Depletion calculation of subcritical system with consideration of spontaneous fission reaction

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

Journal of Nuclear Science and Technology, 59(4), p.424 - 430, 2022/04

https://doi.org/10.1080/00223131.2021.1974970

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

Analytical studies of three-dimensional evaluation of radionuclide distribution in zeolite wastes through gamma scanning of adsorption vessels

Matsumura, Taichi; Nagaishi, Ryuji; Katakura, Junichi*; Suzuki, Masahide*

Nuclear Science and Engineering, 192(1), p.70 - 79, 2018/10

https://doi.org/10.1080/00295639.2018.1493856

The gamma-scanning of SDS (submerged demineralizer system) vessel used as a typical vessel for decontamination of radioactive water at Three Mile Island Unit 2 (TMI-2) accident was simulated in the axial and radial directions of real and cylindrical-shaped vessels by using a Monte Carlo calculation code (PHITS) on the basis of the geometrical and compositional information of vessel and gamma-scanning available in the previous reports at the accident. In the axial simulation, the true distribution of radioactive Cs in the zeolite packed bed of vessel was successfully evaluated when a correction function derived from a virtual constant distribution of Cs was applied to the reported gamma-scanning profile. In the radial simulation, the virtual disk-formed and shell-formed sources of Cs displaced in the packed bed were clearly observed from the top and bottom views of vessel. This new radial gamma-scanning indicates that the radial localization of Cs could be well observed by measuring gamma-ray from the top view of vessel during storage. We further examined the radial gamma-scanning from the side view whether the radial localization of Cs can be confirmed in the normally existing gamma-scanning room or not.

Toward investigation of molecular effects on the muon transfer reaction

Ninomiya, Kazuhiko; Nakagaki, Reiko*; Kubo, Kenya*; Ishida, Katsuhiko*; Kobayashi, Yoshio*; Matsuzaki, Teiichiro*; Matsumura, Hiroshi*; Miura, Taichi*; Higemoto, Wataru; Shinohara, Atsushi*

no journal, , 

no abstracts in English

Consideration of water radiolysis in void volumes of porous zeolite bed loaded in adsorption vessels for decontamination of radioactive water

Nagaishi, Ryuji; Inoue, Masao; Matsumura, Taichi; Yamagishi, Isao; Hino, Ryutaro; Ogawa, Toru

no journal, , 

Hydrogen gas generation in radiolysis of pure water or seawater coexisting with zeolite adsorbents has been investigated by using Co-60 -ray for hydrogen safety in decontamination of radioactive water after Fukushima Daiichi NPS accident. In this work, two types of void volumes present in the zeolite bed were paid attention microscopically, and the difference in water radiolysis between the volumes was considered. The oxygen generated by decomposition of hydrogen peroxide, as the counterpart of hydrogen molecule, contacting with the zeolites were also discussed.

Dose evaluation of adsorption vessels for contaminated water treatment by using radiation transport and shielding calculation codes

Matsumura, Taichi; Nagaishi, Ryuji; Katakura, Junichi*; Suzuki, Masahide*

no journal, , 

no abstracts in English

Studies on radiolysis behavior of carbonate slurry under Co-60 -ray irradiation

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

no journal, , 

no abstracts in English

Summary of reports on environmental radioactivity effected from the accident at the TEPCO Fukushima Daiichi Nuclear Power Plant

Bessho, Kotaro*; Matsumura, Hiroshi*; Miura, Taichi*; Iimoto, Takeshi*; Kinoshita, Norikazu*; Sakaguchi, Aya*; Sugihara, Shinji*; Takamiya, Koichi*; Tagami, Keiko*; Nagao, Seiya*; et al.

no journal, , 

Workshop on Environmental Radioactivity was established in 2000 and has been held every year on February or March at KEK, Tsukuba. The proceedings with peer review has been published after every workshop. After the accident at the TEPCO Fukushima Daiichi Nuclear Power Plant occurred in 2011, large number of scientific reports related to the accident were presented in this workshop. Researchers, technicians, local government staff, and general citizens have participated in the workshop to exchange information on various subjects. The organizing members of the workshop summarized 326 reports in the workshop during 2012 to 2016 and related publications. The summary report was published as follows. KEK Report 2016-3 (ISBN978-4-9907232-9-3)

Evaluation of energy spectrum around structural materials in radiation environments

Matsumura, Taichi; Nagaishi, Ryuji; Katakura, Junichi*; Suzuki, Masahide*

no journal, , 

no abstracts in English

Measurement of hydrogen generation in water radiolysis by low-penetrating radiations

Nagaishi, Ryuji; Kuwano, Ryo*; Matsumura, Taichi

no journal, , 

High-penetrating gamma-rays (Co-60) have been mainly used as an external radiation in irradiation experiments on water radiolysis for the 1F decommissioning, while the experiments using electron beams (EB) simulating beta-rays (Sr-90 and others) and X-rays simulating the bremsstrahlung of electrons have been also expected. However these are difficult because of the low-penetrating property of radiations. In this study, the experiments using EB and X-rays were conducted by using reaction vessels sealed with films having a good penetrating property for their radiations to measure H and its geminate product of HO as radiolysis products of water.