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:
Continued resuspension • Fully mixed conditions • Debris break-up • Pressure equalization • Transport by break flow • Formation of water pool on drywell floor. • Pressure wave • Dynamic piping response • Impulse load on insulation • Peeled covers • Insulation destroyed • Drywell pressurization • Recirculating vapor flows • Entrainment and transport of debris • Resuspension of suppression pool sludge • Initiation on high drywell pressure • Destruction under steady loads • Dislodgement • Erosion of solid insulation • Concrete spallation • Paint chips • Transport by vapor flow • Deposition on structures • RPV pressure > shut-off head • Minimum flow through bypass (10% of rated flow) • Termination of debris generation • Rapid depressurization • Rapid decrease in pool dynamics • Washdown of insulation • Start of sedimentation • Ramps to design flow • Low-energy phase • Recirculation flow patterns • Low intensity turbulence • Transport to strainers • May operate in suppression pool cooling mode. 1000 100 10 50 1 • Water jet impingement • Vent clearing • Pool swell DG-1385, Page 40 D. IMPLEMENTATION The NRC staff may use this regulatory guide as a reference in its regulatory processes, such as licensing, inspection, or enforcement. However, the NRC staff does not intend to use the guidance in this regulatory guide to support NRC staff actions in a manner that would constitute backfitting as that term is defined in 10 CFR 50.109, “Backfitting,” and as described in NRC Management Directive 8.4, “Management of Backfitting, Forward Fitting, Issue Finality, and Information Requests,” dated September 20, 2019 (Ref. 51), nor does the NRC staff intend to use the guidance to affect the issue finality of an approval under 10 CFR Part 52, “Licenses, Certifications, and Approvals for Nuclear Power Plants.” The staff also does not intend to use the guidance to support NRC staff actions in a manner