ML20140F926

Forwards RAI Re Reduced RCS Flow Rate Amend & SBLOCA Evaluation Model

ML20140F926
Person / Time
Site:	Maine Yankee
Issue date:	06/10/1997
From:	Dan Dorman NRC (Affiliation Not Assigned)
To:	Sellman M Maine Yankee
References
TAC-M93323, TAC-M94834, NUDOCS 9706130292
Download: ML20140F926 (4)

Text

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j UNITED STATES NUCLEAR REGULATORY COMMISSION o t WASHINGTON, D.C. 20066-0001 8 June 10, 1997 Y. . . . . ,o Mr. Michael B. Sellman, President Maine Yankee Atomic Power Company 329 Bath Road Brunswick, ME 04011

SUBJECT:

REQUESTS FOR ADDITIONAL INFORMATION (TAC NOS. M93323 AND M94834

Dear Mr. Sellman:

In a meeting on March 20, 1997, representatives of the Maine Yankee Atomic Power Company discussed contingencies for various amounts of tube plugging that may result from steam generator tube inspections during the current outage.

If approximately 230 additional tubes per steam generator required plugging, the increased flow resistance may result in a reactor coolant system flow rate

, less than the minimum required by the current Maine Yankee Technical Specifications (TS). By letter dated August 15, 1995, Maine Yankee requested a TS change regarding operation with reduced reactor coolant system flow rates. (Reference Maine Yankee letter MN-95-97, Accession No. 9508230024.)

In the meeting of March 20, the licensee provided a qualitative assessment concluding that operation in the proposed manner would reduce the peak cladding temperature resulting from a small-break loss-of-coolant accident (SBLOCA).

In the March 20 meeting, the licensee indicated that the license basis analyses for Maine Yankee assume plugging of 830 tubes per steam generator (plus the existing sleeving that is equivalent to approximately 170 tubes per steam generator). If the licensee exceeds this plugging level, reanalysis of the license basis analyses will be necessary. To reanalyze the SBLOCA, the licensee will need staff approval of a SBLOCA evaluation model. By letter dated April 25, 1996 (Accession No. 9604260184), the licensee submitted for staff review and approval a SBLOCA analysis. The staff requested additional information in letters dated June 25, 1996, and October 28, 1996, to which the licensee responded in letters dated October 18, 1996 (Accession No.

9610280155), and March 10, 1997 (Accession No. 9703170231). Telephone g() ,,jl conference calls were conducted between the licensee and the staff on November 14, 22, and 27, 1996 to clarify information provided in the licensee's October 18 response. As a result of these calls further information was provided by the licensee in the March 10 letter and a letter l dated November 27, 1996 (Accession No. 9612090061). { I Based on the March 20 meeting and the staff's review of the licensee's responses, the staff finds that further information is needed before the staff can complete its reviews of the reduced RCS flow rate amendment and the SBLOCA evaluation model. The specific information requested is provided in the NBC R$ CEiffEB COPY  ;

9706130292 970610 PDR ADOCK 05000309 p PDR

o Michael B. Sellman enclosure. We request that you respond to this RAI within 30 days from receipt of this letter. If you have any questions regarding this matter, please call me at (301) 415 1429.

Sincerely, Original signed by Daniel H. Dorman, Project Manager i Project Directorate I-3 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation Docket No. 50-309

Enclosure:

Request for Additional Information cc w/ encl: See next page Distribution Docket File ,

PUBLIC l PDI-3 RF '

SCollins/FMiraglia RZimmerman SVarga JZwolinski PMilano JLyons DDorman EPeyton OGC ACRS CCowgill, RI DOCUMENT NAME: G:\D0RMAN\MYM93323.RAI * - See previous concurrence To ricr4ve a copy of this document, Indicate in the boa: *C" = Copy without attachment / enclosure 'E' = Copy with attachment / enclosure "N" i No copy 0FFICE PM:PDI-3 l LA:PDIV-2 l BC(A):SRXB l D:PDI-3 u _l DD K)8PE l l NAME DDorman b @ EPeyton* JLyons* PMilanom' JZQo'ATnski DATE 06/10/97 04/11/97 04/29/97 06//O /97 06/ I(J/97 0FFICIAL RECORD COPY

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Mr. Michael B. Sellman .' cc:

Mr. Charles B. Brinkman Mr. Robert W. Blackmore i j Manager - Washington Nuclear Plant Manager '

Operations Maine Yankee Atomic Power Station ABB Combustion Engineering P.O. Box 408 12300 Twinbrook Parkway, Suite 330 Wiscasset, ME 04578 Rockville, MD 20852

Mr. Michael J. Meisner i Thomas G. Dignan, Jr., Esquire Vice-President Ropes & Gray Licensing and Regulatory Compliance One International Place Maine Yankee Atomic Power Company i Boston, MA 02110-2624 329 Bath Road i Brunswick, ME 04011 Mr. Uldis Vanags

State Nuclear Safety Advisor Mr. Bruce E. Hinkley, Acting

State Planning Office Vice-President, Engineering j State House Station #38 Maine Yankee Atomic Power Company 4

Augusta, ME 04333 329 Bath Road

! Brunswick, ME 04011

! Mr. P. L. Anderson, Project Manager

, Yankee Atomic Electric Company Mr. Patrick J. Dostie 580 Main Street State of Maine Nuclear Safety Bolton, MA 01740-1398 Inspector Maine Yankee Atomic Power Station i Regional Administrator, Region I P.O. Box 408 i U.S. Nuclear Regulatory Commission Wiscasset, ME 04578 i 475 Allendale Road l King of Prussia, PA 19406 Mr. Graham M. Leitch

! Vice President, Operations First Selectman of Wiscasset Maine Yankee Atomic Power Station Municipal Building P.O. Box 408 U.S. Route 1 Wiscasset, ME 04578 Wiscasset, ME 04578 l Mary Ann Lynch, Esquire i Mr. J. T. Yerokun Maine Yankee Atomic Power Company Senior Resident Inspector 329 Bath Road i Maine Yankee Atomic Power Station Brunswick, ME 04578 U.S. Nuclear Regulatory Commission

! P.O. Box E Mr. Jonathan M. Block j Wiscasset, ME 04578 Attorney at Law l P.O. Box 566 Mr. James R. Hebert, Manager Putney, VT 05346-0566 .

j Nuclear Engineering and Licensing i Maine Yankee Atomic Power Company 4

329 Bath Road

Brunswick, ME 04011 i Friends of the Coast

P.O. Box 98 Edgecomb, ME 04556 a

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MAINE YANKEE ATOMIC POWER COMPANY MAINE YANKEE ATOMIC POWER STATION DOCKET NO. 50-309 RE0 VEST FOR ADDITIONAL INFORMATION

1. Provide a quantitative estimate of the impact on small-break loss-of-coolant accident (SBLOCA) peak cladding temperature of operation with reduced reactor coolant system (RCS) flow rate and reactor thermal power in accordance with the proposed amendment.

2. What is the DNB correlation limit? What are the reserve DNB margin and calculated minimum DNBR associated with the proposed amendment?

3. In the telephone conference call of November 27, 1996, the staff requested clarification of the basis for the reactor coolant pump trip time selected by the licensee for conformance with Three Mile Island Action Item II.K 3.5. This information has not yet been provided. The staff needs this information to complete its review of the licensee's proposed SBLOCA evaluation model.

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