Document: NUREG-0800
Document ID: 48fb37ec-8e3e-4c2c-96c3-daa5e7da62f9
Document Type: srp
Title: of the applicant's SAR is reviewed to identify any missing data,
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340557.pdf
Revision Date: 2023-06
Chapter: 2
Section ID: 2.4.12
CFR Part: 
CFR Title: 

Content:
at such abnormal occur- rences do not adversely affect the integrity of safety-related structures, systems, and components. (d) Sequence of Review Underdrain systems are usually one of the first items constructed and, after backfilling and construction of subsurface facilities, are then no longer visible for regular inspection. In most cases, these systems are initially designed based on rather limited informa- tion from preconstruction field activities, and are tailored specifi- cally for the site and facilities. By necessity then, final review and approval by the staff of the design must rely in some part on information gathered during construction. Therefore, the review and 2.4.12-13 Rev. 2 - July 1981 approval can be accomplished in two ways: (1) design details of the permanent underdrain system, the operational monitoring program and plans for construction dewatering can be submitted in the PSAR, with only confirmation of the details required prior to actual construction; or (2) conceptual designs of the permanent underdrain system and the operational monitoring program and details of construction dewatering can be submitted in the PSAR with the more complete review and approval based on construction dewatering requiring review and approval prior to actual construction. Review and approval of unique designs as post-CP matters is based upon 10 CFR Part 50, Subsections 35(b) and 55(e)(1)(iii). To prevent extending the review schedule, the first procedure would be the most desirable, but the staff recognizes that the detail required may not always be available at the time the PSAR is submitted. IV. Proposed Staff Position We have reviewed and approved the design of a limited number of permanent dewatering systems. However, because of the importance of these systems to plant safety, we have always required that they be designed and used in a con- servative manner. The following is a list of required design provisions which are consistent with requirements in recent