ML17115A142
| ML17115A142 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 04/25/2017 |
| From: | Michael Mahoney Plant Licensing Branch II |
| To: | Fletcher C Duke Energy Corp |
| References | |
| MF9079 | |
| Download: ML17115A142 (3) | |
Text
1 NRR-PMDAPEm Resource From:
Mahoney, Michael Sent:
Tuesday, April 25, 2017 8:46 AM To:
Cecil Fletcher
Subject:
Request for Additional Information - Catawba SG Report - RFO 21 (CAC MF9079)
- Cecil, By letter dated January 6, 2017, (Agencywide Documents Access Management System (ADAMS) Accession No. ML17010A282), Duke Energy, (the licensee), submitted the results of their fall 2016 steam generator inspections performed during refueling outage 21 at the Catawba Nuclear Station, Unit 2.
In order to complete its review, the U.S. Nuclear Regulatory Commission staff requests the following additional information. Please provide your response to the following request for additional information within 30 days of the date of this correspondence.
RAI-1
Results from the steam generator bowl visual inspection discussed on page 8 of 19 in the outage report show an area of missing stainless steel cladding was detected in the D SG hot leg channel head. The report states that no repair of the irregularly shaped area was performed since analysis supports operation until the next planned inspection during Refueling Outage 23. Please discuss the root cause for the area of thin/missing cladding. In addition, confirm that the operational assessment considers potential tube degradation resulting from pieces of stainless steel cladding becoming dislodged from the channel head and being transported into the steam generator tubes.
RAI-2
Most of the steam generator tubes plugged during Refueling Outage 21 were identified as high stress (2-sigma) tubes. All tubes screened as 2-sigma tubes were also inspected with an array probe during the 2015 outage and only one was plugged due to a presumed crack-like indication identified at a tube support plate. Please discuss the plugging criteria for the 2-sigma tubes during Refueling Outage 21 and whether it changed from previous outages.
RAI-3
The steam generator identification is not apparent for the list of steam generator tube service induced indications (pages 11 through 19). Please confirm that the indication lists are presented in the following order: Steam Generators 2A, 2B, 2C and 2D.
RAI-4
Please confirm that pages 7 and 8 should read 13 tubes plugged for Steam Generator 2C.
Once I add this email to ADAMS, I will provide you with the Accession No. for your reference.
Michael Mahoney McGuire and Catawba Project Manager, Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Desk: (301)-415-3867
2 Email: Michael.Mahoney@NRC.GOV
Hearing Identifier:
NRR_PMDA Email Number:
3468 Mail Envelope Properties (169005b0b66d410fa3ac84239b2b66ae)
Subject:
Request for Additional Information - Catawba SG Report - RFO 21 (CAC MF9079)
Sent Date:
4/25/2017 8:45:39 AM Received Date:
4/25/2017 8:45:44 AM From:
Mahoney, Michael Created By:
Michael.Mahoney@nrc.gov Recipients:
"Cecil Fletcher " <Cecil.Fletcher@duke-energy.com>
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