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The ad hoc Working Group of Investigating into the Crack on a Reflector Element of JRR-4
JAEA-Technology 2008-070, 121 Pages, 2008/09
JAEA-Technology-2008-070(errata).pdf:0.06MBJAEA-Technology-2008-070-1.pdf:40.24MBJAEA-Technology-2008-070-2.pdf:56.57MB
A crack was ascertained on a weld area of one reflector element on December 28, 2007. The Department of Research Reactor and Tandem Accelerator set up an ad hoc working group of experts in the JAEA, and investigated cause of crack on the weld area. The following examinations were carried out; visual examination, dimensional examination, fractography examination and so on. It was concluded that the main cause of the crack is the swelling of graphite in the reflector element. The swelling must be due to neutron irradiation. We carried out a radiografical examination of the other reflector elements. As the result, we determined that many of them were not in a suitable state to be used because of swelling of graphite. The design of the new reflector elements should be carried out, based on the relation between the irradiation dose and swelling rate, which has been obtained in these investigation.
JRR-4 Operation Division; Research Reactor Utilization Division
JAERI-Tech 2005-042, 58 Pages, 2005/07
Japan Research Reactor No.4 (JRR-4) was shut down manually, due to the control rod insertion failure occurred during the rated power (3,500kW) operation on June 10, 2005. It became evident by the investigation that a screw bolt at the control rod support got loose and blocked the control rod insertion. The failure was recovered through replacement with the new screw bolt. Considering the importance of this event, we decided to inspect all screw bolts over the core that may cause a control rod insertion failure. Furthermore, we decided to carry out periodical inspection about these screw bolts whether they were tightened enough or not. This report describes the result of inspection carried out as the preventive measures.
JRR-3 Operation Division; Research Reactor Utilization Division
JAERI-Tech 2000-027, p.194 - 0, 2000/03
JAERI-Tech-2000-027.pdf:8.47MB
no abstracts in English
JRR-2 Operations Office
JAERI-Tech 94-014, 279 Pages, 1994/08
no abstracts in English
JRR-2 Control Office; Kambara, Toyozo; Shoda, Katsuhiko; Hirata, Yutaka; Shoji, Tsutomu; Kohayakawa, Toru; Morozumi, Minoru; Kambayashi, Yuichiro; Shitomi, Hajimu; Kokanezawa, Takashi; et al.
JAERI 1027, 57 Pages, 1962/09
no abstracts in English
JRR-2 Operations Office; Kambara, Toyozo; Shoda, Katsuhiko; Hirata, Yutaka; Shoji, Tsutomu; Haginoya, Kinichi; Kohayakawa, Toru; Yamaki, Jikei; Yokota, Mitsuo; Horiki, Oichiro; et al.
JAERI 1024, 79 Pages, 1962/08
no abstracts in English
JRR-2 Operations Office; Kambara, Toyozo; Sakata, Hajime; Sawai, Sadamu; Kaneko, Minoru; Endo, Yuzo; Kitahara, Tanemichi; Oyamada, Rokuro; Iwashita, Akira; Kasahara, Yuko
JAERI 1018, 12 Pages, 1962/07
no abstracts in English