Review of articles related to the accident at the Fukushima Daiichi Nuclear Power Station published in the Japanese Journal of Health Physics; Opinion and others (Secondary Publication)

Takahara, Shogo; Iimoto, Takeshi*; Igarashi, Takayuki*; Kawabata, Masako*

Journal of Radiation Protection and Research, 50(1), p.1 - 9, 2025/03

https://doi.org/10.14407/jrpr.2023.00703

The Health Physics Society of Japan established a working group to obtain insights and findings from articles related to the 1F accident, published in the Japanese Journal of Health Physics. This study describes the review results of 47 articles classified into the field without risk communication, environmental measurement and monitoring, radiation dose measurement and assessment, radiation medicine, and radioactive waste. The reviewed articles contain various insights and issues depending on the authors' standpoints and relevant social interests. As a result, the 1F accident relevant articles offer various discussion points depending on the authors' awareness of the issues, which give an opportunity to make reconsiderations on what kind of academic system health physics or radiation protection should be on the basis of the experiences from the 1F accident. Note that this is an English translation of an article published in Japanese Journal of Health Physics.

Fluorescence X-ray field for radiation dosemeters calibration

Tsuji, Tomoya; Yoshitomi, Hiroshi; Sato, Fuminobu*; Tanimura, Yoshihiko

Radiation Protection Dosimetry, p.ncaf060_1 - ncaf060_15, 2025/00

https://doi.org/10.1093/rpd/ncaf060

Comparison of codes for calculation of projocted radiation-induced cancer risks

Kujiraoka, Ikuo; Noguchi, Yoshihiro*; Shimada, Kazumasa; Hirouchi, Jun; Takahara, Shogo

Radiation Protection Dosimetry, 200(16-18), p.1561 - 1567, 2024/11

https://doi.org/10.1093/rpd/ncae177

Lifetime Attributable Risk (LAR) of cancer induced by radiation exposures is one of the important factors for deciding about radiological protection measures or protective actions for nuclear emergency preparedness and response. In Japan, while a model for estimating LAR for the Japanese population has been developed based on epidemiological data from A-bomb survivors, a flexible projection code implementing this model needs to be developed. This study investigated the existing codes to contribute to the development of the projection code. Based on these investigations, we compared their LAR calculation results, and explored the cause of their differences.

Development of -ray visualization survey meter in high gamma and neutron background environment

Tsubota, Yoichi; Kobayashi, Kenji; Ishii, Tatsuya; Hirato, Misaki; Shioya, Satoshi; Nakagawa, Takahiro

Radiation Protection Dosimetry, 200(16-18), p.1676 - 1680, 2024/11

https://doi.org/10.1093/rpd/ncae169

In the decommissioning of the Fukushima Daiichi Nuclear Power Station (FDNPS, 1F), workers are removing structures from inside the buildings, monitoring radioactive contamination, and decontaminating inside the buildings. For the measurement of contamination of suit surfaces of workers, we have developed a hand-held survey meter that can measure and visualize surface radioactive contamination of -nuclides in a high / -ray background environment. In order to selectively measure -nuclides, we designed and built a prototype hand-held survey meter for -rays, which consists of a thin-film ZnS:Ag scintillator, a multi-anode photomultiplier tube (MA-PMT), individual amplification and counting circuits for each channel of the MA-PMT. Based on the result of -ray counting, the developed device is capable of counting the -radiation beyond 2.110 cpm. In the -ray response test, there was no -ray response even when the detector was in close proximity to a high intensity source; The dose rate was estimated to be more than 1 Sv/h. In the future, we plan to reduce the weight and size of the device, as well as improve the usability of the device through actual testing in contaminated environments.

Establishment of a Am gamma calibration field based on international standards and its conversion coefficients

Tsuji, Tomoya; Yoshitomi, Hiroshi; Kowatari, Munehiko*; Tanimura, Yoshihiko

Radiation Protection Dosimetry, 200(15), p.1416 - 1424, 2024/09

https://doi.org/10.1093/rpd/ncae186

Development of DynamicMC for PHITS Monte Carlo package

Watabe, Hiroshi*; Sato, Tatsuhiko; Yu, K. N.*; Zivkovic, M.*; Krstic, D.*; Nikezic, D.*; Kim, K. M.*; Yamaya, Taiga*; Kawachi, Naoki*; Tanaka, Hiroki*; et al.

