Document: NUREG-0800
Document ID: b8d2b8f5-432a-4c0a-81ab-20231f7d0f28
Document Type: srp
Title: PROBABILISTIC RISK ASSESSMENT AND SEVERE ACCIDENT EVALUATION FOR
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1508/ML15089A068.pdf
Revision Date: 2023-06
Chapter: 19
Section ID: 19.0
CFR Part: 
CFR Title: 

Content:
vessel following loss of the decay heat removal function can be very short during PWR midloop operation (e.g., 12 minutes). Steaming into the containment will lead to intolerable conditions that could seriously affect the ability of personnel to close the containment. C. During reduced inventory operation in a PWR a large vent for the reactor coolant system (RCS), such as a hot leg SG plenum man way, is necessary before opening a cold leg penetration to prevent expelling water from the core following a loss of residual heat removal. RCS piping penetrations may exist below the active fuel and pathways may exist via connected systems that could lead to draining the reactor vessel. In these cases reviewers should identify the isolation functions available and operable and assure that they are treated accurately in the PRA model. Design-Specific PRA (PRA-Based SMA) 1. Staff responsible for the review of the description and results of the applicant’s PRA review the design-specific plant system and accident sequence analysis in accordance with the acceptance criteria given in Section II of this SRP. 2. Staff responsible for the review of the seismic and structural design of the facility review (1) the applicant’s evaluation of seismic fragilities, and (2) the applicant’s determination of plant-level HCLPF in accordance with the acceptance criteria given in Section II of this SRP. The staff reviewing the plant system and accident sequence analysis verifies that the applicant has considered random equipment failures, seismic interactions, as well as operator actions in the plant system and accident sequence analysis as applicable. It is important that the plant systems analysis focus on those sequences leading to core damage or containment failures, 19.0-25 Revision 3 – December 2015 including applicable sequences leading to the following containment failures: (1) loss of containment integrity, (2) loss of containment isolation, and (3) loss of function for