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:
uidance should be provided regarding the scope of ECCS preoperational tests identified in RG 1.79, “Preoperational Testing of Emergency Core Cooling Systems for Pressurized-Water Reactors,” issued September 1975 (Ref. 4), as a result of the NRC’s design certification of the AP1000 and the ongoing NRC review of the design certification applications for the U.S. Evolutionary Power Reactor (U.S. EPR) and the U.S. Advanced PWR (US-APWR). The NRC staff also concluded that this RG should include additional guidance for ECCS preoperational tests based on recent operating experience from PWRs. C. REGULATORY POSITION A comprehensive preoperational test program of the ECCS should ensure that it will accomplish its intended functions when required. The program should cover all test-related activities, including the following: 1. the development of test descriptions, test objectives, and specific acceptance criteria, 2. the preparation of test procedures, 3. the conduct of the tests and acquisition of system and component performance data, and 4. the resolution of deficiencies and deviations from expected performance. The test program should include prerequisites for completion of construction tests and preoperational tests in coordination with the startup test group approval of test procedures, test configuration and test initiation. As a prerequisite to ECCS tests, verify that noncondensable gases in the ECCS systems are kept to an acceptable level. This verification should be accomplished by either performing nondestructive examination techniques, opening vent valves to remove noncondensable gases or by methods justified through an engineering evaluation. The engineering evaluation should consider void volume, void DG-1253, Page 3 transport to pumps and pump void acceptance criteria and include performance of void transport analysis. The evaluation should document the rationale and determination that gas intrusion into the ECCS system would not adversely affect the