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:
the four test holes will be cased and maintained for observation and testing throughout the life of the plant. We conclude that the criteria for the design of retaining wall and placement of the grout curtain meet the requirements of General Design Criterion 4 and are acceptable and should result in an acceptable means of preventing leakage from the turbine building to the permanent dewatering system. In the event of a circulating water system pipe rupture outside of the turbine building, the applicant has stated that the results of an analysis.predict that any additional water which will enter the dewatering system will be minimal, and normal groundwater levels will not be affected. The applicant initially proposed as a design basis for subsurface hydrostatic loads, groundwater levels at the elevation of the under- drain system. During our review the applicant investigated the con- sequences of failures of some of the fluid-containing tanks and piping within the radius of influence of the permanent dewatering system. Consequences of some of those failures which could release fluids directly into or near the permanent dewatering system were analyzed by the applicant. The nuclear service water pipes will pass through the wall drain adjacent to the shield building. As described in Section 9.5.8 of this report, a moderate energy pipe crack within the wall drain would cause overflow of the sump and flooding of the auxiliary building floor, and in addition would cause a localized elevation of water in the wall drain by about 2.5 feet. The applicant in Section 2.4.12 of the PSAR has described the consequences of other accidents and additional design changes that were made to mitigate the consequences of the accidents. Although the accidents do not include all conceiv- able events that could result in excess flow into the sump, the appli- cant proposes to use the break of the nuclear service water pipe as the design basis event for evaluating sump overflow. It would appear