Abstract
The International Commission on Radiological Protection (ICRP) is recognised as the de-facto world authority in the field of radiological protection. The ICRP Recommendations have been used as a basis for regulations and policy in almost every country, and with the current review and revision of the System of Radiological Protection, it will continue to make significant contributions in radiation safety for patients, workers, the public, and the environment. In a society undergoing significant change, it is necessary to give careful thought to which groups will be perceived as authoritative organisations by the constituents of the future. The ideal form of an authoritative organisation in the new society of the future is to continue to show how it came to make such recommendations, how it reflected the opinions of interested parties in the process, and how it discloses its records with as much transparency as possible. The question now is what we must do to ensure that decision-making advances in a way that not only makes sense to the present generation, but will be easily consumed by future generations. The path that ICRP is taking to formulate the next set of General Recommendations is doing just that, in line with the key procedural values of
1. Bo Lindell Medal
It was on 5 November 2020 that Dr Claire Cousins [International Commission on Radiological Protection (ICRP) Chair 2009–2021] reached out to me with the news that I was the recipient of the Bo Lindell Medal. I received congratulatory messages from friends and colleagues all over the world after the announcement was made via ICRP news, and this was one of the most joyous days of my career. The Bo Lindell Medal has been awarded to two scientists in the past, namely Dr Martinez of the USA and Dr Ainsbury of the UK, and it is my great honour to be the third recipient alongside them. The Radiation Protection Societies of Japan, Korea, and Australia jointly prepared a round-table discussion with young scientists on 25 February 2021, and the results are summarised in the joint journal of the three societies (Fujibuchi et al., 2021).
2. Highlights of recent activities
Occupational Radiation Protection Appraisal Service (ORPAS) missions are conducted as an independent appraisal service in the field of radiological protection of workers. The ORPAS mission to the Philippines was held in October 2022, and I had the opportunity to participate in the mission as Deputy Team Leader. We visited regulatory, medical, industrial, and technical service provider sites to discuss how the International Atomic Energy Agency (IAEA)'s Safety Standards, which are developed on a consensus basis using ICRP Recommendations, are being used at each site. This was an opportunity for those of us who develop international recommendations, such as by ICRP and IAEA, to be reminded just how important it is to understand how they are being implemented in the field of radiological protection. For those who will be developing international recommendations, it is extremely important to be aware of what problems they are facing and how new recommendations will lead to an improved level of safety, and to keep these things in mind when conducting discussions and reaching consensus.
From June to July 2022, a review meeting of the contracting parties to the Joint Convention on the Safety of Spent Fuel Management and on the Safety of Radioactive Waste Management was held in Vienna, and I was able to participate in my capacity as coordinator for a country group. The common issues were how to involve interested parties in the decision-making process and how to secure human resources and maintain their capacity, rather than the existence of technical issues that are difficult to solve. I feel strongly that, in a mature society, it is important to make decisions transparently at a certain stage, while listening to as many interested parties as possible, and it is meaningful to share the experiences of countries with advanced efforts in this regard with the world at large. In this sense, it is important that legally binding convention meetings are held on a regular basis to provide opportunities to come together for discussion.
In April 2021, Japan announced the basic policy on handling the treated water stored at Fukushima Daiichi nuclear power station, which is to discharge the treated water into the sea subject to domestic regulatory approvals. The Japanese authorities requested assistance from IAEA to monitor and review these plans and activities to ensure that they will be implemented in a safe and transparent way. The first review mission to the Nuclear Regulation Authority (NRA) took place in March 2022 (IAEA, 2022a). Since 2021, I have reviewed the Environmental Impact Assessment Report submitted by Tokyo Electric Power Company to NRA. I also participated in the first IAEA review mission to explain the status of the domestic review to international experts from the USA, Argentina, Vietnam, Korea, France, China, Russia, and Australia. While there are many opinions surrounding the ocean discharge of treated water, it goes without saying that transparency is vital. The review being conducted by IAEA involves international experts, and – in order to assure quality– radiation measurements are being taken by laboratories around the world.
