Document: NUREG-0800
Document ID: 7b7303eb-a3a7-433b-8301-fcaba03194ea
Document Type: srp
Title: - 15.1.4
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070676.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.1.1
CFR Part: 
CFR Title: 

Content:
core and recirculation loop coolant flow rates (BWR), coolant conditions (inlet temperature, core average temperature (PWR), core average steam volume fraction (BWR), average exit and hot channel exit temperatures, and steam fractions), steam line pressure, containment pressure, pressure relief valve flow rate, and flow rate from the reactor coolant system to the containment system (if applicable) are reviewed. Time-related variations of the following parameters are reviewed: 15.1.1-9 DRAFT Rev. 2 - April 1996 – reactor power; – heat fluxes (average and maximum); – reactor coolant system pressure; – minimum DNBR (PWR) or CPR (BWR); – core and recirculation loop coolant flow rates (BWR); – coolant conditions (inlet temperature, core average temperature (PWR), core average steam volume fraction (BWR), average exit and hot channel exit temperatures, and steam fractions); – steam line pressure; – containment pressure; – pressure relief valve flow rate; and – flow rate from the reactor coolant system to the containment system (if applicable).52 The values of the more important of these parameters, as listed in subsection I of this SRP section, are compared to with those predicted for other similar plants to see that they are within the range expected. The NRC has undertakencompleted a program to reduce the sensitivity of B&W plants to 53 feedwater transients, with emphasis on overcooling events that have occurred at B&W plants54 (Items II.E.5.1 and II.E.5.2, NUREG-0660 and 0718). When this program is complete, the RSB reviewer, with the aid of other branches as appropriate, should incorporate the program results into the review of this SRP section.This sensitivity is attributed to a number of design features including the small secondary water inventory in the once-through steam generators and a relatively small pressurizer. Concerns regarding steam generator overcooling are related to the potential for loss of natural circulation due to bubble