ML20141F798

Discusses 841228 Proposed Addition of Low Temp Overpressure Protection Alarm Circuit to RHR Sys Suction Valves 8702A & 8701B.Proposed 851125 Alarm Circuit Mod Acceptable

ML20141F798
Person / Time
Site:	Callaway
Issue date:	04/15/1986
From:	Oconnor P Office of Nuclear Reactor Regulation
To:	Schnell D UNION ELECTRIC CO.
References
NUDOCS 8604230175
Download: ML20141F798 (3)

Text

. _ _ - - _ - _ _ _ _ _ _ _ - _ _ _ _ _ - _ _ _ _ _ _ _ _ _ _ _ - _ _ _ _ -

4' j#  %,

UNITED STATES p '^

j j NUCLEAR REGULATORY COMMISSION

• e WASHING TON, D. C. 20555

.f 15 APR L Docket No.: 50-483 Mr. D. F. Schnell Vice President - Nuclear Union Electric Company Post Office Box 149 St. Louis, Missouri 63166

Subject:

Low Temperature Over Pressure Protectio'1 By letter dater December 28, 1984 you proposed to add an alam circuit to RHR system suction valves 8702A and 8701B. According to the logic of that circuit if any one of the two valves is either open or has no power to its operator and the reactor coolant system (RCS) pressure has reached or exceeded the valve interlock activation setpoint of 680 psig, an alarm will sound in the control a room. These alarms will provide assurance that the RHR system is properly isolated from the RCS when the plant is returned to operating pressure follow-ing use of the RHR suction relief valves for low temperature over pressure protection. The staff has reviewed the above proposed alam circuit and by letter dated July 30, 1985, concluded that it is acceptable.

Subsequently, during the course of completing the detailed design of this alarm circuit you became aware of a design conflict with the existing plant procedures.

By nomal operating procedures and in satisfaction of another staff position the plant operator is required to close all RHR suction isolation valves and remove their power before the RCS is pressurized to operating conditions.

Although the RHR valves are now closed, when the RCS pressure is at or above the interlock activation setpoint the alarm will be activated and cannot be cleared since one of its conditions is continuously satisfied, i.e., the operators of valves 8702A and 8701B have their power removed. In order to remedy this situation, UE proposed, by letter dated November 25, 1985, to modify the alarm logic so that it will alam only if either of the above two valves is open above the interlock setpoint. Valve position indications will receive their signals from limit switches that are mounted directly on the valve stems. Power to these signals will be provided by the annunciator system power supply. A diverse alarm is provided by the computer annunciator, i

8604230175 860415 PDR ADOCK 05000483 PDR P

}

i Mr. D. F. Schnell The other two RHR suction isolation valves, 8702B and 8701A, continue to be interlocked independently. If open, these valves close automatically if the pressure setpoint of 680 psig is reached or exceeded. Since the proposed modification provides alarms if any of the subject valves were left inadver-tently open, which is the same function as that of the originally proposed alam circuit, this staff concludes that the proposed modification is acceptable.

Sincerely,

\

Paul O'Connor, Project Manager PWR Project Directorate #4 Division of PWR Licensing-A cc: See next page DISTRIBUTION:

J. Docket File I NRC PDR Local PDR PRC System NSIC PWR#4 Rdg MDuncan BJYoungblood Rdg P0'Connor OELD ACRS (10)

JPartlow BGrimes EJordan fp) '

.Iri PWR#4/DPWR-A PWR*4/ WR-A PWR*4/DPWR-A P0'Connor/mac MDun ,n BJYoungbloed 04/ / y /86 04/- 86 04/ q./86 i

2 4

Mr. D. F. Schneli Callaway Plant Union Electric Cotpany Unit No. I cc:

Mr. Nicholas A. Petrick Lewis C. Green, Esq.

Executive Director - SNUPPS Green, Hennings & Henry 5 Choke Cherry Road Attorney for Joint Intervenors Rockville, Maryland 20850 314 N. Broadway, Suite 1830 St. Louis, Missouri 65251 Gerald Charnoff, Esq.

Thomas A. Baxter, Esq. Ms. Marjorie Reilly Shaw, Pittman, Potts & Trowbridge Energy Chairman of the League of l 1800 M Street, N. W. Women Voters of Univ. City, M0 i Washington, D. C. 20036 7065 Pershing Avenue i University City, Missouri 63130 Mr. J. E. Birk Assistant to the General Counsel Mr. Donald Bollinger, Member Union Electric Company Missourians for Safe Energy Post Office Box 149 6267 Delmar Boulevard St. Louis, Missouri 63166 University City, Missouri 63130

' U. S. Nuclear Regulatory Comission Mr. Dan I. Bolef, President Resident Inspectors Office Kay Drey, Representative l RR#1 Board of Directors Coalition Steedman, Missouri 65077 for the Environment St. Louis Region Mr. Donald W. Capone, Manager 6267 Delmar Boulevard Nuclear Engineering University City, Missouri 63130 Union Electric Company Post Office Box'149

(

St. Louis, Missouri 63166 Chris R. Rogers, P.E.

Manager - Electric Department 301 W. High Post Office Box 360 l

Jefferson City, Missouri 65102 Regional Administrator U. S. NRC, Region III 799 Roosevelt Road Glen Eliyn, Illinois 60137 Mr. Ronald A. Kucera, Deputy Director Department of Natural Resources l P. O. Box 176 Jefferson City, Missouri 65102 Mr. Glenn L. Koester Vice President - Nuclear Vansas Gas and Electric Company 201 North Market Street Post Office Box 208 Wichita, Kansas 67201