United Nations Scientific Committee on the Effects of Atomic Radiation SOURCES, EFFECTS AND RISKS OF IONIZING RADIATION UNSCEAR 2020 Report SCIENTIFIC ANNEX B: Levels and effects of radiation exposure due to the accident at the Fukushima Daiichi Nuclear Power Station: implications of information published since the UNSCEAR 2013 Report ADVANCEAnnex COPYB only AMAD activity median aerodynamic diameter ARS acute radiation syndrome ATDM atmospheric transport, dispersion and deposition modelling CNPS Chernobyl Nuclear Power Station CR concentration ratio DoD Department of Defense DOE Department of Energy DRF dose reduction factor EMDB Environment Monitoring Database FDNPS Fukushima Daiichi Nuclear Power Station FM fresh mass FHMS Fukushima Health Management Survey IAEA International Atomic Energy Agency ICRP International Commission on Radiological Protection ICSA intensive contamination survey area JAEA Japan Atomic Energy Agency JST Japan Standard Time M2013 Model used in the UNSCEAR 2013 Report M2020 Model for estimating external doses from deposited radionuclides. An update of the model used in the UNSCEAR 2013 Report for estimating external doses from deposited radionuclides MEXT Ministry of Education, Culture, Sports, Science and Technology MHLW Ministry of Health, Labour and Welfare MOE Ministry of Environment MRI magnetic resonance imaging NIRS National Institute of Radiological Sciences OOP out of prefecture RET rearranged during transfection RIP radiocaesium interception potential SDA special decontamination area TEPCO Tokyo Electric Power Company UNSCEAR United Nations Scientific Committee on the Effects of Atomic Radiation WBC whole-body counting WSPEEDI Worldwide version of System for Prediction of Environmental Emergency Dose Information 1. The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) assessed radiation exposures of the public, workers and non-human biota that resulted from the 11 March 2011 accident at the Fukushima Daiichi Nuclear Power Station (FDNPS) of the Tokyo Electric Power Company (TEPCO) in Japan and reported its findings, including a discussion of the associated health risks and health effects, to the United Nations General Assembly in October 2013 [U10]. A full report with scientific annexes was published by the United Nations on 2 April 2014 [U10]. 2. Most of the scientific information used in the report of the Committee (referred to as the “UNSCEAR 2013 Report” [U10] hereafter) was limited to that published or provided officially (by the Japanese Government, TEPCO and international organizations) by the end of October 2012. Subsequently, a significant amount of relevant information has been published and, with time, questions were anticipated from delegations, government authorities, scientists, civil society and the media about the continuing validity of the UNSCEAR 2013 Report. Accordingly, the Committee implemented a plan to maintain awareness of new scientific developments in the follow-up to the accident and published three white papers [U11, U13, U14] setting out evaluations of the implications of such developments for the period up to the end of 2016. 3. The results of these reviews of new information generally confirmed the broad findings and conclusions of the UNSCEAR 2013 Report [U10] within the inherent uncertainties [U11, U13, U14]. However, the Committee became aware of increasing evidence that some of the doses to the public were overestimates, with those from ingestion significantly so [U10, U11, U13, U14]. In addition, there was a considerable amount of new information becoming available on the levels of radionuclides in the environment, and in particular on concentrations of released radionuclides in the air as a function of time and on their physico-chemical forms. This information could enable better and less uncertain estimates of doses to the public, particularly from inhalation. The Committee recognized that carrying out some more detailed analyses of this information would contribute to an improved understanding and communication of differences in the estimates of doses to the public and of the underlying science and its implications. It would also help address inevitable questions within various constituencies and enable more authoritative statements (with reduced uncertainty) to be made on a number of issues. 4. Against this background, the Committee decided at its sixty-fifth session (11–14 June 2018) to prepare a report summing up all of the information available (up to the end of 2019)1 on the levels and effects of radiation exposure due to the FDNPS accident and on the implications of this information. It was agreed that the report should be based on reviews of the peer reviewed literature supplemented by limited, but more detailed, analyses. These analyses were to focus on doses to members of the public where more recent information, specifically from measurements on people and from measurements of the levels of radionuclides in the environment, would support estimates appreciably different from those presented in the UNSCEAR 2013 Report [U10], and on understanding the reasons for, and implications of, the differences. The aim was to provide an authoritative and updated assessment of the levels and effects of radiation exposure due to the FDNPS accident. 1 The Committee has, exceptionally, taken account of information that became available after this date, where it would affect the findings of the report. 5. The reviews of the literature reported in the three published white papers and carried out subsequently have been conducted by a group of scientific experts (the Expert Group), supported by a group of scientific experts from Japan (the Japanese Working Group), and under the direction of two senior technical advisers, and a project manager. The detailed analyses were conducted by expert task groups set up for the purpose under the leadership of relevant members of the Expert Group and with involvement of relevant members of the Japanese Working Group. Some of the experts were assisted in their work by supplementary staff in their national institutes. An expert supported by Japan assisted the secretariat in Vienna. All involved were required to declare any potential conflicts of interest, which were reviewed by the secretariat to confirm that there were no conflicts of interest for the work in which the experts were involved. The work was carried out in accordance with a quality plan for the project. 6. The secretariat provided support to the technical work, inter alia, by arranging a visit by the Expert Group to Japan to discuss research work being carried out in Japan on the levels and effects of radiation exposure due to the FDNPS accident with Japanese researchers, by convening meetings in Vienna of the task groups carrying out the detailed analyses to facilitate the planning and implementation of this work, by providing a platform for online meetings and an online workspace for sharing and managing data and information, and by liaising with governments and other international organizations. The Governments of Australia, France, Germany, Japan, Norway and the United Kingdom made in kind contributions through expertise in this project. 7. The aim of this scientific annex is to provide a summary of all of the scientific information available (up to the end of 2019) relating to the levels and effects of radiation exposure due to the FDNPS accident and an appraisal of the implications of this information for the UNSCEAR 2013 Report [U10]. Specific objectives are to: (a) Summarize all of the information available and assess its implications for the findings and conclusions presented in the UNSCEAR 2013 Report; (b) Validate and, where necessary, revise estimates of doses to the public, based on more detailed analyses of the available information, and update the commentary on the health implications; (c) Set out an improved appraisal of the uncertainties and variabilities in the estimates of doses to the public; (d) Where possible, better address issues and objectives not fully addressed in the UNSCEAR 2013 Report. While self-standing, the annex is intended to be read in conjunction with the UNSCEAR 2013 Report and the subsequent white papers and does not repeat all of the information available in these publications. In particular, it does not repeat detailed background or contextual information set out in the UNSCEAR 2013 Report or in the subsequent International Atomic Energy Agency (IAEA) report on the accident [I5], for example, about the chronology of the accident or the actions taken in response, where understanding has not significantly changed. Where relevant, the reader is, instead, referred to these reports, where further information can be found. 8. The annex does not address policy issues with respect to human rights, public health protection, environmental protection, radiation protection, emergency preparedness and response, accident management, nuclear safety, radioactive waste management, prospective releases and related issues; it does not intend to provide advice to local governments, the Government of Japan or to national and international bodies. The annex also does not address other effects (not associated with exposure to radiation) that can arise as a result of accidents such as that at FDNPS, including distress and anxiety from, among other things, disruption of life, loss of homes and livelihoods, and social stigma, which can have major impacts on mental and social well-being. Evaluating such effects is