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:
ts of tests that are demonstrated to be either conservative or representative of the plant conditions. b. If the interceptors are credited with capturing fine debris to reduce the ECCS strainer debris load, licensees should perform time-dependent analyses and tests that consider the conditions that would lead to minimum debris capture fractions. The analysis should include the potential for trapped debris further eroding into fines that could then pass through the interceptors. Iterative analyses of the flow in the sump or suppression pool (e.g., multiple CFD simulations that have been acceptably verified) may be necessary if the blockage of the interceptors significantly affects the containment pool flow pattern. 1.3.5 Coating Debris Coating debris is generated from the postulated failure of both design basis accident (DBA)-qualified and unqualified coatings within the ZOI and from the postulated failure of unqualified coatings outside the ZOI. Generally, qualified coatings fail because of jet impingement, and unqualified coatings fail because of environmental conditions. Failure of unqualified coatings within the ZOI is assumed to be due to jet impingement. NRC reports entitled “NRC Staff Review Guidance Regarding Generic Letter 2004-02 Closure in the Area of Coatings Evaluation,” issued March 2008 (Ref. 44), and “Revised Guidance Regarding Coatings Zone of Influence for Review of Final Licensee Responses to Generic Letter 2004-02, ‘Potential Impact of Debris Blockage on Emergency Recirculation during Design Basis Accidents at Pressurized-Water Reactors,’” dated April 6, 2010 (Ref. 45), provide a general approach to conducting plant-specific coatings evaluations. 1.3.5.1 Licensees should use a ZOI for coatings that is determined by applicable testing and plant-specific analysis. The fluid used for the test (steam, air, or two-phase water) should be representative of the plant exposure conditions. 1.3.5.2 All (100 percent of) unqualified coatings should