ML20154R427

Responds to 880328 Submittal of Justification for Removing Tube Vibration Instrumentation Installed in Unit 1 Steam Generator.Concurs in Removal of Tube Vibration Instrumentation at Unit 1

ML20154R427
Person / Time
Site:	Comanche Peak
Issue date:	06/01/1988
From:	Charemagne Grimes NRC OFFICE OF SPECIAL PROJECTS
To:	Counsil W TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
References
NUDOCS 8806070302
Download: ML20154R427 (3)

Text

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June 1, 1988 Docket Nos. 50-445  !

and 50-446 )

Mr. William G. Counsil i Executive Vice President Texas Utilities Electric Company 400 North Olive Street, Lock Box 81 Dallas, TX 75201

SUBJECT:

REMOVAL OF STEAM GENERATOR TUBE VIBRATION INSTRUMENTATION By lettet dated March 28, 1988, you provided justification for removing the tube vibration instrumentation installed in the Comanche Peak Unit I steam generators and requested the staff's concurrence on the elimination of the vibration monitoring program. The staff has reviewed the justification and agrees that the tube vibration instrumentation and vibration monitoring program are no longer necessary at Comanche Peak Unit 1 as discussed below.

The instrumentation was installed subsequent to a modification of the preheat section of the steam generators as part of an effort to address tube vibration 6nd wear in the preheater section of Westinghouse steam generators. The modification included expansion of selected tubes at the elevation of baffle plates and diverting a portion of the feedwater flow through the auxiliary feedwater nozzle. As the expected lead domestic Model D-4 steam generators, one of the Comanche Peak Unit I steam generators was instrumented with acceler-ometers to provide a measurement of the vibration response of representative tubes for comparison with the objectives of the modification.

The staff reviewed and approved the modifications to the steam generators and the feedwater system and the addition of the vibration instrumentation in Supplement 4 to NUREG-0797, "SER Related to the Operation of Comanche Peak Steam Electric Station, Units 1 and 2," (SSER 4). The staff also approved, subject to the receipt of additional information, the vibration monitoring program in SSER 4. The acceptance of the procedures for conducting and reporting the data from the vibration monitoring program was considered a confinnatory item.

Since the issuance of SSER 4, a number of domestic and foreign Model D steem generators with modified preheat sections have gone into operation. The experience from those plants indicates that there has not been accelerated 1

wear of the tubes in the preheat section.

8806070302 880601 DR ADCCK 050 5 i

4 h Mr. William G. Counsil Texas Utilities Electric Company Based on tt.a operating experience to date, the staff finds that the tube vibra-tion instrumentation is no longer necessary to determine if the objectives of the modification have been met. Therefore, the staff concurs in the removal of the tube vibration instrumentation at Comanche Peak Unit 1 and the elimination of the vibration monitoring program.

Sincerely, M

Christopher I Grimes, Director j Comanche Peak Project Division Office of Special Projects cc: See next page i

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, .o June 1, 1988 Mr. William G. Counsil Texas Utilities Electric Company Based on the operatina experience to date, the staff finds that the tube vibra.

tion instrumentation is no longer necessary to determine if the objectives of the modification have been met. Therefore, the staff concurs in the removal of the tube vibration instrumentation at Comanche Peak Unit 1 and the elimination of the vibration monitoring program.

Sincerely, (original signed by PFMcKee for)

Christopher I. Grimes, Director Comanche Peak Project Division Office of Special Projects cc: See next page

_ Distribution:

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