ML15215A771

Summary of July 27, 2015, Meeting with Exelon Generation Company, LLC, on Request for Relief for Alternate Examination Frequency Under ASME Code Case N-729-1 for Reactor Vessel Head Penetration Welds (TAC Nos. MF4809, MF4801, MF4811, and MF

ML15215A771
Person / Time
Site:	Byron, Braidwood
Issue date:	09/14/2015
From:	Joel Wiebe Plant Licensing Branch III
To:
Joel Wiebe
References
RS-14-251, TAC MF4809, TAC MF4810, TAC MF4811, TAC MF4812
Download: ML15215A771 (4)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 September 14, 2015 LICENSEE: Exelon Generation Company, LLC FACILITY: Braidwood Station, Units 1 and 2, and Byron Station, Unit Nos. 1 and 2

SUMMARY

OF JULY 27, 2015, MEETING WITH EXELON GENERATION COMPANY, LLC ON REQUESTS FOR RELIEF FOR ALTERNATE EXAMINATION FREQUENCY UNDER ASME CODE CASE N-729-1 FOR REACTOR VESSEL HEAD PENETRATION WELDS (TAC NOS. MF4809, MF4810, MF4811, AND MF4812)(RS-14-251)

On July 27, 2015, a Category 1 public meeting was held between the U.S. Nuclear Regulatory Commission (NRC) and representatives of Exelon Generation Company, LLC (licensee) at NRC Headquarters, One White Flint North, 11555 Rockville Pike, Rockville, Maryland. The purpose of the meeting was to discuss Exelon's relief request (RR) for alternate examination frequency under American Society of Mechanical Engineers Code Case N-729-1 for reactor vessel head penetration welds. The meeting notice and agenda, dated July 21, 2015, are available in the Agencywide Documents Access and Management System (ADAMS) at Accession No. ML15202A104. A list of attendees is provided as Enclosure 1.

The licensee provided a brief history of the Braidwood and Byron RRs related to the reactor pressure vessel head nozzles, presented their technical basis for the re-examination interval requested, and sought to understand NRC technical questions about the RR as detailed in their presentation (ADAMS Accession No. ML15204A471). The licensee provided clarifications in response to questions from the NRC staff. Additionally, the licensee stated that they intend to submit a separate RR for post-peening inspection frequency. The peening is planned for the Byron Station, Unit No. 2, spring 2016, outage.

The NRC staff questioned the presented material and stated that the time at temperature model is not a bounding analysis and does not address material properties or processing issues that may enhance primary water stress corrosion cracking initiation or crack growth rates. The NRC staff indicated concern that the model used by the licensee has uncertainties associated with the crack growth rate pond that the data used in the licensee's model do not result in sufficient margin to ensure flaws won't result in pressure boundary leakage. Some flaw indications are in the weld material, and NRC staff stated that because volumetric inspection of the weld material is not possible, the size of each of these indications is unknown. The NRC staff made no decisions regarding the licensee's plans.

Members of the public were in attendance. Public Meeting Feedback forms were not received.

No public comments were received.

This meeting generated one action item for the NRC staff: To review the licensee's presentation in a timely manner to determine if additional information is required and if information from the presentation needs to be submitted in a manner necessary for supporting regulatory decisions. The NRC staff acknowledged the time urgency of this request and

understands that the inspections for which relief is being requested are scheduled to be conducted during the first week of the fall 2015, outage.

Please direct any inquiries to me at 301-415-6606, or Joel.Wiebe@nrc.gov.

IRA!

Joel S. Wiebe, Senior Project Manager Plant Licensing 111-2 and Planning and Analysis Branch Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-454, 50-455, 50-456 and 50-457

Enclosure:

List of Attendees cc w/encls: Listserv

LIST OF ATTENDEES JULY 27, 2015, MEETING WITH EXELON GENERATION COMPANY, LLC REQUESTS FOR RELIEF FOR ALTERNATE EXAMINATION FREQUENCY UNDER ASME CODE CASE N-729-1 FOR REACTOR VESSEL HEAD PENETRATION WELDS NRC Staff Eva Brown Office of Nuclear Reactor Regulation (NRR)

Travis Tate NRR John Lubinski NRR Dave Alley NRR Margaret Audrain NRR Jay Collins NRR John Tsao NRR Chip Becker NRR Jennifer Hauser NRR Exelon Generation Company, LLC and Support Personnel Scot Greenlee Exelon Generation Company, LLC (Exelon)

David Gullatt Exelon Jessica Kiejcie Exelon W. J. Feimster Exelon Guy DeBoo Exelon Greg Gerzen Exelon Glenn White Dominion Engineering, Inc.

Markus Burkardt Dominion Engineering, Inc.

Public Alex Cullu Curtiss-Wright Enclosure

Meeting Summary ML15215A771 OFFICE DORL/LPL3-2/PM DORL/LPL3-2/PM DORL/LPL3-2/LA DE/EPNB DORL/LPL3-2/BC NAME JHauser JWiebe SRohrer DAiiey TT ate DATE 9/2/15 9/2/15 9/3/15 9/8/15 9/14/15