Insights and viewpoints from a small-scale survey on current nuclear disaster preparedness measures in Japan after the Fukushima Daiichi Nuclear Power Plant accident

In nuclear disaster prevention, it is essential not only to make daily efforts to prevent accidents from occurring but also to properly apply lessons learnt from actual disasters. Although significant changes have been made to nuclear disaster preparedness in Japan since the Fukushima Daiichi Nuclear Power Plant accident, there is insufficient information on whether these changes have been evaluated as practical and appropriate for the needs of the Japanese public. In this survey, 20 officials of the Cabinet Office and Japan Atomic Energy Agency, in charge of planning nuclear disaster prevention policy, were asked to evaluate the current nuclear disaster prevention plan through a questionnaire, and compare it with that before the accident, and indicate what elements are lacking in the current plan. The survey results revealed that 30% of the participants (six respondents) had a positive view of the enhancement of resources, including physical and human assets. However, as many as 60% (12 respondents) expressed negative sentiments, primarily due to perceived deficiencies in organisational measures, particularly the coordination of these resources. Moreover, the participants expressed keen interest in obtaining health data during evacuation, along with information on the physical and mental effects on evacuees living in evacuation centres. These crucial insights can inform the formulation of effective future preparedness plans for evacuation and radiation protection.


Introduction
A nuclear disaster refers to an incident in which a nuclear facility or facility using radioactive materials experiences a leak, resulting in the extensive release of radioactive materials into the environment.Such disasters have severe impacts on people, the environment, and facilities [1].Human exposure to radioactive materials can be categorised into external exposure, which occurs when individuals are directly exposed to the emitted radiation, and internal exposure, which occurs when radioactive materials enter the body via ingestion or inhalation.
Essential measures in response to external exposure include maintaining a safe distance from radioactive materials, using shields, and minimising time spent near radioactive materials.Regarding internal exposure, measures include limiting the consumption of contaminated materials, using masks to prevent inhalation of radioactive particles, and minimising skin contact with radioactive substances.Adherence to these measures is of utmost importance in the event of a nuclear disaster [2].
Nuclear disasters are classified into seven levels by the International Nuclear Event Scale, which considers their effects both within and outside nuclear power plants.Level 7 represents the highest classification and entails the destruction of nuclear reactors or radioactive barriers along with the external release of radioactive materials in significant quantities.Only accidents at the Chernobyl Nuclear Power Plant in 1986 and Fukushima Daiichi Nuclear Power Plant (FDNPP) in 2011 have been categorised as level 7 nuclear disasters [3].
Apart from the deterministic effects of high-dose radiation exposure, nuclear disaster prevention plans aim to minimise stochastic effects, such as cancer development and genetic impacts [4].In the United States (US), for nuclear disaster preparedness, the operating companies of nuclear power plants, along with the Nuclear Regulatory Commission and the Federal Emergency Management Agency, share responsibilities for developing disaster prevention plans and other related measures.Disaster prevention plans are regularly reviewed and updated to ensure their effectiveness in response to potential disasters.Additionally, nuclear power plant operators in the US only employ individuals who have been engaged in safety operations for more than 10 years, ensuring a skilled and efficient response during emergencies [5].In Japan, regarding nuclear disaster preparedness, the fundamental principle in the event of a nuclear disaster is to minimise the exposure of people living in the surrounding areas to radioactive materials released from nuclear facilities and to protect the health and property of local residents.Nuclear disaster countermeasures have been developed based on this principle [6].Before the FDNPP accident, various measures were implemented based on the Nuclear Disaster Countermeasures Law to strengthen the national emergency response system.These measures included the issuance of emergency declarations by the Prime Minister, establishment of the Nuclear Disaster Response Headquarters, designation of emergency response centres (offsite centres), creation of disaster preparedness plans, establishment of disaster response organisations, clarification of responsibilities for nuclear operators through reporting to the national government and relevant local authorities, and enhancement of cooperation between national and local governments through the dispatch of national officials in response to requests from local authorities [7].
In the FDNPP accident caused by the Great East Japan Earthquake in March 2011 and the subsequent tsunami, significant damage occurred because of inadequate assumptions regarding the tsunami and station blackout scenarios [8].This disaster highlighted the inadequacies of Japan's nuclear disaster preparedness measures and the need for more practical ones.As a result, nuclear disaster preparedness in Japan was reassessed, leading to changes, such as the establishment of priority action zones and urgent protective action planning zones, the introduction of protective measures based on emergency action levels and operational intervention levels, and clarification of the distribution and intake of stable iodine tablets [9].
However, no studies have investigated whether these changes adequately address the practical needs for nuclear disaster preparedness.To bridge this gap, we surveyed the individuals involved in nuclear disaster preparedness.The survey aimed to evaluate current nuclear disaster preparedness plans in terms of physical resources such as equipment and personnel, as well as the organisation and operation of human resources.Additionally, we sought to identify data that may be lacking in the current nuclear disaster preparedness measures.This survey is expected to provide valuable insights for policymakers, enabling them to align preparedness efforts with actual needs in the field and enhance nuclear emergency response from an organisational perspective.

