The revised JIS Z4511:2018 (X and gamma reference radiation for calibrating dosemeters and doserate meters and for determining their response as a function of photon energy) was published in July 2018. JIS Z4511:2018 is MOD to ISO 4037 part 1 to part 4, and the contents are quite different from the previous document. The several calibration methods are added as informative annex. In this paper, points of difference in new and previous documents are explained.

In the history of the world nuclear industry there were four major accidents of operating nuclear reactors, i.e., at plutonium production facility in Windscale, UK, 1957; at NPP Three Mile Island, USA, 1979; at Chernobyl NPP, USSR, 1986; and at Fukushima-1 NPP, Japan, in 2011. The Chernobyl accident was the most severe, causing a huge release and deposition of radionuclides over large areas of Europe. Only after this accident there were real health effects caused by radiation, including carcinogenic effect among the population of the adjacent areas of Belarus, Russia and Ukraine. In this paper, same-type basic radiological characteristics are presented for four reactor accidents with more detail presented for the Chernobyl accident. The latter include mean radiation doses incurred by various groups of inhabitants of the three more affected countries, Belarus, Russia and Ukraine. Those who were children at the time and drank milk with high levels of radioactive iodine received high thyroid doses. Since early 1990s there was dramatic increase in thyroid cancer incidence among those exposed to radioiodine at a young age. Apart from this kind of health effects there was no clearly demonstrated increase in the somatic diseases due to radiation. The paper discusses the reasons why the Chernobyl accident had severe radiological consequences.

In Japan, the Nuclear Emergency Response Guidelines were formulated in 2012, and Nuclear Emergency Core Hospitals and Nuclear Emergency Medical Cooperative Institutions are beginning to be established in various municipalities. In this paper, we report the actual conditions in terms of human resources and material preparations for radiation emergency medicine based on the results of a questionnaire survey conducted at these medical institutions. It was found that the capacity for exposed/contaminated victims at each Nuclear Emergency Core Hospital was approximately one or two persons. In addition, regarding the education of implementing staff, it was found that they expressed a need for education in a wide range of fields. It also became clear that there were problems with a lack of human resources including clerks, and the preparation of radiation measuring instruments. In future, it will be essential to maintain a nationwide radiation emergency medical education system, as well as to hold trainings to meet the various educational needs. In addition, strengthening the cooperation of each organization and improving the preparation of equipment related to radiation medicine will lead to development of a more effective nuclear disaster prevention system.