Protective Action Guide for the Public following Fukushima Accident I

The aims of implementing the public protective actions during a nuclear emergency are to (1) prevent the deterministic effects for the individual, (2) reduce the risks of stochastic effects for the individual, and (3) minimize the collective effective dose for the population. To achieve these aims, basic guides for the protective actions of the public should be provided in the emergency response plans. Under the Nuclear Emergency Response Act, the Emergency Preparedness Guideline is used to establish the emergency response plans and to implement the protective actions. Consequently, intervention levels on radiation doses and action levels (or operational intervention levels) on radioactivity concentrations or dose rates should be established for the protective actions including sheltering, evacuation, administering potassium iodide, food and water control, and temporary/permanent relocation. Based on the experience from the accident at Fukushima Dai-chi Nuclear Power Plant, the government of Japan has revised substantially its nuclear regulatory organization, site area classification, intervention levels, and action levels. Key revisions include the following: (1) Precautionary urgent protective actions are taken on the basis of conditions at the nuclear facility to prevent severe deterministic effects. Consequently, emergency action levels (EAL) are provided for the public in the precautionary action zone (PAZ). (2) At an early stage, quick response is needed to avert ingestion dose from elevated levels of radioactivity. Operational intervention levels OIL) are required for gamma dose rates from the contaminated surface. (3) Consistent policies and criteria for the implementation of urgent and long-term measures including return to normality should be established in the preparedness process. Protective actions have to be considered by the application of optimization procedures using local conditions. In this project, we will try to collect relevant information on the up-to-date international recommendations and guidance for the emergency response plans from lessons following the Fukushima Dai-ich NPP accident. Optimization principles will be used to develop the short- and long-term intervention levels and action levels. These developments will help the governmental officials to select optimized protective actions in a relatively short time period in case of nuclear accident.

Project ID:PC10501-2483
External Project ID:MOST105-NU-E182-001-NU