ML20099K407
| ML20099K407 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 03/01/1985 |
| From: | Kalivianakis N COMMONWEALTH EDISON CO. |
| To: | Case E Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737, TASK-2.K.3.18, TASK-TM NJK-85-70, NUDOCS 8503200262 | |
| Download: ML20099K407 (2) | |
Text
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O Commonwealth Edison Qu:d Citts Nucle:r Power Stati:n
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22710 206 Avenue North Cordova, Illinois 61242 Telephone 309/654-2241 NJK-85-70 March 1, 1985 Mr. Edson G. Case, Deputy Director Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D. C.
20555
Dear Mr. Case:
Enclosed please find a listing of those changes, tests, and experi-ments completed during the month of February,1985, for Quad-Cities Station Units 1 and 2, DPR-29 and DPR-30.
A sunmary of the safety evaluation is being reported in compliance with 10 CFR 50.59.
Thirty-nine copies are provided for your use.
Respect ully, COMMONWEALTil EDISON COMPANY QUAD-CITIES NUCLEAR POWER STATION h
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N. J. Ka ivianakis Station Superintende bb Enclosure cc:
B. Rybak bod h.
i 8503200262 850301 PDR ADOCK 05000254 R
1:
Modification M-4-1-83-47~
Description Modification M-4-1-83-47 installed two 8.5 minute Auto Blowdown timers and an Auto: Blowdown Inhibit keylock switch. The new timer is a result of NUREG 0737, Item II.K.3.18, and the inhibit switch is a result of the new emergency operating procedures. The timers start on a low-low level signal from the 287-72A through D Yarway Reactor level instruments. -If Reactor level remains at or below the low-low level setpoint for 8.5 minutes; the RHR and Core Spray pumps auto start and the Reactor will blowdown.
If Reactor level goes above the low-low level setpoint before the 8.5 minutes is up, the timers auto reset. If a blowdown has occurred.the Auto Blowdown timer reset button must be
" depressed to reset the 8.5 minute timers., The Auto Blowdown Inhibit
-keylock-switch will prevent an_ auto blowdown from occurring. When the keylock switch.on the 901-3 Panel is moved to inhibit, an Auto Blowdown Inhibit. alarm will be received.' The Target Rock and Electromatics will
- open at their pressure setpoints even if the auto blowdown has been inhibited.
Evaluation The basis for the Technical Specification on the Auto Blowdown ~
System is to provide vessel depressurization enabling Core Spray or LPCI protection against small pipe break independent of HPCI. This function'is unchanged. The system will limit fuel cladding temperatures to well below cladding melt point and will assure that core geometry
,will remain intact. The circuitry changes allow Auto Blowdown for more event sequences. ' No single failure can prevent Auto Blowdown from depressurizing the Reactor vessel and the two channels are independent.
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