ML110950221

Electronic Transmission, Draft Request for Additional Information Regarding Review of Flaw Evaluation for Weld NG-E-007

ML110950221
Person / Time
Site:	Oyster Creek
Issue date:	04/11/2011
From:	Geoffrey Miller Plant Licensing Branch 1
To:	Chernoff H Plant Licensing Branch 1
Miller G, NRR/DORL, 415-2481
References
TAC ME5341
Download: ML110950221 (3)

Text

April 11, 2011 MEMORANDUM TO: Harold K. Chernoff, Chief Plant Licensing Branch I-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation FROM: G. Edward Miller, Project Manager /ra/

Plant Licensing Branch I-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

SUBJECT:

OYSTER CREEK NUCLEAR GENERATING STATION - ELECTRONIC TRANSMISSION, DRAFT REQUEST FOR ADDITIONAL INFORMATION REGARDING REVIEW OF FLAW EVALUATION FOR WELD NG-E-007 (TAC NO. ME5341)

The attached draft request for additional information (RAI) was transmitted by electronic transmission on April 11, 2011 to Mr. Tom Loomis, at Exelon Generation Company, LLC (Exelon, the licensee). This draft RAI was transmitted to facilitate the technical review being conducted by the Nuclear Regulatory Commission (NRC) staff and to support a conference call with Exelon in order to clarify the licensees flaw evaluation for reactor recirculation line weld NG-E-007 submitted December 15, 2010 (Agencywide Documents Access and Management System Accession No. ML103500359). The draft questions were sent to ensure that they were understandable, the regulatory basis was clear, and to determine if the information was previously docketed. Additionally, review of the draft RAI would allow Exelon to evaluate and agree upon a schedule to respond to the RAI. This memorandum and the attachment do not represent an NRC staff position.

Docket Nos. 50-219

Enclosure:

As stated

ML110950221 OFFICE DORL/LPLI-2/PM DCI/CPNB/BC NAME GEMiller TLupold DATE 4/11/11 4/7/11 DRAFT REQUEST FOR ADDITIONAL INFORMATION OYSTER CREEK NUCLEAR GENERATING STATION FLAW EVALUATION REACTOR RECIRCULATION WELD NG-E-007 DOCKET NO. 50-219 By letter dated December 15, 2010 (Agencywide Document Access and Management System Accession No. ML103500359), Exelon Generation Company (Exelon or the licensee) submitted a flaw evaluation for reactor recirculation weld NG-E-007 for the Oyster Creek Nuclear Generating Station (Oyster Creek). The NRC staff requests the following information to complete its review.

1. The report states that a circumferential indication in weld NG-E-007 was detected during the 2010 refueling outage. Discuss whether this is the first time the circumferential indication was detected. If not, discuss which year the indication was detected initially and provide the flaw characterization from the earlier inspections.

2. American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),Section XI, IWB-2420, Successive Inspections, requires the licensee to perform three successive examinations of the subject circumferential indication. Discuss the years that the indication will be examined to satisfy IWB-2420. After the 3 successive examinations, discuss whether the indication will be inspected under the normal ASME in-service inspection program.

3. Page 5 of the flaw evaluation states that the code of record is the ASME Code,Section XI, 1995 edition and 1996 addenda. The Oyster Creek plant entered into the period of extended operation in 2009. Clarify why the code of record is not the ASME Code,Section XI, 2004 edition.

4. Section 4.3 of the flaw evaluation states that the flaw is located in the heat affect zone on the cast austenitic stainless steel (CASS) side of weld. Based on this description, the staff notes that the flaw is located in the heat affected zone of the CASS valve base metal. Discuss whether the material properties of the CASS material were used in the flaw evaluation. If so, discuss whether the saturated fracture toughness for CASS base metal considering the thermal aging embrittlement effect was used in the flaw evaluation. If the CASS material properties were not used in the flaw evaluation, provide justification.

Enclosure