Regulatory implementation of the occupational equivalent dose limit for the lens of the eye and underlying relevant efforts in Japan

Abstract

In April 2011, the International Commission on Radiological Protection recommended reducing the occupational equivalent dose limit for the lens. Such a new occupational lens dose limit has thus far been implemented in many countries, and there are extensive discussions toward its regulatory implementation in other countries. In Japan, discussions in the Japan Health Physics Society (JHPS) began in April 2013 and in Radiation Council in July 2017, and the new occupational lens dose limit was implemented into regulation in April 2021. To share our experience, we have published a series of papers summarizing situations in Japan: the first paper based on information available by early 2017, and the second paper by early 2019. This paper (our third paper of this series) aims to review updated information available by mid-2022, such as regarding regulatory implementation of the new occupational lens dose limit, recent discussions by relevant ministries based on the opinion from the council, establishment process of safety and health management systems, the JHPS guidelines on lens dose monitoring and radiation safety, voluntary countermeasures of the licensees, development of lens dose calibration method, and recent studies on exposure of the lens in nuclear workers and biological effect on the lens.

Keywords:

• Implementation of the revised occupational dose limit for the lens of the eye
• radiation workers
• safety and health management

Disclosure statement

The authors report no conflict of interest. The authors alone are responsible for the content and writing of the paper, and the views expressed in this paper represent collective opinions of the authors, and are not necessarily those of their professional affiliations.

Additional information

Notes on contributors

Sumi Yokoyama

Sumi Yokoyama, PhD, is an Associate Professor at Research Promotion Headquarters, Fujita Health University in Aichi, Japan. Her study focuses on radiation protection of the lens of the eye for radiation workers. She is a member of Japanese Radiation Council and was the chair of the Subcommittee on Radiation Protection of the Lens of the Eye established in the Japanese Radiation Council (2017–2018), a member of the IRPA third task group on the implementation of the eye lens dose limit (2018–2019) and a member of the NEA Expert Group on the Dose Limit for the Lens of the Eye (EGDLE) (2019–2022).

Nobuyuki Hamada

Nobuyuki Hamada, RT, PhD, is a Senior Research Scientist at CRIEPI and a Visiting Professor at Hiroshima University Research Institute for Radiation Biology and Medicine. He serves on ICRP Task Groups 102, 111 and 119, NCRP PAC 1, OECD/NEA/CRPPH/HLG-LDR/Rad/Chem AOP Joint Topical Group, IRPA Task Group on Tissue Reactions, and Consultation Committee on AOP development for space flight health outcomes (Canadian project).

Norio Tsujimura

Norio Tsujimura, PhD, is a prime research engineer in the Radiation Protection Department of Nuclear Fuel Cycle Engineering Laboratories, Japan Atomic Energy Agency (JAEA). Since joining PNC (predecessor of JAEA) in 1993, one of his primary interests has been the development of better instrumentation and techniques for measuring neutrons in a MOX fuel fabrication plant.

Naoki Kunugita

Naoki Kunugita, MD, PhD is currently a Dean in the School of Health Sciences, University of Occupational and Environmental Health, Japan (UOEH). He graduated from School of Medicine, UOEH and is studying and teaching in the areas of occupational health, public health and radiation biology and protection. He served as a member of the study group meetings to review dose limits to the lens of the eyes established in the Ministry of Health, Labor and Welfare (2018–2019).

Kazutaka Nishida

Kazutaka Nishida, MS, have studied chemistry at the Graduate School of Osaka University until 1998, and have studied at the Institute of Scientific and Industrial Research, Osaka University from 1997 to 1998. He joined Kansai Electric Power Co., Inc. in 1998. He is a manager of the Radiation Control Group in the nuclear power division. His specialty is radiation protection, radiation measurement and evaluation of exposure dose.

Iwao Ezaki

Iwao Ezaki, BE, graduated from Faculty of Engineering, Tokai University and joined Chiyoda Technol Corporation, both in 1998, then moved to its Nuclear Engineering Department in 2002. He is currently Section Manager with Technical Section, Nuclear Power Business, Chiyoda Technol Corporation and licensed Professional Engineer, Japan (Nuclear and Radiation). His expertise is in radiation protection, radiation measurement and calibration.

Masahiro Kato

Masahiro Kato, PhD, has worked in Ionizing Radiation Standards Group, National Metrology Institute of Japan, National Institute of Advanced Science and Technology for 18 years. Engaged in research on the β radiation dosimetry, monochromatic X-ray measurement, and environmental radiation measurement. Provide the calibration service as the calibration authority of the air kerma standards for γ-radiation fields and of the absorbed dose standards for β radiation fields.

Hideki Okubo

Hideaki Okubo, ME, graduated from the Department of Electrical and Electronic Engineering, Faculty of Engineering, Iwate University in 2015. He completed the master's program at the same graduate school and joined Tokyo Electric Power Company Holdings, Inc in 2017. He had been engaged in work related to radiation measuring instruments and radioisotope management at Fukushima Daini Nuclear Power Station. He has been engaged in work related to individual exposure dose management at the head office since 2021. In particular, he is focusing on exposure dose control at the Fukushima Daiichi Nuclear Power Station.