ML14073A274
| ML14073A274 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 03/13/2014 |
| From: | Mahesh Chawla Division of Operating Reactor Licensing |
| To: | Dotson B, Erickson J Entergy Nuclear Operations |
| References | |
| MF3508 | |
| Download: ML14073A274 (4) | |
Text
1 NRR-PMDAPEm Resource From:
Chawla, Mahesh Sent:
Thursday, March 13, 2014 3:01 PM To:
DOTSON, BARBARA E (bdotson@entergy.com); ERICKSON, JEFFREY S (JERICKS@entergy.com); MIKSA, JAMES P (jmiksa@entergy.com)
Cc:
Lupold, Timothy; Collins, Jay; Carlson, Robert; Duncan, Eric; Hills, David; Sanchez Santiago, Elba; Bilik, Tom
Subject:
Palisades Nuclear Plant - Verbal Authorization for Relief Request RR 4 MF3508 Importance:
High A teleconference was held on March 12, 2014, @ 10.00 am between the staff of Nuclear Regulatory Commission and representatives of Entergy Nuclear Operations, Inc., Palisades Nuclear Plant (the licensee).
The purpose of this email is to document the verbal authorization provided to Palisades on the subject Relief Request RR 4-18, Proposed Alternative to the Requirements of ASME Code Case N-770-1. Following is the transcript of the verbal authorization provided to Palisades Nuclear Plant, for 10 CFR 50.55a(g)(6)(ii)(F)
Proposed Alternative.
Technical Branch By letters dated February 25, 2014, as supplemented by letters dated March 1st, 4th, 6th, 9th and 11th, 2014, Entergy Nuclear Operations, Inc. (ENO, the licensee), proposed an alternative to 10 CFR 50.55a(g)(6)(ii)(F) for Palisades Nuclear Plant (Palisades). This regulation defines the inspection requirement for Class 1 piping and nozzle dissimilar metal butt welds in accordance with American Society of Mechanical Engineers Boiler and Pressure Vessel (ASME) Code Case N-770-1, with NRC conditions. The licensee is requesting an extension of the required baseline volumetric inspection for 9 welds until the next refueling outage based upon hardship under the requirements of 10 CFR 50.55a(a)(3)(ii).
The Nuclear Regulatory Commission (NRC) staff evaluated the licensees basis for hardship. The NRC staff found that without a readily available qualified volumetric inspection technique for these 9 subject welds, any inspection would not provide reasonable assurance of flaw detection and characterization. Further, the radiological dose for performing any unplanned best effort volumetric examinations of the 9 subject welds would be a hardship in relation to the questionable value of these examinations. Additionally, a mitigation strategy has not been developed or approved for these welds. A delay in the inspection requirement for one operating cycle would allow for the development of tooling, qualification of procedures and personnel, and mockup verification to minimize radiation dose to personnel. Therefore the NRC staff finds the licensee has provided sufficient information to identify the hardship.
The licensees basis included a structural evaluation of the 9 subject welds. Of significant impact is that each weld was subject to a post weld heat treatment which reduces the residual stress in each weld. The NRC staff evaluated the licensees flaw evaluations, as part of their structural evaluation, and performed a series of NRC staff and contractor flaw evaluations. While the NRC staff finds reasonable assurance that no flaw will develop in these welds that would challenge the structural integrity of the piping system or branch connection over the next cycle of operation, the NRC staff does find there is a possibility of a leak from a hypothetical axial flaw.
Therefore, the NRC staff does not have reasonable assurance of leaktightness over the next operating cycle.
As such, the NRC staff evaluated the potential effects of leakage from these welds. The NRC staff determined that a program of enhanced leakage monitoring would provide reasonable assurance of safety such that if a leak were to occur, it could be identified in such a time that any potential effects would be minimized, thus ensuring the NRC goal of public health and safety is maintained.
2 In a series of NRC requests for additional information and responses from the licensee, the licensee has revised their original proposed alternative to include an enhanced leakage monitoring program. The items of the licensees proposed alternative are conditions for the authorization of the relief request. As such, if not implemented, the safety evaluation would be invalid and authorization of this relief request would be rescinded. The licensees final proposed alternative is as follows,
- 1) Perform periodic system leakage tests in accordance with ASME Section XI Examination Category B-P, Table IWB-2500-1.