Method
A lecture was conducted in a hybrid format with Zoom on 7 October 2021 to address the risks of evacuation to prevent the radiation exposure of residents during the FDNPP accident.The lecture centred on the indirect health effects experienced by the residents following the FDNPP accidents and especially emphasised the negative health consequences of evacuation, particularly on those confined to elderly care facilities and hospitals.The lecture was attended by the staff members of the organisation responsible for nuclear disaster prevention, known as the Department of Nuclear Disaster Prevention at the Cabinet Office, and those of the Japan Atomic Energy Agency (JAEA).The JAEA functions as an organisation engaged in nuclear energy research and technical development.It provides diverse technical assistance to local governments and other entities upon request, during nuclear emergencies [10].The Department of Nuclear Disaster Prevention of the Cabinet Office is responsible for the overall coordination of nuclear disaster prevention in both normal and emergency situations.This entity collaborates closely with relevant ministries, agencies, and local governments and serves as the secretariat for the Nuclear Emergency Management Council and the Nuclear Emergency Response Headquarters [11].
Subsequently, a questionnaire survey was administered to participants who attended the lecture.Participants were asked to assess the current nuclear disaster prevention measures using a choice-type survey, with specific consideration given to whether these measures had been enhanced in comparison with the period before the FDNPP accident.Additionally, participants were asked to express whether they deemed these measures to be entirely sufficient by providing their reasons in a descriptive format.
The survey encompassed various aspects, including the understanding of local residents; improvement of knowledge and response capabilities of local government officials; motivation and knowledge of those engaged in disaster prevention activities within the private sector; decision-making capabilities of national organisations; comparisons of non-radiation health hazards associated with evacuation activities and benefits from protective measures; and the responsibilities and division of roles within private organisations, such as local hospitals and care facilities, during emergency response.The survey selectively evaluated the need for detailed planning in certain areas.Furthermore, the survey aimed to identify current data deficiencies in the creation of nuclear emergency preparedness plans using a descriptive format.
This study was approved by the Institutional Review Board of Minamisoma Municipal General Hospital (approval number: 2-07) and Fukushima Medical University (approval number: 2019-269).All participants provided informed consent for the study before giving a response to the questionnaire.The study was performed in accordance with the principles of the Declaration of Helsinki.

