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Cs in radioactive wastes generated from contaminated water treatment system in Fukushima Daiichi Nuclear Power StationKato, Jun; Meguro, Yoshihiro
E-Journal of Advanced Maintenance (Internet), 7(2), p.138 - 144, 2015/08
Concentration of Cs in radioactive wastes such as used cesium adsorption vessels and sludge generated from the cesium adsorption device, the 2nd cesium adsorption device, and the decontamination device, which have operated or been suspended as a part of the contaminated water treatment system in Fukushima Daiichi Nuclear Power Stations, was calculated by using analysis data of the contaminated water. The total decontamination amount of Cs from Jun 6, 2011 to Aug 12, 2014 was estimated.
Kamiji, Yu; Taniguchi, Masashi*; Nishihata, Yasuo; Nagaishi, Ryuji; Tanaka, Hirohisa*; Hirata, Shingo*; Hara, Mikiya; Hino, Ryutaro
Proceedings of 2nd International Conference on Maintenance Science and Technology (ICMST-Kobe 2014), p.87 - 88, 2014/11
For hydrogen mitigation, a new type passive autocatalytic recombiner is under development. In this study, the activation energy of hydrogen-oxygen recombination reaction was examined to clarify the basic characteristics of the catalyst. In addition, the degradation of the catalyst by 
-ray irradiation simulating the environmental condition in nuclear power plants was also examined. As a result, the activation energy was experimentally estimated at 5.75 kJ/mol. Besides, no significant differences were observed in the compositional distribution from the EPMA results between the non-irradiated and the irradiated catalyst. However, the irradiated catalyst showed much more activity because of larger specific surface area of the catalyst and surface area of the precious metals. It showed that -ray irradiation up to 1.0 MGy can increase activity of the catalyst.
Tanaka, Masaaki; Miyake, Yasuhiro*; Karakida, Yasuhisa*
Proceedings of 2nd International Conference on Maintenance Science and Technology (ICMST-Kobe 2014), p.79 - 80, 2014/11
A coupled method of fluid-structure thermal interaction simulation and thermal stress analysis has been developed through the interface program to carry out direct numerical estimation of the thermal fatigue. The prototype method was applied to the thermal mixing phenomena in T-junction Piping System.
Takaya, Shigeru; Machida, Hideo*; Kamishima, Yoshio*; Asayama, Tai
no journal, ,
This paper describes benchmark evaluation of independently programmed structural reliability evaluation codes, MSS-REAL and GENPRO/PEPPER. First, a procedure of structural reliability evaluation of passive components of fast reactors for a failure due to fatigue-creep interaction damage is explained. The procedure consists of evaluations of crack initiation, crack propagation, and crack penetration or unstable fracture. Next, input data for evaluation of structural reliability of a reactor vessel is prepared. Then, the structural reliability of a reactor vessel is evaluated deterministically and probabilistically. The results estimated by two codes agreed well for both deterministic and probabilistic evaluations, which shows that these codes are programmed properly according to the evaluation procedure.
Hirabayashi, Masaru; Ara, Kuniaki; Hino, Ryutaro
no journal, ,
Since existing hydrogen monitors cannot be used with the sampling method in severe accident conditions, a new type hydrogen monitor by using acoustic technique is under development. The measurement principle that the sound velocity is changed according to the hydrogen concentration in a mixed gas is utilized for the new type monitor. In the basic performance tests, it was confirmed that the hydrogen concentration could be measured in a high accuracy. Also, influence of environment conditions was evaluated.