Radiation Protection Dosimetry, 200(2), p.130 - 142, 2024/02

https://doi.org/10.1093/rpd/ncad278

Previously, we have developed DynamicMC for modelling relative movement of ORNL phantom in a radiation field for MCNP. Using this software, 3-dimensional dose distributions in a phantom irradiated by a certain mono-energetic source can be deduced through its graphical user interface (GUI). In this study, we extended DynamicMC to be used in combination with the PHITS by providing it with a higher flexibility for dynamic movement for a less sophisticated anthropomorphic phantom. We anticipate that the present work and the developed open-source tools will be in the interest of nuclear radiation physics community for research and teaching purposes.

Interlaboratory comparison of electron paramagnetic resonance tooth enamel dosimetry with investigations of the dose responses of the standard samples

Toyoda, Shin*; Inoue, Kazuhiko*; Yamaguchi, Ichiro*; Hoshi, Masaharu*; Hirota, Seiko*; Oka, Toshitaka; Shimazaki, Tatsuya*; Mizuno, Hideyuki*; Tani, Atsushi*; Yasuda, Hiroshi*; et al.

Radiation Protection Dosimetry, 199(14), p.1557 - 1564, 2023/09

https://doi.org/10.1093/rpd/ncad150

Interlaboratory comparison studies are important for radiation dosimetry in order to demonstrate how the technique is universally available. The set of standard samples are examined in each participating laboratory in the present study. After a set of standard samples together with the samples with unknown doses, which were prepared in the same laboratory as the standard samples, are measured at a participating laboratory, those samples are sent to another participating laboratory for next measurement. There is some small difference observed in the sensitivity (the slope of the dose response line) of the standard samples while the differences in the obtained doses for the samples with unknown doses are rather systematic, implying that the difference is mostly due to the samples but not to measurements.

Development of a method of evaluating PuO particle diameters using an alpha-particle imaging detector

Morishita, Yuki; Sagawa, Naoki; Takada, Chie; Momose, Takumaro; Takasaki, Koji

Radiation Protection Dosimetry, 199(13), p.1376 - 1383, 2023/08

https://doi.org/10.1093/rpd/ncad186

It is very important to evaluate the diameters (activity median aerodynamic diameter) of Plutonium dioxide (PuO) particles for internal exposure dose evaluation. In this study, a method of evaluating PuO particle diameters using an alpha-particle imaging detector was developed. PuO particles with different diameters were modeled by Monte Carlo simulation, and the change in the shape of the energy spectrum for each particle diameter was evaluated. Two different patterns were modeled, namely, the case of PuO and the case of PuO (including isotopic composition of Pu). Multiple regression analysis was performed to determine the PuO particle diameter from the obtained parameters. The simulated diameters and the diameters obtained with the regression model were in good agreement. The advantage of using the alpha-particle imaging detector is to measure the alpha energy spectrum for individual particle, and this allows accurate measurement of particle diameter distribution.

SUMRAY: R and Python codes for calculating cancer risk due to radiation exposure of a population

Sasaki, Michiya*; Furukawa, Kyoji*; Satoh, Daiki; Shimada, Kazumasa; Kudo, Shinichi*; Takagi, Shunji*; Takahara, Shogo; Kai, Michiaki*

Journal of Radiation Protection and Research, 48(2), p.90 - 99, 2023/06

https://doi.org/10.14407/jrpr.2022.00213

This paper reports on the calculation code that is the result of the activities of the "Task Group for Development of Cancer Risk Estimation Codes Associated with Radiation Exposure (FY2020-2021)" established by the Japan Health Physics Society. In order to promote research on the estimation of cancer risk associated with radiation exposure, the Task Group decided to disclose the source code, including the algorithm and parameters used in the calculations, and to release the code under a license that permits modification and redistribution of the code. The computational code was named SUMRAY and coded in two computer languages, that is R and Python. The code is capable of calculating the accumulated excess risk using Monte Carlo methods with a 95% confidence interval. The results of SUMRAY were compared with the results of the existing codes whose source code is not publicly available, under the same calculation conditions. From the results, it was found that they were in reasonable agreement within the confidence interval. It is expected that SUMRAY, an open-source software, will be used as a common basis for cancer risk estimation studies associated with radiation exposure.

Visualization software for radioactive contamination based on Compton camera: COMRIS

Sato, Yuki; Minemoto, Kojiro*; Nemoto, Makoto*

Radiation Protection Dosimetry, 199(8-9), p.1021 - 1028, 2023/06

https://doi.org/10.1093/rpd/ncad106