ML20246Q147

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Confirms Util Commitment to Reg Guide 1.61 for Selection of Damping Values Used in Corrective Action Program HVAC Design Validation & Clarifies Actual Damping Values That Can Be Used
ML20246Q147
Person / Time
Site: Comanche Peak  Luminant icon.png
Issue date: 08/30/1989
From: William Cahill
TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
RTR-REGGD-01.061, RTR-REGGD-1.061 TXX-89511, NUDOCS 8909110364
Download: ML20246Q147 (2)


Text

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. C 903.7 r -C Ref. # SSER 18 TUELEC7RIC August 30, 1989 UuYa$0Nc !ll U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555

SUBJECT:

COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)

DOCKET NOS. 50-445 AND 50-446 DAMPING VALUES FOR HVAC DUCT AND DUCT SUPPORTS REF: NRC letter from C. I. Grimes to W. G. Counsil dated December 6, 1988, " Issuance of Supplement 18 to NUREG-0797" Gentlemen:

The purpose of this letter is to confirm the CPSES commitment to Regulatory Guide 1.61 for the selection of damping values used in CPSES Corrective Action Program (CAP) HVAC design validation and to clarify the actual damping values that can be used.

Supplement 18 of the Safety Evaluation Report (SER) reviewed and evaluated the seismic analysis methods employed in the CAP design validation. The NRC ,

reviewed documents that provided the design-basis that ensures licensing commitments, including those in the CPSES Final Safety Analysis Report ;FSAR),

are properly documented and appropriately addressed in the design procedures.

The NRC specifically delineated in Supplement 18 the use of amplified respons spectra curves in the HVAC design validation of 2-percent for the OBE and 4-percent for the SSE. The NRC presented the results of their review in Supplement 18 to the SER as follows: "The damping values used in the HVAC design validation are consistent with the guidelines applicable to welded steel structures provided in Regulatory Guide 1.61, Damping Values for Seismic Design of Nuclear Power Plants (Reference 26), and are, thus acceptable. "

This statement is based on the documentation reviewed by the NRC and represents the practice in effect at the time. The SSER statement can be interpreted to imply that CPSES is committed to only using the 2-percent and 4-percent damping values and that the use of any other values would exceed our licensing basis.

CPSES FSAR sections IA(B) and 3.7B.3 provide TV Electric's commitment to Regulatory Guide 1.61 guidelines for the selection of damping values used in the CAP HVAC design validation. The implementation of this commitment l requires that acceptable damping values be selected and justified based on the l HVAC design. The possible acceptable values are not limited to 2 and 4 percent. The actual values used at CPSES are documented in the validation documentation and are available for review.

8909110364 890830 poM

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2DR ADOCK 05000445 PDC L 3

400 North Olive Street LB 81 Dallas, Texas 75201

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-l TXX-89511 1 August 30, 1989 Page'2 of 2 The clarification provided in this letter has been previously discussed with C. I. Grimes and J. Wilson of your staff. If you have any questions, please contact H. A. Marvray at (214)_812-8296.

Sincerely, William J. Cahill, Jr.

HAM /ddm c - Mr. R. D. Martin, Region IV Resident Inspectors, CPSES (3)

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