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Nishi, Yoshihisa*; Arai, Kenji*; Oikawa, Hirohide*; Fujii, Tadashi*; Umezawa, Shigemitsu*; Yamada, Hidetomo*; Nakamura, Hideo
no journal, ,
no abstracts in English
Nishimura, Satoshi*; Satake, Masaaki*; Soga, Shota*; Nishi, Yoshihisa*; Kaji, Yoshiyuki; Nemoto, Yoshiyuki
no journal, ,
Using the severe accident code MAAP5.03, simulation of the loss of cooling function accident in spent fuel pool was conducted and cooling performance of the emergency cooling systems such as spray or water inlet was evaluated.
Goto, Daisuke*; Tojo, Masayuki*; Kobayashi, Kensuke*; Nemoto, Yoshiyuki; Kaji, Yoshiyuki
no journal, ,
Steady-state heat transfer analysis method for the BWR spent fuel rack system was adopted to evaluate the cladding temperature in spent fuel pool accident condition. The cladding temperature seems to depend on spent fuel distribution, and the evaluation results were compared with the results obtained by using the MAAP. Ideas for the deployment of the fuels to prevent temperature elevation during the spent fuel pool water level decrease will be discussed.
Kobayashi, Kensuke*; Tojo, Masayuki*; Goto, Daisuke*; Nemoto, Yoshiyuki; Kaji, Yoshiyuki
no journal, ,
It is suggested that effective multiplication factor would increase if there is a water level difference between in and out of channel box of BWR fuel. Monte Carlo criticality analysis was conducted in consideration of the water density and the water level in and out of the channel box which were indicated in the evaluation using void fraction correlation obtained in previous works simulating several irradiation conditions of BWR fuels.
Tojo, Masayuki*; Kanazawa, Toru*; Kobayashi, Kensuke*; Goto, Daisuke*; Nemoto, Yoshiyuki; Kaji, Yoshiyuki
no journal, ,
Computational fluid dynamics (CFD) analysis for the loss of coolant accident in spent fuel pool (SFP) with Zircalloy-2 cladding was conducted. In the higher region of spent fuel rack internal, oxygen content in the atmosphere was decreased because of oxigen consumption during the oxidation reaction of cladding material. This oxygen depression is thought to surpress the oxidation of claddings.
Goto, Daisuke*; Kobayashi, Kensuke*; Tojo, Masayuki*; Nemoto, Yoshiyuki; Kaji, Yoshiyuki
no journal, ,
Influence of base temperature of the spent fuel pool (SFP), rack dimension, structure, and decay heat distribution, for the maximum temperature of cladding in spent fuel rack during the SFP loss of coolant accident was evaluated in this study, by using the previously developed 3 dimensional steady-state heat transfer analysis method.
Kobayashi, Kensuke*; Goto, Daisuke*; Tojo, Masayuki*; Nemoto, Yoshiyuki; Kaji, Yoshiyuki
no journal, ,
Experiment and analysis simulating the water level mismatch between inside and outside of chanel box of BWR fuel under loss of cooling system were conducted for validation of the equation for void fraction correlation.
Nishimura, Satoshi*; Satake, Masaaki*; Nishi, Yoshihisa*; Kaji, Yoshiyuki; Nemoto, Yoshiyuki
no journal, ,
Oxidation models in dry air, in steam, and in mixture of air and steam, were previously proposed by JAEA. These oxidation models were introduced in the severe accident code MAAP, and applied for spent fuel pool accident analyses. The comparison of the analytical results with different oxidation model were conducted in this study.
Nishimura, Satoshi*; Satake, Masaaki*; Nishi, Yoshihisa*; Kaji, Yoshiyuki; Nemoto, Yoshiyuki; Nagatake, Taku
no journal, ,
In order to validate a spray cooling model for spent fuel pool (SFP) in the severe accident code "MAAP", benchmark analysis of SFP spray cooling tests was conducted with MAAP ver. 5.04. In a current spray cooling model in MAAP code, spray water entered into a fuel assembly flows down uniformly on the surface of fuel pins and fuel racks in the form of liquid film and cools the fuel pin from its top to the bottom. As a result, the current MAAP model causes effective cooling and leads to the tendency of overestimation of spray cooling rate comparing to the measured data.