Document: NUREG-0800
Document ID: 2cd63ebf-9196-42c0-880d-a80500b202a4
Document Type: srp
Title: - 15.1.4
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0705/ML070550005.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.1.1
CFR Part: 
CFR Title: 

Content:
ted. The NRC has completed a program to reduce the sensitivity of B&W plants to feedwater transients, with emphasis on overcooling events that have occurred at B&W plants (Items II.E.5.1 and II.E.5.2, NUREG-0737). This sensitivity is attributed to a number of design features including the small secondary water inventory in the once-through steam generators and a relatively small pressurizer. Concerns regarding steam generator overcooling are related to the potential for loss of natural circulation due to bubble formation and the high frequency of high-pressure safety injection actuation during the transients. These transients may produce undesirable pressure/temperature conditions (pressurized thermal shock) that may cause excessive cycles of safety-related equipment, such as thermal cycling of safety injection nozzles and operation of primary system safety relief valves. A related concern is the possible overfilling of the steam generators by which water may be introduced in the steam lines, producing loads beyond the design basis. The resolution of these concerns consists of design modifications that provide for automatic auxiliary feedwater flow and steam generator level control, and main feedwater overfill protection. The resolution of Items II.E.5.1 and II.E.5.2 is contained in References 13 and 14. 7. For review of a DC application, the reviewer should follow the above procedures to verify that the design, including requirements and restrictions (e.g., interface requirements and site parameters), set forth in the final safety analysis report (FSAR) meets the acceptance criteria. DCs have referred to the FSAR as the design control document (DCD). The reviewer should also consider the appropriateness of identified COL action items. The reviewer may identify additional COL action items; however, to ensure these COL action items are addressed during a COL application, they should be added to the DC FSAR. For review of a COL application, the scope of the review is