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:
valuations indicate that a component may not be able to fulfill its design function throughout its mission time, and that it is not practicable to install a suction strainer with openings small enough to filter out the debris that would cause the predicted failure, the licensee should take action to ensure that the ECCS pumps will operate long-term under the postulated conditions. WCAP-16793-NP-A, Revision 2, “Evaluation of Long-Term Cooling Considering Particulate, Fibrous and Chemical Debris in the Recirculating Fluid,” issued July 2013 (Ref. 33), discusses a method for evaluating the downstream impact of debris on fuel assemblies. Additional guidance on PWR in-vessel debris evaluations can be found in “U.S. Nuclear Regulatory Commission Staff Review Guidance for In-Vessel Downstream Effects Supporting Review of Generic Letter 2004-02 3 WCAP-16406-P-A, Revision 1, contains information proprietary to Westinghouse Electric Company, LLC, and is not publicly available. DG-1385, Page 17 Responses” (Ref. 9). The NRC evaluation of PWR in-vessel effects used extensive information from WCAP-17788-P, Revision 1, “Comprehensive Analysis and Test Program for GSI-191 Closure (PA-SEE-1090),” dated July 17, 2015 (Ref. 34). For BWRs, the in-vessel issue was evaluated by the BWROG and the NRC staff. The NRC evaluation of the BWR in-vessel issue appears in a staff technical evaluation dated May 2018 (Ref. 24). The reader should refer to Section C.1.3.8.2 for additional discussion of in-vessel effects. WCAP-16530-NP-A, “Evaluation of Post-Accident Chemical Effects in Containment Sump Fluids to Support GSI-191,” issued March 2008 (Ref. 35) and its SE (Ref. 36), provides one approach to conducting chemical effects evaluations, as discussed in Section C.1.3.10 of this guide. 1.1.1.11 ECCS strainers and suction inlets for pumps required for long-term ECCS, CSS, or suppression pool cooling functions should be designed to prevent degradation of pump performance through air