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JAEA Reports

Investigations on distribution of radioactive substances owing to the Fukushima Daiichi Nuclear Power Station Accident in the fiscal year 2020 (Contract research)

Group for Fukushima Mapping Project

JAEA-Technology 2021-025, 159 Pages, 2022/01

JAEA-Technology-2021-025.pdf:46.66MB

This report presents results of the investigations on the distribution-mapping project of radioactive substances owing to TEPCO Fukushima Daiichi Nuclear Power Station (FDNPS) conducted in FY2020. Car-borne surveys, a flat ground measurement using survey meters, a walk survey and an unmanned helicopter survey were carried out to obtain air dose rate data. Air dose rate distribution maps were created and temporal changes of the air dose rates were analyzed. Regarding radiocesium deposition into the ground, surveys on depth profile of radiocesium and in-situ measurements were performed. Based on these measurement results, effective half-lives of the temporal changes in the air dose rates and the deposition were evaluated. In the examination of scoring for classifying the importance of measurement points, a score map was created for Fukushima Prefecture and the 80 km zone from the FDNPS, and the factors causing changes in the score when monitoring data from multiple years were used were discussed. Using the Bayesian hierarchical modeling approach, we obtained maps that integrated the air dose rate distribution data obtained from aircraft monitoring, car-borne surveys, and walk surveys with respect to the region within 80 km from the FDNPS and Fukushima Prefecture. The measurement results for FY2020 were published on the "Expansion Site of Distribution Map of Radiation Dose", and measurement data were stored as CSV format. Radiation monitoring and analysis of environmental samples owing to the comprehensive radiation monitoring plan were carried out.

Journal Articles

Validation of a model for estimating individual external dose based on ambient dose equivalent and life patterns

Sato, Rina; Yoshimura, Kazuya; Sanada, Yukihisa; Sato, Tetsuro*

Journal of Radiation Protection and Research, 9 Pages, 2022/00

After the Fukushima Daiichi Nuclear Power Station (FDNPS) accident, a model was developed to estimate the external exposure doses for residents who were expected to return to their homes after evacuation orders were lifted. However, the model's accuracy and uncertainties in parameters used to estimate external doses have not been evaluated. This study validates the model's accuracy by comparing the estimated effective doses with the measured personal dose equivalents. The personal dose equivalents and life pattern data were collected for 36 adult participants who lived or worked near the FDNPS in 2019. The estimated effective doses correlated significantly with the personal dose equivalents, demonstrating the model's applicability for effective dose estimation. However, the lower value of the effective dose relative to personal dose equivalent indoors could be because the conversion factor from ambient dose equivalent to effective dose did not reflect the actual environment.

JAEA Reports

Effective dose coefficients for internal exposure dose assessment in accordance with ICRP 2007 recommendations (Contract research)

Takahashi, Fumiaki; Manabe, Kentaro; Sato, Kaoru

JAEA-Review 2020-068, 114 Pages, 2021/03

JAEA-Review-2020-068.pdf:2.61MB

Radiation safety regulations have been currently established based on the 1990Recommendation by the International Commission on Radiological Protection (ICRP) in Japan. Meanwhile, ICRP released the 2007 Recommendation that replaces the 1990 Recommendation. Thus, the Radiation Council, which is established under the Nuclear Regulation Authority (NRA), has made discussions to incorporate the purpose of the 2007 Recommendation into Japanese regulations for radiation safety. As ICRP also has published effective dose coefficients for internal exposure assessment in accordance with the 2007recommendation, the technical standards are to be revised for the internal exposure assessment method in Japan. Currently, not all of the effective doses have been published to revise concentration limits for internal exposure protections of workers and public. The published effective dose coefficients are applied to radionuclides which are important in radiation protection for internal exposure of a worker. Thus, we review new effective dose coefficients as well as basic dosimetry models and data based upon Occupational Intakes of Radionuclides (OIR) parts 2, 3 and 4 that have been published from 2016 to 2019 by ICRP. In addition, issues are sorted out to provide information for revision of the technical standards for internal exposure assessment based on the 2007 Recommendations in future.

