ML092470216
| ML092470216 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 09/24/2009 |
| From: | Thadani M Plant Licensing Branch IV |
| To: | Halpin E South Texas |
| Thadani, M C, NRR/DORL/LP4, 415-1476 | |
| References | |
| TAC ME0166 | |
| Download: ML092470216 (4) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 September 24, 2009 Mr. Edward D. Halpin Chief Nuclear Officer STP Nuclear Operating Company South Texas Project P. O. Box 289 Wadsworth, TX 77483
SUBJECT:
SOUTH TEXAS PROJECT, UNIT 1 - REVIEW OF RESULTS OF THE 2008 STEAM GENERATOR TUBE INSPECTIONS PERFORMED DURING REFUELING OUTAGE 14 (TAC NO. ME0166)
Dear Mr. Halpin:
By letter dated September 23, 2008 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML082820569), STP Nuclear Operating Company (the licensee),
submitted information summarizing the results of the 2008 steam generator (SG) tube inspections performed at the South Texas Project (STP), Unit 1 during refueling outage 14.
The Nuclear Regulatory Commission (NRC) staff has completed its review of the inspection summary report and concludes that the licensee provided the information required by the STP, Unit 1 Technical Specifications and no additional follow-up is required at this time. The results of the NRC staff's review of the report submitted by the licensee are summarized in the enclosed NRC staff's evaluation. If you have any questions, please contact me at 301-415-1476 or via e-mail at Mohan.Thadani@nrc.gov.
Sincerely,
/rJMM{i)fi~
Mohan C. Thadani, Senior Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-498
Enclosure:
As stated cc w/encl: Distribution via Listserv
OFFICE OF NUCLEAR REACTOR REGULATION THE STAFF'S EVALUATION OF INSPECTION REPORT FOR 2008 STEAM GENERATOR TUBE INSPECTIONS PERFORMED DURING REFUELING OUTAGE 14 STP NUCLEAR OPERATING COMPANY SOUTH TEXAS PROJECT, UNIT 1 DOCKET NO. 50-498 By letter dated September 23, 2008 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML082820569), STP Nuclear Operating Company (the licensee),
submitted information summarizing the results of the 2008 steam generator (SG) tube inspections performed at South Texas Project, (STP), Unit 1 during refueling outage 14.
STP, Unit 1 has four Westinghouse recirculating Model Delta 94 SGs. Each SG contains 7585 thermally-treated Alloy 690 tubes. Each tube has a nominal outside diameter of 0.688 inches with a nominal wall thickness of 0.040 inches. The tubes were hydraulically expanded at both ends for the full depth of the tubesheet and are supported by a flow distribution baffle, support plates, and anti-vibration bars.
The licensee provided the scope, extent, methods, and results of its SG tube inspections in the submittal referenced above. In addition, the licensee described corrective actions, such as tube plugging, taken in response to the inspection findings.
The Nuclear Regulatory Commission (NRC) staff has reviewed the information provided by the licensee, and has the following comments and observations:
A large number of wire fragments entered SG 1D during cycle 11 as a result of damage to a cable stabilizer that was installed in a feedwater heater. The wire fragments have since been removed from this SG since their discovery during the licensee's 2005 outage. The licensee performed foreign object search retrieval on SG 1D to address tube structural integrity concerns due to presence of the wire fragments. Additional information on this issue is contained in the NRC letter dated May 27,2005, under ADAMS Accession No. ML051510378.
Inspections were only performed in SG 1D during the 2008 outage. The primary and secondary side inspections were focused on the remaining loose parts that may exist in the lower part of the SG.
The licensee performed +Point inspections on all open tubes in SG 1D from 3 inches below the top of the tubesheet to 6 inches above the top of the first tube support plate. These inspections included the flow distribution baffle, which lies between the tubesheet and the first tube support plate. The +Point inspections Enclosure
- 2 were performed on both the hot-and cold-leg side of the SG. No bobbin coil inspections were performed during refueling outage 14. Additionally, visual inspections of the secondary side were performed at the top of the tUbesheet, the flow distribution baffle, and the first tube support plate.
A total of 220 loose parts were identified in SG 'I D. Of these 220 loose parts, 150 were removed from SG 1D and 70 objects remain in the SG. The licensee performed an evaluation of the 70 objects that remain in SG 1D and determined that no tube wear is expected over the next two cycles.
The license reported that the only new indication of wear identified during the 2008 outage was a 9 percent through-wall indication above the top of tubesheet on the hot-leg side of the SG.
No tubes were plugged during the 2008 outage.
The licensee indicated that the inspections were not required by its Technical Specifications (TSs) with respect to maintaining tube integrity and were not intended for surveillance credit. The licensee indicated that the inspection plan was developed to address tube wear and consequent structural integrity concerns. The NRC staff understood this to mean that the inspections were not intended to satisfy the prescriptive requirements to periodically inspect the tubes.
Instead, the inspection results were used to verify the as-found and continued acceptability of the tubes until the next scheduled tube inspections. The staff notes that condition monitoring is required to be performed following any inspection regardless of the reason for that inspection.
Based on a review of the information provided, the NRC staff concludes that the licensee provided the information required by the TSs for STP, Unit 1. In addition, the 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 that inspection results appear to be consistent with industry operating experience at similarly designed and operated units.
September 24, 2009 Mr. Edward D. Halpin Chief Nuclear Officer STP Nuclear Operating Company South Texas Project P. O. Box 289 Wadsworth, TX 77483
SUBJECT:
SOUTH TEXAS PROJECT, UNIT 1 - REVIEW OF RESULTS OF THE 2008 STEAM GENERATOR TUBE INSPECTIONS PERFORMED DURING REFUELING OUTAGE 14 (TAC NO. ME0166)
Dear Mr. Halpin:
By letter dated September 23, 2008 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML082820569), STP Nuclear Operating Company (the licensee),
submitted information summarizing the results of the 2008 steam generator (SG) tube inspections performed at the South Texas Project (STP), Unit 1 during refueling outage 14.
The Nuclear Regulatory Commission (NRC) staff has completed its review of the inspection summary report and concludes that the licensee provided the information required by the STP, Unit 1 Technical Specifications and no additional follow-up is required at this time. The results of the NRC staff's review of the report submitted by the licensee are summarized in the enclosed NRC staff's evaluation. If you have any questions, please contact me at 301-415-1476 orvia e-mail at Mohan.Thadani@nrc.gov.
Sincerely, IRA!
Mohan C. Thadani, Senior Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-498
Enclosure:
As stated cc w/encl: Distribution via Listserv DISTRIBUTION:
PUBLIC LPLIV Reading RidsAcrsAcnw_MailCTR Resource RidsNrrDorlLpl4 Resource RidsNrrPMSouthTexas Resource RidsNrrLAJBurkhardt Resource RidsOgcRp Resource RidsRgn4MailCenter Resource ADAMS Accession No ML092470216 OFFICE NRR/LPL4/PM NRR/LPL4/LA NRR/LPL4/BC NRR/LPL4/PM NAME MThadani JBurkhardt MMarkley MThadani DATE 9/15/09 9/11/09 9/23/09 9/24/09 OFFICIAL RECORD COpy