During performance of a plant shut down personnel entered the Drywell to investigate a steam leak. At
0635 hours0.00735 days <br />0.176 hours <br />0.00105 weeks <br />2.416175e-4 months <br />, personnel identified steam leaking from a flexible hose instrument line (approximately 1" diameter) that is welded to an elbow tap on the C
Main Steam line and concluded that the leak constitutes
pressure boundary leakage. This required entry into
TS 3.4.5, Condition C. This requires that the unit be in Mode 3 in
12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and Mode 4 in
36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />, which is a TS required shutdown.
The station has determined that this event is reportable under the provisions of: 10 CFR 50.72 (b)(2)(i) for the plant shutdown required by Technical Specifications, as a 4-hour notification; 10 CFR 50.72 (b)(3)(ii)(A) as an event or condition that resulted in the condition of the nuclear power plant, including its principal safety barriers being seriously degraded, as an 8-hour notification.
The NRC resident inspector has been notified.
The leaking line goes to a steam line flow instrument. The leak indication was first noticed yesterday and the licensee decided to shutdown to investigate before the leak was verified by the drywell entry.
