Document: NUREG-0800
Document ID: 00049a4f-6345-4415-8ec0-0e63d8d04990
Document Type: srp
Title: NUREG-0800
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070482.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6
CFR Part: 
CFR Title: 

Content:
MD code utilizes an ice condenser heat transfer 50 DRAFT Rev. 3 - April 1996 6.2.1.1.B-10 coefficient obtained from the 1974 full-scale section tests of the ice condenser. The TMD code also utilizes a compressibility factor "Y" to account for compressible flow effects. As stated in the D. C. Cook Safety Evaluation Report, the SCSB has reviewed 51 the assumptions and equations used in the TMD-code and with the exception of the critical flow model used to predict subcompartment vent mass flow rates, has concluded that the TMD code conservatively calculates transient pressure response. The TMD code calculates the critical flow of a two-component, two-phase fluid (air, steam, and water) assuming a thermal equilibrium condition. However, a correction factor is then applied to the calculated critical flow. The SCSB has not accepted the use 52 of this corrected critical flow, referred to as "augmented flow," and has required that the short-term transient responses of subcompartments be determined using the TMD code without applying a correction factor to the critical flow; i.e., without the "augmented flow" correlation. Before accepting the containment transient responses calculated by the TMD code, the SCSB reviews the modeling of the containment subcompartments, the size and area of 53 assumed vents between nodes, volumes of nodes, the flow loss coefficients for each vent modeled, and the heat transfer coefficients within the ice condenser. The SCSB will determine from the safety analysis report that the TMD code, without the "augmented flow" correlation, has been utilized to determine the transient pressure response in each subcompartment that contains a high energy line, and in adjoining subcompartments. The SCSB reviews the maximum calculated differential pressures and pressure profiles for each subcompartment. For plants at the construction permit stage of review, the SCSB will ascertain that it is the applicant's intent to design all internal structures with a