JAEA Reports

Investigations on distribution of radioactive substances owing to the Fukushima Dai-ichi Nuclear Power Station Accident in the fiscal year 2019 (Contract research)

Group for Fukushima Mapping Project

JAEA-Technology 2020-014, 158 Pages, 2020/12

JAEA-Technology-2020-014.pdf:23.82MB

This report presents results of the investigations on the distribution-mapping project of radioactive substances owing to TEPCO Fukushima Daiichi Nuclear Power Station (FDNPS) conducted in FY2019. Car-borne surveys, a flat ground measurement using survey meters, a walk survey and an unmanned helicopter survey were carried out to obtain air dose rate data. Air dose rate distribution maps were created and temporal changes of the air dose rates were analyzed. Regarding radiocesium deposition into the ground, surveys on depth profile of radiocesium and in-situ measurements were performed. Based on these measurement results, effective half-lives of the temporal changes in the air dose rates and the deposition were evaluated. In the examination of scoring to classify the importance of measurement points, we created a score map of Fukushima Prefecture and that within 80 km from the FDNPS based on the "score" method developed in 2018. The way of monitoring radioactive materials in land area was examined and the representativeness of monitoring points was proposed. Using the Bayesian hierarchical modeling approach, we obtained maps that integrated the air dose rate distribution data obtained from aircraft monitoring, car-borne surveys, and walk surveys with respect to the region within 80 km from the FDNPS and Fukushima Prefecture. The measurement results for FY2019 were published on the "Expansion Site of Distribution Map of Radiation Dose", and measurement data were stored as CSV format. Radiation monitoring and analysis of environmental samples owing to the comprehensive radiation monitoring plan were carried out.

JAEA Reports

Applied research for the establishment of radiation monitoring and evaluation of exposure dose of residence at the zone designated for reconstruction and recovery

Funaki, Hironori; Takahara, Shogo; Sasaki, Miyuki; Yoshimura, Kazuya; Nakama, Shigeo; Sanada, Yukihisa

JAEA-Research 2018-016, 48 Pages, 2019/03

JAEA-Research-2018-016.pdf:29.73MB

Cabinet Office Nuclear Emergency Response Headquarters starts to consider radiation protection in the "specific reconstruction reproduction base area" of which evacuation order will be lifted by 2023. It is essential to grab the present situations of radiation contamination and evaluate exposure dose in the area to realize the plan. Many surveys have evaluated the distributions of air dose rate and exposure dose has been estimated based on the results since the Fukushima Daiichi Nuclear Power Plant accident. Nevertheless, more detailed information on exposure is needed for the areas because its radiation level is relatively high. That is also to help make prudent evaluation plan. This study aimed to evaluate the detailed contamination situation there and estimate exposure dose with considering areal circumstances. Investigations were carried out for (1) airborne survey of air dose rate using an unmanned helicopter (2) evaluation of airborne radiocesium and (3) estimation of external/internal effective doses for typical activity patterns assumed. Additionally, we applied new methods for the airborne survey to evaluate exposure dose. Our study showed a detailed three-dimensional map of air dose rate and clarified the distribution pattern in the areas. Results of effective dose estimation suggested that the internal effective dose due to inhalation accounts for less than 1% of the external effective dose.

