indicated that the temperature-transient-to-burst property of PNC316 was not influenced by irradiation in lower hoop stress region. (3) The life time of the irradiated PNC316 cladding at any thermal transient condition was evaluated by means of LMP-Life Fraction Rule method. Consequently, the result of estimation for failure temperature of heavily irradiated PNC316 showed the possibility for rising the design limit of the cladding highest temperature for MONJU.

Activity of safety review for the facilities using nuclear material and improvement in the future

Fujishima, Tadatsune; Omori, Tsuyoshi

no journal, , 

no abstracts in English

Current status toward the reoperation of JMTR

Kaminaga, Masanori; Tanimoto, Masataka; Ooka, Makoto; Ishihara, Masahiro; Kusunoki, Tsuyoshi; Komori, Yoshihiro; Suzuki, Masahide

no journal, , 

The Japan Materials Testing Reactor (JMTR) in Japan Atomic Energy Agency (JAEA) is a light water cooled tank type reactor with 50 MW thermal power. From its first criticality in March 1968, the JMTR has been utilized for fuel/material irradiation examinations of LWRs, HTGR, fusion reactor as well as for RI productions. In August 2006, the JMTR operation was once stopped in order to have a check & review for the reoperation which was discussed by internal as well as external committees. As a result of the national discussion, the JMTR was determined, finally, to restart after necessary refurbishment works. The refurbishment was started from the beginning of JFY 2007, and replaced were motors of primary and secondary cooling pumps, nuclear instrumentation system, process control system, safety protection system and so on. The refurbishment was finished in March 2011 taking four years as planned schedule. Unfortunately, at the end of the JFY 2010 on March 11, the Great-Eastern-Japan-Earthquake occurred, and functional tests before the JMTR restart, such as cooling system, reactor control system and so on, were delayed by the earthquake. Moreover, a detail inspection found some damages such as small cracks in the concrete structure. Consequently, the restart of the JMTR will delay from June 2011 to this year. Now, the safety evaluation after the earthquake disaster is being carried out aiming at the restart of the JMTR. The renewed JMTR will be started from JFY 2012 and operated for a period of about 20 years until around JFY 2030. Expected utilization fields after reoperation will be a safety research of LWRs for materials/fuels, basic research for nuclear engineering such as HTGR fuels/materials, fusion reactor materials, industrial use such as production of Mo-99 for medical use, and education & training of nuclear scientists and engineers.

Development of safety review method for hot laboratories, 2; Operation experiences and safety review of hot laboratories

Fujishima, Tadatsune; Mizukoshi, Yasutaka; Sakamoto, Naoki; Amagai, Tomio; Omori, Tsuyoshi

no journal, , 

no abstracts in English

Conceptual design of next generation MTR

Nagata, Hiroshi; Yamaura, Takayuki; Naka, Michihiro; Kawamata, Kazuo; Izumo, Hironobu; Hori, Naohiko; Nagao, Yoshiharu; Kusunoki, Tsuyoshi; Kaminaga, Masanori; Komori, Yoshihiro; et al.

no journal, , 

Conceptual design of the high-performance and low-cost next generation materials testing reactor which will be assumed to introduce to the nuclear power plant introduction country started from 2010 in the JAEA. Japanese atomic energy-related companies participate in this project, and this activity role as the environmental management and nuclear human resource development for the new research reactor designs. 10 MW thermal power by plate type fuel elements and swimming pool type was assumed as a design base. High safety, high cost performance, high reactor operation rate, high technology irradiation are targets of this conceptual design.