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:
should consider (1) debris existing before the pipe rupture that is transported to the suppression or containment pool, (2) debris created by the reactor pressure vessel environment (i.e., thermal and chemical), (3) debris created by the atmospheric environment (i.e., thermal and chemical), and (4) debris created by the environment of the submerged containment or suppression pool, as appropriate. Examples of debris created by the environment include unqualified coatings that fail in the form of chips and particulates, and the formation of chemical products caused by chemical reactions occurring anywhere within the containment, including the ECCS pool or the suppression pool and the reactor vessel (see Sections C.1.3.5 and C.1.3.10). 1.3.3.5 The analyses should consider debris erosion that results from continued degradation of insulation and other debris when subjected to turbulence caused by cascading water flows from upper containment, containment spray, or flows in the sump or suppression pool. Chemical decomposition or environmental conditions may also damage materials so that they can erode and become transportable to the pool. The determination of eroded quantities for various types of debris should be based on testing that is prototypical of plant conditions. In the absence of applicable testing, demonstrably conservative assumptions should be used. (For example, Appendix III to the SE for NEI 04-07 recommends a bounding value of 90-percent erosion for fibrous debris.) 1.3.4 Debris Transport The debris transport evaluation determines the fraction of containment debris that is transported to the ECCS strainer. 1.3.4.1 The calculation of debris quantities transported to the ECCS strainers should comprise all modes of debris transport, including blowdown transport, spray transport, washdown transport, and transport within the containment pool. Consideration of containment pool debris transport should address (1) debris transport during the pool fill phase, as