PNO-IV-89-013, on 890120,manual Turbine/Generator Trip Initiated When Hydrogen Fueled Fire Occurred in Main Generator.Testing Revealed That Wall Thickness of Bottom Mounted Instrumentation Thimble Tubes Below Requirement

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PNO-IV-89-013:on 890120,manual Turbine/Generator Trip Initiated When Hydrogen Fueled Fire Occurred in Main Generator.Testing Revealed That Wall Thickness of Bottom Mounted Instrumentation Thimble Tubes Below Requirement
ML20235T753
Person / Time
Site: South Texas STP Nuclear Operating Company icon.png
Issue date: 03/02/1989
From: Hunnicutt D
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
To:
References
PNO-IV-89-013, PNO-IV-89-13, NUDOCS 8903080460
Download: ML20235T753 (1)


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March 2, 1989 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE -- PNO-IV-89-13 This preliminary notification constitutes EARLY. notice of events of POSSIBLE safety or public interest significance. The information is as initially received without verification or evaluation, and .is basically all that is known by the Region IV staff on this date.

FACILITY: Houston Lighting & Power Company Licensee Emergency Classification:

South Texas Project, Unit 1 Notification of Unusual Event Docket: 50-498 Alert Site Area Emergency General Emergency X Not Applicable

SUBJECT:

RETURN TO OPERATING STATUS FOLLOWING EXTENDED SHUTDOWN South Texas Project, Unit 1, achieved criticality at 4:05 a.m. (CST) March 2, 1989. A manual turbine / generator trip was initiated January 20, 1989, when a hydrogen fueled fire occurred in the main generator. The main generator was disassembled and inspected, upgrading modifications were installed, and the generator was reassembled. No damage to the main generator occurred as a result-of the fire.

The wall thickness of the bottom mounted instrumentation (BMI) thimble tubes was measured by the eddy current method during this extended shutdown. The testing determined that the wall thickness of six thimble tubes was less than permitted. These six thimble tubes were capped and magnetic check valves were installed on each of the six thimble tubes. Isolation valves had previously been installed on the thimble tubes.

Unit I was at 1 percent thermal power at 8 a.m., (CST) March 2,1989.

Neither the licensee nor the NRC plans to issue a press release.

The state of Texas has been informed.

Region IV received notification of this occurrence by telephone from SRI at 8 a.m., March 2, 1989. Region IV has informed EDO, NRR, and PA.

This information has been confirmed with a licensee representative.

CONTACT: D. M. Hunnicutt, FTS 728-8137 DISTRIBUTION:

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