Document: NRC Regulatory Guide
Document ID: 6f0a99f2-d25a-44e3-b7f2-3286449a9752
Document Type: regulatory_guide
Title: Water Sources for Long-Term Recirculation Cooling Following a Loss-of-Coolant Accident (Rev. 5)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2126/ML21266A185.pdf
Revision Date: 2023-05
Chapter: 
Section ID: RG-1.82
CFR Part: 
CFR Title: 

Content:
ntainment should terminate so that streams of water will neither directly impinge on nor discharge close to the ECCS strainers. Streams of drainage from upper containment may contain entrained debris; they can also cause air ingestion and other issues if they directly impinge on the strainers. The drains, drain piping internal clearances, and other pathways that connect containment compartments with potential break locations to the sump or suppression pool should be designed so as not to become blocked by debris; this will ensure that water needed for an adequate NPSH margin will not be held up or diverted from the pool. DG-1385, Page 16 1.1.1.5 Trash racks, suction strainers, and debris interceptors should be able to withstand the loads imposed by expanding jets, missiles, debris accumulation, and pressure differentials caused by post-LOCA blockage under design-basis or realistic flow conditions, whichever cause the greatest loads. When evaluating the impacts from potential expanding jets and missiles, licensees should justify credit for any protection offered by surrounding structures or credit for remoteness of trash racks and strainers from potential high-energy sources. 1.1.1.6 ECCS strainers, trash racks, and debris interceptors should be designed to withstand the inertial and hydrodynamic effects of the vibratory motion of a safe-shutdown earthquake following a LOCA without loss of structural integrity. 1.1.1.7 Licensees should select materials for debris interceptors, trash racks, and suction strainers that do not degrade during periods of inactivity or operation, and that have low sensitivity to stress-assisted corrosion or general corrosion that may be induced by chemically reactive spray or by the containment or suppression pool liquid. 1.1.1.8 Licensees should choose a suction strainer design (i.e., size and shape) that will prevent unacceptable loss of NPSH margin from debris accumulation during the period that the ECCS and CSS are required to operate