Document: NUREG-0800
Document ID: b694ca5b-4dcc-4098-be04-431e0137a936
Document Type: srp
Title: - 15.5.2
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0708/ML070820081.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.5.1
CFR Part: 
CFR Title: 

Content:
or coolant inventory include feedwater system malfunctions (increasing flow), steam pressure regulator malfunctions (decreasing flow), loss of electrical load, turbine trip, main steam isolation valve (MSIV) closure, and loss of condenser vacuum. Although these transients are the subject of other SRP sections that consider their effects on system parameters other than coolant inventory, the potential impact of these transients on RCS inventory is considered herein. 2. Pressurized Water Reactors (PWRs) — Inadvertent operation of ECCS, or a malfunction of the chemical and volume control system (CVCS). It is important to consider the inadvertent operation of ECCS in PWRs in which the charging pumps are started and aligned to the ECCS upon receipt of a safety injection (SI) signal. High pressure safety injection pumps are not normally capable of delivering flow to the RCS when the RCS is at nominal pressure. The review of events leading to an increase in reactor coolant inventory considers the sequence of events, the analytical model, the values of parameters used in the analytical model, and the predicted consequences of the transient. The reviewer concentrates on the need for the reactor protection system, the engineered safety systems, and especially operator action to secure and maintain the reactor in a safe condition. The analytical methods are reviewed to ascertain whether the mathematical modeling and computer codes have been previously reviewed and accepted by the staff, and have been applied in accordance with any limitations that may have been specified in the staff’s acceptance. If a referenced analytical method has not been previously reviewed, the reviewer initiates a generic evaluation of the new analytical model. In addition, the values of all the parameters used in the new analytical model, including the initial conditions of the core and system, are reviewed. The predicted results of those transients analyzed are reviewed to ensure that the