Results
Table 1 shows the characteristics of the 20 respondents.Out of 20 participants, two respondents (10%) were in their 30s, three (15%) in their 40s, 11 (55%) in their 50s, and four (20%) in their 60s.Nine respondents (45%) were a part of the JAEA, and 11 respondents (55%) were a part of the Department of Nuclear Disaster Prevention at the Cabinet Office.
Figure 1 shows the opinions of the respondents on nuclear disaster prevention.The degree of fulfilment of the nuclear disaster prevention plan was as follows: regarding the level of fulfilment before and after the accident, 19 respondents (95%) answered that the current nuclear disaster prevention plan was well-improved; still, 12 respondents (60%) answered that the current plan was 'not sufficient' or 'not so sufficient' .The respondents' opinions on the various data necessary for enhancing nuclear disaster preparedness measures are as follows: Regarding the necessity of public understanding of those measures, 19 individuals (95%) responded that it is 'necessary' or 'somewhat necessary' , indicating a positive response.Concerning the need for a benefit comparison between evacuation and protection, 18 individuals (90%) responded that it is 'necessary' or 'somewhat necessary' , indicating a positive response.About the necessity of detailed emergency plans in medical facilities, 19 individuals (95%) responded that it is 'necessary' or 'somewhat necessary' , indicating a positive response.With regard to the necessity of elevating the skills of municipal employees, fostering motivation among private enterprises, and enhancing the decision-making capabilities of national organisations, 20 individuals (100%) responded that these are 'necessary' or 'somewhat necessary' , indicating a positive response.
Table 2 shows the freely stated opinions of the respondents regarding the current nuclear disaster prevention plan.Nineteen respondents (95%) answered that the reason for the improvement in nuclear disaster preparedness after the FDNPP accident was to enhance the response capabilities by improving training and facilities.However, the respondents were divided based on their evaluation of current nuclear disaster preparedness measures.On the positive side, three respondents (15%) cited increased flexibility owing to the earthquake experience, and three respondents (15%) cited the success of capital investment.On the negative side, 12 respondents (60%) cited the immaturity of cooperation between organisations and society.The following are some of the most typical comments from respondents who expressed negative opinions: 'I am aware of the tangible measures of the facility, but I am not sure if the intangible measures, such as the improvement of organisational coordination, will work' .
Four respondents (20%) cited the physical and mental effects of evacuation and protection as the information deficit in the current nuclear disaster prevention measures, and one respondent (5%) each acknowledged that there is a lack of information on the aspects of basic knowledge about radiation for residents, the response procedures of DMAT (Disaster Medical Assistance Team), and the current radiation protection and countermeasures in municipalities when implementing nuclear disaster preparedness measures.
The following are some of the most salient points from respondents' opinions: 'For the general population, in order to consider efforts to prevent voluntary evacuation, we would be interested in comparing the risks of evacuating indoors and staying in one's home versus evacuating and living in an evacuation shelter.' In addition, six respondents (30%) mentioned that data on diseases caused by exposure and evacuation are a necessary resource for policymaking.One respondent (5%) highlighted the importance of prompt communication with hospitals in the nuclear emergency preparedness priority zone, and two respondents Abbreviation: JAEA, Japan Atomic Energy Agency.

Figure Opinions on Nuclear Disaster
Preparedness.These Pie-Charts illustrate the results of an investigation into the comparison of nuclear disaster preparedness before and after earthquake, current evaluation of nuclear disaster preparedness and necessity of public understanding, elevating municipal employees' skills, fostering motivation among private enterprises, enhancing decision-making capability of national organizations, benefit comparison between evacuation and protection, and detailed emergency plans in medical facilities.(10%) mentioned the development status of nuclear disaster response manuals in those hospitals is required for policy decision-making.

Discussion
This study is the first in Japan to highlight the gap between the strategic plan that the government made and the actual on-ground experience after the FDNPP accident in the realm of nuclear disaster preparedness.This study reveals that government officials believe that the current nuclear disaster preparedness system has the necessary physical resources but that there is room for improvement in the use of the systems and human resources.The results of this study indicate that, although the hardware of nuclear facilities has been improved through enhanced training and capital investment, the operation of these facilities and organisations is still inadequate.
Regarding evacuation due to nuclear disasters, clarifying evacuation standards, establishing evacuation routes, organizing traffic, managing and protecting the properties of evacuees, preparing for special populations and facilities, such as hospitalized patients, considering livestock and pets, and responding to the needs of the evacuees are considered important [4].The needs of displaced populations are important.However, this study also shows that it is necessary to anticipate the needs of displaced populations in shelters.Based on the results of this study, minimizing the effects of evacuation, and protecting on the physical and mental health of displaced populations should also be considered.
There are several limitations in this study.First, this study is an indicative study providing the opinion of a group of experts in the field, instead of a statistically representative sample of some larger population.Nonetheless, there are no more recognised nuclear policy-making experts in Japan other than this study's participants, and it may not be beneficial to conduct further research on a larger population.Second, research on health issues caused by evacuation in the FDNPP accident-including studies targeting non-communicable diseases, such as diabetes-that has been conducted since the FDNPP accident does not provide sufficient evidence to inform evacuation policy decisions, necessitating additional research into the health implications of evacuations [12].

Conclusion
Policymakers in Japan consider that nuclear disaster preparedness has improved to a certain extent since the FDNPP accident, partly owing to enhancements in physical resources.However, they consider the current preparedness inadequate in terms of human resources, flexibility, and medical knowledge.Therefore, it is necessary to keep abreast of the latest information and continue to improve these measures in the future.

Table 1 .
Characteristics of Survey Respondents.

Table 2 .
Opinions on Nuclear Disaster Preparedness (Open-ended Responses).