  A study on the behavior of off-site AC power failure recovery times at three
nuclear plant sites is presented. It is shown, that power law is appropriate
for the representation of failure frequency-duration correlation function of
off-site power failure events, based on simple assumptions about component
failure and repair rates. It is also found that the annual maxima of power
failure duration follow Frechet distribution, which is a type II asymptotic
distribution, strengthening our assumption of power law for the parent
distribution. The extreme value distributions obtained are used to extrapolate
for failure durations beyond the observed range.
