Saving Lives and Preventing Injuries From Unjustified Protective Actions-Method for Developing a Comprehensive Public Protective Action Strategy for a Severe NPP Emergency

Assessment of Protective Action Decision Making during Nuclear Power Plant Biennial Exercises

ABSTRACT

Radiological emergency preparedness for commercial nuclear power plants provides planning for implementing predetermined, prompt protective actions such as evacuation and shelter-in-place. In the event of a significant radiological release, onsite emergency response organizations will notify offsite response organizations and provide a protective action recommendation. The cognizant offsite authority will then make a protective action decision and inform the public of the need to act. Both the protective action recommendation and decision are driven by US Environmental Protection Agency protective action guides. Protective action strategies contain conservatisms and are intended to balance protection against other factors to ensure that actions result in more benefit than harm. But added conservatism can potentially shift the risks to those inherent to the protective action with no added benefit of protection. Protective action recommendations and protective action decisions made during biennial exercises were analyzed to assess how well they comport with the protective action guides. Trends in precautionary actions and the use of potassium iodide were also investigated. The analysis shows that protective action decisions typically exceed the protective action recommendation, resulting in an increase in the number of potential evacuees. However, exercise dose projection data do not appear to support such extensive initial evacuation decisions based on consideration of the protective action guides.

What's better for our health? Conducting protective actions during a nuclear emergency or accepting a certain radiation dose?

The threat caused by ionising radiation has resulted in the establishment of strict radiation protection guidelines. This is especially true for severe nuclear power plant (NPP) accident scenarios, which may involve the release of significant amounts of ionising radiation. However, we believe that the fine balance between the benefit of a certain protective action (e.g. evacuation) and its risks is not always accounted for properly. Deaths and mental health problems have been associated with protective actions (e.g. evacuation) implemented in the response to the Fukushima Daiichi (NPP) accident in 2011. The protective actions were implemented consistent with international recommendations, to reduce radiation-induced health effects, even though the off-site effective doses were too low to indicate that there would be any discernible radiation-induced health effects. In this paper, we will provide a first step for the development of tools to evaluate the risk of protective actions versus the radiation-induced health risk. Over 50 papers were selected as useful from more than 600 reviewed papers to characterise the health impact of protective actions taken during different emergencies (including, technical and natural emergencies). An analysis was performed comparing the radiation-induced health effects averted by protective actions with the health effects associated with the protective actions. We concentrated our analysis on deaths and mental health problems associated with protective actions compared with the inferred radiation-induced deaths averted by the protective actions. Our analysis is stated in terms of absolute risk (cases per 1000) of health effects to allow for a direct comparison. It indicates that taking protective actions consistent with dose criteria typically used in many countries could result in more excess deaths than the inferred radiation-induced deaths prevented, as well as resulting in mental health problems. We identified that residents of facilities for long stays and the elderly are particularly vulnerable and a significant number of the deaths among the general public are associated with a lack of emergency preparedness provisions.