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:
capacity of the ECCS strainer to support water flow through the strainer and debris bed under limiting flow rates. The criteria will depend on strainer geometry (i.e., fully submerged versus partially submerged or vented designs). 1.3.9.4 Load combinations (e.g., safe-shutdown earthquake, deadweight, crush pressure, thermal, and live loads) used for structural analysis should be selected in accordance with the specific plant licensing-basis requirements and the applicable design code of record. Licensees should also refer to RG 1.92, Revision 3, “Combining Modal Responses and Spatial Components in Seismic Response Analysis,” issued October 2012 (Ref. 47), when analyzing the seismic loading conditions during the structural analyses of the strainers. 1.3.9.5 Licensees should include the effects of the fluid temperature and containment ambient temperature (e.g., restrained thermal growth, temperature-dependent material properties) in determining the structural integrity of the strainer. 1.3.9.6 Licensees should perform an evaluation to determine the possibility of dynamic loading on the strainers caused by HELBs and other structures, systems, and components that could produce missiles, pipe whipping, or jet impingement loads. Chugging and condensation oscillation loads can be a significant factor in some BWR designs. This evaluation should conform to GDC 4 and should be based on the plant’s design basis for postulated dynamic DG-1385, Page 29 effects within the region of the strainers. Based on the SE for NEI 04-07, in general, if a postulated pipe break is located more than 10 pipe diameters away from the strainer, the dynamic effects of such a break on the structural integrity of the strainer may be neglected. 1.3.10 Chemical Reaction Effects 1.3.10.1 Chemical reaction products in the containment post-LOCA environment can contribute to blockage of the ECCS strainers and increase the associated head loss. The final SE by the Office of Nuclear Reactor Regulation