ML092600269

Review of the 2008 Steam Generator Tube Inspections Performed During Refueling Outage 1RF13

ML092600269
Person / Time
Site:	Comanche Peak
Issue date:	09/25/2009
From:	Balwant Singal Plant Licensing Branch IV
To:	Flores R Luminant Generation Co
Singal, Balwant, 415-3016, NRR/DORL/LPL4
References
TAC ME0367
Download: ML092600269 (4)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 September 25, 2009 Mr. Rafael Flores Senior Vice President and Chief Nuclear Officer Attention: Regulatory Affairs Luminant Generation Company LLC P.O. Box 1002 Glen Rose, TX 76043 SUB~IECT: COMANCHE PEAK STEAM ELECTRIC STATION, UNIT 1 - REVIEW OF THE 2008 STEAM GENERATOR TUBE INSPECTIONS PERFORMED DURING REFUELING OUTAGE 1RF13 (TAC NO. ME0367)

Dear Mr. Flores:

By letter dated January 7, 2009 (Agencywide Documents Access and Management System (ADAMS) Accession No. IVIL090300118), as supplemented by letter dated April 21, 2009 (ADAMS Accession No. ML091180326), Luminant Generation Company LLC (the licensee),

submitted information summarizing the results of the 2008 steam generator tube inspections performed at the Comanche Peak Steam Electric Station (CPSES), Unit 1 during the thirteenth refueling outage (1 RF13).

The U.S. Nuclear Regulatory Commission (NRC) has completed its review of these reports and concludes that the licensee provided the information required by the CPSES, Unit 1, Technical Specifications and that no additional follow-up action is required at this time. The results of the NRC staff's review of the reports submitted by the licensee are summarized in the enclosure to this letter. If you have any questions, please contact me at 301-415-3016 or via e-mail at balwant.singal@nrc.gov.

Sincerely, b"", \W~~ t~~\1~~

Balwant K. Singal, Senior Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-445

Enclosure:

As stated cc w/encl: Distribution via Listserv

OFFICE OF NUCLEAR REACTOR REGULATION REVIEW OF INSPECTION REPORTS FOR 2008 STEAM GENERATOR TUBE INSPECTIONS PERFORMED DURING UNIT 1 REFUELING OUTAGE 1RF13 LUMINANT GENERATION COMPANY LLC COMANCHE PEAK STEAM ELECTRIC STATION, UNIT 1 DOCKET NO. 50-445 By letter dated January 7, 2009 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML090300118), as supplemented by letter dated April 21 ,2009 (ADAMS Accession No. ML091180326), Luminant Generation Company LLC (the licensee),

submitted information summarizing the results of the 2008 steam generator (SG) tube inspections performed at the Comanche Peak Steam Electric Station (CPSES), Unit 1 during refueling outage "RF13.

CPSES, Unit 1 has four Westinghouse Model Delta 76 SGs. Each SG contains 5,532 thermally treated Alloy 690 tubes. Each tube has a nominal outside diameter of % inch and a nominal wall thickness of 0.043 inch. The row 1 and 2 tubes have a nominal wall thickness of 0.044 inch. The tubes were hydraulically expanded at both ends for the full length of the tubesheet and are supported by four sets of type 405 stainless steel anti-vibration bars.

The licensee provided the scope, extent, methods, and results of their SG tube inspections in the documents referenced above. In addition, the licensee described corrective actions, such as tube plugging, taken in response to the inspection findings. The tubes in all four SGs were inspected during CPSES, Unit 1 thirteenth refueling outage (1 RF13).

The Nuclear Regulatory Commission (NRC) staff has reviewed the information provided by the licensee, and has the following comments and observations:

• The licensee replaced its SGs in 2007 during CPSES, Unit 1 refueling outage 12 (1 RF12). The 2008 inspections were the first inservice inspections of the SGs since the replacement.

• During the pre-service inspection, a condition was identified that suggested reduced tube-to-tube clearance in the U-bend region in the eddy current data in 28 tubes. These indications are classified as trackable anomalies and there was no tube wear associated with this condition. The licensee reported that there was no change in these eddy current signals between the pre-service inspection Enclosure

-2 and the 2008 inspection.

• Bobbin inspections in SG1 resulted in the identification of possible loose part indications in six tubes. Further investigation of these signals with a rotating probe suggested that the bobbin signals were the result of the presence of axially oriented deposits on the outside surface of the tube. These deposits were reported to generally increase with proximity to the 10lh hot leg tube support plate and, in some cases, extend through the tube support plate at the trefoil lobe.

These deposits were observed visually.

• The licensee provided its operational assessment for tube wear indications.

Although the NRC staff did not review this analysis in detail, the results appear reasonable based on operating experience at similarly designed and operated units.

Based on a review of the information provided, the NRC staff concludes that the licensee provided the information required by the Technical Specifications. In addition, the NRC staff concludes that there are no technical issues that warrant follow-up action at this time since the inspections appear to be consistent with the objective of detecting potential tube degradation and the inspection results appear to be consistent with industry operating experience at similarly designed and operated units.

Principal Contributor: A. Obodoako Date: September 25, 2009

September 25, 2009 Mr. Rafael Flores Senior Vice President and Chief Nuclear Officer Attention: Regulatory Affairs Luminant Generation Company LLC P.O. Box 1002 Glen Rose, TX 76043

SUBJECT:

COMANCHE PEAK STEAM ELECTRIC STATION, UNIT 1 - REVIEW OF THE 2008 STEAM GENERATOR TUBE INSPECTIONS PERFORMED DURING REFUELING OUTAGE 1RF13 (TAC NO. ME0367)

Dear Mr. Flores:

By letter dated January 7, 2009 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML090300118), as supplemented by letter dated April 21, 2009 (ADAMS Accession No. ML091180326), Luminant Generation Company LLC (the licensee),

submitted information summarizing the results of the 2008 steam generator tube inspections performed at the Comanche Peak Steam Electric Station (CPSES), Unit 1 during the thirteenth refueling outage (1 RF13).

The U.S. Nuclear Regulatory Commission (NRC) has completed its review of these reports and concludes that the licensee provided the information required by the CPSES, Unit 1, Technical Specifications and that no additional follow-up action is required at this time. The results of the NRC staff's review of the reports submitted by the licensee are summarized in the enclosure to this letter. If you have any questions, please contact me at 301-415-3016 or via e-mail at balwant.singal@nrc.gov.

Sincerely, Ira/

Balwant K. Singal, Senior Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-445

Enclosure:

As stated cc w/encl: Distribution via Listserv DISTRIBUTION:

PUBLIC RidsNrrLAJBurkhardt Resource LPLIV Reading RidsOgcRp Resource RidsAcrsAcnw_MailCTR Resource RidsRgn4MailCenter Resource RidsNrrDciCsgb Resource AObodoako, NRR/DCI/CSGB RidsNrrDorlLpl4 Resource KKarwoski, NRR/DCI RidsNrrPMComanchePeak Resource ADAMS Accession No: ML092600269

• Memo dated 9/1/09 OFFICE NRRlLPL4/PM NRRlLPL4/LA NRR/CSGB/BC(A) NRR/LPL4/BC NRR/LPL4/PM NAME BSingal JBurkhardt MGavriias' MMarkley BSingal DATE 9/25/09 9/24/09 9/1109 9/25/09 9/25/09 OFFICIAL AGENCY RECORD