The results presented are based on the following scenarios for the accident frequencies:

IAEA scenario: The "International Nuclear Safety Advisory Group", a working group initiated by IAEA, has defined a minimum goal for the safety of existing NPPs in its 1988 report: the frequency of a severe accident with a large release of radionuclides should not exceed 10E-5 per reactor year (1 accident in the time intervall of 100,000 years). Today, more then ten years later, still not all of the operational NPPs fulfill this safety goal. In the IAEA scenario, the release frequency is defined as 10E-5 per reactor year for all the NPPs.
References: INSAG Reports 1-10.

RT scenario: In this scenario, a generic accident frequency (accidents with large radioactive releases) was defined for each reactor typ. Plant-specific differences (such as age of a NPP, different safety systems and containment types, external hazards, ...) have not been considered. For a reactor-specific scenario it would be necessary to know the accident frequency with large radioactive releases (level-2 PSA) for each of the more than 200 operational reactors in Europe.