ML092110120

Update on the Status of the November 21, 2008 Request for Additional Information (RAI) and Additional Testing Pursuant to NRC Generic Letter 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation

ML092110120
Person / Time
Site:	Catawba
Issue date:	07/28/2009
From:	Morris J Duke Energy Carolinas
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
GL-04-002
Download: ML092110120 (3)

Text

0 Duke JAMES R. MORRIS, VICE PRESIDENT 062Energy Duke Energy Carolinas, LLC Carolinas Catawba Nuclear Station 4800 Concord Road / CN01 VP York, SC 29745 803-701-4251 803-701-322) fax July 28, 2009 U. S. Nuclear Regulatory Commission Washington, DC 20555-0001 ATTENTION: Document Control Desk

Subject:

Duke.Energy Carolinas, LLC (Duke)

Catawba Nuclear Station, Units 1 and 2 Docket Nos. 50-413 and 50-414 Update on the Status of the November 21, 2008 Request for Additional Information(RAI) and Additional Testing for Catawba Units 1 and 2 Pursuant to NRC Generic Letter(GL) 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors" Pursuant to the November 21, 2008 RAI letter from Nuclear Regulatory Commission (NRC) and the February 17, 2009 update letter from Duke, Duke is providing an update on its RAI response plan and confirmatory conventional debris head loss testing (subsequently referred to herein as "testing") progress.

Since February 2009, Catawba has continued to make progress on development of responses to the RAI questions using insights from teleconferences with NRC.

On May 20, 2009, a teleconference was held to discuss testing protocols, and another one on June 17, 2009 to discuss chemical effects.

The testing at Wyle Laboratories was completed on June 25, 2009. This testing incorporated the guidance of the document titled "NRC Staff Review Guidance Regarding Generic Letter 2004-02 Closure in the Area of Strainer Head Loss and Vortexing" dated March 2008, as well as lessons learned from earlier testing and inputs from NRC. The results from this testing are being finalized and will be incorporated into the RAI responses.

One specific aspect of this confirmatory testing bears highlighting here: As reported in Generic Letter 2004-02 supplemental responses dated February 29, 2008 and April 30, 2008, Catawba used the findings of WCAP-16710-P, "Jet Impingement Testing to Determine the Zone of Influence (ZOI) of Min-K and NUKONO Insulation for Wolf Creek and Callaway Nuclear Operating Plants," to

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www. duke-energy, com

Document Control Desk July 28, 2009 Page 2 reduce the ZOI for jacketed fiber insulation from 17D to 7D. While Catawba feels the WCAP remains a technically valid approach and is continuing to support industry efforts surrounding use of the WCAP, it is recognized there is currently a certain amount of regulatory uncertainty in invoking a ZOI reduction.

With the aim of resolving Generic Letter 2004-02, Catawba chose to conduct the confirmatory testing using future state, 17D) ZOI values for jacketed insulation.

This future state involves replacement of approximately 1,400 ft3 of fibrous insulation with reflective metal insulation (RMI) in the Unit 1 containment which will achieve a lower overall transportable debris quantity. The insulation replacement will occur during 1 EOC 18, currently scheduled to begin in the fall of 2009. Catawba Unit 2 debris quantities will still remain bounded by Unit 1quantities even following the Unit 1 insulation replacement.

Testing and analysis using the 17D ZOI values now allows Catawba to proceed independently of the ongoing industry processing of WCAP-16710-P. In the future, findings of the WCAP may be invoked to gain margin once the regulatory uncertainty has been mitigated. Finally, by using the 17D ZOI values in the design basis, several of the RAI questions will no longer be applicable. Catawba will clarify these RAIs during the upcoming RAI discussions with the NRC as described below.

On June 23, 2009, NRC conducted a public meeting to provide the status and path forward on Generic Safety Issue (GSI) 191. Based on this meeting, Duke will follow the process of conducting discussions with NRC priorto submitting the responses to the RAI questions. Duke is currently working with the NRC Project Manager to plan these series of discussions, including a follow-up to the June 17, 2009 teleconference associated with the subject of chemical effects.

This letter contains no regulatory commitments. Questions regarding this update should be directed to A. P. Jackson at (803) 701-3742.

Very truly yours, ames R. Morris

Document Control Desk July 28, 2009 Page 3 xc:

Luis A. Reyes Regional Administrator, Region II U.S. Nuclear Regulatory Commission 61 Forsyth Street, S.W., Suite 23T85 Atlanta, GA 30303-8931 J. H. Thompson, Project Manager (CNS & MNS)

U. S. Nuclear Regulatory Commission 11555 Rockville Pike Mail Stop 8G9A Rockville, MD 20852-2738 G. Hutto NRC Senior Resident Inspector Catawba Nuclear Station