CPSES-200502282, Technical Specification Reports for Steam Generator Meeting C-3 Category and 15-day Tube Plugging and Repair

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Technical Specification Reports for Steam Generator Meeting C-3 Category and 15-day Tube Plugging and Repair
ML053200044
Person / Time
Site: Comanche Peak Luminant icon.png
Issue date: 11/07/2005
From: Madden F
TXU Power
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
CPSES-200502282, TXX-05192
Download: ML053200044 (5)
v • d • e


Text

A'A PTXU t9Power TXU Power Mike Blevins Comanche Peak Steam Senior Vice President &

Electric Station Chief Nuclear Officer P. O. Box 1002 (E01)

Glen Rose, TX 76043 Ref: Technical Specification 5.6.10 Tel: 254 897 5209 Fax: 254 897 6652 mike.blevins~txu.com CPSES-200502282 Log #-TXX-05192 November 7, 2005 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555

SUBJECT:

COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)

UNIT 1, DOCKET NO. 50-445 TECHNICAL SPECIFICATION REPORTS FOR STEAM GENERATOR MEETING C-3 CATEGORY AND 15-DAY TUBE PLUGGING AND REPAIR Gentlemen:

As Attachment 1 to this letter, TXU Generation Company LP (TXU Power) hereby submits a report pursuant to CPSES Technical Specification 5.6.10.c for Steam Generators (SGs) meeting C-3 conditions during the current refueling outage.

Attachment 2 of this letter submits the 15-day report of tubes plugged, repaired, or designated as an F* tube pursuant to CPSES Technical Specification 5.6.10.a.

Should you require any other additional information please contact Mr. Bob Kidwell at (254) 897-5310.

This communication contains no new licensing basis commitments regarding CPSES Unit 1.

A0oD A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway

  • Comanche Peak
  • Diablo Canyon
  • Palo Verde
  • Wolf Creek

TXX-05 192 Page 2 of 2 Sincerely, TXU Generation Company LP By: TXU Generation Management Company LLC Its General Partner Mike Blevins By: v )

Fred W. Madden Director, Regulatory Affairs RJK - Report of Steam Generators in Category C3 condition. - Report of Steam Generator Tubes Plugged or Repaired c - B. S. Mallett, Region IV M. C. Thadani, NRR Resident Inspectors, CPSES to TXX-05 192 Page 1 of 2 TXU GENERATION COMPANY LP COMANCHE PEAK STEAM ELECTRIC STATION UNIT 1 REPORT OF STEAM GENERATOR IN C-3 CATEGORY The following information meets the reporting requirements of CPSES Technical Specification 5.6.10.c., which states:

"Results of steam generator tube inspections which fall into Category C-3 shall be reported to the Commission in a report within 30 days and prior to resumption of plant operation. This report shall provide a description of investigations conducted to determine cause of the tube degradation and corrective measures taken to prevent recurrence."

Comanche Peak Steam Electric Station (CPSES) Unit 1 was taken off line on October 8, 2005 for the eleventh refueling outage (lRF1 1). As part of the scheduled surveillance requirements of CPSES Technical Specification (TS) 5.5.9, analysis of eddy current testing data on the Steam Generators (SGs) indicated that greater than 1 percent of the total tubes inspected in the #4 SG were defective and the #4 SG fell into Category C-3 of the Technical Specifications.

The majority of the tube defects across all SGs are attributed to circumferential outside diameter stress corrosion cracking (ODSCC) at the hot leg top of tubesheet (TTS) transition.

All defective tubes did meet the criteria of NUREG 1022, Revision 2, for structural integrity.

The extent of the tube degradation found during 1RF 1 was less than predicted by the tube degradation models, largely due to the reduced amount of degradation at the TTS transition in #1, #2 and #3 SGs. Past inspection results and tube degradation prediction models indicated that the degradation of the tubing in the Unit 1 SGs would accelerate as the plant ages. This has generally been true of other plants with original Westinghouse SGs fabricated with Alloy 600 tubing. However, the reduced number of defective tubes found at the TTS transition in the above SGs supports a proposition that the larger populations found in previous outages may have manifested from SCC initiates which originated prior to chemical cleaning. With many of these defects by now having been identified and removed from service, and the potential crevice conditions supporting the development of new initiates mitigated, the number of degraded tube indications at the TTS transition due to ODSCC is displaying a decreasing trend.

to TXX-05 192 Page 2 of 2 TXU GENERATION COMPANY LP COMANCHE PEAK STEAM ELECTRIC STATION UNIT 1 REPORT OF STEAM GENERATOR IN C-3 CATEGORY To prevent further degradation of the tubes displaying these defects, TXU Power has plugged all defective tubes identified during the current refueling outage. In addition, TXU Power will continue to follow the requirements of NEI 97-06 and the EPRI guidelines for future cycles of operation. These guidelines include maintaining primary and secondary water chemistry below recommended levels, primary to secondary leakage monitoring, inspection scope and frequency, pressure testing degraded tubes, and performing integrity assessments to ensure tube structural and leakage integrity. The Condition Monitoring and Preliminary Operational Assessment, performed in accordance with the EPRI Integrity Assessment Guidelines during 1RF 11, addresses the as-found condition of the steam generator tubing and justifies operation for the next operating cycle. The assessment is based on degradation identified and conservative analysis to assure tube structural and leakage integrity for the entire cycle length.

to TXX-05 192 Page 1 of 1 TXU GENERATION COMPANY LP COMANCHE PEAK STEAM ELECTRIC STATION UNIT 1 REPORT OF STEAM GENERATOR TUBES PLUGGED OR REPAIRED The following information meets the reporting requirements of CPSES Technical Specification 5.6.1 O.a., which states:

"Within 15 days following the completion of each inservice inspection of steam generator tubes, the number of tubes plugged, repaired or designated as an F* tube in each steam generator shall be reported to the Commission;"

CPSES Unit I Steam Generator 1

  • 1 tube was designated as an F* tube (as defined in CPSES TS)

CPSES Unit 1 Steam Generator 2

  • 2 tubes were designated as an F* tube (as defined in CPSES TS)

CPSES Unit 1 Steam Generator 4

  • 1 tube was designated as an F* tube (as defined in CPSES TS)

No tubes were repaired by sleeving in this outage.

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