3. Safety design

Combining proven safety systems with passive safety systems of different design significantly reduces the risk of common mode failure. Compared with plants in service, the probability of core damage following an accident originating inside the plant is reduced by two orders of magnitude. Calculated using proven methods, the probability of core damage following an event initiated during plant operation or shutdown is only 8.4 × 10 ^–8 per year.

Passive safety systems are either self-triggering, requiring no external activation, or activated...