Estimation des excès de risque de cancer de la thyroïde et de leucémie suite à un accident grave sur un REP.
Florence Charpin, Hilaire Mansoux, Jean Brenot, IRPA 11, 23-28/05/2004, Madrid, Espagne.
In this study, the health effects (cancers) of a major nuclear accident at a PWR are assessed and the number of cancers which could be avoided by the implementation of population protective actions is estimated.
The accident scenario chosen is that forming the basis of emergency plans; it is considered as the most serious nuclear accident that could take place in France. The study focuses on the early phase of the accident, that is to say the duration of the release. Protective actions in that phase are sheltering, evacuation of the population and intake of stable iodine to saturate the thyroid gland.
The number of thyroid cancers and leukaemia cases is calculated for a group of 41 000 children and teenagers under 15 years of age, assumed to be evenly distributed in the first 50 kilometres around the nuclear power plant and exposed to the radioactive release. For management purpose, life time risks have been considered. The life time thyroid cancers and leukaemias expected in a non-exposed similar group are compared to the additional cases due to radiation exposure in two cases: in absence or in presence of protective actions (i.e. countermeasures).
Calculations have shown that there would be around 100 thyroid cancer cases in the population in absence of exposure. Exposure to radioactive release for the accident scenario considered could lead to a few tens of potential additional thyroid cancer cases in absence of countermeasures. 60 to 80 % of these cancers could be avoided by the implementation of countermeasures.
Regarding leukaemias, calculations have shown that there would be around 170 cases in the population in absence of exposure and that the number of additional radiation-induced cases would be very low (less than one case) compared to the number of leukaemia cases expected in absence of release.
Despite a number of limitations, the study provides useful information to guide public health and civil defence authorities in the management of short-term and longer term consequences of an accident, would it occur.