- 2) Perform visual examinations (per Code Case N-722-1) and dye penetrant surface examinations (per ASME Section XI Examination Category B-J, Table IWB-2500-1) of the welds in accordance with ASME requirements.
- 3) Perform a volumetric examination, using ASME Code,Section XI, Appendix VIII, Supplement 10 qualified procedures, equipment and personnel, on each of the nine subject welds of this alternative during the next scheduled refueling outage (1R24).
- 4) Until the next scheduled refueling outage, if unidentified PCS [Primary Coolant System] leakage increases by 0.15 gpm above the WCAP-16465NP baseline mean, and is sustained for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, ENO will take action to be in Mode 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and Mode 5 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />, and perform bare metal visual examinations of the nine subject welds of this alternative, unless it can be confirmed that the leakage is not from these welds.
Given the licensees identified hardship, structural evaluation and conditions of relief identified in the proposed alternative, the NRC staff finds the licensee has provided sufficient information to demonstrate reasonable assurance of the structural integrity of the 9 subject welds for one cycle of operation without performing a volumetric examination. Further, while leakage may occur, the licensees actions will ensure that the leakage will be promptly identified and as such the NRC staff finds the effects of any such leakage would be minimal on other plant components.
Hence, the NRC staff finds that compliance with the specified requirements would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety. Therefore, as Branch Chief of the Component Performance, NDE and Testing Branch, I recommend authorization of the licensees proposed alternative until the next scheduled refueling outage at Palisades.
Licensing Branch As set forth above, the NRC staff determines that the licensee provided sufficient technical basis to demonstrate that compliance with the requirements of 10 CFR 50.55a(g)(6)(ii)(F) would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety. Accordingly, the NRC staff concludes that the licensee has adequately addressed the regulatory requirements set forth in 10 CFR 50.55a(a)(3)(ii). Therefore, the NRC staff authorizes the licensees proposed alternative, Relief Request RR 18, as supplemented by letters dated March 1st, 4th, 6th, 9th and 11th, 2014, at Palisades, until the next scheduled refueling outage in the fall of 2015.
All other ASME Code,Section XI requirements for which relief was not specifically requested and approved in this relief request remain applicable, including third party review by the Authorized Nuclear Inservice Inspector.
This verbal authorization does not preclude the NRC staff from asking additional clarification questions regarding the proposed relief request while preparing the subsequent written safety evaluation.
3 List of Participants NRC Entergy Nuclear Operations, Inc.
Robert Carlson Jeff Erickson Tim Lupold Jim Miksa Jay Collins Barb Dotson Eric Duncan Barry Davis Dave Hills William Sims Elba Sanchez Tom Bilik Mac Chawla Mahesh Chawla Project Manager Phone: 301-415-8371 Fax: 301-415-1222 mahesh.chawla@nrc.gov
Hearing Identifier:
NRR_PMDA Email Number:
1167 Mail Envelope Properties (Mahesh.Chawla@nrc.gov20140313150000)
Subject:
Palisades Nuclear Plant - Verbal Authorization for Relief Request RR 4 MF3508 Sent Date:
3/13/2014 3:00:55 PM Received Date:
3/13/2014 3:00:00 PM From:
Chawla, Mahesh Created By:
Mahesh.Chawla@nrc.gov Recipients:
"Lupold, Timothy" <Timothy.Lupold@nrc.gov>
Tracking Status: None "Collins, Jay" <Jay.Collins@nrc.gov>
Tracking Status: None "Carlson, Robert" <Robert.Carlson@nrc.gov>
Tracking Status: None "Duncan, Eric" <Eric.Duncan@nrc.gov>
Tracking Status: None "Hills, David" <David.Hills@nrc.gov>
Tracking Status: None "Sanchez Santiago, Elba" <Elba.SanchezSantiago@nrc.gov>
Tracking Status: None "Bilik, Tom" <Tom.Bilik@nrc.gov>
Tracking Status: None "DOTSON, BARBARA E (bdotson@entergy.com)" <bdotson@entergy.com>
Tracking Status: None "ERICKSON, JEFFREY S (JERICKS@entergy.com)" <JERICKS@entergy.com>
Tracking Status: None "MIKSA, JAMES P (jmiksa@entergy.com)" <jmiksa@entergy.com>
Tracking Status: None Post Office:
Files Size Date & Time MESSAGE 7727 3/13/2014 3:00:00 PM Options Priority:
High Return Notification:
No Reply Requested:
No Sensitivity:
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