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:
. b. Licensees should use the volume of material contained within the ZOI to estimate the amount of debris generated by a postulated break. The size distribution of debris created in the ZOI should be determined from applicable experiments. It is noted that if robust barriers intersect the postulated jet zone, the extended volume may be truncated within the limitations of NEI 04-07, Section 3.4.2.3, and its associated SE. c. Licensees should use jet pressure isobars from the jet generated from the postulated pipe break as the basis for estimating the amount and the size or size distribution of the debris DG-1385, Page 23 generated within the ZOI. The pressure distribution within the jet will vary depending on the pressure and temperature of the fluid and the size of the break. d. Licensees should use the results of debris generation testing to determine the ZOI in a manner that is prototypical of the plant condition. Test scaling is complicated because material destruction may result from both pressure waves and jet impingement. Scaling considerations for debris generation testing include the test fluid used (e.g., air or saturated water), the initial thermodynamic conditions of the test fluid, the rupture disk opening time, the blowdown period, the size and orientation of the test nozzle relative to the target, and the specific configuration of the target material compared to the various plant materials to which the testing is being applied (e.g., insulation jacketing seam, jacketing thickness, and banding and latching strength). The staff has not developed specific guidance for the performance of ZOI testing. Methods and results are reviewed case by case. One example is the Air Jet Impact Tests documented in Section 3.2.1 of the URG. More recent testing and analyses to refine ZOIs for some materials are documented in WCAP-17561-P, Revision 0, “Testing and Analysis to Reduce Debris Generation Zones of Influence for GSl-191,” issued May 2012 (Ref. 41), and