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Ishikuro, Yasuhiro; Hirane, Nobuhiko; Kato, Tomoaki
Proceedings of 8th International Symposium on Materials Testing Reactors (ISMTR-8) (Internet), 5 Pages, 2015/10
Japan Research Reactor No.4 (JRR-4) is a swimming pool type reactor moderated and cooled with light-water. The maximum thermal power of JRR-4 is 3,500 kW. Since its initial criticality in January 1965, JRR-4 had been operated about 45 years until in December 2010. Subsequently, the Great East Japan Earthquake occurred on March 11, 2011. Although JRR-4 was no severe damage, we have determined to decommission JRR-4 in consideration of various things, and will submit the decommissioning plan of JRR-4 to the nuclear regulatory body in the near future.
Tsuchiya, Kunihiko; Kawamata, Kazuo; Takeuchi, Nobuhiro*; Ishizaki, Hiroyuki*; Niizeki, Tomotake*; Kakei, Sadanori*; Fukumitsu, Nobuyoshi*; Araki, Masanori
no journal, ,
no abstracts in English
Tsuchiya, Kunihiko; Takeuchi, Tomoaki; Otsuka, Noriaki; Shibata, Hiroshi; Nakano, Hiroko; Ishida, Takuya; Uehara, Toshiaki; Yamamoto, Keiichi; Saito, Takashi; Nakamura, Jinichi; et al.
no journal, ,
no abstracts in English
Takeuchi, Tomoaki; Otsuka, Noriaki; Nakano, Hiroko; Shibagaki, Taro*; Komanome, Hirohisa*; Tsuchiya, Kunihiko
no journal, ,
Considering that reactor buildings could be filled with water under severe accidents, a development of the wireless transmission system in water is necessary. In this study, transmission method using visible light was adopted because of its relatively lower attenuation rate and higher transmission rate in water. In the designed transmission system, two-dimensional transmission devices were adopted. LEDs arranged in a two-dimensional array and a camera using a CMOS image sensor, that is like a 2D aggregation of PDs, were used as the light emission and receiving devices, respectively. Moreover, both of pattern and flicker signals can be simultaneously emitted. To confirm the environmental robustness, the in-water transmission tests using the two-dimensional transmission devices were performed with and without air bubbles. The results indicated the pattern signals were more easily influenced than the flicker signals by the air bubbles. In addition, surface mounting LEDs were more suitable than bullet-type LEDs because of their good distinctiveness of the light spots from each LED. On the other hand, irradiation tests for the LEDs were performed. The results again indicated surface mounting LEDs were advantageous because the decrease rates of the total luminous flux with absorbed dose were lower than that of the bullet-type LEDs.