ML15127A170

Relief Request Serial Number 15-CN-001, Proposed Alternative Repair for Main Steam System Braided Flex-Hose - Submitted Pursuant to 10 CFR 50.55a(z)(2)

ML15127A170
Person / Time
Site:	Catawba
Issue date:	05/04/2015
From:	Henderson K Duke Energy Carolinas
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
15-CN-001, CNS-1 5-044
Download: ML15127A170 (3)

Text

Kelvin Henderson DUKE Vice President 4n ENERGY. Catawba Nuclear Station Duke Energy CNO1VP 1 4800 Concord Road York, SC 29745 o: 803.701.4251 f: 803.701.3221 CNS-1 5-044 May 4, 2015 10 CFR 50.55a U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555-0001

Subject:

Duke Energy Carolinas, LLC (Duke Energy)

Catawba Nuclear Station, Unit 1 Docket Number 50-413 Relief Request Serial Number 15-CN-001, Proposed Alternative Repair for Main Steam System Braided Flex-Hose - Submitted Pursuant to 10 CFR 50.55a(z)(2)

References:

1. Letter from Duke Energy to NRC, same subject, dated March 19, 2015, ADAMS Accession Number ML15082A074.

2. Electronic mail from NRC to Duke Energy, Acceptance Review for 15-CN-001, dated April 20, 2015.

The Reference 1 letter submitted Relief Request 15-CN-001 requesting approval to use an alternative repair for a Main Steam System leaking braided flex hose. The Reference 2 electronic mail requested additional information to enable the NRC to complete its acceptance review of the Reference 1 letter.

The Reference 2 electronic mail contained the following request "By letter dated March 19, 2014 (Agencywide Documents Access and Management System Accession No. ML15082A074, Duke Energy Carolinas, LLC (Duke Energy) requested approval of an alternative to the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code. Specifically, the proposed alternative would allow the use of an alternate repair method for a leaking Main Steam System braided flex hose.

The NRC staff has reviewed your application and preliminarily concluded that the following information is necessary to enable the NRC staff to make an independent assessment regarding the acceptability of the proposed amendment request in terms of regulatory requirements and the protection of public health and safety and the environment:

www.duke-energy.com

U.S. Nuclear Regulatory Commission May 4, 2015 Page 2

1. Section 5.1 of your submittal indicates that NRC approval is required for continued operation. Since your submittal also indicates that the flex hose has been isolated, it is unclear whether this is correct. Please clarify the statement."

Duke Energy responds to this request as follows:

The leaking flex hose has been isolated, but the isolation valves are not leak-tight and some leakage through the damaged flex hose continues. For this reason, Duke Energy believes that the guidance in Regulatory Issue Summary 2005-20, "Revision to NRC Inspection Manual Part 9900 Technical Guidance, "Operability Determinations & Functionality Assessments for Resolution of Degraded or Nonconforming Conditions Adverse to Quality or Safety"", Rev. 1, Appendix C. 12, "Operational Leakage From Code Class 1, 2, 3 Components", applies. This guidance states, in part, that "The NRC staff does not consider through-wall conditions in components, unless intentionally designed to be there such as sparger flow holes, to be in accordance with the intent of the ASME Code or construction code and, therefore, would not meet code requirements, even though the system or component may demonstrate adequate structural integrity. Thus, unless a through-wall flaw is evaluated and found acceptable using an applicable and NRC endorsed code case, in which all provisions are met including any additional requirements or limitations imposed by the RG endorsing the code case, a relief request is necessary."

Duke Energy believes that because of the guidance in Regulatory Issue Summary 2005-20, Rev. 1, Appendix C.12, relief is also required to defer making an immediate Code compliant repair to the leaking flex hose. As such, Duke Energy would like to clarify our relief request by revising Section 5.1 as follows:

"In lieu of the requirement of IWB-3522.1 to correct the degraded condition prior to continued service, Duke Energy requests NRC approval to defer performing a Section XI repair/replacement activity until such time that an ASME Code Section Xl repair/replacement activity can be performed in accordance with IWA-4000."

There are no regulatory commitments contained in this letter.

If you have any questions or require additional information, please contact L.J. Rudy at (803) 701-3084.

Very truly yours, Kelvin Henderson Vice President, Catawba Nuclear Station LJR/s

i . . .

U.S. Nuclear Regulatory Commission May 4, 2015 Page 3 xc:

V.M. McCree Regional Administrator U.S. Nuclear Regulatory Commission - Region II Marquis One Tower 245 Peachtree Center Ave., NE Suite 1200 Atlanta, GA 30303-1257 G.A. Hutto, III NRC Senior Resident Inspector Catawba Nuclear Station G.E. Miller (addressee only)

NRC Project Manager (Catawba)

U.S. Nuclear Regulatory Commission One White Flint North, Mail Stop 8 G9A 11555 Rockville Pike Rockville, MD 20852-2738