ML20064E061

Forwards Corrected Page 4 to Response Attached to Re Reactor Coolant Sys Overpressurization Mitigating Sys

ML20064E061
Person / Time
Site:	Farley
Issue date:	11/09/1978
From:	Clayton F ALABAMA POWER CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
References
NUDOCS 7811140111
Download: ML20064E061 (2)

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Te epree 205 323-5341 s

i F. L CbYTON, JR.

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the sournem ewnc system.

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-Hovember 9, 1978 e

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Docket Nos.

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Director of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D.C.

20555 JOSEPH M. FARLEY NUCLEAR PLANT-UNITS 1 AND 2

~ sREACTOR COOLANT SYSTEM OVERPRESSURIZATION MITIGATING SYSTEM Gentlemen:

Enclosed please find a corrected page 4 to the responses attached to my November 3, 1978 letter on the above subject.

Should you have any questions please advise.

p-s Yours very truly, a

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hL.Clayton,i Jr.

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4 Enclosure

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u-As shown in Figures 4 and 6, the peak RCS pressure following the worst mass and heat input transients remains below the limiting Appendix G pressure for cooldown rates of 00F/hr and 20 F/hr.

For cooldown rates of 60 F/hr and 100 F/hr the peak RCS pressure gxceeds the limiting Appendix G pressure when the RCS temperature is below 95 F and 126 F, respectively. We consider this to be 'of an insignificant nature for the following reasons:

Temperatures below 126 F are very impractical to achieve due to the decay 0

(a) heat generat. ion and the heat capacity of the RCS.

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The normal cooldown rates are always below 60 F/hr. The 100 F/hr cooldown (b) rate is a limiting condition which, if ever achieved, is restricted in accordance with the Farley Technical Specification to a very short dura-tion of one hour. Thus, the possibilities of an overpressurization event coupled with a 100 F/hr cooldown rate is highly unlikely.

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Since the ASME Section III, Appendix G analysis per 10CFR50, Appendix (c)

G of the reactor vessel has significant built-in conservatism, potential un-j -

likely violations as explained earlier will not cause vessel degradation.

Figures 5 and 7 show the peak RCS pressure following the worst mass and heat input transients remains below the limitin0 ppendix G pressure for heatup A

rates of 00F/hr, 200F/hr, 600F/hr and 100 F/hr for all RCS temperatures.

Therefore, conformance to Appendix G is assured.

7.

Question:

provide assurance that no portion of the RHR system is subjected to pressure in excess of 110% of desian during any water-solid overpressurization.

Response

The RHR system pumps, piping, valves and the heat exchangers are designed for a minimum pressure of 600 psig. As shown in Figures 4, 5, 6, and 7 of our 9/6/78 submittal, the peak pressure following the worst overpressurization transients is 565 psig which is less than 660 psig (110% of 600 psig).

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