The Fukushima Daiichi Accident. Technical Volume 4/5. Radiological Consequences

This technical volume describes the consequences associated with radioactivity and radiation from the accident at the Fukushima Daiichi nuclear power plant (NPP) for people and the environment. A number of international organizations have already issued reports on the potential health and environmental consequences of the accident, notably the World Health Organization (WHO) and the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). The intention of the assessments presented in this volume is to build on their work, using more recent data where available. Quantitative information arising from both personal and environmental monitoring has been provided by the Government of Japan. Section 4.1 provides the best estimates of the magnitude and form of radioactive releases during the accident to the atmosphere and directly into the surrounding sea. It also explains the movement of the discharged radionuclides through air and water and the eventual deposition of the atmospheric activity on land in Japan and other countries worldwide, as well as on the open oceans. The goal is to provide a consolidated repository of information on releases to, and levels of radionuclides in, the environment. Some of this information is used in the analyses in subsequent sections of this volume. Section 4.2 gives an overview of exposures to the main groups of emergency workers at the Fukushima Daiichi NPP, to groups of off-site workers and to members of the public. Where sufficient data are available, average effective dose and thyroid equivalent doses derived from personal measurements are compared with the results of previous assessments for specific locations, population groups and time periods. Section 4.3 summarizes relevant aspects of the system of radiation protection in place at the time of the accident. It includes an overview of the legislation and guidance used to implement the radiation protection framework in Japan. This section also provides a description of the main aspects of radiation protection related to the accident at the Fukushima Daiichi NPP. Section 4.4 presents a review of post-accident studies of the health of members of the public and workers, including the possible radiation induced health effects and psychological consequences to individuals resulting from the accident. Section 4.5 covers the impact of the radioactive releases from the Fukushima Daiichi NPP on the environment (more specifically on non-human biota). The International Commission on Radiological Protection (ICRP) methodology has been applied to estimate dose and effects to a range of reference animals and plants from the marine, terrestrial and freshwater environments. There are 2 appendices and 12 annexes that provide supplementary information. Appendix I contains maps of levels of radioactivity and radionuclides in the environment. Appendix II provides details of a statistical analysis of individual dose data. The annexes are included on the CD-ROM attached to this volume and provide the following information: – Annex I: Characteristics and measurement of radioactivity and radiation levels. – Annex II: Local and regional meteorological conditions in east Japan during 11–23 March 2011. – Annex III: Levels of radioactivity in the terrestrial environment. – Annex IV: Radioactivity in the marine environment arising from releases following the Fukushima Daiichi accident. – Annex V: UNSCEAR assessment of the dose to the public