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.

Dosimetric dependence of ocular structures on eye size and shape for external radiation fields of electrons, photons, and neutrons

Furuta, Takuya; El Basha, D.*; Iyer, S. S. R.*; Correa Alfonso, C. M.*; Bolch, W. E.*

Journal of Radiological Protection, 39(3), p.825 - 837, 2019/09

https://doi.org/10.1088/1361-6498/ab2bcb

Despite large variation of human eye, only one computational eye model has been adopted in almost all the radiation transport simulation studies. We thus adopted a new scalable and deformable eye model and studied the radiation exposure by electrons, photons, and neutrons in the standard radiation fields such as AP, PA, RLAT, ROT, by using Monte Carlo radiation transport code PHITS. We computed the radiation exposure for 5 eye models (standard, large, small, myopic, hyperopic) and analyzed influence of absorbed dose in ocular structures on eye size and shape. Dose distribution of electrons is conformal and therefore the absorbed doses in ocular structures depend on the depth location of each ocular structure. We thus found a significant variation of the absorbed doses for each ocular structure for electron exposure due to change of the depth location affected by eye size and shape. On the other hand only small variation was observed for photons and neutrons exposures because of less conformal dose distribution of those particles.

Integrating radiation protection criteria for radioactive waste management into remediation procedures in existing exposure situations after a nuclear accident

Sugiyama, Daisuke*; Kimura, Hideo; Tachikawa, Hirokazu*; Iimoto, Takeshi*; Kawata, Yosuke*; Ogino, Haruyuki*; Okoshi, Minoru*

Journal of Radiological Protection, 38(1), p.456 - 462, 2018/03

https://doi.org/10.1088/1361-6498/aaa155

Experience after the accident at the Fukushima Daiichi Nuclear Power Station has shown that there is a need to establish radiation protection criteria for radioactive waste management consistent with the criteria adopted for the remediation of existing exposure situations. A stepwise approach to setting such criteria is proposed. Initially, a reference level for annual effective dose from waste management activities in the range 1-10 mSv should be set, with the reference level being less than the reference level for ambient dose. Subsequently, the reference level for annual effective dose from waste management activities should be reduced in one or more steps to achieve a final target value of 1 mSv. The dose criteria at each stage should be determined with relevant stakeholder involvement. Illustrative case studies show how this stepwise approach might be applied in practice.

Operational quantities and new approach by ICRU

Endo, Akira

Annals of the ICRP, 45(1_suppl.), p.178 - 187, 2016/06

https://doi.org/10.1177/0146645315624341

The protection quantities, equivalent dose in an organ or tissue and effective dose, were developed by ICRP to allow quantification of the extent of exposure of the human body to ionizing radiation to be used for the implementation of the limitation and optimization principles. The body-related protection quantities are not measurable in practice. Therefore, ICRU developed a set of operational dose quantities for use in radiation measurements for external radiations that provide assessment of the protection quantities. ICRU has examined the rationale for operational quantities taking into account the changes in the definitions of the protection quantities in the ICRP 2007 Recommendations. The committee has investigated a set of alternative definitions for operational quantities different to the existing quantities. The major change in the currently favoured set of quantities is the redefinition of the operational quantities for area monitoring from being based on doses at a point in the ICRU sphere to ones based on particle fluence and the relationship to the protection quantities.

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

https://doi.org/10.3769/radioisotopes.63.519

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 (10) and individual dose equivalent p(10) for radiation measurements.

Development of dose monitoring system applicable to various radiations with wide energy ranges

Sato, Tatsuhiko; Satoh, Daiki; Endo, Akira; Yamaguchi, Yasuhiro

Journal of Nuclear Science and Technology, 42(9), p.768 - 778, 2005/09

https://doi.org/10.3327/jnst.42.768

A new inventive radiation monitor, designated to DARWIN (Dose Assessment system applicable to various Radiations with WIde energy raNges), has been developed for monitoring doses at workspaces of high energy accelerator facilities and on ground. Characteristics of DARWIN were studied by both calculation and experiment. The calculated results indicate that DARWIN gives reasonable estimations of doses at most radiation fields. It was found from the experiment that DARWIN has an excellent property of measuring doses from all particles that significantly contribute to the background dose - photon, muon and neutron with wide energy ranges.

Simulations of an accelerator-based shielding experiment using the particle and heavy-ion transport code system PHITS

Sato, Tatsuhiko; Sihver, L.*; Iwase, Hiroshi*; Nakashima, Hiroshi; Niita, Koji*

Advances in Space Research, 35(2), p.208 - 213, 2005/06

https://doi.org/10.1016/j.asr.2005.01.041

In order to estimate the biological effects of HZE particles, an accurate knowledge of the physics of interaction of HZE particles is necessary. Since the heavy ion transport problem is a complex one, there is a need for both experimental and theoretical studies to develop accurate transport models. RIST and JAERI (Japan), GSI (Germany) and Chalmers (Sweden) are therefore currently developing and bench marking the General-Purpose Particle and Heavy-Ion Transport code System (PHITS). In this paper, we report simulations of an accelerator-based shielding experiment, in which a beam of 1 GeV/n Fe-ions has passed through thin slabs of polyethylene, Al, and Pb at an acceptance angle up to 4&ordm.

Profile of energy deposition in human body irradiated by heavy ions

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

Journal of Nuclear Science and Technology, 41(Suppl.4), p.287 - 290, 2004/03

http://www.tandfonline.com/doi/abs/10.1080/00223131.2004.10875702

Radiological protection against heavy ions has been an essential issue in the planning of long term space missions. We performed Monte Carlo calculations of dose distributions in terms of the linear energy transfer (LET) of ionizing particles using Particle and Heavy Ion Transport code System, PHITS, for incidences of various kinds of heavy ions with energies up to 3 GeV/A. Based on the results, we found that large amounts of energies are imparted by particles with an LET above 10 keV/mm even for the incidences of heavy ions with high energies. This tendency is different from that for high energy hadron incidences, where more than 80% of the total deposited energies are imparted by particles with an LET below 10 keV/mm.

Annual report of the activities of Health Physics in JAERI in 2002; April 1, 2002March 31, 2003

Department of Health Physics; Safety Division, Naka; Safety Division, Takasaki; Radiation Control Division, Oarai; Safety Division, Kansai; Operation Safety Administration Division, Mutsu

JAERI-Review 2003-034, 208 Pages, 2003/11

JAERI-Review-2003-034.pdf:13.41MB

no abstracts in English

NuTEC annual report; April l, 2001 - March 31, 2002

Nuclear Technology and Education Center

JAERI-Review 2003-003, 81 Pages, 2003/05

JAERI-Review-2003-003.pdf:3.48MB

This report summarizes the educational activities and related management of the Nuclear Technology andEducation Center (NuTEC) during the 2001 fiscal year. Both Tokyo and Tokai Education Centers have successfully conducted almost all the planned domestic and international training courses. In addition Tokai Education Center has performed the 3nd nuclear supervisor training course and introduced a new course for special nuclear emergency preparedness in response to the legal amendment after the criticality accident. The sum total number of participants was 1,310. The International Technology Transfer Division has not only planned and organized the international training courses, but also taken charge of the 3nd workshop on Human Resource Development in Nuclear Field in Asian and Pasific Region. Various researches have been made to improve the educational program.