MAAP code analysis for the in-vessel phase of Fukushima-Daiichi Nuclear Power Station Unit 1 and comparison of the results among Units 1 to 3

Sato, Ikken; Yoshikawa, Shinji; Yamashita, Takuya; Shimomura, Kenta; Cibula, M.*; Mizokami, Shinya*

Nuclear Engineering and Design, 422, p.113088_1 - 113088_24, 2024/06

https://doi.org/10.1016/j.nucengdes.2024.113088

Comparison of nuclear medicine therapeutics targeting PSMA among alpha-emitting nuclides

Kaneda-Nakashima, Kazuko*; Shirakami, Yoshifumi*; Kadonaga, Yuichiro*; Watabe, Tadashi*; Oe, Kazuhiro*; Yin, X.*; Haba, Hiromitsu*; Shirasaki, Kenji*; Kikunaga, Hidetoshi*; Tsukada, Kazuaki; et al.

International Journal of Molecular Sciences (Internet), 25(2), p.933_1 - 933_14, 2024/01

https://doi.org/10.3390/ijms25020933

Cs contamination of Japanese mustard spinach by resuspended particles in areas with different contamination conditions

Tatsuno, Takahiro*; Yoshimura, Kazuya; Nihei, Naoto*

Journal of Radioanalytical and Nuclear Chemistry, 8 Pages, 2024/00

https://doi.org/10.1007/s10967-023-09347-9

Validation of the applicability of the best-fit fatigue curves for 550C in Mod.9Cr-1Mo steel to 110 cycles

Toyota, Kodai; Imagawa, Yuya; Onizawa, Takashi; Kato, Shoichi; Furuya, Yoshiyuki*

Nihon Kikai Gakkai Rombunshu (Internet), 89(928), p.23-00206_1 - 23-00206_15, 2023/12

https://doi.org/10.1299/transjsme.23-00206

In order to design fast reactors, it is necessary to consider high cycle fatigue of structural materials up to 110 cycles; to evaluate high cycle fatigue at 110 cycles, it is necessary to develop a best-fit fatigue curve applicable up to 110 cycles. In this study, high cycle fatigue tests were conducted under strain-controlled conditions and ultrasonic fatigue tests were also conducted to develop a high cycle fatigue evaluation method for Mod.9Cr-1Mo steel, which is a candidate material for fast reactor structural materials. Based on the test results, the best-fit fatigue curves were extended and the applicability of the JSME best-fit fatigue curves up to 110 cycles was verified.

Survey of air dose rate distribution inside and outside of wooden houses in Fukushima Prefecture; Actual condition of dose reduction factor

Kim, M.; Malins, A.*; Machida, Masahiko; Yoshimura, Kazuya; Saito, Kimiaki; Yoshida, Hiroko*

Nihon Genshiryoku Gakkai Wabun Rombunshi (Internet), 22(4), p.156 - 169, 2023/11

https://doi.org/10.3327/taesj.J23.001

Dose reduction factor of a Japanese house is important information in the external exposure estimation of returning residents. In 2019, a total of 19 wooden houses were surveyed in Iitate Village and Namie Town using a gamma plotter that can continuously measure the air dose rate. In addition, the characteristics of the reduction factor were investigated from the measured air dose rate. In the vicinity of houses, uncontaminated areas exist underneath houses and, the ratio of paved surfaces such as asphalt roads is relatively high; furthermore, the pavement has a tendency for the radiation source to decay quickly. Therefore, the air dose rate near the house showed a relatively low value in common at all sites. Air dose rates above unpaved surfaces showed higher values and larger variations than those above paved surfaces within a radius of 50 m form the center of a house. The reduction factor was widely distributed even for one house, if the ratio of every air dose rate observed inside and outside the house is considered. It is suggested that a realistic reduction factor may not be obtained when the reduction factor is obtained based on the measured values at a small number of points that do not have the representativeness of the radiation field to be measured.

