L-05-076, R11 Steam Generator C-3 Report

R11 Steam Generator C-3 Report

ML051150335
Person / Time
Site:	Beaver Valley
Issue date:	04/19/2005
From:	Pearce L FirstEnergy Nuclear Operating Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
L-05-076
Download: ML051150335 (2)

Text

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Beaver Valley Power Station PO. Box 4 First Energy Nuclear Operating Company Shippingport. PA 15077-0004 L. William Pearce 724-682-5234 Vice President Fax: 724-643-8069 April 19, 2005 L-05-076 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555-0001

Subject:

Beaver Valley Power Station, Unit No. 2 Docket No. 50-412, License No. NPF-73 2R1 I Steam Generator C-3 Report In accordance with Beaver Valley Power Station (BVPS) Unit No. 2 Technical Specification 4.4.5.5.c, the NRC is required to be notified with the results of steam generator tube inspections which fall into Category C-3. The following information documents the C-3 examination category for steam generator 2RCS-SG21B. 100 percent of all inservice steam generator tubes were inspected during the 2R11 refueling outage in each of the three BVPS Unit No. 2 steam generators.

As of April 14, 2005, a total of thirty-four tubes (34) in 2RCS-SG21B, were found to be defective from the eddy current examinations (bobbin coil and plus point probes). This represents greater than 1% of the inspected tubes being defective and this places steam generator 2RCS-SG21B in the C-3 examination category. The examination of 2RCS-SG2IB was 100% complete as of April 14, 2005.

A total of fourteen (14) tubes in 2RCS-SG21A and seven (7) tubes in 2RCS-SG21C were found to be defective from the eddy current examinations. The examinations were 100%

complete in these steam generators as of April 14, 2005.

All defective tubes will be removed from service through tube plugging.

The primary degradation mechanism affecting the Unit No. 2 steam generators is Outside Diameter Stress Corrosion Cracking (ODSCC) at or near the hot leg top-of-tubesheet.

The ODSCC observed at the hot leg top-of-tubesheet has historically been located in the sludge pile region. However, during this 2R1 1 refueling outage, 21 tubes were plugged due to indications outside the sludge pile region.

Boric acid addition to the secondary water is continuing in an effort to reduce the propensity for ODSCC. Additionally, secondary water chemistry molar ratio control has been implemented to further mitigate the growth and propagation of ODSCC. Sludgefl

Beaver Valley Power Station, Unit No. 2 Steam Generator C-3 Report L-05-076 Page 2 lancing the secondary side top-of-tubesheet has been performed to remove accumulated sludge that contributes to the formation of the aggressive environment that can result in the initiation of ODSCC in this region. Furthermore, secondary water chemistry control is optimized to keep corrosion product transport to the steam generators as low as possible to minimize the accumulation of new sludge during the operating cycle.

No new regulatory commitments are contained in this submittal. If there are any questions concerning this matter, please contact Mr. Larry R. Freeland, Manager, Regulatory Compliance at 724-682-4284.

Sincerely,

&U44e&4 William Pearce c: Mr. T. G. Colburn, NRR Senior Project Manager Mr. P. C. Cataldo, NRC Sr. Resident Inspector Mr. S. J. Collins, NRC Region I Administrator