In the United States of America, the National Council on Radiation Protection and Measurements (NCRP) has prepared NCRP Report No. 180 “Management of exposure to ionizing radiation: radiation protection guidance for the United States (2018)”, that updates the basic radiation protection recommendations published as NCRP Report No. 116 in 1993. The recommendations build on previous recommendations of the International Commission on Radiological Protection (ICRP) and NCRP, and are supported and informed by scientific knowledge, ethical principles, and experience. The recommendations are designed to prevent occurrence of tissue reactions, reduce the probability of stochastic effects in humans, and establish a guideline for nonhuman biota focused on population maintenance, while maintaining the benefits to the individual and to the society. Radiation protection principles recommended to address human exposures are justification, optimization of protection, and numeric protection criteria for management of dose to an individual. The key to radiation protection is optimization of protection, which is to be applied in all exposure situations and circumstances. Ethical principles of beneficence, non-maleficence, autonomy and justice are highlighted and useful to clarify interests when making decisions on complex situations. This review provides an outline and summary of the key points of NCRP Report No. 180.

The optimization of radiation protection is not just the minimization of radiation exposure but is now viewed more broadly to reflect the increasing role of individual equity, the safety culture, and stakeholder involvement in our modern societies. Since less importance should be given to individual exposures received in the distant future owing to the increasing uncertainties in long-term safety assessment, the optimization principle should be carefully considered for the disposal of long-lived radioactive waste. In this paper, we review the relevant international discussions on the optimization of radiation protection and extract the following key elements: (1) broadening of the optimization process towards judgmental decision-making, (2) the dose level that would be achieved as a consequence of the optimization process, (3) the use of predicted doses beyond a time frame of a few generations, and (4) the need for a dialogue between the authorities and the operating management. We examine the role of dose constraints from an ethical point of view and discuss the importance of reducing the inequity in the dose distribution of individual exposures when selecting a protective option for the design of a radioactive waste disposal facility. Furthermore, we review the concept of exemption from regulatory control, which is totally different from the disposal of radioactive waste in a facility.

This paper presents theoretical solutions for mean traveling distance of primary photons emitted from ground contaminated with radionuclide. Three typical patterns of radioactivity distribution are considered: (1) plane superficial source, (2) homogeneous volume source and (3) exponentially decreasing activity as a function of soil depth. Radiation dose rate can be easily estimated using the fluence rate of primary photons and the buildup factor. We assume the buildup factor is possible to be evaluated using the mean traveling distance. Comparisons between the results calculated in the present work and those obtained using detail Monte Carlo simulation codes indicate a good agreement for various radioactivity distributions and for photon energy ranging from 0.5 to 2 MeV. This methodology is very useful to estimate environmental radiation dose rates in a short time and can be practically used by residents and local government agents to evaluate impacts of radioactivity as well as utilizing it for studies of reducing the influence of radioactivity.

The Nuclear Regulatory Authority Japan mandates municipalities to prepare for “inspection to confirm whether radiation protection measures should be implemented for evacuees in case of nuclear disaster (Evacuation Exit Inspection: EEI).” While the EEI system itself was built after Fukushima accident, there are few educators nationwide who understand the details. Therefore, in this study, we developed desk-top teaching materials that comprehensively helps students understand the purpose and outline of EEI and confirmed its educational effect. As a result, 81% of the trainees understood the objectives of EEI after they had undergone a two-hour lecture that involved the utilization of the developed teaching materials. By combining these desk-top teaching materials with evacuation drills that include actual residents, it will be possible to initiate the human resource development necessary for building and implementing a stronger nuclear disaster prevention system. Development of such an educational program is very important for improving nuclear disaster prevention in Japan.

The demand for education of college students on radiation protection is strongly emphasized recently in Japan. We here aimed at developing an effective way to teach the radiation protection-related laws to students who have so little practical experience in radiation protection that the learning motivation tends to be very low, and a high training effectiveness is hardly expected. For this purpose, we tested a combination of an ordinary classroom lecture and a group work in which the students positively and cooperatively tackled the specific task that was given by the lecturer. The tasks included such as making up an application form to be submitted to Nuclear Regulatory Agency to respond to an altered condition of utilization of a radiation source in a radiation-controlled area. The students had to investigate and solve what is necessary to comply with the law by themselves. As a result, it was suggested that the group work had an effect on improvement of learning motivation of the students.