ML16222A125

Request for Additional Information - Relief Request No. RR-ISI-04-11, 2016/08/08 E-mail from R.Guzman to T.Loomis

ML16222A125
Person / Time
Site:	Calvert Cliffs
Issue date:	08/09/2016
From:	Richard Guzman Plant Licensing Branch 1
To:	Tom Loomis Calvert Cliffs, Exelon Nuclear Generation Corp
Guzman R
References
CAC MF7291, RR-ISI-04-11
Download: ML16222A125 (2)

Text

From: Guzman, Richard Sent: Tuesday, August 09, 2016 7:28 AM To: 'Loomis, Thomas R:(GenCo-Nuc)'

Subject:

Calvert Cliffs Request for Additional Information - Relief Request No. RR-ISI-04-11 (CAC No. MF7291)

Tom, The NRC staff has reviewed the information provided in the subject relief request letter dated January 28, 2016 (ADAMS Accession No. ML16028A156), and has determined that additional information is needed to complete its review. Shown below is the NRC staffs request for additional information. Please provide your formal response within 30 days of the date of this e-mail transmittal. If you have any questions, please contact me.

~~~~~~~~~

Rich Guzman Sr. PM, Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Office: O-8E10 l Phone: 301-415-1030 REQUEST FOR ADDITIONAL INFORMATION PROPOSED RELIEF REQUEST NO. RR-ISI-04-11 FOR DISSIMILAR METAL BUTT WELD EXAMINATIONS CALVERT CLIFFS NUCLEAR POWER PLANT, UNIT 2 EXELON GENERATION COMPANY, LLC DOCKET NUMBER. 50-318 By letter dated January 28, 2016, Exelon Generation Company, LLC submitted for Nuclear Regulatory Commission (NRC) staff review and approval, Relief Request No. RR-ISI-04-11, which requests an alternative to the requirements of 10 CFR 50.55a(g)(6)(ii)(F) regarding examination coverage of dissimilar metal butt welds for the Fourth 10-year Inservice Inspection (ISI) interval at Calvert Cliffs Nuclear Power Plant, Unit 2 (CCNPP2). To complete its review, the NRC staff requests the following additional information.

1. Recent operational experience with the ISI of dissimilar metal butt welds in nuclear power plants include several instances of human errors in the application of qualified nondestructive examination procedures. Licensee Event Report No. 2016-002 dated April 14, 2016 (ADAMS Accession No. ML16106A304) describes an event at Calvert Cliffs Nuclear Power Plant, Unit 1 (CCNPP1) on February 20, 2016, which identified an 81.8 percent through-wall flaw. This flaw had been previously examined in 2010, with techniques which appear to be similar to those used on CCNPP2 in 2011 as described in the January 28, 2016 submittal, without identifying

the true extent of the through-wall flaw. Please describe lessons learned from the February 2016 CCNPP1 event which will be applied to the 2017 CCNPP2 examinations to insure the quality and effectiveness of the ultrasonic examinations.