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:
of postulated single 22 failures of active components in the secondary systems, such as steam and feedwater line isolation valves and feedwater pumps, to determine whether the single failure has been selected which maximizes containment pressure and temperature. The SCSB will request EMEB to review the acceptability of nonsafety valves in limiting the 23 mass and energy releases from the steam and feedwater systems. The SCSB will request the ASBSPLB to review the rationale for determining the time at which operator action can be 24 relied upon to terminate auxiliary feedwater flow to the affected steam generator. The SCSB25 6.2.1.4-5 DRAFT Rev. 2 - April 1996 will review the applicant's calculations for main feedwater flow into the affected steam generator to determine that the flow rate is conservatively maximized. If liquid entrainment is calculated in the applicant's steam line break model, the SCSB will determine the validity of the experimental data provided to support the entrainment calculation. The SCSB will also ascertain that the effect of steam separators located upstream from the postulated steam line break have been taken into account in the analysis. The SCSB reviews 26 comparisons to experimental data made by the applicant and makes comparisons to other available experimental data to determine the amount of conservatism in the mass and energy release models. The SCSB reviews the results of a spectrum of steam line breaks, beginning with the 27 double-ended break and decreasing in area until no entrainment occurs, to be sure that the steam line break size producing the highest containment temperature and pressure has been identified. The SCSB performs confirmatory analyses of the containment pressure and temperature 28 response to steam and feedwater line breaks inside the containment using the CONTEMPT-LT computer code (References 20 and 21) . 29 For standard design certification reviews under 10 CFR Part 52, the procedures above should be followed,