ML19296A983

Forwards Simulated Control Rod Out Pushbutton, Fuel Moves in Shutdown Mode & Local Leak Rate Test of Target Rock Valve Pneumatic Sys, Describing Changes,Tests & Experiments Completed Jan 1980

ML19296A983
Person / Time
Site:	Quad Cities
Issue date:	02/01/1980
From:	Kalivianakis N COMMONWEALTH EDISON CO.
To:	Case E Office of Nuclear Reactor Regulation
References
NJK-80-40, NUDOCS 8002190600
Download: ML19296A983 (4)

Text

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Corcova, it:mcis 61242 kb/ Telophone 303/654-2241 flJ K 40 february 1, 1980 Mr. Edson G. Case, Deputy Director Office of fluclear Reactor Regulation U. S . fluc l ear Regul a tory Corarai ss ion Washington, D.C. 20555

Dear Mr Case:

Enclosed please find a listing of those changes, tests, and experirnents completed during the conth of January, 1980, for Quad-Cities Station Units 1 and 2, DPR-29 and DPR-30. A suramary of the safety evaluation is being reported in compliance with 10 CFR 50.59 Thirty-nine copeis are provided for your use.

Very truly yours, C0l'.MONWEALTH EDI SON COMPANY QUAD-C ITIES !!UCLEAR POWER STATION

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O N. J. Kalivianakis Station Superintendent flJ K/B B/ san Enclosure cc: R. F. Janecek 9boR/Tb(sC6

• i 11-4-2-76-58 SIMULATED CONTROL ROD OUT PUSHBUTTON Description of Modification A normally closed pushbutton switch was installed in the reactor manual control system which will simulate a rod out condition in the refuel interlock circuitry when opened. The addition of this switch will clininate the need to remove wires each time refuel interlock cht.cks are performed.

Sum.aary of Safety Evaluation The probability of an accident is not increased by this change since the failure of this pushbutton would limit the travel of the refueling bridge the same as a rod out condition. The modification will i rap rove the margin of safety since it restores the interlock circuit by release of the switch instead of attaching a wire.

M-4-2-76-62 REFUEL BRIDGE INTERLOCK BYPASS SUITCH Description of Modification A switch was installed in the reactor manual control system so that the refueling platform interlocks can be bypassed when the platform is not over the reactor vessel. This will allow control rods to be withdrawn with the refueling bridge circuitry de-energized which will increase the life of the platform control circuitry.

Summary of Safety Evaluation

.The safety function of the refueling platform interlocks is to prevent a control rod from being withdrawn when the platform is over the core with fuel en a hoist. This modification cannot circumvent these interlocks unless the platform is not over the vessel, and once the interlocks are bypassed, the platform cannot be moved. Therefore, no FSAR evaluation will be changed and no new type of accident can occur.

M-4-2-77-24 FUEL MOVES IN SHUTD0VN MODE Description of Modification This modification involved wiring the reactor mode switch SHUTDOWN relays in parallel with the refuel platform bridge interlock relay.

This will permit fuel moves when the reactor mode switch is in the SHUTDOWN position, and eliminate the need for rod block interlock checks during fuel movements. All interlocks in REFUEL mode and refuel bridge interlocks remain the same. This modification will not be utilized until appropriate Technical Specific; tion changes have been approved and issued.

Summary of Safety Evaluation The safety function of the refueling platform interlocks is to prevent a control rod from being withdrawn when the platform is over the core with fuel on a hoist. This modification does not increase the probability of a previously evaluated accident or create the possibility of a new type of accident since no control rods can be withdrawn in the SHUTDOWN mode.

All Technical Specification requirements will remain the same except for the reactor mode switch position requirement.

M-4-2-77-25 DIESEL GENERATOR ACCUMULATOR CHECK VALVES Description of Modification A check valve was installed in the discharge line of the "C" "D" diesel generator air start accumulator pair. This modification will prevent blowdown of both accumulator pairs in the event of a rupture in the "C"-

"D" accumulator pair.

Summary of Safety Evcluation This modification will not affect the design function of the standby diesel generator or the air compressors. The starting capability of the diesel generator is enhanced by climinating the possibility of blowdown rupture. The possibility for additional accidents or malfunctions is not created.

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SPECIAL TEST 2-30 LOCAL LEAK RATE TEST OF TARGET-ROCK VALVE PilEUMATIC SYSTEM Description This test consisted of performing a leak check of the piping system and solenoid operator with the system pressurized at normal operating pressure.

Also, a local leak rate test was performed on the system up to the check valve. This test was performed as a result of NRC IE Bulletin 80-01.

Summary of Safety _ Evaluation The test was perforn:ed wi th the unit shutdown for a refueling outage, with the Target-hock Safety-Relief Valve removed for overhaul. The test did not potentially degrade the performance of the drywall pneumatic system. The test was performed at normal operating pressure.