How long has the NRC been studying PWR sump performance?
The NRC first published regulatory guidance on the performance of pressurized-water reactor (PWR) containment sumps and boiling-water reactor (BWR) suction strainers in 1974 with the issuance of revision 0 of Regulatory Guide (RG) 1.82, “Water Sources for Long-Term Recirculation Cooling Following a Loss-of-Coolant Accident.” BWR suction strainers perform the same function as PWR containment sump screens. The NRC continually assesses the design and operation of nuclear power plants to determine whether its regulations, its guidance, or nuclear power plant design or operations need to be modified. The NRC began its first reassessment of PWRs sump and BWRs suction strainer performance in 1979. The first reassessment (including all technical and regulatory actions) was completed in 1985. In 1992, the NRC started a second reassessment of BWR suction strainer performance and completed the reassessment (including all technical and regulatory actions) in 2000. In 1996, the NRC started a second
