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:
lant-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 be assumed to fail. However, licensees may also be able to demonstrate the performance of their unqualified coatings through plant-specific and coating-specific testing. Generally, unqualified coatings should be assumed to fail as fine particulate. However, if a filtering fibrous bed does not form on the strainer, it may be conservative to treat the unqualified coatings as chips. 1.3.5.3 Licensees should determine the debris characteristics (e.g., size, shape, density) of failed coatings separately for each coating system within containment. 1.3.5.4 Licensees may determine coating chip debris transportability in flowing water by using the results from NUREG/CR-6916, to the extent that they apply to a licensee’s plant-specific coating types. 1.3.6 Latent Debris 1.3.6.1 Latent debris present in containment during operation may contribute significantly to head loss across the ECCS strainers. Licensees must determine the types, size, quantities, and locations of latent debris. NEI 04-07 and its associated SE provide general considerations for the potential impact of latent debris on strainer blockage. In collecting latent debris samples for analysis, licensees should use a sampling technique with demonstrated collection DG-1385, Page 27 efficiency for fine particulate and fibrous debris. NEI 02-01, Revision 1, “Condition Assessment Guidelines: Debris Sources inside PWR Containments,” issued September 2002 (Ref. 46), provides an accepted approach for determining latent debris quantities. 1.3.6.2 Licensees should not assume that their foreign material exclusion programs have entirely eliminated latent debris. Results from plant-specific walkdowns should be used to determine a realistic amount of latent debris in containment and to monitor cleanliness programs for