Overview of Site Specific Blockage Solutions at US PWRs

The potential for LOCA-generated debris to degrade PWR ECCS performance during recirculation has gained international industry and regulatory attention. Many US PWR owners are still in the early stages of determining the significance of this issue for their particular plants. For a sizable number of these plants, resolution of the ECCS debris blockage issue will require a combination of analytical evaluation, changes to operating or maintenance protocols, and modifications or additions to some plant components. This paper provides an overview of site-specific ECCS debris blockage solutions anticipated to be used by US PWRs. The overview begins with a brief review of the variability in containment floor and ECCS sump configurations found in the US PWR fleet. With this variability in mind, discussion then focuses on the several different resolution modes ...