ML20195C984

Forwards Request for Addl Info Re Westinghouse Analyses & Util Explanation on Changes in delta-T.Response to Request Should Be Submitted within 45 Days of Ltr Receipt

ML20195C984
Person / Time
Site:	McGuire, Mcguire
Issue date:	10/31/1988
From:	Hood D Office of Nuclear Reactor Regulation
To:	Tucker H DUKE POWER CO.
References
TAC-68218, TAC-68219, NUDOCS 8811040118
Download: ML20195C984 (4)

Text

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Octobor 31, 1988 Docket Nos.: 50-369 50-370 Mr. H. B. Tucker, Vice President Nuclear Production Department Duke Power Company 422 South Church Street i Charlotte, Nurth Carolina 28242

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION REGARDING CHANGES IN DELTA-T

-MCGUIRE NUCLEAR STATION, UNITS 1 AND 2 (TACS 68218/68219)

The NRC staff has reviewed your letter of May 9,1988, which proposes changes to the McGuire Technical Specifications associated with the gradual decrease in indicated delta-T observed since May 1985. Our review included associated LER 370/85-24 and your supplemental letter of August 1,1988, forwarding Westinghouse's "Analysis of Coolant AT Reduction Observed at McGuire Unit 2."

We fino that your understanding of this phenomenon is presently uncertain.

Additional information regarding Westinghouse's analyses and Duke's explanation i is needed for completion of our review. The enclosure identifies the additional information needed.

Your reply to the enclosure is requested within 45 days of receipt of this i letter. Should you have questions, contact re et (301) 492-1442.  !

l The reporting and/or recordbeeping requirements cont:ined in this letter effect fewer than ten respondents; therefore, OMB clearance is not required under P. L.96-511.

Sincerely, original Signed By: j Darl S. Hood, Project Manager Project Directorate 11-3 Division of Reactor Projects - 1/I!

Enclosure:

As stated cc: See next page DISTRIBUTION hu EoS DocIret Filf NRC PDR )

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Mr. H. B. Tucker Duke Power Company McGuire Nuclear Station CC:

Mr. A.V. Carr, Esq. Dr. John M. Barry Duke Power Company Department of Environmental Health P. O. Box 33189 Mecklenburg County 422 South Church Street 1210 Blythe Boulevard Charlotte, North Carolina 28242 Cha,lotte, North Carolina 28203 County Manager of Mecklenburg County Mr. Dayn H. Brown, Chief 720 East Fourth Street Radiation Protection Branch Charlotte, North Carolina 28202 Division of Facility Services {

Department of Human Resources 701 Barbour Drive Mr. Robert Gill Raleigh, North Carolina 27603-2008 Duke Power Company Nuclear Production Department P. O. Box 33189 Charlotte, North Carolina 28242 J. Michael McGarry,111. Esq.

Bishop, Liberman, Cook, Purcell and Reynolds 1200 Seventeenth Street, N.W.

Washington, D. C. 20036 Senior Resident Inspector c/o U.S. Nuclear Regulatory Commission Route 4, Box 529 Hunterville, North Carolina 28078 Regional Administrator, Region II U.S. Nuclear Regulatory Commission 101 Marietta Street, N.W., Suite 2900 Atlanta, Georgia 30323 S. S. Kilborn Area Manager, Mid-South Area ESSD Projects Westinghouse Electric Corporation MNC West Tower - Bay 239 P. O. Box 355 Pittsburgh, Pennsylvania 15230 b

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ENCLOSURE REQUEST FOR ADDITIONAL INFORMATION: MCGUIRE NUCLEAR POWER STATION, TECHNICAL SPECIFICATION CHANGES, DELTA-T INCIDENT The staff has reviewed the proposed Technical Specification changes (T.S.

4.2.3.5 and Table 4.3-1),the associated justification and safety analysis and the related LER 370/85-24 The Ilcensee states that the proposed change is conservative and has already been implemented administrative 1y. The explanation of the .1T change provided in the Westinghouse report "Analysis of Coolant AT Reduction Observed at McGuire Unit-2" is uncertain. The evaluation does not address the following:

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1. The phenomena exhibited by McGuire appear,in some respects, similar to

those observed on other W plants as described,1,n WCP-11578 (RCS flow Anomaly). On what basis does Duke dismiss these flow phenomena as a 1 possible explanation of the AT phenomena in McGuire?

2. Duke states that the observed AT is in part due to feedwater venturi fouling. Duke stated in a 1985 LER that the venturi foulings would be investigated. Describe this earlier investigation, its results, and how

! these results contributed to the conclusions of the present report.

3. The corrective actions proposed are based upon an unjustified i

assumption that venturi fouling is responsible for about 0.5'F AT.

Discuss the corrective actions necessary if the venturi fouling is respcnsible for as such as l'F 6T.

4 Westinghouse recossendations (pg. 9) are in terms of rated thermal

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output. Yet neither the evaluation nor the proposed mudifications ar*

! expressed in terms of the possible limits of the real thermal output.

Please explain.