ML20129H640
| ML20129H640 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 07/15/1985 |
| From: | Tucker H DUKE POWER CO. |
| To: | Adensam E, Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8507190278 | |
| Download: ML20129H640 (2) | |
Text
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Dunn Powrit GoxPAxy P.O. BOX."l3180 CHARLOTTE, N.O. 28242 IIAL B. TUCKER TELEPHONE (704) 373-<4531 WICE PEFBIDENT Nt:CLRAN PSODEMTION July 15, 1985 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C.
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Attention:
E. G. Adensam, Chief Licensing Branch No. 4
Subject:
McGuire Nuclear Station Docket Nos. 50-369 and 50-370 Technical Specifications for the Groundwater Monitoring System
Dear Mr. Denton:
This letter la in response to NRC staff questions concerning Duke's license amendment request of October 31, 1984. This amendment request concerned the McGuire huclear Station Groundwater Monitoring System.
The proposed amendment seeks to eliminate inconsistensies between the existing Technical Specifications and the capabilities of the Groundwater Monitoring System as installed at McGuire Nuclear Station. Presently, the interior groundwater monitors detect and alarm the exterior groundwater level rise when it is 2' - 8" above the monitored floor level. Contrary to this, the current Technical Specifications specify that the interior groundwater level monitors detect and alarm when the groundwater level rises to the top of the monitored floor slab. Siace the monitors in questions alarm at 2' - 8" above the floor level rather than at floor level, there is less time for the opera-tors to respond and take action for an alarm prior to the groundwater level reaching the next monitored level of 5 feet. Duke Power has analyzed this situation to determine how much time is lost and what impact this has on operator rerponse time.
For this analysis total blockage of the underground drainage system was used as the worst case scenario (discussed in the McGuire Nuclear Station FSAR Section 2.4.13.5).
It was calculated that with the underground drainage system totally blocked, it would take 38.4 1 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> for the water level to rise from a monitored floor slab level to 5 feet above the slab level.
For the as built situation, it was calculated that it would take 19.2 ! 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> for the water level to rise from 2' - 8" above a monitored floor slab level to 5 feet above the slab level. This analysis indicates a difference of approximately 19.2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> for undetected groundwater icvel rise.
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4 Mr. Harold R. Denton July 15, 1985 Page 2 The groundwater monitor alarm procedure was reviewed and the determination was made that it would take an operator approximately 10 minutes to respond to a groundwater level alarm and take appropriate actions. The results of this analysis illustrate that there is no impact on operator response time.
The amount of response time continues to allow operators time to take re-quired actions without jeopardizing any safety margins.
Please feel free to contact us if you require any further information on this topic.
Very truly yours, k
A g
Hal B. Tucker WHM:smh cc:
Dr. J. N. Grace, Regional Administrator U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, Suite 3100 Atlanta, Georgia 30323 W. T. Orders Senior Resident Inspector McGuire Nuclear Station