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Journal Articles

Characterization of bremsstrahlung and $$gamma$$-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

Journal Articles

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

 Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)

Journal Articles

Comparison of photon spectra emitted from fuel debris using different decay data libraries

Matsumura, Taichi; Okumura, Keisuke; Fujita, Manabu*

JAEA-Conf 2021-001, p.144 - 149, 2022/03

We require reliable nuclear data that can appropriately evaluate the radiation characteristics of fuel debris for the purpose such as development of new sensors, non-destructive assay technologies and optimization of radiation shielding. In the past, even if different results were obtained depending on calculation codes, it was difficult to clarify what caused the differences. To overcome it, we have developed a new reliable code to calculate radiation decay and radioactive source spectra that can accurately treat with large amounts of nuclides and all decay modes in the decay data file. As the first step, we compared the photon spectra of fuel debris by using the recent decay data files: JENDL/DDF-2015, decay sub-libraries of ENDF/B-VIII.0 and JEFF-3.3. In the presentation, we will report requests for the modifications on the decay scheme and branching ratio of decay mode for the next JENDL decay data file.

Journal Articles

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

Journal Articles

Evaluation of energy spectrum around structural materials in radiation environments

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

Radiation Physics and Chemistry, 166, p.108493_1 - 108493_9, 2020/01

 Times Cited Count:0 Percentile:0.01(Chemistry, Physical)

In this work, when radiation sources of $$^{137}$$Cs, $$^{90}$$Sr and $$^{90}$$Y were assumed to be put in the front of a plain SUS304 plate as a typical material submerged in water, energy spectra of secondary photons and electrons at the front and back sides of plate were simulated with changing the thickness of plate, and spacing between the source and plate by using a Monte Carlo calculation code of PHITS. In the case of $$^{137}$$Cs gamma-ray (monochromatic 662 keV), the energy spectra at the front side was smaller than those at the back side due to the existence of plate. Then the dependence of spectra on the plate thickness was observed more clearly at the back side than at the front side. It was clearly shown how the energy spectra of photons and electrons varied with the incident radiation type, the spacing, and the thickness.

Journal Articles

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

 Times Cited Count:1 Percentile:15.51(Nuclear Science & Technology)

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 $$^{137}$$Cs in the zeolite packed bed of vessel was successfully evaluated when a correction function derived from a virtual constant distribution of $$^{137}$$Cs was applied to the reported gamma-scanning profile. In the radial simulation, the virtual disk-formed and shell-formed sources of $$^{137}$$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 $$^{137}$$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 $$^{137}$$Cs can be confirmed in the normally existing gamma-scanning room or not.

Journal Articles

Summary of study on environmental radioactivity effected from the accident at the TEPCO Fukushima Daiichi Nuclear Power Plant in 5 years after the accident

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

KEK Report 2016-3, 134 Pages, 2017/03

This report is summary of study on environmental radioactivity effected from the accident at the TEPCO Fukushima Daiichi Nuclear Power Plant in 5 years after the accident. It was compiled efforts related to the accident reported from the 13th to the 17th "Workshop on Environmental Radioactivity" which was held at the High Energy Accelerator Research and Development Organization.

Oral presentation

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

Oral presentation

Experimental studies on hydrogen generation by water radiolysis in aqueous suspensions of bentonite

Nagaishi, Ryuji; Inoue, Masao; Endo, Keita*; Matsumura, Taichi; Ogawa, Toru

no journal, , 

no abstracts in English

Oral presentation

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 $$gamma$$-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.

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

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

Oral presentation

Studies on three-dimensional evaluation of nuclide distribution in zeolite wastes by $$gamma$$-scanning of adsorption vessels

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

no journal, , 

no abstracts in English

Oral presentation

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

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

no journal, , 

no abstracts in English

Oral presentation

Radiation-chemical estimation of energy deposition around fuel debris, 1; Estimation of energy distributions dependent on radiation types

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

no journal, , 

no abstracts in English

Oral presentation

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)

Oral presentation

Radiation-chemical estimation of energy deposition around fuel debris, 2; Radiation-chemical integration of energy distributions

Nagaishi, Ryuji; Matsumura, Taichi; Okumura, Keisuke

no journal, , 

no abstracts in English

Oral presentation

Evaluation of energy spectrum around structural materials in radiation environments

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

no journal, , 

no abstracts in English

Oral presentation

Estimation of thermal decomposition rates of hydrogen peroxide in aqueous solution systems of coexisting solid materials

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

no journal, , 

no abstracts in English

Oral presentation

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$$_{2}$$ and its geminate product of H$$_{2}$$O$$_{2}$$ as radiolysis products of water.

30 (Records 1-20 displayed on this page)