3. 20 years of research and international recommendations
My first research engagement was in the development of a compact medical accelerator using laser Compton scattering. This was a national project advanced by Professor Uesaka of the University of Tokyo to develop a device that generates monochromatic high-energy x rays by accelerating electron beams with a high-frequency accelerator (an ‘X-band’), and colliding them with a YAG laser. In order to enhance the number of photons generated, a system that orbits the laser was conducted, and demonstration experiments were conducted using a low-energy laser (Ogino et al., 2006). As a member of a cutting-edge national project, I was able to work with kind instructors and colleagues. The various techniques learned laid the foundation for the life in research and science.
In April 2006, I joined the Central Research Institute of Electric Power Industry (CRIEPI), and one of the first studies was an experimental study on obtaining basic parameters of radioactive surface contamination, such as source efficiencies and removal factors (Ichiji and Ogino, 2007, 2011). The topic of my subsequent research was also surface contamination. At that time, Japan introduced a clearance system for nuclear reactor facilities using the radioactivity concentration given by IAEA Safety Guide RS-G-1.7. The research team led by Dr Hattori of CRIEPI developed a dose assessment model for surface contamination, and proposed such levels in units of surface density (Ogino and Hattori, 2009a,b). In October 2022, these results from 2009 were internationally reflected in the revised IAEA's Safety Standards on exemption and clearance, in which the surface contamination dose assessment model developed by CRIEPI is introduced as an example.
Five years after I joined CRIEPI, the accident occurred at Fukushima Daiichi nuclear power station. This had a profound impact on those involved in radiological protection. I turned my attention to the screening levels that were being applied to surface contamination of body surfaces and objects. It was found that even if surface contamination equivalent to the screening value existed on an item, the radiation dose would be below the intervention exemption level (Ogino et al., 2012). Subsequently, operational levels for the unconditional release of non-food commodities from the areas affected were proposed (Ogino and Hattori, 2013). There were not always clearly defined standards for non-food commodities. This issue on safety of non-food commodities is also being discussed by IAEA's Radiation Safety Standards Committee (RASSC), and I had the opportunity to chair the topical session on this topic at the 53rd RASSC meeting in November 2022. Furthermore, my interest extended to food safety regulations, together with Dr Hamada of CRIEPI (Hamada and Ogino, 2012; Hamada et al., 2012).
My research interests also covered how information on radiation exposure and health effects was disseminated after the Fukushima accident. It has been stated several times that approximately 30% of Japanese people die from cancer as a result of their daily lifestyle, and radiation exposure to 100 mSv adds 0.5% to this figure. Given that the average value was approximately 30%, I wondered how much regional difference there might be among the 47 prefectures. Using recent statistical data, the lifetime risk of cancer mortality in Japan was calculated (Ogino and Hattori, 2014), and this showed that the lifetime risk of cancer mortality ranges from 24% to 28% among the 47 prefectures. In 2020, ICRP issued Publication 146 (ICRP, 2020) on radiological protection in the event of a large nuclear accident, and the above work (Ogino and Hattori, 2014) was cited as one of the references. It should be emphasised that I do not condone such regional differences, as measures against cancer should be promoted so that people can live healthy lives. It is meaningful to have basic information on the baseline risk level as a benchmark, and how much is added to it by radiation exposure.
My next interest was about the approach of provability of radiation-related cancers. In ICRP Publication 99 (ICRP, 2005), the relationship between radiation dose and population size is presented in terms of statistical power (e.g. a population size of 600,000 is needed to detect effects of doses on the order of 10 mGy, which increases to 60 million on the order of 1 mGy). This was based on the assumption that the baseline risk was a constant value of 10%, and I wondered if the increase in cancer might be even more difficult to detect because of the unavoidable existence of unadjusted risk factors. The research team led by Dr Hattori of CRIEPI estimated age and gender differences in cancer risks in a Japanese population using ICRP methodology, and discussed approaches to account for provability in a quantitative manner (Ogino et al., 2016). In light of the United Nations Scientific Committee on the Effects of Atomic Radiation 2012 Report on attribution of radiation health effects and inference on radiation risks (UNSCEAR, 2015), IAEA developed a Safety Report (IAEA, 2022b) to consider application of the IAEA Safety Standards, and the paper by Ogino et al. (2016) is cited as a reference to lead the reader for further discussions. Also, ICRP Publication 147 (ICRP, 2021) on the use of dose quantities cites Ogino et al. (2016) on the results on organ-specific cancer risk calculations for the Japanese population.
