Document: NUREG-0800
Document ID: 9e785a38-4746-4e32-949d-a145ddb95511
Document Type: srp
Title: MASS AND ENERGY RELEASE ANALYSIS FOR POSTULATED
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070491.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6.2.1.4
CFR Part: 
CFR Title: 

Content:
ater line isolation provisions or feedwater pumps, such that the containment peak pressure and temperature are maximized, should be assumed to occur in steam and feedwater line break analyses. For the assumed failure of a safety grade steam or feedwater line isolation valve, operation of nonsafety grade equipment may be relied upon as a backup to the safety grade equipment. In this event, the SCSB reviewer will confer with the ASB SPLB and EMEB reviewers to ensure a 12 13 14 consistent staff position regarding the acceptability of the design criteria for the nonsafety grade equipment. Feedwater flow to the affected steam generator should be calculated considering the diversion of flow from the other steam generators, feedwater flashing and increased feedwater pump flow caused by the reduction in steam generator pressure. An acceptable method for computing feedwater flow is to assume all feedwater travels to the affected steam generator at the pump runout rate before isolation. After isolation, the unisolated feedwater mass should be added to the affected steam generator. The RELAP4 code (Reference 3) may also be used to compute feedwater flow. 15 DRAFT Rev. 2 - April 1996 6.2.1.4-4 Operator action to terminate auxiliary feedwater flow will be reviewed by ASBSPLB as part of its review responsibility under. (See SRP Section 10.4.9.) 16 Acceptable computer codes for calculating mass and energy releases for steam line breaks are SGN-III (Reference. 1619) and TRAP-2 (Reference. 1531). Other methods 17 18 will be acceptable if they are found by SCSB to be conservative for these calculations. 19 Technical Rationale20 The technical rationale for application of the above acceptance criteria to the mass and energy release analysis for postulated loss-of-coolant accidents is discussed in the following paragraph. GDC 50 requires the containment structure and associated heat removal system to be designed with margin to accommodate any loss-of-coolant accident such that the