Table 2: Worldwide number 𝑅 𝑊 of reactors at the time of accident, cumulative reactor years since 1967 and hazard for NPP reactor accidents with INES level 5 (95% CI in brackets are calculated only for the latest value based on three events).

Reactor location Number of reactors 𝑅 𝑊 Cum. reactor years
𝐶 𝑊 since 1967
Hazard 𝑊    CI
(per 1 0 4 RY)

Three Mile Island 133 4754 2.1
Chornobyl 302 9267 2.2
Fukushima 441 14097 2.1
(0.44; 6.2)