This report describes an invalid actuation of the Unit 1 Turbine Driven
Auxiliary Feedwater (
TDAFW) pump that occurred on June 28, 2008. This report is being made in accordance with
10CFR50.73(a)(1), which states, in part, 'In the case of an invalid actuation reported under
10CFR50.73(a)(2)(iv), other than actuation of the
Reactor Protection System (
RPS) when the reactor is critical, the licensee may, at its option, provide a telephone notification to the NRC Operations Center within 60 days after discovery of the event instead of submitting a written LER.'
On June 28, 2008, Comanche Peak Nuclear Power Plant Unit 1 was in Mode 1 operating at 100% power. At 1904 CDT, the steam supply valve from Main Steam Line 1-04 to the TDAFW pump opened due to a failed diaphragm. Turbine load was subsequently reduced from 1207MWe to 1150MWe per Operations procedures. The upstream isolation valve for the steam supply to the TDAFW pump was closed and the TDAFW pump was stopped. Unit 1 was returned to full power at 2120 CDT and the failed diaphragm was subsequently replaced.
The specific train and system that actuated was the third AFW train on Unit 1. The train actuation was complete and during the TDAFW start the system started and functioned correctly.
The licensee has notified the NRC Resident Inspector.
