ML091030192

Byron, Unit 2, Correction to Relaxation Request to First Revised NRC Order EA-03-009, Dated February 20, 2004

ML091030192
Person / Time
Site:	Byron
Issue date:	04/03/2009
From:	Enright D J Exelon Generation Co, Exelon Nuclear
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
1.10.0101, BYRON 2009-043, EA-03-009, TAC MD6638
Download: ML091030192 (2)

Text

Exelkn.Exelon Generation Company, LLC Byron Station 4450 North German Church Road Byron, IL 61010-9794 www.exeloncorp.com Nuclear April 3, 2009'LTR: BYRON 2009-043 File: 1.10.0101 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Byron Station Unit 2 Facility Operating License No. NPF-66 NRC Docket No. STN 50-455

Subject:

Correction to Relaxation Request to First Revised NRC Order EA-03-009, Dated February 20, 2004

References:

(1)Letter from David M. Hoots (Exelon Generation Company, LLC) to U. S. NRC, "Relaxation Request From First Revised NRC Order EA-03-009 Establishing Interim Inspection Requirements for Reactor Pressure Vessel Heads at Pressurized Water Reactors," dated August 30, 2007 (2) Letter from Russell Gibbs (U.S. NRC) to Charles Pardee (Exelon Generation Company, LLC), "Byron Station, Unit No. 2 -Relaxation of the First Revised Order EA-03-009 (TAC No. MD6638)," dated February 7, 2008 In Reference-1, Exelon Generation Company, LLC (EGC), requested relaxation from certain inspection requirements of the First Revised Order EA-03-009.

Specifically, the proposed alternative would revise the minimum volumetric inspection coverage requirement for sixteen reactor pressure vessel (RPV) control rod drive mechanism (CRDM) penetration nozzles at Byron Station, Unit 2, to the lowest elevation that can be practically inspected.

In Reference 2, the NRC authorized the proposed relaxation.

/JCYD April 3, 2009 U. S. Nuclear Regulatory Commission Page 2 Due to the identification of an indication on CRDM nozzle 68 during the spring 2007 Byron Station Unit 2 refueling outage and the attribution of this indication to primary water stress corrosion cracking (PWSCC), the Byron RPV head was re-categorized as high susceptibility.

For an RPV head in the high susceptibility category, the NRC Order EA-03-009 required that the CRDM RPV head penetration nozzles be inspected on an refueling outage frequency.

Recently, after review of the examination data, in preparation for submittal of Byron relief requests 13R-1 6 and 13R-1 7, an error was identified in the lower extent of coverage for CRDM nozzle 68. The original relaxation request used a value of 0.800 inches. Due to removal of the lower portion of the nozzle in Spring 2007 to facilitate repair of the nozzle through an embedded flaw technique and repair of the area that had a sample removed, the actual value is 0 inches.At the time of Byron Station's Relaxation Request submittal, the original data provided by the examination vendor for completion of the CRDM nozzle volumetric examination and subsequent repair were used as the basis for determining coverage found on each of the CRDM nozzles, which was then used as the basis for the relaxation request. The tables did not reflect the actual removal of the lower portion of the nozzle, but when re-review of the actual examination data sheets was completed, theerror was identified.

This issue has been entered into the Corrective Action Program.There was no adverse impact resulting from this error. The penetration nozzles for the Unit 2 RPV Head, including CRDM penetration nozzle 68, were inspected in the subsequent Unit 2 refueling outage in fall 2008 (i.e., B2R14).There are no regulatory commitments contained in this letter. Should you have any questions or desire additional information regarding this letter, please contact David Gudger, Regulatory Assurance Manager, at (815) 406-2800.Respectfully, Daniel J. Enright Site Vice President Byron Station DJ E/DG/cy