B--W operating experience of reactor internals vent valves

The purpose of this report is to provide evidence accumulated on B and W plants in commercial operation demonstrating that the vent valves remain closed during all reactor coolant system operations. The operating information presented consists of the following: (1) Oconee inspection results obtained during hot functional testing and during the recent refueling outage demonstrating continued freedom of valve operation. (2) Internals vent valve thermocouple data from Rancho Seco indicating that vent valve leakage was not a problem and that the valves remained closed over a range of power levels. (3) Loose parts monitoring (noise and vibration analysis) system results, also from Rancho Seco, indicating that no noises which are detected could be attributed to vent valve vibration or impacts on either the vent valve seats or the reactor vessel shell. A brief description of the sensitivity of this system is provided to demonstrate that had valve activity been present, it would have been detected. (auth)