ML19209B562
| ML19209B562 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 09/17/1979 |
| From: | Ippolito T Office of Nuclear Reactor Regulation |
| To: | Parris H TENNESSEE VALLEY AUTHORITY |
| References | |
| NUDOCS 7910100136 | |
| Download: ML19209B562 (2) | |
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UNITED STATES E jp. s n [9,h NUCLEAR REGULATORY COMMISSION g,., { j u ;
WASHINGTON. D. C. 20555
\\Y EEPTEMBER 1 7 1979 Docket No. 50-259 fjr. Hugh G. Parris Manager of Power Tennessee Valley Authority 500 A Chestnut Street, Tower II Chattanooga, Tennessee 37401
Dear fir. Parris:
Reference is made to your letter of July 20, 1979 regarding periodic response tine testing of the end-of-cycle recirculation pump trip (RPT) system at Browns Ferry. As you stated in your letter, our Safety Evaluation supporting Amendment No. 48 to License No. DPR-33 noted that although TVA was not in agreement with the NRC staff on the need for periodic response time testing of the RPT system, you had committed in your letter of January 23, 1979 to submit a proposal to us on this subject.
The core analyses which you have submitted for Browns Ferry Units Nos.1, 2 and 3 rely on credit from the RPT systems in establishing the operating limit minimum critical power ratios (0LMCPR).
Your analysis shows thats to be effective, the RPT system nust interrupt the pump motor circuit within 175 milliseconds of the start of valve closure. Of this,10 ms is allotted for system action and sensor response, 30 ms for logic response and 135 ms for breaker action. At the time the RPT system was approved for Browns Ferry Unit No.1 (February 1979), only one other operating facility (Hatch Unit No. 2) had a similar RPT system. Since then, you have installed the RPT system on Unit No. 2 and are installing it on Unit No. 3.
Also, several other facilities either have or plan to install similar RPT systens. All of these systens were required to be preoperationally tested to verify response time. We have not seen any of this preoperational test data, so we do not know how much leeway there is between actual and required response time in "e installed RPT systems.
At
+;ent, we cannot concur with your position on periodic response time testing 01 t, e RPT systems as presented in your letter of July 20, 1979. To support your position, we would need additional data on actual performance history, industry experience on sensible degradation in cycle time for the components in the system and a more detailed analysis to show that the monthly logic tests of the system and
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the monthly breaker functional surveillance will insure that there has not been any significant degradation in response time of the overall RPT system.
Si ncerely, l}34-Ob
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y to Thon Ippolito, Chief Operating Reactors Branch #3 Division of Operating Reactors 3D 7910SP10 lN
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Mr. Hugh G. Parris tennessee Valley Authority 2
cc:
H. S. Sanger, Jr., Esquire General Counsel Tennessee Valley Authority 400 Commerce Avenue E llB 33 C Knoxville, Tennessee 37902 Mr. Dennis McCloud Tennessee Valley Authority 400 Chestnut Street, Tower II Chattanooga, Tennessee 37401 Mr. E. G. Beasley Tennessee Valley Authority 400 Commerce Avenue W 10C 131C Knoxville, Tennessee 37902 Robert F. Sullivan U. S. iluclear Regulatory Commission P. O. Box 1863 Decatur, Alabama 35602 Athens Public Library South and Forrest Athens, Alabama 35611 1134
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