Guides for Nuclear Emergency Response after Fukushima Accident

The aims of implementing the public protective actions during a nuclear emergency are to (1) prevent deterministic effects from the acute exposure for an individual, (2) reduce stochastic effect risks from the chronic exposure for an individual, and (3) minimize collective effective doses for the population. To achieve these aims, guidelines using the ICRP emergency exposure reference levels for the protective actions should be established in the emergency response preparedness. Also, the IAEA dose criteria for urgent, early and late protective actions should be referenced in the emergency preparedness and response. Under the R.O.C. Nuclear Emergency Response Act, the Emergency Preparedness Guidelines requires establishments of the intervention levels for radiation doses and the action levels for radioactivity concentrations for sheltering, evacuation, iodine prophylaxis, food and water restrictions, temporary/permanent relocation, etc. From lessons learned from the Fukushima accident, it was demonstrated that the decision making process based on the computer-prognosis system for initiating off-site protective actions was impractical. This was largely due to the unpredictable wind direction and precipitation and so the release of radioactivity to the atmosphere in hours or days. In the new decision making framework, the computer-based prognosis was abolished and a new system was introduced to use the emergency action levels (EALs) from plant conditions for the precautionary protective actions and to use the operational intervention levels (OILs) from measured monitoring data for the emergency protective actions. Consequently, precautionary action zone (PAZ), urgent protective zone (UPZ), extended planning distance (EPD) and ingestion and commodities planning distance (ICPD) should be predetermined for the implementation of, respectively, precautionary protective actions, urgent protective actions, dose rate monitoring to locate hotspots which could require urgent protective actions, and the restriction of water, food, milk, etc. consumptions. Since protective actions depend on the optimization of local conditions, we will try to collect relevant information on the up-to-date international recommendations and guidelines for the emergency response by considering lessons learned from the Fukushima Dai-ich NPP accident. Optimization will be performed to establish OILs for the short- and long-term protective actions. The findings of this project will help the governmental to implement optimized protective actions in a timely phase in case of nuclear accident. This is a two-year project. The on-going first-year project performs the OIL studies for early and intermediate protective actions. This proposal of second-year project will perform the OIL studies for the late or recovery protective actions.

Project ID:PC10602-0053
External Project ID:MOST106-NU-E182-001-NU