Review of Core Damage Frequency CDF for Nuclear Power Plants in the World

BAPETEN plays an active role in proving the safety level of nuclear power plants to be built and operated in Indonesia. For commercial Power Reactors, the applicant must submit a probabilistic safety analysis report, including calculating the core damage frequency (CDF).

The purpose of this paper is to compare CDF from various counties (regulatory bodies requirements) and the core damage accidents that ever happened in the world.

Three Core Damage accidents (with INES greater than 5) ever happened in the world: TMI, Chernobyl, and Fukushima. Sixty-six years ago, on 27 June 1954, the world's first nuclear power station at Obninsk was connected to the Moscow electrical grid. For 66 years, there were three core damage accidents, so on average, there is one core damage accident every 22 years. One core damage accident every 22 years is a rare event, but it's made a significant impact in the nuclear industry, especially the last accident (Fukushima Daiichi).

From various countries, CDF range from 10-4 /yr to 10-6 /yr. CDF 10-4 /yr means that the probability of core damage is once in 10,000 years of reactor operation.

There are 443 operational NPPs. If we assume that they have precisely the same core damage frequency, for CDF 10-4 /yr, the probability of one core damage in 443 NPPs is one core damage accident every 22.574 years.

Those assumptions about all reactor that has precisely same core damage frequency are never happen. We want to emphasize that it is better to have a smaller number of CDF, especially if we have hundreds, thousands, or even more NPPs operated in the world. Some newer NPP design has CDF less than 10-6 /yr.

Mobile emergency diesel generators, passive autocatalytic hydrogen recombiners, and core catcher are implementing DEC in NPP. DEC has a significant role in reducing CDF to be lower.