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Journal Articles

A Unique high natural background radiation area; Dose assessment and perspectives

Hosoda, Masahiro*; Nugraha, E. D.*; Akata, Naofumi*; Yamada, Ryohei; Tamakuma, Yuki*; Sasaki, Michiya*; Kelleher, K.*; Yoshinaga, Shinji*; Suzuki, Takahito*; Rattanapongs, C. P.*; et al.

Science of the Total Environment, 750, p.142346_1 - 142346_11, 2021/01

 Times Cited Count:5 Percentile:96.3(Environmental Sciences)

The biological effects of low dose-rate radiation exposures on humans remains unknown. In fact, the Japanese nation still struggles with this issue after the Fukushima Dai-ichi Nuclear Power Plant accident. Recently, we have found a unique area in Indonesia where naturally high radiation levels are present, resulting in chronic low dose-rate radiation exposures. We aimed to estimate the comprehensive dose due to internal and external exposures at the particularly high natural radiation area, and to discuss the enhancement mechanism of radon. A car-borne survey was conducted to estimate the external doses from terrestrial radiation. Indoor radon measurements were made in 47 dwellings over three to five months, covering the two typical seasons, to estimate the internal doses. Atmospheric radon gases were simultaneously collected at several heights to evaluate the vertical distribution. The absorbed dose rates in air in the study area vary widely between 50 nGy h$$^{-1}$$ and 1109 nGy h$$^{-1}$$. Indoor radon concentrations ranged from 124 Bq m$$^{-3}$$ to 1015 Bq m$$^{-3}$$. That is, the indoor radon concentrations measured exceed the reference levels of 100 Bq m$$^{-3}$$ recommended by the World Health Organization. Furthermore, the outdoor radon concentrations measured were comparable to the high indoor radon concentrations. The annual effective dose due to external and internal exposures in the study area was estimated to be 27 mSv using the median values. It was found that many residents are receiving radiation exposure from natural radionuclides over the dose limit for occupational exposure to radiation workers. This enhanced outdoor radon concentration might be as a result of the stable atmospheric conditions generated at an exceptionally low altitude. Our findings suggest that this area provides a unique opportunity to conduct an epidemiological study related to health effects due to chronic low dose-rate radiation exposure.

Journal Articles

External dose evaluation based on detailed air dose rate measurements in living environments

Sato, Tetsuro*; Ando, Masaki; Sato, Masako*; Saito, Kimiaki

Journal of Environmental Radioactivity, 210, p.105973_1 - 105973_7, 2019/12

 Times Cited Count:3 Percentile:29.49(Environmental Sciences)

A method was devised for estimation of external doses of Fukushima residents expected to return to their homes after evacuation orders are lifted. 211 residents expected to return to six towns and villages were surveyed in FY 2014, FY 2015, and FY2016. Interviewing returning residents about their expected life patterns after returning, air dose rate were measured along the reported personal trails representing their patterns of movement in daily life. Excluding 15 residents from whose homes we were unable to take air dose rate measurements, the maximum external effective dose and the average external effective dose were estimated respectively as 4.9 mSv/y and 0.86 mSv/y. Although the mean values and dispersion of external effective doses differ depending on the evacuation level, for 93.3% of all residents, the estimated external effective doses were less than 2 mSv/y. The average exposure dose at home accounts for 66.8% of the annual exposure dose.

Journal Articles

Challenges for enhancing Fukushima environmental resilience, 10; Dose evaluation and risk communication

Saito, Kimiaki; Takahara, Shogo; Uezu, Yasuhiro

Nihon Genshiryoku Gakkai-Shi ATOMO$$Sigma$$, 60(2), p.111 - 115, 2018/02

no abstracts in English

Journal Articles

Measurements and evaluations of air dose rates around the Fukushima NPP site, 6; Status and issues on evaluation of individual doses due to external exposures

Saito, Kimiaki; Kurihara, Osamu*; Matsuda, Norihiro; Takahara, Shogo; Sato, Tetsuro*

Radioisotopes, 65(2), p.93 - 112, 2016/02

Late information is introduced on dose evaluation due to external exposures which employ an important role in the exposures due to the Fukushima accident. First, merits and demerits of the currently used two methods, that is the estimation based air dose rates and the measurements using personal dosimeters, are discussed indicating some basic data after a fundamental concept of external dose evaluation is provided. Next, main activities are summarized on external dose measurements and evaluations after the accident. Finally, a new trial on dose evaluation in introduced.

Journal Articles

RCA/IAEA third external dosimetry intercomparisons in East Asia region

Yamamoto, Hideaki; Yoshizawa, Michio; Murakami, Hiroyuki; Momose, Takumaro*; Tsujimura, Norio*; Kanai, Katsuta*; Cruz-Suarez, R.*

Radiation Protection Dosimetry, 125(1-4), p.88 - 92, 2007/07

 Times Cited Count:0 Percentile:0.01(Environmental Sciences)

The purpose of this paper is to discuss the results of the third intercomparison exercise of external radiation dosimetry organized under the Regional Cooperative Agreement (RCA) in the East Asia region of the International Atomic Energy Agency (IAEA). Twenty five laboratories from 16 member states participated in the exercise. Japan Atomic Energy Research Institute (JAERI) and Japan Nuclear Cycle Development Institute (JNC) arranged the standard irradiation of the participants' dosimeters. The results of the measurements of the irradiated dosimeters for the determination of external doses were satisfactory for all participants, demonstrating good performance in their external dosimetry.

