Document: NRC Regulatory Guide
Document ID: c256f223-ee35-43e0-82e7-aa7b14469259
Document Type: regulatory_guide
Title: Preoperational Testing of Emergency Core Cooling Systems for Pressurized Water Reactors + HISTORY - HISTORY DG-1253 , Proposed Revision 2 (Rev. 2)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1101/ML110110480.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.79
CFR Part: 
CFR Title: 

Content:
nent such as a containment emergency sump. This test should also demonstrate the capability to realign the valves for recirculation mode. (a) Testing should verify proper vortex control in the suction lines from the sump and acceptable pressure drops in filtering mechanism, suction lines, and valves. Water level should be at a minimum level that may exist when recirculation flow from a containment emergency sump is initiated under actual accident conditions when assessing vortex behavior. To avoid RCS contamination, the sump water may be discharged to external drains or other systems. DG-1253, Page 5 (b) Testing should verify that the available net positive suction head (NPSH) is greater than that required for the pumps to achieve their design function. Containment pressure and pump fluid temperature do not have to be controlled, but the NPSH available should be adjusted to the maximum design pumped fluid temperature and the minimum design containment pressure before the postulated LOCA. The postulated effect of debris should be considered when evaluating test results since test conditions and actual accident conditions may differ. (See Regulatory Position C.2.c(2) below). (c) Testing should demonstrate proper operation of the containment sump instrumentation by simulating the containment flood-up water levels. d. Core Flooding (Current Fleet of PWRs, US-APWR, U.S. EPR) (For AP1000 design, see Regulatory Position C.1.f below.) (1) Flow Test—Cold Conditions. This test should demonstrate proper system actuation and flow rates. For this test, the accumulators should be discharged one at a time into the reactor vessel after being filled to their normal level and pressurized with gas. Accumulator pressure and temperature are not critical, and the test may be conducted at any pressure up to normal precharge pressure. Test results for flow rates should be adjusted for the actual test pressure and temperature versus the design temperature and pressure. These tests apply