Accident management for loss of feedwater in PWRs

The SPES integral test facility is a three-loop scale down simulator of a pressurized water reactor (PWR) (Westinghouse 312-type, three loops, 2,775-MW (thermal) core power) designed for thermal-hydraulics safety research. Volume and power scaling factor are 1/400, approximately. A complete loss-of-feed water (LOFW) experiment was performed in 1988 and chosen as ISP22 by the Committee on the Safety of Nuclear Installations of the Organization for Economic Cooperation and Development. Following the LOFW, reactor scram occurred after a low-level signal in one steam generator and pump trip after a low subcooling indication in the cold leg. The recovery procedure was based on the actuation of emergency feedwater (EFW) in one loop {approximately}2 h after the beginning of the test as a result of dryout in the core region. In the period up to EFW actuation, the pressurizer power-operated relief valve (PORV) avoided primary-side overpressure. The procedure led to quenching of the core and to partial depressurization. More details concerning the transient scenario can be deduced. The purpose of this work is to evaluate the consequences on the accident evolution of different operations of the EFW system, also assuming the PORV in a stuck-open position.