ML20205L697

Requests Further Info & Documentation Re Steam Generator Tube Vibration Problem for Generic CESSAR Sys 80 Steam Generator Design by 870410.Specific Questions Re Request Encl

ML20205L697
Person / Time
Site:	Palo Verde, 05000000, 05000470
Issue date:	03/27/1987
From:	Knighton G Office of Nuclear Reactor Regulation
To:	Scherer A ABB COMBUSTION ENGINEERING NUCLEAR FUEL (FORMERLY
References
NUDOCS 8704020175
Download: ML20205L697 (4)

Text

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• MAR 3 7 W l

Docket No.: STN 50-470F Mr. A. E. Scherer, Director Nuclear Licensing Combustion Engineering, Inc.

1000 Prospect Hill Road Wind:;or, Connecticut 06095

Dear Mr. Scherer:

Meetings were held on February 9 and 24,1987, between representatives of Arizona Public Service Company (APS), Combustion Engineering and the NRC staff regarding the steam cenerator tube degradation problem found on the CESSAR System 80 steam generator design at Palo Verde, Units 1 and 2. With regard to this matter APS has provided to the staff its proposed measures for mitigating and monitoring tube vibration at the Palo Verde steam generators.

The purpose of this letter is to request further information and documentation regarding the steam generator tube vibration problen for the generic CESSAR System 80 steam generator design. The specific questions relating to this request, sore of which were asked during the February 9 and 24, 1987 meeting, are listed in the enclosure.

We ask that by April 10, 1987, you submit your responses to the enclosed questions or provide a schedule when the questions will be addressed. If you have any questions regarding this letter please contact me.

Sincerely George W. Knighton, Director PWR Project Directorate No. 7 Division of PWR Licensing-B

Enclosure:

As stated cc: See next page Distribution Docket File NRC PDR Local PDR PBD-7 Reading JPartlow h

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EJordan Attorney OGC JRaleigh EAlicitra Gb GWKnighton gju / L. B. Marsh PBD7p g 7 PBD7h (A D PBD7 K. Wichman j JRaleigh EAL1Yitra GWKnighton 3g/87 3Q7/87 3p/87

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Combustion Engineering, Inc. Docket No. STN 50-470 (CESSAR) ,

cc w/o enclosure: ,

Mr. G. Davis, Manager ~

Standard Plant Licensing .

1000 Prospect Hill Road i

Windsor, Connecticut 06095 Mr. C. B. Brinkman, Manager ,

Washington Nuclear Operations Combustion Engineering, Inc.

7910 Woodmont Avenue Bethesda, Maryland 20014 Mr. E. E. Van Brunt, Jr.

Vice President - Construction Projects Arizona Public Service Company P. O. Box 21666 Phoenix, Arizona 85036

',' Ms. Patricia Lee Hourihan 6413 S. 26th Street Phoenix, Arizona 85040 Mr. Daniel F. Giessing Division of Nuclear Regulation and Safety Office of Converter Reactor Deployment, NE-12 i Office of Nuclear Energy Washington, D.C. 20545 Mr. Douglas Coleman I.fcensing Project Manager Washington Public Power Supply System P. O. Box 1223 Elma, Washington 98541 1

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, ENCLOSURE ,

1. During the 2/24/87 meeting, you stated that the vibration was due to high recirculation flow impinging the tubes on the cold leg (economizer) side of the steam generator. Describe this flow path and specif/ the flow velocities, and explain why the tubes in the hot leg side are not similarly affected. Based on the tube' degradation experienced, determine the flow rates, directions, and paths and show the boundaries of the tubes that could experience flow induced vibration.

2. Describe the analyses and tests that will be cenducted to investigate this problem further. We understand that the analytical flow analyses currently underway have never been validated using scale model tests.

It is the staff's belief that steam generator tube vibration phenomena requires thorough analyses, validated by tests, to ensure all relevant factors are understood and properly accounted for.

j 3. What equipment changes will be made to provide a permanent long-term correction to this problem? If not a part of your long-term fix, show why modifications to the steam generator's recirculation flow path need not be made to correct the problem permanently.

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4. In the light of providing information for modification of the design of CE System 80 steam generators, it is the staff's belief that valuable knowledge of the vibration phenomenon may be obtained by instrumenting the steam generator tubes at an operating CESSAR plant. For example, the vibration frecuency and location of peak smplitude may give definitive insights regarding the actual flow rates and directions taking place in the steam generator secondary side. Also, pulling a tube in the affected area will confirm and provide detailed infomation regarding the wear pattern and vibration actually occurring. With the cooperation of the affected CESSAR utility evaluate the usefulness and practicability of providing this instrumentation and the possibility of pulling a tube in an affected steam generator.

5. Describe your plans for the CE System 80 steam generators. Justify the design of the CE System 80 steam generators in terms of this vibrational phenomenawhichwasnotanticipatedinthissteamgenerator'sdesiggand in the design of the steam generators of CE's 2825 MW(t) System 80 recently reviewed by the NRC staff.

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