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Yamano, Hidemasa; Sakai, Takaaki; Kurisaka, Kenichi
no journal, ,
no abstracts in English
Uchikawa, Sadao; Nakano, Yoshihiro; Okubo, Tsutomu
no journal, ,
no abstracts in English
C transfer model in atmosphere-vegetation-soil system and model evaluation of C accumulation in a cultivated fieldOta, Masakazu; Nagai, Haruyasu; Koarashi, Jun
no journal, ,
no abstracts in English
Yada, Hiroki; Shobu, Takahisa; Yamada, Tomonori; Muramatsu, Toshiharu
no journal, ,
no abstracts in English
Shobu, Takahisa; Urushisaki, Yukinori*; Ichimura, Makoto*; Amaya, Koichi*; Yada, Hiroki; Takase, Kazuyuki; Muramatsu, Toshiharu
no journal, ,
no abstracts in English
Motooka, Takafumi; Yamamoto, Masahiro; Ueno, Fumiyoshi; Ishijima, Yasuhiro; Uchiyama, Gunzo; Nojima, Yasuo*; Fujine, Sachio*; Sakai, Junichi*; Shiimori, Fusae*; Miyasaka, Yuto*
no journal, ,
As a part of studies on ageing behavior of reprocessing plants, the amount of hydrogen gas generated from nitrate solutions under 
irradiation and the amount of hydrogen absorbed to titanium alloy were measured after irradiation in order to evaluate the hydrogen degradation of instruments made of titanium alloy. The amount of hydrogen gas was decreased with increase of nitrate concentration. Only a little hydrogen was absorbed to titanium. It is necessary to consider the long-time prediction model for hydrogen adsorption to evaluate hydrogen degradation.
Sugaya, Atsushi; Horiguchi, Kenichi; Akutsu, Shigeru
no journal, ,
A large amount of nitrate in the effluent occurring from the Tokai reprocessing plant might cause the environmental pollution. The effluent is planning to be encapsulated by cement after treated in the nitrate ion decomposition process using a reductant and catalyst. Cement based encapsulation trials for low-radioactive effluent from the nitrate decomposition process is reported.
Koura, Hiroyuki; Iwamoto, Osamu; Chiba, Satoshi
no journal, ,
no abstracts in English
Yamashita, Shinichi; Hirade, Tetsuya; Matsuura, Chihiro*; Iwamatsu, Kazuhiro; Taguchi, Mitsumasa; Katsumura, Yosuke*
no journal, ,
Fukushima Daiichi Nuclear Power Plant Unit-4 was under an inspection on the day of Tohoku earthquake, and all of the fuels were cooled in the fuel storage pool. However, the explosion occurred only four days after the cooling of the pool stopped. Later, the pool was investigated and it was clarified that the fuels were not so damaged and the water was not contaminated with radioisotopes. There are several explanations of the cause of the explosion. We picked up one possibility that the radiolysis of the water was the source of the hydrogen and that the vapor condensation could make the high hydrogen density behind the cold roof or walls, and investigated by an experiment of boiled water radiolysis by -rays. The results can explain some of the typical things happened on the explosion of Unit-4.
Yoshida, Hiroyuki; Nagatake, Taku; Takase, Kazuyuki; Monji, Hideaki*; Kaneko, Akiko*; Abe, Yutaka*
no journal, ,
no abstracts in English
Amano, Yuki; Watanabe, Koji; Abe, Hitoshi; Ishikawa, Jun; Tashiro, Shinsuke; Yamane, Yuichi; Uchiyama, Gunzo
no journal, ,
no abstracts in English
Tamai, Hidesada; Nagayoshi, Takuji; Katono, Kenichi; Ito, Takashi; Takase, Kazuyuki
no journal, ,
no abstracts in English
Ando, Masaki; Fukushima, Masahiro; Kitamura, Yasunori; Kugo, Teruhiko; Iwasaki, Tomohiko*; Konashi, Kenji*
no journal, ,
Experimental study to evaluate feasibility of hafnium hydride neutron absorber has been planned at FCA. This presentation reports the scpe of the plan and the results of the first experiment and analysis using plate-shaped simulating materials. The calculation accuracy of the standard fast reactor analysis method with the use of the JENDL-3.3 for the experimental results with boron carbide and hafnium hydride absorbers were compared. Underestimation of several % was observed for the calculation of the hafnium hydride in comparison with that of the boron carbide.
