Characterization of bremsstrahlung and -rays of fuel debris

Matsumura, Taichi; Okumura, Keisuke; Fujita, Manabu*; Sakamoto, Masahiro; Terashima, Kenichi; Riyana, E. S.

Radiation Physics and Chemistry, 199, p.110298_1 - 110298_8, 2022/10

https://doi.org/10.1016/j.radphyschem.2022.110298

Gamma detector response simulation inside the pedestal of Fukushima Daiichi Nuclear Power Station

Riyana, E. S.; Okumura, Keisuke; Terashima, Kenichi; Matsumura, Taichi; Sakamoto, Masahiro

Mechanical Engineering Journal (Internet), 7(3), p.19-00543_1 - 19-00543_8, 2020/06

https://doi.org/10.1299/mej.19-00543

Calculation of low-energy electron antineutrino spectra emitted from nuclear reactors with consideration of fuel burn-up

Riyana, E. S.*; Suda, Shoya*; Ishibashi, Kenji*; Matsuura, Hideaki*; Katakura, Junichi*; Sun, G. M.*; Katano, Yoshiaki

Journal of Nuclear Science and Technology, 56(5), p.369 - 375, 2019/05

https://doi.org/10.1080/00223131.2017.1291370

Nuclear reactors produce a great number of electron antineutrinos mainly from beta-decay chains of fission products. Such neutrinos have energies mostly in MeV range. We are interested in neutrinos in a region of keV, since they may have information on fuel burn-up and may be detected in future with advanced measurement technology. We calculate reactor antineutrino spectra especially in the low energy region. In this work we present neutrino spectra from various reactors such as typical PWR reactor and others types of reactors for comparison. Our result shows the electron antineutrino flux in the low energy region increases with burn-up of nuclear fuel by accumulated nuclides with low Q values in beta decay.

A Method for the prediction of the dose rate distribution in a primary containment vessel of the Fukushima Daiichi Nuclear Power Station

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

https://doi.org/10.15669/pnst.6.108

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.

Technology development to predict dose rate distribution in PCV of Fukushima Daiichi Nuclear Power Station

Riyana, E. S.; Okumura, Keisuke

no journal, , 

A technology to predict the most probable dose rate distribution in the primary containment vessel (PCV) of the Fukushima Daiichi Nuclear Power Station (1F) have been developed by combined use of sophisticated theoretical calculation and local measurement results. It was applied to the Unit-1 of 1F.

Prediction of decay heat of fuel debris considering volatilization of fission products

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.

Technology development to evaluate dose rate distribution and to search for fuel debris submerged in water for decommissioning of Fukushima Daiichi Nuclear Power Station, 8; A Prediction of the three-dimensional dose rate distribution in the primary containment vessel

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.

Neutron irradiation test of bubble detector for fuel debris detections

Terashima, Kenichi; Matsumura, Taichi; Kaburagi, Masaaki; Sakamoto, Masahiro; Riyana, E. S.; Okumura, Keisuke

no journal, , 

no abstracts in English

Application of bubble detector to fuel debris detection

Terashima, Kenichi; Sakamoto, Masahiro; Matsumura, Taichi; Kaburagi, Masaaki; Riyana, E. S.; Nomi, Takayoshi; Okumura, Keisuke

no journal, , 

no abstracts in English

Criticality evaluation of fuel debris with unclear shape and material composition; Development of a new subcritical depletion code for monitoring noble gases

Riyana, E. S.

no journal, , 

no abstracts in English

Characterization of neutrons emitted from fuel debris

Matsumura, Taichi; Sakamoto, Masahiro; Terashima, Kenichi; Riyana, E. S.; Okumura, Keisuke

no journal, , 

no abstracts in English