Document: NUREG-0800
Document ID: f90f6920-8ff7-4a39-b6a6-85bf7887d69f
Document Type: srp
Title: CONTAINMENT HEAT REMOVAL SYSTEMS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340671.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6.2.2
CFR Part: 
CFR Title: 

Content:
dic inservice inspection and operability testing to ensure that the system and components are accessible for inspection and all active components can be tested; and reviewing the capability to monitor system performance and control active components from the control room so that the operator can exercise control over system functions or isolate a malfunctioning system component. CSB reviews analyses of the net positive suction head available to the spray system pumps. CSB assures that the analyses for the recirculation phase are done in accordance with the guidelines of Regulatory Guide 1.1, i.e., are based 6.2.2-5 Rev. 4 - October 1985 on maximum expected temperature of the pumped fluid and with atmospheric pressure in the containment. For clarification, the analyses should be based on the assumption that the containment pressure equals the vapor pressure of the sump water. This ensures that credit is not taken for containment pressurization during the transient. CSB assures that calculations of the available NPSH are based on transient values of the suction head and the friction head. The CSB reviews information provided by the applicant to identify and justify the conservatisms applied in determining the water level in the containment and the friction losses in the recirculation system suction piping. *For example, the uncertainty in determining the free volume in the lower part of the containment that may be occupied by water, and the quantity of water that may be trapped by the reactor cavity and the refueling canal, should be factored into the calculation of the suction head. The CSB reviews analyses of the available NPSH for subatmospheric containments for the period prior to termination of the injection phase of containment spray to determine that containment pressure and sump water temperature transients have been conservatively used in the NPSH calculations. The CSB reviews information provided by the applicant to identify and justify the conservatisms in