Journal Articles

Validation of PHITS spallation models from the perspective of the shielding design of transmutation experimental facility

Iwamoto, Hiroki; Meigo, Shinichiro

EPJ Web of Conferences, 153, p.01016_1 - 01016_9, 2017/09

 Times Cited Count:2 Percentile:82.8

Journal Articles

Calculation of fluence-to-effective dose conversion coefficients for the operational quantity proposed by ICRU RC26

Endo, Akira

Radiation Protection Dosimetry, 175(3), p.378 - 387, 2017/07

 Times Cited Count:11 Percentile:80.67(Environmental Sciences)

The International Commission on Radiation Units and Measurements (ICRU) has been discussing to propose a new system of the operational quantities for external radiations based on protection quantities. The aim of this study is to provide a set of conversion coefficients for use in defining personal dose equivalent for individual monitoring. Fluence-to-effective dose conversion coefficients have been calculated for photons, neutrons, electrons, positrons, protons, muons, pions and helium ions for various incident angles of radiations. The data sets comprise effective dose conversion coefficients for incident angles of radiations from 0 $$^{circ}$$ to 90 $$^{circ}$$ in steps of 15$$^{circ}$$ and at 180$$^{circ}$$. Conversion coefficients for rotational, isotropic, superior hemisphere semi-isotropic and inferior hemisphere semi-isotropic irradiations are also included. The conversion coefficients are used to define the operational quantity personal dose equivalent which is being considered by ICRU and utilized for the design and calibration of dosemeters.

Journal Articles

Measurements and evaluations of air dose rates around Fukushima, 2; Meanings and features of dose quantities used in radiation protection

Saito, Kimiaki; Yamamoto, Hideaki

Radioisotopes, 63(11), p.519 - 530, 2014/11

This article aims to provide the basic meanings and features of the doses frequently used in the measurements and evaluations of environmental radiation due to the Fukushima Dai-ichi Nuclear Power Plant accident. The following doses are explained and compared: absorbed dose as basic physical quantity; effective dose and equivalent dose for judgment in radiation protection; and ambient dose equivalent $$H^{*}$$(10) and individual dose equivalent $$H$$p(10) for radiation measurements.

JAEA Reports

Calculation of age-dependent dose conversion coefficients for radionuclides uniformly distributed in air

Tran, V. H.; Satoh, Daiki; Takahashi, Fumiaki; Tsuda, Shuichi; Endo, Akira; Saito, Kimiaki; Yamaguchi, Yasuhiro

JAERI-Tech 2004-079, 37 Pages, 2005/02

JAERI-Tech-2004-079.pdf:5.02MB

no abstracts in English

Journal Articles

3-45MeV/u ion beam dosimetry using thin film dosimeters

Kojima, Takuji; Sunaga, Hiromi; Takizawa, Haruki*; Hanaya, Hiroaki; Tachibana, Hiroyuki*

Radiation Physics and Chemistry, 68(6), p.975 - 980, 2003/12

 Times Cited Count:2 Percentile:19.48(Chemistry, Physical)

Four kinds of film dosimeters well-characterized for low LET radiations were applied to 3-45 MeV/u ions. The dose responses relative to those for low LET radiations are almost one up to about 10 MeV/(mg/cm$$^{2}$$) and gradually become smaller with increase of the stopping power. Overall uncertainty in ion beam dosimetry using these characterized dosimeters is better than $$pm$$5%(1$$sigma$$) including uncertainty in fluence measurement($$pm$$2%). Lateral and depth dose profile measurements were achievable using characterized Gafchromic dosimeters with the spatial resolution of better than 1 and 10 $$mu$$m, respectively.

Journal Articles

Conversion coefficients from fluence to effective dose for heavy ions with energies up to 3 GeV/A

Sato, Tatsuhiko; Tsuda, Shuichi; Sakamoto, Yukio; Yamaguchi, Yasuhiro; Niita, Koji*

Radiation Protection Dosimetry, 106(2), p.137 - 144, 2003/11

 Times Cited Count:19 Percentile:77.05(Environmental Sciences)

Radiological protection against high energy heavy ions has been an essential issue in the planning of long-term space missions. We calculated fluence to effective dose conversion coefficients for heavy ions using the Particle and Heavy Ion Transport code System PHITS coupled with an anthropomorphic phantom of the MIRD5 type. The calculations were performed for incidences of protons and typical space heavy ions with energies up to 3 GeV/A in the isotropic and anterior-posterior irradiations. Based on the results, we propose a simple fitting formula that can predict the effective dose from almost all kinds of space heavy ions below 3 GeV/A within an accuracy of 30%.

