ML20002C987
| ML20002C987 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 03/11/1970 |
| From: | Haueter R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | Morris P, Skovholt D US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| NUDOCS 8101150666 | |
| Download: ML20002C987 (3) | |
Text
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Regulatory Fife cy, Dr. P. A. Morris, Director Re: Big Rock Point Division of Reactor Licensing Ibcket 50-155 United States Atomic Energy Commicsion Washington, DC 20545
Dear Dr. Morris :
Attention:
Mr. D. J. Skovholt In response to your letter of November 6,1969, in which you expressed concern about additional transient cycles on the Nuclear Steam Supply System if the main steam bypasc valve was not operational, we have checked our records regarding loss of trans-mission lines which resulted in a reactor trip. We have concluded that on only two occasions in the past seven years (since plant start-up) would the bypass valve have prevented a reactor trip upon loss of outside transmission. These occurred on September 17, 1965, from a load of Th MWe(gross), and on August 8,1966, from a load of 40 MWe(gross).
In each case, the reactor scrammed automatically with the emergency condenser limiting the pressure transient and reducing system pressure.
We cannot presume to know what frequency of transients might have been factored into the original safety evaluation, but it is our opinion that the demonstrated transmission system reli-ability durir.g the first seven years of service is well within the bounds of such an evaluation.
On the other hand, the past testing on the bypass valve and the difficulties expe.. iced with the valve nave resulted in consid-erably more transients on the Nuclear Steam Supply System. As we stated in our letter of September 10, 1969, we believe that presently we have a reliable system, but one that will probably not prevent a reactor trip for load rejections above 50 MWe.
A new 30 MWe load rejection test should permit us to evaluate the results of recent changes and predict the ultimate capability of the system as in-stalled. We do not believe that further testing at higher power levels is warranted or desirable.
The Big Rock Point Plant is presently down for refueling and we expect to be starting up in late March. The 30 MWe load rejection test will b2 performed ut this time.
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Dr. P. A. Morris 2
March 11, 1970 We will be happy to discuss the results of this test or any other matters with you if you should so desire.
Yours very truly, y
L7 J
T RLH/ deb Robert L. Haueter Electric Production Superintendent -
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FROMs DATE cP DOCUMENT DATE GECEIVE3 NO.:
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CLA04,4 Fs POS1 OFFICE FILE CODEa REG.NO DE.AIPTION: (Must Bp UnclaS5ified)
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