ML12206A078
| ML12206A078 | |
| Person / Time | |
|---|---|
| Site: | Kewaunee  |
| Issue date: | 07/23/2012 |
| From: | Feintuch K Division of Operating Reactor Licensing |
| To: | Gadzala J Dominion Generation |
| References | |
| TAC ME7727 | |
| Download: ML12206A078 (4) | |
Text
1 NRR-PMDAPEm Resource From:
Feintuch, Karl Sent:
Monday, July 23, 2012 12:55 PM To:
Jack Gadzala
Subject:
FW: ME7727 - KPS Reactor Vessel Internals Inspection Plan review - 7/23/2012 Conference Call Record - discussion of RAII EVIB-Cher-017 Attachments:
ME7727 RAII-Cher-017.docx; Clevis Bolts IMG_1403.pdf FYI - Record of todays conference call From: Feintuch, Karl Sent: Monday, July 23, 2012 12:46 PM To: Cheruvenki, Ganesh; Hiser, Allen; Medoff, James
Subject:
ME7727 - KPS Reactor Vessel Internals Inspection Plan review - 7/23/2012 Conference Call Record - discussion of RAII EVIB-Cher-017 Call started at 9:30 AM ET.
Participation -
NRC: Karl Feintuch, Ganesh Cheruvenki, Al Hiser, James Medoff Dominion / Kewaunee: Jack Gadzala, Phil Bukes, Chuck Tomes Agenda:
Discussion of RAI item -
ME7727-RAII-EVIB-Cher-017-2012-07-17 (see attached Word document)
(Color photo (.JPG) is attached from which a black and white copy was used to facilitate discussion during the 7/23/12 call.)
The licensee response to this RAI item is planned for August 23, 2012.
Hearing Identifier:
NRR_PMDA Email Number:
419 Mail Envelope Properties (Karl.Feintuch@nrc.gov20120723125400)
Subject:
FW: ME7727 - KPS Reactor Vessel Internals Inspection Plan review - 7/23/2012 Conference Call Record - discussion of RAII EVIB-Cher-017 Sent Date:
7/23/2012 12:54:43 PM Received Date:
7/23/2012 12:54:00 PM From:
Feintuch, Karl Created By:
Karl.Feintuch@nrc.gov Recipients:
"Jack Gadzala" <jack.gadzala@dom.com>
Tracking Status: None Post Office:
Files Size Date & Time MESSAGE 823 7/23/2012 12:54:00 PM ME7727 RAII-Cher-017.docx 15306 Clevis Bolts IMG_1403.pdf 616865 Options Priority:
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DRAFT REQUEST FOR ADDITIONAL INFORMATION (RAI)
ME7727-RAII-EVIB-Cher-017-2012-07-17 RELATED TO LICENSEES REACTOR VESSEL INTERNALS INSPECTION PLAN REVIEW REQUEST KEWAUNEE POWER STATION (TAC NO. ME7727)
DOCKET NO. 50-305 By letter dated December 12, 2011, Dominion Energy Kewaunee, Inc. (DEK, the licensee),
submitted an inspection plan for the reactor vessel internals (RVI) components at Kewaunee Power Station (KPS). In its e-mail submittal dated March 19, 2012, the licensee submitted the Technical Report KLR-1309A, License Renewal Project, Aging Management Program, ASME Section XI, In-service Inspection, Subsection IWB, IWC, and IWD, Reactor Vessel Internals Inspection, Kewaunee Power Station, to the NRC staff for review. Pursuant to the license renewal commitments items 1 and 2 addressed in Chapter 15, Table 15.7.1, License Renewal Commitments, of the Updated Final Safety Evaluation Report (UFSAR), the licensee requested that the NRC staff review and approve the subject inspection plan.
The NRC staff reviewed the licensees response (dated June 28, 2012) to its question ME7727-RAII-EVIB-CHER-006-2012-05-09, and the NRC staff has some concerns regarding the aging degradation in Alloy X-750 clevis insert bolts. Consequently, the NRC staff developed a follow-up question (below) to address this issue.
ME7727-RAII-EVIB-Cher-017-2012-07-17 According to Section A.1.4 in MRP-175, Materials Reliability Program: PWR Internal Aging Degradation Mechanism Screening Threshold Values, susceptibility to stress corrosion cracking (SCC) in Nickel Base Alloy X-750 depends on the type of heat treatment that is performed on the alloy. High temperature heat treatment (HTH) process that is used on Alloy X-750 offers better resistance to SCC than the other age hardened heat treatment processes.
Previous operating experience in a US PWR unit indicates that the Alloy X-750 clevis insert bolt experienced cracking. In Table 4-9 of the MRP-227-A report, the MRP identified only wear as an aging mechanism for the clevis insert bolts.
A - Based on the operating experience as stated above, the staff believes that cracking should also be included as an active aging degradation in the clevis insert bolts. Therefore, the staff requests that the licensee confirm that Alloy X-750 material in HTH condition was used for clevis insert bolts at KPS.
B - If the Alloy X-750 material is not in HTH condition, the staff requests that the licensee include verification of aging degradation due to cracking in its inspection and evaluation guidelines for these bolts at KPS.
C - VT-3 examination of the bolts every 10 years would detect completely failed or missing bolts but not partially cracked bolts. Therefore, the staff requests the licensee to provide:
(1) justification that VT-3 technique would be adequate for monitoring the cracking issue in the clevis insert bolts before it fails; (2) information on the number of clevis insert bolts that are necessary for maintaining their function during the extended period of operation; and, (3) information on the number of clevis insert bolts that are currently present at KPS.