Table 2-4-4 Ministry of the Environment Origin of Specified Waste and Assumed Waste

Source	Assumed waste
Water facility	Sediments such as sludge, created sludge, soot dust, incineration ash, burned embers, etc.
Waste disposal facility	Soot dust, incineration ash, and other burned embers
Operator, etc.	Waste paddy straw, waste compost, etc.
Land to be decontaminated	Grass and wood, metals, plastics, etc.
Source: Ministry of the Environment, “Guidelines for specified waste” (December 2011, first edition)

when the exposure dose is 100 mSv or less. This is because the carcinogenic risk of radiation is overshadowed by carcinogenic risks due to other factors. At the present time, our scientific knowledge is not sufficient to identify these risks. However, regardless of scientific verification, we must adopt measures to reduce risks, even at exposure levels as low as 100 mSv or less.

Even though the health effects of low dose exposure of 20 mSv per year (the numerical criteria set for an evacuation order) cannot be simply compared to other randomly chosen risk factors affecting people's health, it can be said that the effect of low dose exposure is sufficiently low compared to other carcinogenic factors (e.g., smoking, obesity, insufficient vegetable intake, and so on). In terms of radiation protection, risks can be avoided by carrying out decontamination and by thoroughly managing food security. Therefore, the numerical value of 20 mSv per year can be deemed adequate as a "scratch line" for further pursuing reduction of radiation doses.

## b) Considerations for children and pregnant women

Top priority should be given to children and pregnant women, as it is known that exposure to over 100 mSv is more harmful to children than to adults in terms of the carcinogenic risk of radiation exposure. At the same time, it is difficult to verify significant increases in carcinogenic risk due to low radiation exposures of 100 mSv or less. Placing top priority on children and pregnant women is still critical, however, even when their radiation exposure is low (100 mSv or less), to assuage the great anxiety felt by local residents.

Detailed responses are required for children, as children are more sensitive to the life stress arising from avoiding exposure to radiation.

## c) Communications regarding risk

As to risk communication, it is important to clearly present risk assessments to residents based on scientific knowledge relating to the current situation in Fukushima. Consequently, the residents should devise voluntary countermeasures with reference to proper information they have obtained on radiation and radioactivity.

Also, in order to implement radiation protection and health management effectively in the long term, voluntary participation of the residents is essential. Therefore, the government shall provide residents with the means of obtaining information to help them understand their own current situation, as it is important to create circumstances in which residents can act spontaneously and continuously toward restoration and reconstruction.

Furthermore, the government and experts should provide information to the residents clearly, by discussing it with them directly through improved communications, and this should help residents implement measures including reducing exposure doses and health management, with everyone adopting the same perspective on the issues.

## (2) The Survey for Health Care of Residents in Fukushima Prefecture

Fukushima prefecture has conducted the survey for health care so as to implement middle-long term health care targeted all people living in Fukushima prefecture. This survey includes monitoring radiation dose, and physical examination of the thyroid gland with medical ultrasonography and medical checkup targeted the young who were under 18 years old when the earthquake occurred.

The central government has taken efforts, including providing supports by technical and financial assistance, making public and educational efforts about the scientific knowledge of radiation and impact on health by low dose exposure, and conducting basic research about the impact of health, combined with United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) and International Commission on Radiological Protection (ICRP).

# Section 5 Turning Point for the Nuclear Safety Regulation

1 Reconciding the nuclear safety reflecting the nuclear accident

The nuclear power plant has been expected so far as energy source that would support economic growth, and as power source that would not emit greenhouse gas. Before the Great East Japan Earthquake, the relationship between environmental concerns and nuclear disasters was rarely discussed as a political matter.

Regarding the above, the accident at the TEPCO Fukushima Daiichi NPS shed light on another aspect of NPSs: the enormous environmental impact that NPSs can cause in a nuclear disaster. Environmental contamination due to radioactive materials is now highlighted as an unprecedented environmental concern. Similarly, overall energy policy including nuclear policy has become a hot topic in the wake of the earthquake. For example, the Annual Reports on the Environment before the massive earthquake indicate that nuclear power generation should be encouraged with top priority given to safety issues. However, after the earthquake, the 2011 Annual Report on the Environment mentioned that deliberations on energy policy as a whole including nuclear policy should be carried out while verifying the causes of accidents.

An issue for nuclear safety measures is how to define potential risks, since nuclear accidents can cause serious environmental contamination. The Great East Japan Earthquake has forced us to confront the difficulty of assessing risk with probability theory, and of deciding on the permissible level of risk from natural disasters and tsunami. In the meantime, it has also revealed that risks must be considered in terms of multiple aspects: the environmental risk of radioactive contamination; the social risk of evacuating residents; the economic risk of damaging; for the productive activities accompanied by power shortages; and the health risk of low dose exposure.

It is difficult to assess all of these risks. However, to fully face them, it is desirable to decide on the permissible level of risks for serious accidents through open and highly transparent discussions. Risk can be defined in various ways by various experts, civil groups, and residents. Thus it is necessary to disclose the related risk information and invite various kinds of information, and to have highly transparent forms of communication, in order for policymakers and citizens to make rational choices. Developing science literacy also helps to acknowledge and determine the current situation.

Avoiding severe accidents and improving facility safety will be achieved through ceaseless effort, and it is essential to reassess the risks from the perspective of the latest scientific knowledge to improve existing facilities.

It is vital that we accept the fact that absolute safety is impossible and natural disasters and accidents are fundamentally unavoidable. Needless to say, the occurrence of severe accidents at nuclear-related facilities is intolerable. Despite this, it is reasonable to think that responsibility and a sense of urgency are truly required in the administration of nuclear regulations, since nuclear accidents directly lead to irremediable problems for the environment, society, and the economy, including environmental contamination by radioactive materials, dangers to human health, loss of local livelihood accompanied by evacuation and tight power supply and demand.

## 2 Discussion towards the revision of Nuclear Safety Regulation

As is pointed out in the Report of the Japanese Government to the IAEA Ministerial Conference on Nuclear Safety published in June 2011, the primary responsibility of Japan's nuclear regulation and monitoring before the Great East Japan Earthquake was not clearly defined. The proposal from the Advisory Committee for Prevention of Nuclear Accidents (December 13, 2011) mentioned later notes that "public trust in administrative safety of atomic energy has reached its nadir," and that "both the government and the operator were overconfident and conceited of the security measures, which lead to the devastating accident that released massive amounts of radioactive materials and destroyed the daily life and community of many people as a result." The Report also stated, "the government must promptly rebuild the nuclear safety regulation system engaged in the mission of preventing the recurrence of similar accidents."

The government made an announcement on its Basic Policy for Restructuring Organizations Related to Nuclear Safety Regulation (approved by the Cabinet on August 15, 2011; hereinafter referred to as the "Basic Policy"). As a "Temporary policy for review of organizations related to safety regulations," it stated five revisions: "separation of regulation and use"; "unification of related work concerning nuclear safety regulation"; "risk management"; "securing qualified human resources from the public and private sectors"; and review of the ideal regulation and related institution. It also included the preparation of a bill for a law to establish the new organization by April 2012, and noted that a flexible response would be required when verification results were provided from the accident investigation and verification commission organized after the TEPCO Fukushima Daiichi NPS accident. Furthermore, nuclear and energy policy in the mid and long term shall be reviewed and consideration should be advanced broadly, taking the verification results based on the investigation committee on the accident. A final draft is to be submitted near the end of 2012 regarding the assignment of the role adopted by the