Document: NUREG-0800
Document ID: 919b8fa0-8b11-41bd-9694-2c62120b843b
Document Type: srp
Title: Revision 7 - March 2007
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0636/ML063600403.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6
CFR Part: 
CFR Title: 

Content:
mately the peak drywell to wetwell differential pressure following the high-pressure structural test of the diaphragm. b. Low-Pressure Leak Tests A post-operational low pressure leakage test should be performed on each Mark I, II, and III unit to detect leakage in the drywell to suppression chamber vent piping, penetration downcomers, vacuum breakers, floor seals, vent seals, and the diaphragm. This test should be performed at each refueling outage at a differential pressure corresponding to approximately the submergence of the vents. c. Acceptance Criteria for Leakage Tests The Mark II and Mark III acceptance criteria for both the high and low pressure leakage tests shall be a measured bypass leakage which is less than 10% of the capability of the containment as defined in Position B.1 above. For Mark I containment the acceptance criterion is that the measured leakage is not greater than the leakage that could result from a 2.54 cm (one inch) diameter opening. d. Surveillance Requirements A visual inspection should be conducted to detect possible leak paths at each refueling outage. Each vacuum relief valve and associated piping should be checked at this time to determine that it is clear of foreign matter. 6.2.1.1.C-16 Revision 7 - March 2007 3. Vacuum Relief Valve Requirements a. Position Indicators and Alarms Redundant position indicators should be placed on all vacuum breakers with redundant indication and an alarm in the control room. The vacuum breaker position indicator system should be designed to provide the plant operators with continuous surveillance of the vacuum breaker position. The indicators should have adequate sensitivity to detect a total valve opening, for all valves, that is less than the bypass capability for a small break (Note for Mark I: this corresponds to the acceptance criteria described in 2.c above). The detectable valve opening should be based on the assumption that the valve opening is evenly divided among all the vacuum breakers. b.