One of the last studies that I conducted before I accepted my new position with NRA was about optimisation in radioactive waste disposal. The research team, led by Dr Sugiyama of CRIEPI, examined the role of dose constraints from an ethical point of view, and discussed the importance of reducing inequity in the dose distribution of individual exposures when selecting a protective option for the design of a radioactive waste disposal facility (Ogino et al., 2019). ICRP has established Task Group 97 on near-surface disposal, and conducted a consultation with Special Liaison Organisations in 2022, and Ogino et al. (2019). is cited in the draft report to support its recommendations. I was also involved in a study on the quantification of conservatism in the committed dose concept for internal exposure (Sasaki et al., 2021). When judging compliance with dose limits, it is recommended to assume that all doses are given in the year in which internal exposure occurs, when, in fact, the radiation emitted by the nuclide will continue beyond the second year. In terms of radiosensitivity, the cancer risk generally decreases with each additional year, so the study led by Dr Sasaki of CRIEPI aimed to quantitatively determine how conservative this committed dose concept is by calculating cancer risk in detail.
4. the direction we should take for the benefit of present and future generations
ICRP is a registered charity in the UK, and is also recognised as the de-facto world authority in the field of radiological protection. ICRP is where it is today because of almost 100 years of wisdom and experience provided by committed volunteer experts from around the world. ICRP Recommendations have been used as a basis for regulations and policy in almost every country, and with the current review and revision of the System of Radiological Protection, I have no doubt that ICRP will continue to make significant contributions in radiation safety for patients, workers, the public, and the environment.
Looking back over the past 20 years, not much has changed in terms of information on the purely scientific aspects of radiological protection. However, ethical values, one of the key pillars underlying the System of Radiological Protection, have become more important and defined. In addition, a great deal of experience has been accumulated, including a dramatic increase in the amount of information due to the sophistication of networks. Not to mention the fact that the world has experienced a pandemic that has greatly advanced means of communication. Furthermore, the experience of the large nuclear accident in Fukushima taught us lessons such as implementation of the basic principles of radiological protection (e.g. justification, optimisation) in the actual society that supports the lives of many people, the importance of co-expertise to restore management capacity in the recovery phase, and trust in experts and government. The accumulation of experience in these and other circumstances will become even more significant in society over the next few decades in terms of involvement of interested parties in decision-making processes.
In a society undergoing significant change, it is necessary to give careful thought to which groups will be perceived as authoritative organisations by the constituents of the future. In an age when smartphones have become so ubiquitous and the public can easily connect with experts in their field and have access to a vast amount of information, creation of international recommendations in a transparent manner is a necessary component for any organisation to continue to be recognised as an authoritative body. The ideal form of an authoritative organisation in the new society is to continue to show how it came to make such recommendations, how it reflected the opinions of interested parties in the process, and how it discloses its records with as much transparency as possible. I am aware that some have pointed out that, by involving more people than necessary, we are losing our authority. However, we have already entered a society where simply deciding things behind closed doors and announcing that we want the rest to follow suit is not considered an authoritative organisation. At a minimum, the world needs information that can be accessed at any time through digital content. It is extremely important to engage in interactive discussions with interested parties at events like the ICRP symposia, and to take steady steps with well-documented discussion processes to not only reduce radiation risks but also to improve overall safety. The question now is what we must do to ensure that decision-making advances in a way that not only makes sense to the present generation but will be easily consumed by future generations. I believe that the time will come when organisations that continue to adopt such an attitude will be recognised as authoritative organisations in the new society of the future. The path that ICRP is taking to formulate the next set of General Recommendations is doing just that, in line with the key procedural values of