ML20064M641
| ML20064M641 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 03/22/1994 |
| From: | Powers K TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| TAC-M74468, TAC-M74469, NUDOCS 9403280310 | |
| Download: ML20064M641 (3) | |
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inrn;%ee VW/ 4ilfxwt, f46f ONe 6n PICO Scd:N Daic., fenrer,,ee 37.379 March 22, 1994 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk 3
. Washington, D.C. 20555 Centlemen:-
In the Matter of
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Docket Nos. 50-327 Tennessee Valley Authority
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50-328 SEQUOYAH NUCLEAR PLANT (SQN) - REVISED RESPONSE TO SQN'S INDIVIDUAL PLANT EXAMINATION (IPE) REQUEST FOR ADDITIONAL INFORMATION RESPONSE (TAC NOS. M74468 AND M74469)
Reference:
TVA letter to NRC dated February 25, 1994, "Sequoyah Nuclear Plant (SQN) - Response to Request for Additional Information Related to the SQN Units 1 and 2 Individual Plant Examination (IPE) Submittal (TAC Nos. M74468 and M74469)"
The purpose of this letter is to provide a revised response to General
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Question 3. Insight 3, which is contained within the above reference.--As discussed with D. E. LaBarge on March 8, 1994, a revised response is needed te Insight 3 because the " area" coolers described in the response do not receive a start signal upon pump start as stated in the response.
This discrepancy was identified by the NRC Senior Resident Inspector and uas the result of ambiguous information contained within the associated logic drawings and design criteria. This information is being corrected.
The electrical schematic. drawings correctly reflect the' cooler start criteria. Note that " room" coolers do receive a start signal upon pump-start.
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I U.S. Nuclear Begulatory Commission Page 2 March 22, 1994
-The revised response to Insight 3 is as shown in the enclosure. We regret any inconvience this may have caused. Please direct questions concerning, a
this issue to J. D. Smith st (615) 843-6672.
1 Sincerely, ANAb iff b
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Ken Powers j
Site Vice President Sequoyah Nuclear. Plant 1
Enclosure cc (Enclosure):
Mr. D. E. LaBarge,. Project Manager U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852-2739 NRC Resident Inspector-Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy-Daisy, Tennessee 37379-3624 Regional Administrator U.S. Nuclear Regulatory Commiss: m Region Il 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323-2711
. ENCLOSURE 4
NRC Review Question General 3:
Section 6.4 discusses insights and recommendations that you view as potential enhancements.
Please discuss the status of these insights and recommendations, vis-a vis, actual implementation at Sequoyah. If relevant, provide a schedulefor the evaluation and!or implementation of these issues.
Response
Insight 3. Area ventilation is provided to the motor-driven AFW pumps and the CCS pumps from multiple systems. Current room heatup analyses suggest that, without successful area ventilation, temperatures would exceed the motor-driven pump temperature limits within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. Perform an evaluation of the CCS/AFW area cooling requirements.
Status 3. The AFW and CCS pumps areas are cooled and ventilated for normal plant operation by non-safety related equipment. When these ESF pumps are needed for accident conditions, the associated safety-related pump area coolers will operate upon receipt of an ABI signal or high space temperature. The safety-related coolers are redundant and seismically qualified.
The likelihood of all the safety related and non-safety related cooling and ventilation being inoperable during operation of the AFW and CCS pumps for accident conditions is remote. The non-safety related ventilation and r
cooling equipment normally runs all the time and even has equipment redundancy to provide for some additional reliability. Discussion with plant personnel have indicated that the availability of the non-safety-related ventilation and cooling equipment over the past years has been acceptable.
A transient analysis of the cooling requirements in these pump areas can determine what the heat up rate and temperature would be for various equipment and plant alignment scenarios. The results could be used in the event of loss of safety-related and/or non-safety related ventilation and cooling equipment. While the results of a temperature analysis may provide some benefit, the cost and resource commitment to perform the analysis would be substantial and is not justified.
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