Document: NUREG-0800
Document ID: c97c665c-1f0f-4a2d-a4db-4e0dbd99eab3
Document Type: srp
Title: CHANNEL DIVERSIONS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0707/ML070730434.pdf
Revision Date: 2023-06
Chapter: 2
Section ID: 2.4.9
CFR Part: 
CFR Title: 

Content:
ne candidate locations where geologic or human-induced events increase the likelihood of channel diversions. Evaluate the channel geographic layout (meanders), cross-section (width and depth), profile (slope), discharge (velocity and energy), and material (bed, bank, and suspended). If considered necessary, identify the most likely types of channel diversion conditions and the potential impact on plant design of each type. For each type of condition, preliminary independent conservative estimates of the “worst case” should be made qualitatively. The USACE and the NCHRP have provided methods of predicting channel migration. USGS and state departments of natural resources provide databases of landslide mapping. The Federal Emergency Management Agency (FEMA) has completed a reverine erosion hazard area mapping study. The reviewer needs to consider the possibility the channel could divert by blockage or as a result of uplift or subsidence. The reviewer needs to consider potential diversions that can result from gradual progressive causes, or from quick catastrophic change. If the applicant’s assessment of channel diversion effects is comparable to the staff’s preliminary bounding analysis, the staff should concur with the applicant’s assessment. If the preliminary bounding analysis indicates the two are not comparable, the staff's analysis should be repeated using more realistic techniques. If the two remain 2.4.9-8 Revision 3 - March 2007 non-comparable then the staff should analyze data and methods used by the applicant and use alternative techniques of analysis. 3. Ice Causes: Estimates of the most severe ice-induced channel diversion should be consistent with the applicant’s estimates in SAR Section 2.4.7 (Ice Effects). Flow available under the most severe channel diversion should be sufficient to meet safety- related water supply requirements. If ice blockage of the river or estuary is possible, it should be demonstrated that the resulting water level