The following information was obtained from the licensee via facsimile:
On February 9, 2005, at 1222 hours0.0141 days <br />0.339 hours <br />0.00202 weeks <br />4.64971e-4 months <br /> [CST], South Texas Project Unit 2 commenced a reactor shutdown required by Technical Specification (TS) 3.4.6.2, 'Reactor Coolant System - Operational Leakage.'
Following investigation into an increasing containment atmosphere particulate radiation monitor trend, primary leakage (steam plume) was discovered coming from a 3/4 inch vent line off of the 'A' Cold Leg Safety Injection line. The leak is located in an area between the Safety Injection line and the first vent line isolation valve, and is therefore considered an unisolable pressure boundary leak. TS 3.4.6.2 requires that with any Pressure Boundary Leakage, the Unit must be in at least Hot Standby within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in Cold Shutdown within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />. At the time of discovery, the total unidentified reactor coolant system leak rate was determined to be 0.13 gpm.
The vent line pipe and weld material is stainless steel.
This notification is being made in accordance with 10 CFR 50.72 (b)(2)(i) for commencement of a TS required shutdown, and 10 CFR 50.72 (b)(3)(ii)(A) for the condition of the nuclear power plant, including its principal safety barriers, being seriously degraded.
There is no impact on South
Texas Project Unit 1. The licensee has notified the NRC Resident Inspector.
