PWR (Pressurized Water Reactor) interfacing system LOCAs (loss-of-coolant accidents): Analysis of risk reduction alternatives

This analysis suggests that the most cost-effective method to reduce the risk due to Interfacing System Loss of coolant accidents (ISLs) would be to establish a minimum testing frequency for pressure isolation valves. The suggested minimum frequency would be to perform leak testing of the pressure isolation valves at each refueling and after specific individual valve maintenance. In addition, it would also appear that the tests could be performed during descent from power without significantly increasing the risk of an ISL even and effecting considerable cost savings to the utilities.