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Okumura, Keisuke; Riyana, E. S.; Sato, Wakaei*; Maeda, Hirobumi*; Katakura, Junichi*; Kamada, So*; Joyce, M. J.*; Lennox, B.*
Progress in Nuclear Science and Technology (Internet), 6, p.108 - 112, 2019/01
In order to establish the prediction method of the dose rate distribution in the primary containment vessel (PCV) of the Fukushima Daiichi Nuclear Power Station, a series of calculations were carried out in the following way; (1) burnup calculation to obtain fuel composition at the time of accident, (2) activation calculation for the structural materials including impurities, (3) estimation of Cs contamination in PCV based on the result of severe accident analysis by IRID, (4) decay calculation of radioactive nuclides, (5) photon transport calculation to obtain dose rate distribution. After that, Cs concentration around the dry-well of 1F was modified to be consistent with locally measured dose rates in the PCV-investigation by IRID.
Okumura, Keisuke; Sato, Wakaei; Maeda, Hirobumi; Wakaida, Ikuo; Washiya, Tadahiro; Katakura, Junichi*
no journal, ,
In order to develop the evaluation technology of the most probable radiation source and dose rate distributions in the primary containment vessel (PCV), we evaluated the radiation source distribution based on the results of fuel burn-up calculation, activation calculation of structural materials and severe accident analysis. Then, we built a three-dimensional PCV model for the particle transport Monte Carlo calculation code PHITS. From the PHITS calculation, we obtained the response function of the dose rate distribution due to each unit radiation source.
Okumura, Keisuke; Riyana, E. S.; Sato, Wakaei*; Maeda, Hirobumi*; Katakura, Junichi*
no journal, ,
Based on the results of fuel burn-up calculations and activation calculations for structural materials and on those of severe accident progression analyses and internal investigations by IRID, we predicted a three-dimensional dose rate distribution in the containment vessel of Unit 1 at the Fukushima Daiichi Nuclear Power Station.
Okumura, Keisuke; Riyana, E. S.; Sato, Wakaei*; Maeda, Hirobumi*; Fujita, Manabu*
no journal, ,
In order to contribute to the decommissioning of the Fukushima Daiichi Nuclear Power Station (1F) and characterization of 1F fuel debris, we predicted the decay heat of the fuel debris from the time of accident to future and its contributing nuclides, by considering release of volatile fission products.
Okumura, Keisuke; Riyana, E. S.; Sato, Wakaei*; Maeda, Hirobumi*; Katakura, Junichi*
no journal, ,
The three-dimensional dose rate distribution at the end of 2021 in the primary containment vessel of the Fukushima Daiichi Nuclear Power Station was predicted by combining various numerical calculations such as Monte Carlo calculation and measured data obtained in the internal investigations.
