ML20235V849

Responds to NRC Bulletin 88-011, Pressurizer Surge Line Thermal Stratification. Bulletin Action Item 1a Completed During Last Refueling Outage & No Indication of Piping or Support Degradation Observed.Plant Analysis Being Performed

ML20235V849
Person / Time
Site:	Yankee Rowe
Issue date:	03/03/1989
From:	Drawbridge B YANKEE ATOMIC ELECTRIC CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
BYR-89-42, IEB-88-011, IEB-88-11, NUDOCS 8903100362
Download: ML20235V849 (2)

Text

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YANKEEATOMICELECTRIC COMPANY "'fy"*,fglllg";*l" g.

g * ~Y 580 Main Street, Bolton, Massachusetts 01740-1398

,'[AN KEE

• March 3, 1989 BYR 89-42 United States Nuclear Regulatory Commission I Doument Control Desk l Washington, DC 20555 l

l

References:

(a) License No. DPR-3 (Docket No. 50-29)

(b) NRC Bulletin No. 88-11: Pressurizer Surge Line Thermal Stratification, dated December 20, 1988

Subject:

Alternative Schedule For Evaluation of Pressurizer Surge Line at Yankee Nuclear Power Station (YNPS)

Dear Sir:

The referenced bulletin requests all addressees to establish and implement a program to confirm pressurizer surge line integrity including the effects of thermal stratification. We have completed bulletin action item la during our refueling outage last month. The entire length of piping was examined in accordance with ASME Section IX, VT-3. No indication of piping or support degradation was observed.

The pressurizer surge line at YNPS is 4 inch diameeer schedule 160 pipe made from A376, Type 316 material. It is supported by 3 spring hangers.

There are no pipe whip restraints or other encumbrances on this line. Although the bulletin was received during the final days of our refueling outage, we were able to take temperature data during plant heat-up. The maximum temperature variation between the top and bottom of the pipe at either of the 2 locatians measured was less than 70 F.

At the present time we are performing analyses requested by the bulletin and are developing a course of action to best resolve this issue. The two options being considered are (1) joining an owner's group which would implement a generic resolution program, or (2) performing a plant-specific analysis.

Due to the uniqueness of our plant we believe at the present time that a plant-specific analysis may be the most appropriate option. For this reason we propose to complete bulletin action item lb by December 3, 1989. If Yankee or the staff decide that a generic solution is more appropriate, then we may request an additional schedule extension in keeping with the owner's group program.

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, United States Nuclear. Regulatory Commission l Page 2 FYR 89J2 A 6 month schedule extension will not create a significant safety issue.

No degradation of the piping or support has been observed in over 25 years' of operation. Also, the relatively small pipe sire,: flexible piping and support configuration, and small thermal gradient indicate that thermal stratification is not a significant issue. The schedule extension'will allow a more complete evaluation and increase opportunities-for additional data collection.

Very truly 70 rs, ANKEE ATOMIC ELECTRIC COMPANY l

> . i htGvWS B. L. DrBw ridge Vice Presiden Manager of Operations' -l BLD/ p.bc . f COMMONWEALTH OF MASSACHUSETTS)

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MIDDLESEX COUNTY )

. . l Then personally appeared:before me, B. L. Drawbridge, who,;being duly sworn,

- did state that he is Vice President of Yankee Atomic Electric Company, that he is duly-authorized to execute and file the foregoing document in the name and on the behalf of Yankee Atomic Electric Conipany- and that the statements j therein are true to the best of his knowledge and belief.

. [h . m ,., s u -  ;

H. D. Sammarco Notary Public My Commission Expires November 7, 1991 cc: USNRC Region I USNRC Resident Inspector, YNPS W. T. Russell - Regional Administrator USNRC Region I H

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