Document: NUREG-0800
Document ID: 74980693-f1d2-4f59-a418-b297e1cc6509
Document Type: srp
Title: SURFACE FAULTING
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0707/ML070730597.pdf
Revision Date: 2023-06
Chapter: 2
Section ID: 2.5.3
CFR Part: 
CFR Title: 

Content:
pecified in Subpart C of 10 CFR Part 52 which allows for a COL (i.e., a combined CP and OL) as an alternative to the two-step licensing process previously defined in 10 CFR Part 50 which includes a CP (Step 1) separate from an OL (Step 2). Under the COL approach defined in 10 CFR Part 52, the Safety Evaluation Report (SER) will have been written by staff and a license granted to the applicant before plant construction excavations and geologic mapping of the excavations begin. Therefore, the geologic reconnaissance performed by staff notwithstanding, geologic features discovered in plant excavations of applicants granted a COL may not have been evaluated by staff. To alleviate potential problems, clear statements must be provided in the site-specific portion of the COL application that the applicant commits to (1) notifying staff immediately if previously unknown geologic features that could represent a safety hazard to the plant are discovered in the excavations; (2) at a minimum, undertaking detailed geologic mapping of walls and floors of all excavations for Seismic Category I facilities; and (3) notifying NRC staff when the excavations and geologic maps of those excavations are available for examination and evaluation. Furthermore, staff should also be contacted if a fault not previously identified in the application is found within 8 km (5 mi) of the site (i.e., in site area). Staff may collect samples from fault zones or other parts of an excavation for age dating and analysis. Previous applicants have often excavated trenches in areas where major facilities were to be located to reduce the chance of surprises when excavations were started for plant construction. The two-step licensing process defined in 10 CFR Part 50 requires applicants to obtain a CP (Step 1), followed by an OL (Step 2) after construction excavations and required geologic mapping of all Seismic Category I excavations have been completed and plant design bases have been approved by staff.