Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
-ray irradiationMotooka, Takafumi; Nagaishi, Ryuji; Yamagishi, Isao
no journal, ,
We conducted ray irradiation test using simulated carbonate slurry to obtain the basic knowledge of the cause of stagnant water over the High Integrity Container. We observed a rise in water level, air bubbles in the slurry, a supernatant when the carbonate slurry with 95 g/L density was irradiated by ray at 8.5 kGy/h. The cause of the rise in water level was regarded as the volume expansion by the gas retention in the carbonate slurry.
Sasaki, Takayuki*; Akimoto, Yuji*; Seki, Kotaro; Nagano, Misato*; Ishimori, Kenichiro; Ueno, Takashi; Kameo, Yutaka
no journal, ,
no abstracts in English
-concrete system under randomizationUeki, Taro
no journal, ,
Analysis framework under indeterminate material distribution is investigated for the Monte Carlo (MC) criticality calculation of continuously mixed media formed via molten core concrete interaction. Randomized Weierstrass functions (RWF) are utilized to represent the volume fractions of constituent materials. The possibility of several percent fluctuation of effective multiplication factor is shown by the MC simulation with delta-tracking.
Asahi, Yoshimitsu; Nakajima, Masayoshi; Ayame, Yasuo
no journal, ,
no abstracts in English
Sato, Hiroyuki; Nishida, Akemi; Furuya, Osamu*; Muramatsu, Ken*; Itoi, Tatsuya*; Takada, Tsuyoshi*; Tanabe, Masayuki*; Yamamoto, Tsuyoshi*
no journal, ,
The proposed research aims to establish a probabilistic risk assessment method for high temperature gas-cooled reactors fully utilizing their design and safety characteristics. The method will be developed for the incorporation of a graded approach as well as a component failure evaluation model using the operation and maintenance experience in the high temperature engineering test reactor into an accident frequency analysis. In addition, a source term evaluation method considering failures in core graphite components will be developed.
Takase, Kazuyuki; Yoshida, Hiroyuki; Okada, Hidetoshi*; Koikari, Soji*; Tsuzuki, Nobuyoshi*
no journal, ,
no abstracts in English
Suzuki, Kenta; Isowa, Mitsuru; Kawabata, Kuniaki; Torii, Tatsuo
no journal, ,
no abstracts in English
Nagai, Haruyasu
no journal, ,
no abstracts in English
Osaka, Masahiko; Miwa, Shuhei; Nakajima, Kunihisa; Di Lemma, F. G.; Suzuki, Chikashi; Nagase, Fumihisa
no journal, ,
Chemical behavior of fission product (FP) are of crucial importance for the improvement of FP release and transport behavior under the severe accident. Fundamental research on FP sorption behavior and evaluation of FP chemical composition in the reactor are introduced.
Nagaishi, Ryuji; Motooka, Takafumi; Yamagishi, Isao; Inoue, Masao; Matsumura, Taichi
no journal, ,
no abstracts in English
Satou, Yukihiko*; Sueki, Keisuke*; Sasa, Kimikazu*; Minowa, Haruka*; Yoshikawa, Hideki; Fujiwara, Kenso; Nakama, Shigeo
no journal, ,
We separated radioactive particles from soil and dust sample obtained around Fukushima Dai-ichi Nuclear Power Plant. Separated all particles can categorize unit-1 and unit-2 origin. And 
Sb was detected from unit-1 origin samples. Moreover, radioactive particle was made up 80 weight percent silica.
Hirouchi, Jun; Takahara, Shogo; Watanabe, Masatoshi; Munakata, Masahiro
no journal, ,
no abstracts in English
Watanabe, Masatoshi; Takahara, Shogo; Hirouchi, Jun; Munakata, Masahiro
no journal, ,
no abstracts in English
Suzuki, Masashi; Yoshida, Eiichi; Imamura, Hiroaki; Amano, Katsunori; Shimoyama, Kazuhito
no journal, ,
no abstracts in English
Yamane, Yuichi
no journal, ,
For criticality accidents due to instantaneous insertion of reactivity to the system with non-linear temperature reactivity feedback, an equation has been derived based on one-point kinetics, by which equation the total fission energy is expressed as a function of initial excess reactivity and other kinetics parameters. The results obtained by using the equation and one-point kinetics code, AGNES, were compared to each other to show that the difference between them decreased with increase of excess reactivity from several ten % to 4%.
Furuta, Takuya; Takahashi, Fumiaki
no journal, ,
Precise radiation dose assessment for residents is desired for radiation protection under contaminated environment due to the accident at Fukushima Daiichi Nuclear Power Station. Evaluation of dose rates inside houses is important for this assessment as well as those outside houses by monitoring because people stays inside houses for a large part of a day. We have studied radiation dose reduction inside buildings standing on isolated flat field as the typical data. However, radiation dose reduction for houses in urban area may be different from that for isolated houses because of influence of neighboring buildings. We therefore simulated a situation of infinitely aligned houses virtually by using reflection walls placed at the boundary of geometry containing a house. The radiation dose rate inside this house was computed by transporting radiations using PHITS. We found that dose rates per unit radiation concentration inside the house was lowered as the distance between houses was reduced because of shielding effect by neighboring houses and reduction of radiation source contributed to the dose rate.
Koura, Hiroyuki; Chiba, Satoshi*
no journal, ,
no abstracts in English
Akaoka, Katsuaki; Oba, Masaki; Miyabe, Masabumi; Wakaida, Ikuo
no journal, ,
For quantitative analysis of the fuel debris using Laser Induced Breakdown Spectroscopy (LIBS), great deal of analysis and identification of spectra are necessary. Therefore, we tried "the analysis of the LIBS spectrum by the least-squares method" as quantitative analysis without identification and analysis of the spectra. As a result, the calibration curves for quantitative analysis could be got without them.
Iguchi, Yukihiro; Yanagihara, Satoshi*; Tezuka, Masashi; Koda, Yuya; Kato, Yasuaki
no journal, ,
Fugen Decommissioning Engineering Center is promoting Knowledge Management (KM) for the decommissioning in order to transfer knowledge and technology of the employees. One of the approaches is a KM support system by using VR and AR technology based on the 3D-CAD data.
Yokoyama, Kenji; Yamamoto, Akio*
no journal, ,
no abstracts in English