Journal Articles

Evaluation of $$gamma$$-ray dose components in criticality accident situations

Sono, Hiroki; Yanagisawa, Hiroshi*; Ono, Akio*; Kojima, Takuji; Soramasu, Noboru*

Journal of Nuclear Science and Technology, 42(8), p.678 - 687, 2005/08

 Times Cited Count:4 Percentile:32.08(Nuclear Science & Technology)

Component analysis of $$gamma$$-ray doses in criticality accident situations is indispensable for further understanding on emission behavior of $$gamma$$-rays and accurate evaluation of external exposure to human bodies. Such dose components were evaluated, categorizing $$gamma$$-rays into four components: prompt, delayed, pseudo components in the period of criticality, and a residual component in the period after the termination of criticality. This evaluation was performed by the combination of dosimetry experiments at the TRACY facility using a thermoluminescent dosimeter (TLD) made of lithium tetra borate and computational analyses using a Monte Carlo code. The evaluation confirmed that the dose proportions of the above components varied with the distance from the TRACY core tank. This variation was due to the difference in attenuation of the individual components with the distance from the core tank. The evaluated dose proportions quantitatively clarified the contribution of the pseudo and the residual components to be excluded for accurate evaluation of $$gamma$$-ray exposure.

JAEA Reports

Nuclear Decay Data for Dosimetry Calculation; Revised data of ICRP Publication 38

Endo, Akira; Yamaguchi, Yasuhiro; Eckerman, K. F.*

JAERI 1347, 114 Pages, 2005/02

JAERI-1347.pdf:6.57MB

no abstracts in English

Journal Articles

Development and assessment of new radioactive decay database used for dosimetry calculation

Endo, Akira; Yamaguchi, Yasuhiro; Eckerman, K. F.*

Radiation Protection Dosimetry, 105(1-4), p.565 - 569, 2003/09

 Times Cited Count:11 Percentile:61.24(Environmental Sciences)

The present paper discusses a strategy for the development of a new radioactive decay database, which will succeed ICRP Publ.38 used for dosimetry calculations. The development of the database requires 1) Consistency checking of the ENSDF used for compilation of the decay data, 2) Improvement of the computer code EDISTR for processing the ENSDF, and 3) Comparison with other decay data prepared from the different computer codes and libraries for the verification of the compiled data. This paper identifies several technical issues that need to be addressed for the development of the new radioactive decay database.

JAEA Reports

Compilation of nuclear decay data used for dose calculation; Revised data for radionuclides listed in ICRP publication 38

Endo, Akira; Yamaguchi, Yasuhiro

JAERI-Data/Code 2001-004, 157 Pages, 2001/03

JAERI-Data-Code-2001-004.pdf:11.27MB

New nuclear decay data used for dose calculation have been compiled for 817 radionuclides that are listed in ICRP Publication 38 (Publ.38) and for 6 additional isomers. The decay data were prepared using decay data sets from the Evaluated Nuclear Structure Data File (ENSDF), the latest version in August 1997. Basic nuclear properties in the decay data sets that are important for calculating energies and intensities of emissions were updated by referring to NUBASE. In addition, possible revisions of partial and incomplete decay data sets were done for their format and syntax errors, level schemes, normalization records, and so on. After that, the decay data sets were processed by EDISTR in order to compute the energies and intensities of $$alpha$$ particles, $$beta$$ particles, $$gamma$$ rays, internal conversion electrons, X rays, and Auger electrons. The compiled data were prepared in two different types of format: Publ.38 and NUCDECAY formats. The decay data will be widely used for dose calculations in radiation protection and will be beneficial to a future revision of ICRP Publ.38.

Journal Articles

External doses in the environment from the Tokai-mura criticality accident

Endo, Akira; Yamaguchi, Yasuhiro; Sakamoto, Yukio; Yoshizawa, Michio; Tsuda, Shuichi

Radiation Protection Dosimetry, 93(3), p.207 - 214, 2001/00

 Times Cited Count:6 Percentile:45.58(Environmental Sciences)

no abstracts in English

Journal Articles

Reassessment and reinforcement of nuclear decay database used for dose calculations

Endo, Akira; Yamaguchi, Yasuhiro

Proceedings of 10th International Congress of the International Radiation Protection Association (IRPA-10) (CD-ROM), 8 Pages, 2000/05

no abstracts in English

JAEA Reports

Compilation of nuclear decay data used for dose calculations; Data for radionuclides not listed in ICRP Publication 38

Endo, Akira; *; Yamaguchi, Yasuhiro

JAERI-Data/Code 99-035, 355 Pages, 1999/07

JAERI-Data-Code-99-035.pdf:14.77MB

no abstracts in English

JAEA Reports

GARDEC; A Computer code for estimating dose-rate reduction by garden decontamination

Togawa, Orihiko

JAERI-Data/Code 98-038, 21 Pages, 1998/12

JAERI-Data-Code-98-038.pdf:1.13MB

no abstracts in English

JAEA Reports

JAEA Reports

Conversion and modification of the MLSOIL and DFSOIL codes

Togawa, Orihiko

JAERI-Data/Code 95-009, 35 Pages, 1995/07

JAERI-Data-Code-95-009.pdf:1.43MB

no abstracts in English

Journal Articles

Estimation of collective external dose during dismantling of JPDR (BWR,90 MWt)

*; Yanagihara, Satoshi; Sukegawa, Takenori; Tanaka, Mitsugu

Nihon Genshiryoku Gakkai-Shi, 33(6), p.574 - 584, 1991/06

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

no abstracts in English

Journal Articles

The dose evaluation method emergency by using puff model combined with three-dimensional wind field

;

Nihon Genshiryoku Gakkai-Shi, 26(10), p.897 - 904, 1984/00

 Times Cited Count:0 Percentile:0.02(Nuclear Science & Technology)

no abstracts in English

25 (Records 1-20 displayed on this page)