samples in a uranium fueled coreSuzuki, Motomu*; Yamamoto, Toru*; Ando, Yoshihira*; Nakajima, Tetsuo*; Ando, Masaki; Kugo, Teruhiko; Okajima, Shigeaki
no journal, ,
To obtain experimental data to evaluate calculation accuracy for the Doppler effect in MOX fueled LWR, a series of experiment has been carried out at FCA with the use of uranium and plutonium samples. Parametric survey calculations as for the modeling, nuclear data library and calculation method were carried out for the experiments in the uranium core using uranium samples. The effect of those parameters for the calculation of the Doppler effect was obtained.
Nakayoshi, Akira; Kitawaki, Shinichi; Kano, Yoshiharu; Tayama, Toshimitsu; Nagai, Takayuki; Koyama, Tadafumi*
no journal, ,
no abstracts in English
Ishijima, Yasuhiro; Takada, Juntaro; Ueno, Fumiyoshi; Yamamoto, Masahiro; Uchiyama, Gunzo; Nojima, Yasuo*; Fujine, Sachio*; Kimura, Kazuhiro*
no journal, ,
Effect of ageing on mechanical properties of nickel based refractory alloy was evaluated for study on ageing behavior of nuclear fuel reprocessing plants. Solution treated and aged Alloy 625 was elected to test material. Creep tests and tensile tests were carried out at 1027 K. From test results, aged alloy 625 showed linear relationship between test stress and secondary creep rate. On the other hand, solution treated alloy 625 showed deformation behavior change at 100 MPa. This result indicates that the ageing behavior of reducing furnace can evaluate by straight line extrapolation. Aged alloy 625 showed remarkable decreasing of ductility at room temperature. This result suggests that room temperature embrittlement should be considered on the ageing behavior of reducing furnace.
Liu, W.; Nagatake, Taku; Takase, Kazuyuki
no journal, ,
In order to understand a fast changing transient heat transfer phenomenon such as boiling, Japan Atomic Energy Agency has begun to develop a measuring technology for the surface temperature and surface heat flux, without sensors set on the surface. The technique for the measurement of surface temperature and surface heat flux involves two steps: (1) measurement of the inner block temperatures using special micro temperature sensors, which are placed at a depth of several micrometers beneath the surface; (2) solving an inverse heat conduction problem (IHCP) to obtain the surface heat flux and surface temperature by using the measured inner block temperature data. This paper gives the description for the development result of the special micro temperature sensors in the year 2010.
Hamada, Nobuyuki; Watanabe, Junji; Higashiura, Norikazu; Shime, Masanori
no journal, ,
no abstracts in English
Mihara, Takeshi; Fukuda, Takuji; Udagawa, Yutaka; Sugiyama, Tomoyuki; Nagase, Fumihisa
no journal, ,
High burnup PWR fuel rods includes hydride rims that hydride accumulate the periphery of the rods. NSRR experiments of the fuels indicate that hydride rims plays a role of an initial crack of RIA failure behavior. In order to clarify the influence of interior hydrides other than the rims about RIA failure behavior, hydrided RAG (Roll after Grooving) fabricated fuel rods were performed with EDC (Expansion Due to Compression) experiments. Stress intensity factor analyses indicate that in case the radially-oriented hydrides are precipitated at the tip of the pre-crack, the stress state of the matrix at the tip of the hydrides is the same.
Fukuda, Takuji; Sugiyama, Tomoyuki; Mihara, Takeshi; Nagase, Fumihisa
no journal, ,
The hydride Precipitation occurs due to absorption of hydrogen and its oxidation in the high burn-up fuel cladding. The hydride precipitated densely near the outer surface of the cladding could be considered the origin of the crack growth its own brittle property. RAG (Roll After Grooving) has been developed to simulate the outer surface of hydride precipitation on the origin of the crack. The fracture behavior was evaluated to define the effect of origin of the crack compared with milled cladding by EDC (Expansion Due to Compression) test. The crack extension occurred in smaller circumferential strain on RAG cladding than milled cladding. It was shown that RAG can simulate the crack growth of outer surface hydride cracking.