1 Efficiency of Various Strategies of Short Term Countermeasures in Case of a Severe Nuclear accident.

In case of a severe nuclear accident at PWR plants, countermeasures should be initiated in the short term by authorities to reduce the consequences of the atmospheric radioactive releases on the neighbouring population. Various factors influence the level of protection afforded by the countermeasures. For instance, a too early intervention would lead to a lack of efficiency in terms of dosimetric impact if the actual evolution of th