ML14090A344
| ML14090A344 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 03/31/2014 |
| From: | Peter Bamford Plant Licensing Branch IV |
| To: | Markley M Office of Nuclear Reactor Regulation |
| References | |
| MF3711 | |
| Download: ML14090A344 (3) | |
Text
1 NRR-PMDAPEm Resource From:
Bamford, Peter Sent:
Monday, March 31, 2014 8:43 AM To:
Markley, Michael Cc:
Lupold, Timothy; Tsao, John; Alexander, Ryan; Drake, James; Hipschman, Thomas; Walker, Wayne
Subject:
Documentation of NRC Verbal Approval for Diablo Canyon Unit 1 Proposed Alternative -
Main Steam Vent Line Temporary Clamp Repair Mr. Michael Markley, In accordance with Nuclear Reactor Regulation (NRR) Office Instruction LIC-102, Relief Request Reviews, (Agencywide Documents Access and Management System (ADAMS) Accession No. ML091380595) the staff may provide verbal approval of relief requests (proposed alternatives) provided:
- The proposed alternative is in writing and all information that the staff requires to write the SE has been docketed.
- An identified need for the verbal authorization is recognized given the circumstances of the licensees request.
- The NRC technical staff has completed its review and determined that the proposed alternative is technically justified, but has not yet formally documented it in an SE.
- The technical branch and the Division of Operating Reactor Licensing (DORL) branch chiefs have agreed to the verbal authorization.
As documented in the licensees submittal dated March 28, 2014, it is the Office of Nuclear Reactor Regulation (NRR) staffs understanding that Diablo Canyon, Unit 1 is currently at power and that approval of the subject proposed alternative is necessary to avoid a plant shutdown for a permanent repair. Such a plant shutdown would involve an associated increase in radiological exposure to plant personnel, as compared to continuing operations at power. The steam leak for which the proposed alternative applies to was discovered during inservice inspection activities conducted with the plant in a hot, fully pressurized condition, and thus the condition was emergent and not foreseeable. The proposed alternative will install a temporary clamp on a leaking vent line connected to the main steam header to ensure continued pressure integrity of this section of main steam piping, which is also a secondary containment boundary. The NRR staff believes that the above criteria for granting temporary verbal approval has been met. Temporary verbal approval was granted on March 29, 2014, via the script below, and the staff expects to provide a written safety evaluation within 150 days of the verbal approval.
The purpose of this e-mail to document the verbal authorization of the subject relief request in accordance with LIC-102.
A copy of this email will be placed into ADAMS.
Participants in the verbal discussion were:
From the NRC:
Timothy Lupold, Chief, Component Performance, NDE, and Testing Branch, Division of Engineering Michael Markley Chief, Plant Licensing Branch 4-1, DORL John Tsao, Component Performance, NDE, and Testing Branch, Division of Engineering Peter Bamford, Diablo Canyon Project Manager, DORL James Drake, Senior Inservice Inspection Inspector, NRC Region IV From the licensee:
Barry Allen - Site Vice President Jeff Summy - Sr. Director of Engineering and Technical Services Bob Waltos - Engineering Manager David Gonzalez - Inservice Inspection Supervisor Ken Schrader - Senior Advising Regulatory Services Engineer Philippe Soenen - Licensing Supervisor Technical Evaluation read by Timothy Lupold, Chief of the Component Performance, Non-Destructive Examination, and Testing Branch, NRR
2
[Timothy Lupold speaking]
By letter dated March 28, 2014, Pacific Gas and Electric Company (PG&E, the licensee) requested relief from the requirements of the American Society of Mechanical Engineer Boiler and Pressure Vessel Code (ASME Code),Section XI, Appendix IX, at Diablo Canyon Power Plant Unit 1 (PG&E Letter Number DCL-14-027). The licensee proposed an alternate repair for the leaking 3/4-inch vent line off main steam system line 1066 as documented in Request for Relief from the Requirements of Appendix IX of ASME Section XI, 2001 Edition with 2003 Addendum.
To repair the leaking vent line, the licensee proposed to install a mechanical clamp following the requirements of Appendix IX to the ASME Code,Section XI except paragraph IX-1000(c)(2) and IX-6000(a) which are related to the containment boundary and inservice volumetric examination of the defect area, respectively. The NRC staff finds that the proposed repair provides adequate measures to compensate for the two deviations. Based on the review of the clamp design and calculations, the NRC staff has determined that the clamp provides reasonable assurance that the vent line will be restrained should the line separate from the socket weld.
On the basis of information submitted, the NRC staff has determined that the proposed repair will restore the pressure boundary and provide reasonable assurance that the structural integrity of the degraded vent line will be maintained. The NRC staff finds that complying with the specified ASME Code requirement would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.
Authorization read by Michael Markley, Chief of the Plant Licensing Branch 4-1, NRR
[Michael Markley speaking]
As Chief of the Plant Licensing Branch 4-1, Office of Nuclear Reactor Regulation, I concur with the conclusions of the Component Performance, Non-Destructive Examination, and Testing Branch.
The NRC staff determines that the proposed alternative provides reasonable assurance of structural integrity of the subject vent valve line. The NRC staff finds that complying with the specified ASME Code requirements 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 all of the regulatory requirements set forth in 10 CFR 50.55a(a)(3)(ii) and is in compliance with the requirements of the ASME Code,Section XI for which relief was not requested. Therefore, on March 29, 2014, the NRC staff authorizes the use of the proposed alternative detailed in PG&E Letter Number DCL-14-027 at Diablo Canyon Power Plant, Unit 1, until the next scheduled refueling outage in fall 2015.
All other requirements of ASME Code,Section XI, for which relief was not specifically requested and authorized by the NRC staff remain applicable, including the third party review by the Authorized Nuclear In-service 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.
[Conclusion of discussion]
Peter Bamford NRR/DORL/LPL4-1 Diablo Canyon and ANO Project Manager 301-415-2833
Hearing Identifier:
NRR_PMDA Email Number:
1196 Mail Envelope Properties (Peter.Bamford@nrc.gov20140331084300)
Subject:
Documentation of NRC Verbal Approval for Diablo Canyon Unit 1 Proposed Alternative - Main Steam Vent Line Temporary Clamp Repair Sent Date:
3/31/2014 8:43:06 AM Received Date:
3/31/2014 8:43:00 AM From:
Bamford, Peter Created By:
Peter.Bamford@nrc.gov Recipients:
"Lupold, Timothy" <Timothy.Lupold@nrc.gov>
Tracking Status: None "Tsao, John" <John.Tsao@nrc.gov>
Tracking Status: None "Alexander, Ryan" <Ryan.Alexander@nrc.gov>
Tracking Status: None "Drake, James" <James.Drake@nrc.gov>
Tracking Status: None "Hipschman, Thomas" <Thomas.Hipschman@nrc.gov>
Tracking Status: None "Walker, Wayne" <Wayne.Walker@nrc.gov>
Tracking Status: None "Markley, Michael" <Michael.Markley@nrc.gov>
Tracking Status: None Post Office:
Files Size Date & Time MESSAGE 6487 3/31/2014 8:43:00 AM Options Priority:
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