Assessment and inspection tasks of the Spanish regulatory body staff regarding I and C and related systems backfitting in old plants

Based on our experience working on backfits of the two oldest plants in Spain, we believe that: (1) Reaching backfitting decisions is one of the most difficult tasks being performed by a regulatory body. (2) Any backfitting decision should be preceded by a thorough review of the safety importance of the situation the backfit is aimed to correct. (3) Backfitting decisions should be reached in an integrated way. A complete review of the plant should be performed to put each backfit in perspective. PRA may be a useful tool to achieve it. (4) Except when there is an immediate need of corrective actions backfitting schedules should be long enough to allow appropriate review by all involved parties