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:
see analyses. 1.1.2.2 When latent debris is a significant source (i.e., contributes more than a minimal amount to strainer head loss) that can affect strainer performance or create downstream effects, periodic containment surveys or sampling should be performed to verify that the amount of latent debris is within the assumed limits. Such periodic monitoring may not be necessary if the latent debris evaluation incorporates sufficient conservatism to account for uncertainties associated with latent debris sampling (see Section C.1.3.6 for more information on latent debris). 1.1.2.3 Licensees should assess any new or unanalyzed potential debris sources (e.g., fiber and coatings) resulting from equipment modifications or discoveries to ensure that the post- accident sump/pool analysis is bounding of the plant condition. DG-1385, Page 18 1.1.2.4 Licensees should assess tags and labels that may fail and be transported to the strainer and should determine a sacrificial strainer area to account for the area that could become fully blocked by such transportable tags and labels and by other miscellaneous debris. 1.1.2.5 Licensees should consider using insulation types (e.g., reflective metallic insulation) that are less readily transported and would cause less severe head losses if deposited onto the strainer, in place of insulation types (e.g., fibrous and microporous insulation) that are more readily transported to the strainer and would cause higher head losses. If insulation is replaced or otherwise removed during maintenance, abatement procedures should be established to avoid generating latent debris in the containment. 1.1.2.6 To minimize the potential for debris created by the chemical reaction of the pool water with metals in the containment, licensees should reduce the exposure of bare metal surfaces (e.g., aluminum and uncoated carbon steel) to containment cooling water through spray impingement or immersion. These materials may be removed or protected by