| This research applied probabilistic risk assessment to a pyro-processing facility to calculate the probability of an air ingress event occurring. Four configurations of the system were modeled, first a generalized system, second being the generalized system with door interlocks, third being an extended system with redundant solenoid valves, and fourth being the extended system with the addition of door interlocks. Eight fault rates for solenoid valves and three fault rates for door seals were used. For a one-day interval, the addition of the extra valves was significant, however, a one-year test interval showed little improvement for the total air ingress probability, which is resultant of some, possibly questionable, fault rates. The failure probability was found to be between the 10-3-10-1 range per year. An analysis of maintenance of risk critical components indicated that with monthly testing, the overall air ingress probability was reduced to 10-5-10-4 per year. |