ML20076C937

Responds to NRC 830711 Telcon Request for Addl Info Re Control Room HVAC Failure Criteria.Five Dampers Identified W/More Conventional Dv Damper Valve Nomenclature.Corrected List of Valve Identification Numbers Encl

ML20076C937
Person / Time
Site:	Fort Saint Vrain
Issue date:	07/28/1983
From:	Brey H PUBLIC SERVICE CO. OF COLORADO
To:	Madsen G NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
TASK-3.D.3.4, TASK-TM P-83261, TAC-46448, NUDOCS 8308230227
Download: ML20076C937 (5)

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! 2420 W. 26th Avenue, Suite 100D Denver, Colorado 80211

. l July 28, 1983 Fort St. Vrain Unit No. 1 P-83261 Mr. G. L. Madsen, Chief Reactor Project Branch 1 7

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]@][M]3 U.S. Nuclear Regulatory Commission Region IV # E I 51983 611 Ryan Plaza Drive, Suite 1000 ug Arlington, Texas 76011 - -

DOCKET N0: 50-267

SUBJECT:

Fort St. Vrain Unit No. 1 Coatrol Room HVAC Failure Criteria

REFERENCE:

NRC Letter Dated June 27, 1983 Madsen to Lee Gentlemen:

In a phone conversation with Mr. Wagner on July 11, 1983, points of your inquiry were clarified along with some typographical errors on valve (damper) identification numbers in the above reference letter.

We assume your references to V75432 and V75499 should have been V75482 and V75449, respectively.

l It should be noted that a modification has been implemented to identify the "V" dampers with a more conventional "DV" damper valve nomenclature. This new identification has been included for your use and information. (Figure 2)

The following are responses to your inquiry for additional information:

ITEM 1 Both of these fans are protected by low flow sensors which shut the fans down automatically.

8308230227 830728 DR ADOCK 05000267 .iap I PDR t1 hl

7 P-83261 Page 2 i

S ITEM 2 It is our understanding that operating plants are not obligated to follow the guidelines of the SRP.

All control room HVAC dampers are not accessible for repair as discussed in So.P Section 6.4, Appendix A, since some have internal linxages. However, appropriate dampers required to close for isolation of the Control Room are accessible and can be manually positioned.

ITEN 3 V75482 is now identified as DV75363 and is closed during normal operation.

ITEM 4 V75404 now identified as DV75300 is a modulating damper and is not normally closed during operation.

ITEM _5 From an actual test perforrr.ed in April 1976, the maximum temperature rise over 11 hours1.273148e-4 days <br />0.00306 hours <br />1.818783e-5 weeks <br />4.1855e-6 months <br /> was 13 F. These results are within the FSAR limits.

ITEM 6 V75402 now DV75298 V75405 now DV75301 V75407 now DV75303 V75482 now DV75363 V75449 now DV75330 V75400 now DV75296 V75401 now DV75297 V75406 now DV75302 The valve "line-up" detailed in this comment will put the Control Room and Auxiliary Electric Room in a recirculation mode with "make-up" air coming from the Turbine Building. Since the Control Room supply fan (C-7504X) is of a higher capacity than l the Control Room return fan (C-7505), it is not evident that the l Control Room will be subatmospheric. Low pressure in the Control Room can be detected by a pressure differential indicator (PDI-7556), and low flow at the discharge of C-7506 will alarm XA-7501-1. Corrective action might include modulation of damper DV-75327 (formerly V-75446) or shutting down of return fan C-7505.

P-83261 Page 3 ITEM 7 The HVAC isolation dampers and associated fans are tested annually per the requirements of Technical Specification SR5.10.1.

Please contact J.R. Reesy at (303) 571-8406 with further questions on this matter.

Very truly yours, H. L. Brey, Manager Nuclear Engineering Division Attachments l

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