ML20215N803
| ML20215N803 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 10/31/1986 |
| From: | Tiernan J BALTIMORE GAS & ELECTRIC CO. |
| To: | Thadani A Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8611070293 | |
| Download: ML20215N803 (5) | |
Text
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BALTIMORE i
GAS AND ELECTRIC CHARLES CENTER R O. BOX 1475 BALTIMORE, MARYLAND 21203 JOSEPH A.TIERNAN vict PREslOENT NUCLEAR ENERGY October 31,1986 U.S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Washington, D.C. 20555 ATTENTION:
Mr. Ashok C. Thadani, Director PWR Project Directorate #8 '
Division of PWR Licensing-B
SUBJECT:
Calvert Cliffs Nuclear Power Plant Unit Nos.1 & 2; Docket Nos. 50-317 & 50-318 Control Room Ventilation
REFERENCE:
(a)
Letter from Mr. D. H. Jaffe (NRC), to Mr. 3. A. Tiernan (BG&E),
Request for AdditionalInformation, dated April 11,1986-(b)
Letter from Mr. 3.A. Tiernan (BG&E), to Mr. A.C. Thadani (NRC),
same subject, dated June 16,1986 Gentlemen:
You asked for more information on the relationship between ambient te:aperature measured on the control room wall and the temperature within the control panels and instrumentation cabinets 'in Reference (a). In our response (Item 1, Reference b), we stated we would conduct a temperature survey within the panels and cabinets. We have conducted this survey and the results are presented in Attachment 1.
The results indicate that the difference between the ambient temperature and the temperature in the instrumentation cabinets is insignificant. Therefore, the location where we measure ambient temperature is adequate. We attribute the favorable results to our cabinet design of open framework construction. This is shown by the attached photographs.
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Mr. Ashok C. Thadani October 31,1986-Page 2 Please contact us if you have any questions regarding this matter.
Very truly yours, _
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e4 G f J. A. Tiernan JAT/ WPM / dim Attachments cc:
D.A. Brune, Esquire.
J.E. Silberg, Esquire S.A. McNeil, NRC T. Foley, NRC
ATTACHMENT 1 Control Room Instrumentation Cabinet Temperature Survey Results Survey Period:
August 8-22,1986 Outdoor Temperature Range:
72 - 39 F 0
Control Room Ambient Temperature Range:
68 - 76 F Definitions:
- Ambient Temperature - The control room air temperature measured on the control room wall.
- 1.ocal Ambient Temperature - An air temperature measured within the walkway between the front and back cabinets.
Local Temperature - An air temperature measured within a cabinet, very close to the individual components.
Findings:
- Over 100 local ambient temperature measurements were made along the walkway between the front and back cabinets. None of these measurements exceeded the ambient temperature by 20 F and the. highest temperature recorded was 90 F.
- Over 1000 local temperature measurements were made in close proximity to components within the cabinets. Only 13% of these measurements exceeded the ambient temperature by more than 25 F.
==
Conclusions:==
- A 20 F ambient temperature difference is insignificant when assessing the performance of electrical equigment within this temperature range (68-90 F).
The high end of this range (90 F)is below the recognized industry design limit of 104 F for continuous service.
None of the local ambient temperature measurements in the walkway exceeded the control rocm ambient temperature by 20 F; therefore, the location where ambient temperature is measured is adequate to control the local ambient temperature within the cabinets.
Based on our Technical Fpecifications, the ambient temperature may reach 104 F. This may occur for short time periods (relative to the design life of the equipment). The corresponding local ambient temperature could increase by the noted 20 F to 124 F. This exceeds the continuous duty temperature rating of 104 F.
We find this acceptable because exposure to this temperature for short periods does not significantly degrade ~the equipment's performance.
' ATTACHMENT 1
- It is to be expected that the temperature will rise appreciably when in close proximity to certain heat-producing components such as resistors. A majority
. of the local temperature readings were no more than 25 F higher than the
~
ambient temperature. We identified a few hot spots where heat-producing components are surrounded by metal channels for purposes of meeting separation criteria. Hot spots will be evaluated and modifications made if appropriate.
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Control Room anels and Inst rumentat ion Cabinets
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