A risk assessment method for accidental releases from nuclear power plants in Europe

At present over 200 nuclear power reactors are operational. The question raised is to what extent possible accidents with nuclear power reactors pose a risk for the European population. In this report a method is described for evaluating the probability of death due to stochastic effects, combining the probability of accidental releases with the consequences in terms of the excess doses received over a lifetime (70 years). The study is limited to stochastic deaths: victims of death due to very high short term radiation doses possibly occurring in the close proximity of the nuclear power reactor (< 5-10 km) are not included in the risk estimates. The nuclear power reactors have been categorized according to major (safety) characteristics and operational features. Accident and release probabilities have been estimated for each of these reactor categories. Dispersion and deposition calculations are based on statistical estimates in order to account for different weather conditions and their frequency of occurrence. The various exposure pathways, including ingestion of contaminated food products, inhalation and external exposure, are modelled. Countermeasures to reduce exposure are not considered. The radiation exposure following an accidental release is modelled over a period of 70 years. The results are given as the excess death risk per year forthcoming from the combined operation of all nuclear power reactors involved. Because of large uncertainties the calculated risk should be considered as an indication. A preliminary estimate amounts to an overall uncertainty of a factor of about 15 in western Europe up to a factor of 20 in eastern Europe. Nevertheless, the risk map provides an indication of the probabilistic risk involved (outside the 5-10 km zone around the reactors) due to accidental releases of nuclear power reactors, and the possible reduction of risk due to the improvement of reactor safety in eastern European reactors. This report can be considered as the scientific basis of a technical-scientific report no. 743030001, entitled: "Risks of potential accidents of nuclear power plants in Europe"