ML12206A055

Second Interim Report Pursuant to 10 CFR 21 - Unexpected Degradation of Vital Batteries III and IV

ML12206A055
Person / Time
Site:	Watts Bar
Issue date:	07/24/2012
From:	Grissette D Tennessee Valley Authority
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML12206A055 (4)

Text

Tennessee Valley Authority, Post Office Box 2000, Spring City, Tennessee 37381-2000 July 24,2012 10 cFR 21 .21(a)(2)

ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Watts Bar Nuclear Plant, Unit 1 Facility Operating License No. NPF-90 NRC Docket No. 50-390

Subject:

Second lnterim Report Pursuant to 10 CFR 21 - Unexpected Degradation of Vital Batteries lll and lV

References:

1. Letter from TVA to NRC, Licensee Event Report 39012012-001, "Failure to Meet Technical Specifications due to lssues Associated with Vital Battery Surveillance Program," dated March 16,2012 (ADAMS Accession No. ML12076A180)

2. Letter from TVA to NRC, "10 CFR 21 Interim Report - Unexpected Degradation of Vital Batteries lll and lV," dated May 25,2012 (M112145A670)

On March 16,2012, the Tennessee Valley Authority (TVA) submitted Licensee Event Report (LER) 39012012-001, "Failure to Meet Technical Specifications due to lssues Associated with Vital Battery Surveillance Program." The LER described an incident where the acceptance criterion of Technical Specification Surveillance Requirement 3.8.4.14 was not met due to unexpected degradation of Vital Batteries lll and lV.

Preliminarily, TVA determined that a manufacturing deficiency was the direct cause of the unexpected degradation, and on March 26,2012, it was determined that a possible reportable condition could exist pursuant to 10 CFR 21, "Reporting of Defects and Noncompliance."

On May 25,2012, TVA submitted an Interim Report pursuant to the reporting requirements of 10 CFR 21.21(aX2). TVA continues to investigate this matter; however, the investigation will not be completed within 60 days from the May 25,2O12 letter.

U.S. Nuclear Regulatory Commission Page 2 July 24,2012 Therefore, pursuant to the reporting requirements of 10 CFR 21.21(a)(2), this Interim Report is being submitted. The enclosure to this letter provides information required by 10 CFR 21.21(aX2) for the Interim Report of this condition.

There are no new regulatory commitments contained in this letter. Should you have any questions concerning this submittal, please contact D. K. Guinn, WBN Site Licensing Manager, at (423) 365-1 589.

Respectfully, D. E. Grissette Site Vice President Watts Bar Nuclear Plant

Enclosure:

Second Interim Report Pursuant to 10 CFR 21 - Unexpected Degradation of Vital Batteries lll and lV cc (Enclosure):

NRC Regional Administrator - Region ll NRC Senior Resident Inspector - Watts Bar Nuclear Plant

ENCLOSURE Second Interim Report Pursuant to 10 CFR 21 - Unexpected Degradation of Vital Batteries lll and lV Name and Address of the Individual Makins the Interim Report Mr. D. E. Grissette Site Vice President Watts Bar Nuclear Plant Tennessee Valley Authority 1270 Highway 68 Spring City, TN 37381 Description of the Deviation or Failure to Complv that is beinq Evaluated On March 16,2012, the Tennessee Valley Authority (TVA) submitted Licensee Event Report (LER) 39012012-001, "Failure to Meet Technical Specifications due to lssues Associated with Vital Battery Surveillance Program." The LER described an incident where the acceptance criterion of Technical Specification Surveillance Requirement (SR) 3.8.4.14 was not met due to unexpected degradation of Vital Batteries lll and lV.

Vital Battery lll failed to meet the acceptance criterion of the battery capacity test in accordance with Technical Specification SR 3.8.4.14 on November 21, 2011. During the performance of the root cause analysis for the unexpected degradation of Vital Battery lll, an independent engineering analysis of the completed capacity test surveillance package for Vital Battery lV determined that the recorded results of the Vital Battery lV battery capacity test performed on February 10,2011 were incorrect, and that the battery capacity test for Vital Battery lV did not meet the acceptance criterion of Technical Specification SR 3.8.4.14. Therefore, both Vital Batteries lll and lV failed to meet the Technical Specification SR 3.8.4.14 acceptance criterion for the referenced capacity tests. Vital Batteries lll and lV have been replaced and returned to service. .

Vital Batteries lll and lV were approximately 16 years old when they failed their capacity tests, and had a vendor qualified service life of 20 years. Both batteries were maintained and operated in a manner that is consistent with vendor requirements and the recommendations of the Institute of Electrical and Electronics Engineers (IEEE) standards IEEE 450-1980 and IEEE 450-1995. Therefore, there were no known conditions to promote premature aging or damage of Vital Batteries lll and lV. The Tennessee Valley Authority (TVA) preliminarily determined that a manufacturing deficiency associated with the forming of the Vital Batteries lll and lV cells' positive plates was the direct cause of the unexpected degradation of Vital Batteries lll and lV.

This determination was based on the initial results of the vendor's destructive failure analysis. The final results of the vendor's analysis have not yet been provided to TVA.

ENCLOSURE Second Interim Report Pursuant to 10 CFR 21 - Unexpected Degradation of Vital Batteries llland lV Evaluation Status The vendor is analyzing cells from Vital Batteries lll and lV to determine the cause of the unexpected degradation. Upon receipt of the vendor's final report, TVA will evaluate the vendor's results and determine if this condition is reportable pursuant to 10 cFR 21.

Date on which Evaluation will be Completed The evaluation will be completed by September 22,2012 or a follow-up Interim Report will be submitted pursuant to 10 CFR 21.21(a)(2).