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Oral presentation

Irradiation experiments of simulated carbonate slurry in HIC, 2; Gas retention behavior of simulated carbonate slurry under $$gamma$$-ray irradiation

Motooka, Takafumi; Nagaishi, Ryuji; Yamagishi, Isao

no journal, , 

We conducted $$gamma$$ 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 $$gamma$$ 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.

Oral presentation

Study on rapid analysis of the radioactive tritium in groundwater into the Fukushima-1 Nuclear Power Plant, 1; Applicability confirmation of the tritium column

Sasaki, Takayuki*; Akimoto, Yuji*; Seki, Kotaro; Nagano, Misato*; Ishimori, Kenichiro; Ueno, Takashi; Kameo, Yutaka

no journal, , 

no abstracts in English

Oral presentation

Uncertainty of criticality analysis of UO$$_{2}$$-concrete system under randomization

Ueki, 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.

Oral presentation

Simulation of TVF glass melter operation with forming of thick sediments composed of platinum group elements

Asahi, Yoshimitsu; Nakajima, Masayoshi; Ayame, Yasuo

no journal, , 

no abstracts in English

Oral presentation

Probabilistic risk assessment method development for high temperature gas-cooled reactors

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.

Oral presentation

Necessity of fundamental experiments for evaluating two-phase flow behavior in a RCIC system of the Fukushima Dai-ichi Nuclear Power Plant No.2 unit

Takase, Kazuyuki; Yoshida, Hiroyuki; Okada, Hidetoshi*; Koikari, Soji*; Tsuzuki, Nobuyoshi*

no journal, , 

no abstracts in English

Oral presentation

Remote technology development for function advancement of research base, 3; Development of robot simulator for nuclear emergency response

Suzuki, Kenta; Isowa, Mitsuru; Kawabata, Kuniaki; Torii, Tatsuo

no journal, , 

no abstracts in English

Oral presentation

Source term estimation based on environmental monitoring data

Nagai, Haruyasu

no journal, , 

no abstracts in English

Oral presentation

Behavior of fission products in Fukushima Daiichi NPP under severe accidents overview of FP behavior under accidents and approaches toward advanced source term analysis, 4; Fundamental aspects of FP behavior and challenge toward further research subjects

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.

Oral presentation

Irradiation experiments of simulated carbonate slurry in HIC, 3; Studies on radiolysis behavior of simulated carbonate slurry

Nagaishi, Ryuji; Motooka, Takafumi; Yamagishi, Isao; Inoue, Masao; Matsumura, Taichi

no journal, , 

no abstracts in English

Oral presentation

Radioactive particles discovered in the vicinity of Fukushima Nuclear Plant

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 $$^{125}$$Sb was detected from unit-1 origin samples. Moreover, radioactive particle was made up 80 weight percent silica.

Oral presentation

Examination of the decreasing effect on internal exposure by sheltering, 2; Sensitivity analysis

Hirouchi, Jun; Takahara, Shogo; Watanabe, Masatoshi; Munakata, Masahiro

no journal, , 

no abstracts in English

Oral presentation

Examination of the decreasing effect on internal exposure by sheltering, 1; Literature search on variation factors

Watanabe, Masatoshi; Takahara, Shogo; Hirouchi, Jun; Munakata, Masahiro

no journal, , 

no abstracts in English

Oral presentation

Study on the monitoring of impurities in sodium by plugging meter

Suzuki, Masashi; Yoshida, Eiichi; Imamura, Hiroaki; Amano, Katsunori; Shimoyama, Kazuhito

no journal, , 

no abstracts in English

Oral presentation

Energy released in criticality accident by instantaneous reactivity insertion to system with non-linear temperature feedback

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%.

Oral presentation

Analysis of influence of indoor radiation dose rates on existence of neighboring buildings using reflection boundary

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.

Oral presentation

Oral presentation

Development of quick and remote analysis for severe accident reactor, 5; Analysis of spectra using the least-square method

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.

Oral presentation

Integration of knowledge management support system for the decommissioning of nuclear facilities, 5; Study for the support system by VR/AR technology

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.

Oral presentation

Cross section adjustment methods based on minimum variance unbiased estimate

Yokoyama, Kenji; Yamamoto, Akio*

no journal, , 

no abstracts in English

249 (Records 1-20 displayed on this page)