JAEA Reports

Dose coefficients for radionuclides produced in high energy proton accelerator facilities; Coefficients for radionuclides not listed in ICRP publications

Kawai, Katsuo; Endo, Akira; Noguchi, Hiroshi

JAERI-Data/Code 2002-013, 66 Pages, 2002/05

JAERI-Data-Code-2002-013.pdf:2.75MB
JAERI-Data-Code-2002-013-DoseCD.pdf:81.85MB

Effective dose coefficients by inhalation and ingestion have been calculated for 334 nuclides, including (1) nuclides with half-lives $$ge$$ 10min and their daughters that are not listed in ICRP Publications and (2) nuclides with half-lives $$<$$ 10min that are produced in a spallation target. Dose calculation was carried out using a nuclear decay database DECDC and a decay data library newly compiled from the ENSDF. The dose coefficients were calculated with the computer code DOCAP based on the respiratory tract model and biokinetic model of ICRP. The calculated results are presented as tables, which are the same forms as those in ICRP Publs.68 and 72. The complete listings of the dose coefficients are arranged on a CD-ROM, DoseCD, as indexed tables for inhalation of ten particle sizes, ingestion and injection into blood for workers and members of the public. The dose coefficients calculated in the present study are useful to calculate internal doses for a variety of radionuclides produced in high energy proton accelerator facilities.

JAEA Reports

Dose conversion coefficients in the shielding design calculation for high energy proton accelerator facilities

Sakamoto, Yukio; Yamaguchi, Yasuhiro

JAERI-Tech 2001-042, 29 Pages, 2001/06

JAERI-Tech-2001-042.pdf:1.79MB

no abstracts in English

JAEA Reports

Dose coefficients for intakes of radionuclides by workers; Coefficients for radionuclides not listed in ICRP Publication 68

Endo, Akira; Yamaguchi, Yasuhiro

JAERI-Data/Code 99-047, p.24 - 0, 1999/12

JAERI-Data-Code-99-047.pdf:0.88MB

no abstracts in English

Journal Articles

Calculation of the effective dose and its variation from environmental gamma ray sources

Saito, Kimiaki; N.Petoussi*; Zankl, M.*

Health Physics, 74(6), p.698 - 706, 1998/06

 Times Cited Count:44 Percentile:94.56(Environmental Sciences)

no abstracts in English

Journal Articles

Dose analysis in safety and site evaluation for the JMTR core conversion to LEU fuel

Tsuchida, Noboru; ; ; ; ; Saito, Minoru;

ANL/RERTR/TM-19, CONF-9209266, 0, p.259 - 266, 1995/00

no abstracts in English

Journal Articles

Influence of alteration in colon and remainder specification on effective dose values

Yamaguchi, Yasuhiro

Journal of Nuclear Science and Technology, 31(11), p.1233 - 1235, 1994/11

 Times Cited Count:0 Percentile:0.49(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Effective dose for external neutron exposure

Yamaguchi, Yasuhiro

Radioisotopes, 42(1), p.35 - 36, 1993/01

no abstracts in English

Journal Articles

Angular dependence of organ doses and effective dose for external photon irradiation

Yamaguchi, Yasuhiro; Yoshizawa, Michio

Proc. of the Int. Radiation Protection Association,Vol. 2, p.1237 - 1240, 1992/00

no abstracts in English

Journal Articles

Organ doses as a function of body weight for environmental gamma rays

Saito, Kimiaki; N.Petoussi*; Zankl, M.*; R.Veit*; P.Jacob*; G.Drexler*

Journal of Nuclear Science and Technology, 28(7), p.627 - 641, 1991/07

no abstracts in English

29 (Records 1-20 displayed on this page)