ML070310265
| ML070310265 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 02/06/2007 |
| From: | Farideh Saba NRC/NRR/ADRO/DORL/LPLIV |
| To: | Forbes J Entergy Operations |
| Saba F, NRR/DORL/LPL4, 301-415-1447 | |
| References | |
| TAC MD0931 | |
| Download: ML070310265 (5) | |
Text
February 6, 2007 Mr. Jeffrey S. Forbes Site Vice President Arkansas Nuclear One Entergy Operations, Inc.
1448 S. R. 333 Russellville, AR 72802
SUBJECT:
ARKANSAS NUCLEAR ONE, UNIT 2 - REVIEW OF THE REFUELING OUTAGE 17 (2005) STEAM GENERATOR TUBE INSERVICE INSPECTION (TAC NO. MD0931)
Dear Mr. Forbes:
By letter dated April 11, 2005, Entergy Operations, Inc. (the licensee), submitted the steam generator (SG) plugged tube report for refueling outage (RFO) 17 in accordance with Technical Specification (TS) Section 6.6.7.a. On April 1, 2005, U.S. Nuclear Regulatory Commission (NRC) staff participated in a conference call with Arkansas Nuclear One, Unit 2 (ANO-2) representatives regarding the SG tube inservice inspection (ISI) being performed during RFO 17. By letter dated March 16, 2006, the licensee submitted the 12-month SG tube ISI report for RFO 17 in accordance with TS Section 6.6.7.b. Additional information regarding the RFO 17 SG tube ISI was provided by the licensee in a letter dated September 19, 2006.
The NRC staff has completed its review of the information provided by the licensee and concludes that the licensee provided the information required by ANO-2 TSs and that no additional follow-up is required at this time. The NRC staffs review is enclosed.
If you have any questions regarding this matter, please contact me at (301) 415-1447.
Sincerely,
/RA/
Farideh E. Saba, Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-368
Enclosure:
As stated cc w/encl: See next page
ML070310265 OFFICE NRR/LPL4/PM NRR/LPL4/LA NRR/CSGB/BC NRR/LPL4/BC NAME FSaba LFeizollahi AHiser DTerao DATE 2/6/07 2/5/07 10/18/06 2/6/07
December 2006 Arkansas Nuclear One cc:
Executive Vice President
& Chief Operating Officer Entergy Operations, Inc.
P.O. Box 31995 Jackson, MS 39286-1995 General Manager Plant Operations Entergy Operations, Inc.
Arkansas Nuclear One 1448 SR 333 Russellville, AR 72802 Director, Nuclear Safety Assurance Entergy Operations, Inc.
Arkansas Nuclear One 1448 SR 333 Russellville, AR 72802 Manager, Licensing Entergy Operations, Inc.
Arkansas Nuclear One 1448 SR 333 Russellville, AR 72802 Director, Nuclear Safety & Licensing Entergy Operations, Inc.
1340 Echelon Parkway Jackson, MS 39213-8298 Section Chief, Division of Health Radiation Control Section Arkansas Department of Health and Human Services 4815 West Markham Street, Slot 30 Little Rock, AR 72205-3867 Section Chief, Division of Health Emergency Management Section Arkansas Department of Health and Human Services 4815 West Markham Street, Slot 30 Little Rock, AR 72205-3867 Senior Resident Inspector U.S. Nuclear Regulatory Commission P.O. Box 310 London, AR 72847 Regional Administrator, Region IV U.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-8064 County Judge of Pope County 100 W. Main Street Russellville, AR 72801 Vice President, Operations Support Entergy Operations, Inc.
P.O. Box 31995 Jackson, MS 39286-1995
ARKANSAS NUCLEAR ONE, UNIT 2,
SUMMARY
OF THE STAFFS REVIEW OF THE REFUELING OUTAGE 17 STEAM GENERATOR TUBE INSERVICE INSPECTIONS TAC NO. MD0913 DOCKET NO. 50-368 By letter dated April 11, 2005 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML051090243), Entergy Operations, Inc. (the licensee) submitted the steam generator (SG) tube plugging report for refueling outage (RFO) 17 in accordance with Technical Specification (TS) Section 6.6.7.a. On April 1, 2005 (ADAMS Accession No. ML052560042), U.S. Nuclear Regulatory Commission (NRC) staff participated in a conference call with Arkansas Nuclear One, Unit 2 (ANO-2) representatives regarding the SG tube inservice inspections (ISI) being performed during RFO 17. By letter dated March 16, 2006 (ADAMS Accession No. ML060880337), the licensee submitted the 12-month SG tube ISI report for RFO 17 in accordance with TS Section 6.6.7.b. Additional information regarding the RFO 17 SG tube ISI was provided by the licensee in a letter dated September 19, 2006 (ADAMS Accession No. ML062770265).
ANO-2 has two Westinghouse model D109 SGs. Each SG has 10,637 thermally-treated Alloy 690 tubes with an outside diameter of 0.688 inch and a nominal wall thickness of 0.040 inch. The tubes are hydraulically expanded for the full depth of the tubesheet at each end. The tubes are supported by stainless steel support plates with broached trefoil-shaped holes and the upper bundle supports consist of five sets of staggered stainless steel anti-vibration bars.
The licensee provided the scope, extent, methods, and results of the ANO-2 SG tube inspections in the documents referenced above. In addition, the licensee described corrective actions (i.e., tube plugging) taken in response to the inspection findings.
During the RFO 17 SG tube inspections, the licensee inspected approximately 50 percent of the tubes full-length with a bobbin coil probe in both SG A and SG B. In addition, the licensee performed a 20-percent +Point' inspection at the top of the tubesheet, plus or minus 3 inches in both SGs. Both the 50-percent bobbin and 20-percent +Point' inspections were biased toward the periphery of the bundles (i.e., 15 tubes in from the periphery in SG A and 8 tubes in from the periphery in SG B).
Prior to the tube inspections, the licensee observed one tube in SG A to be dripping under a static head on the hot-leg side at the outer periphery. Eddy current testing revealed indications just above the tubesheet for the leaking tube and two adjacent tubes. Secondary side visual inspection revealed a piece of metal wedged among these tubes and the licensee indicated that the piece was removed. The leaking tube was in-situ pressure tested and the licensee indicated that it was successfully tested to three times normal operating differential pressure.
The licensee also indicated that the amount of primary-to-secondary leakage during a steamline break was well within the accident-induced leakage limit. The leaking tube and adjacent tubes were plugged and stabilized.
The licensee indicated that both SG A and SG B had a number of small foreign objects that could not be retrieved from the interior of the bundle. The licensee determined that these objects were located in relatively low flow areas and do not pose a concern with respect to tube damage for the upcoming cycle.
In an e-mail, the licensee provided clarification to its September 19, 2006, response to the NRC staffs request for additional information and indicated that inspected 20 percent of the hot-leg dents and dings greater than or equal to 2.0 volts were +Point' during the ANO-2 RFO 17 SG tube ISI. The licensee indicated that the relative conditions of the dents and dings did not change.
Based on the review of the information provided, the NRC staff concludes that the licensee provided the information required by ANO-2 TSs. 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.