Document: NUREG-0800
Document ID: 7ed8e5d3-fcfd-49cc-84ad-3b25caba06af
Document Type: srp
Title: STEAM SYSTEM PIPING FAILURES INSIDE AND OUTSIDE OF CONTAINMENT
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0705/ML070550006.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.1.5
CFR Part: 
CFR Title: 

Content:
r simultaneously with the pipe break or during the accident, or offsite power may not be lost. Analyses should be made to determine the most conservative assumption appropriate to the particular plant design. The reviewer should note that the assumption that offsite power is not lost may maximize heat removal from the core and reactor 15.1.5-6 Revision 3 - March 2007 system and thereby maximize containment pressure and reactivity feedback within the core. The analyses should take account of the effect that loss of offsite power has on reactor coolant pump and main feedwater pump trips and on the initiation of auxiliary feedwater flow, and the effects on the sequence of events for these accidents. For new applications, loss of offsite power should be considered in addition to any limiting single active failure. (This position is based upon interpretation of GDC 17, as documented in the Final Safety Analysis Report for the ABB-CE System 80+ design certification.) 3. The effects (pipe whip, jet impingement, reaction forces, temperature, humidity, etc.) of postulated steam line breaks on other systems should be considered in a manner consistent with the intent of Branch Technical Position (BTP) 3-3 and BTP 3-4. 4. The worst single active component failure should be assumed to occur. For new applications, loss of offsite power should not be considered as a single failure, (see assumption b above). The assumed single failure may cause more than one steam generator to blow down, failure of main feedwater to isolate, or may be in any of the systems required to control the transient. 5. The maximum-worth rod should be assumed to be held in the fully withdrawn position. An appropriate rod reactivity worth versus rod position curve should be used. Local power peaking at the location of the stuck out control rod should be considered. Local power peaking will affect the DNBR analysis in the initial period as the safety rods are entering the core and during any subsequent return