Document: NUREG-0800
Document ID: d53aca30-dbc8-4ddf-8aa5-2b1d5f31d140
Document Type: srp
Title: Revision 3 - March 2007
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0708/ML070850008.pdf
Revision Date: 2023-06
Chapter: 5
Section ID: 5
CFR Part: 
CFR Title: 

Content:
fication pressure-temperature limits are provided for operating the plant. The primary concern of this position is that, during startup and BTP 5-2-2 Revision 3 - March 2007 shutdown conditions at low temperature, especially in a water-solid condition, the RCS pressure might exceed the reactor vessel pressure-temperature limitations in the technical specifications established for protection against brittle fracture. Any one of a variety of malfunctions or operator errors could generate this inadvertent overpressurization. Many incidents have occurred in operating plants as described in NUREG-0138. NUREG-0138 includes additional discussion on the background of this position. B. BRANCH TECHNICAL POSITION 1. A system should be designed and installed that will prevent exceeding the applicable technical specifications and Appendix G limits for the RCS while operating at low temperatures. The system should be capable of relieving pressure during all anticipated overpressurization events at a rate sufficient to satisfy the technical specification limits, particularly while the RCS is in a water-solid condition. 2. The low-temperature overpressure protection system should be operable during startup and shutdown conditions below the enable temperature, defined as the water temperature corresponding to a metal temperature of at least RT(NDT) + 50EC (90EF) at the beltline location (1/4t or 3/4t) that is controlling in the Appendix G limit calculations. 3. The system should be able to perform its function assuming any single active component failure. Analyses using appropriate calculational techniques must demonstrate that the system will provide the required pressure relief capacity assuming the most limiting single active failure. The cause for initiation of the event (e.g., operator error, component malfunction) should not be considered as the single active failure. The analyses should assume the most limiting allowable operating conditions and systems configuration at the