In-operando distribution measurement of internal temperature and stress in lithium-ion battery

Hirano, Tatsumi*; Maeda, Takehiro*; Murata, Tetsuyuki*; Yamamoto, Takahiro*; Matsubara, Eiichiro*; Shobu, Takahisa; Shiro, Ayumi*; Yasuda, Ryo*; Takamatsu, Daiko*

SPring-8/SACLA Riyo Kenkyu Seikashu (Internet), 11(5), p.345 - 353, 2023/10

https://doi.org/10.18957/rr.11.5.345

no abstracts in English

Radio-tellurium released into the environment during the complete oxidation of fuel cladding, containment venting and reactor building failure of the Fukushima accident

Hidaka, Akihide; Kawashima, Shigeto*; Kajino, Mizuo*

Journal of Nuclear Science and Technology, 60(7), p.743 - 758, 2023/07

https://doi.org/10.1080/00223131.2022.2142311

An accurate estimation of radionuclides released during the Fukushima accident is essential. Therefore, authors investigated Te release using the Unit emission-regression estimation method, in which the deposition distribution is weighted based on the hourly deposition obtained from mesoscale meteorological model calculations assuming Unit emissions. The previous study focused on confirming the applicability of this method. Subsequent examination revealed that if any part of the time when a release have occurred is missing from the estimated release period, the entire source term calculation will be distorted. Therefore, this study performed the recalculation by extending the estimation period to cover all major releases. Consequently, unspecified release events were clarified, and their correspondence to in-core events was confirmed. The Te release caused by Zr cladding complete oxidation can explain the regional dependence of the Te/Cs ratio in the soil contamination map.

Cs transfer from soils contaminated by resuspended particles to Japanese mustard spinach in difficult-to-return zone of Fukushima

Tatsuno, Takahiro*; Nihei, Naoto*; Yoshimura, Kazuya; Ote, Nobuhito*

Journal of Radioanalytical and Nuclear Chemistry, 332(6), p.1677 - 1686, 2023/06

https://doi.org/10.1007/s10967-023-08899-0

Measurement of the spatial polarization distribution of circularly polarized gamma rays produced by inverse Compton scattering

Taira, Yoshitaka*; Endo, Shunsuke; Kawamura, Shiori*; Nambu, Taro*; Okuizumi, Mao*; Shizuma, Toshiyuki*; Omer, M.; Zen, H.*; Okano, Yasuaki*; Kitaguchi, Masaaki*

Physical Review A, 107(6), p.063503_1 - 063503_10, 2023/06

https://doi.org/10.1103/PhysRevA.107.063503

no abstracts in English

Thirty-year simulation of environmental fate of Cs in the Abukuma River basin considering the characteristics of Cs behavior in land uses

Ikenoue, Tsubasa; Shimadera, Hikari*; Nakanishi, Takahiro; Kondo, Akira*

Science of the Total Environment, 876, p.162846_1 - 162846_12, 2023/06

https://doi.org/10.1016/j.scitotenv.2023.162846

We conducted 30 years simulation of environmental fate of Cs in the Abukuma River basin considering the characteristics of the Cs behavior in land uses. Overall, in the Abukuma River basin, the Cs transported into the ocean for 30 years was estimated to correspond to 4.6% of the initial deposition in the basin, and the effective half-life of Cs deposited in the basin was estimated to be 3.7 years shorter (by 11.6%) than its physical half-life. These results suggested that Cs deposited from the accident could still remain for decades. Based on the analysis of the Cs behavior in land use, in 2011, the contribution of Cs export to the ocean from urban lands was estimated to correspond to 70% of the total Cs export. Meanwhile, from 2012 to 2040, the contribution of Cs export from agricultural lands was estimated to correspond to 75% of the total Cs export. The reduction ratios excluding radioactive decay of Cs remained in areas with and without human activities for 30 years after the accident, defined as the ratios of the total outflow to the initial deposition, were estimated to be 11.5%-17.7% and 0.4%-1.4%, respectively. These results suggested that human activities enhance the reduction of Cs remaining in land in the past and future.