ML20083Q843

Responds to Re Violations Reported to NRC on 720420 & 1006.Corrective Actions:Bldg Ventilation Sys Circuitry Mod Implemented & Liquid Poison Pump Circuitry Modified by Adding Interposing Relay to Control Cabinet

ML20083Q843
Person / Time
Site:	Oyster Creek
Issue date:	03/29/1973
From:	Ross D JERSEY CENTRAL POWER & LIGHT CO.
To:	Schemel R US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20083Q846	List: ML20083Q843
References
NUDOCS 8303300644
Download: ML20083Q843 (2)

Text

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o n O U 3 ysa Jersey Central Power & Light Company  ;

/\# s Q/ 50-219 MADISON AVENUE AT PUNCH BOWL Ro AD 9 MoRRISToWN, N.J. 07960 e 539 611 f March 29, 1973 "rf pri . 1 ll @- W h

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Mr. Robert J. Schemel, Chief is- -

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^L) (: .i Operating Reactors Branch #1 g- APR2 1973 Si Directorate of Licensing r.t. inn ... g CJ ti[

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United States Atomic Energy Commission QJ/

Washington, D. C. 20545 6 .

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D N. T. W . '

Dear Mr. Schemel:

In accordance with your letter dated January 17, 1973, the following information was assembled regarding the corrective action taken to avoid a reoccurrence of incidences of the nature reported to (f/ j the AEC on April 20, 1972 and October 6, 1972.

t r rs Reactor Building Ventilation System Circuitry Modification jV As was reported on April 20, 1972, a Limiting Condition for p' Operation was violated when a circuit malfunction prevented the reactor

y building supply dampers from shutting regardless of the operation of a' the supply fans. It was discovered that this malfunction would occur every time one of the three supply fan circuit breakers was " racked out". This happened because a " racked out" breaker would supply a e' " fan running" signal to each of the twenty supply damper's logic 3 circuits. Since the three " fan running" signals fed a series OR

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K circuit, one racked out breaker and two deenergized fans would create the logic to allow the dampers to remain open.

f'p : On August 29, 1972, a circuit modification was implemented s

(- ! which corrected the above situation. Now a " racked out" fan sends a " fan stopped" signal to a parallel OR circuit. For a supply damper to remain open, it is now necessary for at least one fan to be running.

I Liquid Poison Pump Circuitry Modification The problem with the control circuitry for these pumps is similar to that discussed above. Whenever one pump's breaker was

" racked out", the other pump was rendered inoperable. The control circuit has a feature which will not allow both pumps to run simultaneously. Originally, this was implemented by having a normally closed auxiliary switch from the A pump's starter in the B pump's starting circuit (and vice versa) . hhen the A pump was started, the auxiliary switch would open and thereby Because the auxiliary prevent the B pump from being energized.

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l 8303300644 730329 M,N3 PDR ADOCK 05000219 G PDR

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. Mr. Rob J. Sch::mel .

March 29, 1973 switch was mounted to the circuit breaker frame, its contacts in the standby pump's starting circuit were physically removed when the breaker was racked out. This simulated one pump operating and subsequently locked out the standby pump.

On December 20, 1972, both pump circuits were modified as follows: An interposing relay mounted to the control cabinet was added to each control circuit. These relays are normally deenergized and have nomally closed contacts which function as interlocks for t

the standby pump. The auxiliary switches have been removed from the pump starting circuits and have been changed to normally open contacts which control the interposing relay, hhen a pump is started, its auxiliary switch closes and causes the interposing relay to energize.

This, in turn, opens the contacts in the standby pump's starting circuit and thereby prevents it from starting. If a breaker is racked out, it has no affect on the state of the interposing relay. Therefore, the operability of the standby pump is not affected.

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In addition to the above ciodifications, an investigation was conducted for all Engineered Safeguards Systems which could possibly exhibit failures similar to those discussed above.

Specifically, the study concentrated on racking out a breaker of a component and its affects on other redundant components in the system. The study was completed on December 1,1972 and revealed no additional problem areas.

l Regarding your request for a proposed Technical Specification i change, we do not feel it to be warranted. The Technical Specifications at present delineate the action to be taken if redundant safeguard system equipment is rendered inoperabic. Recently we have issued a Standing Order which requires the testing of a redundant system immediately after its counterpart is rendered inoperable or found to be inoperable.

Since these meet the intent of your request, no changes to the Technical Specifications are deemed necessary.

Very truly yours, i

l o W Donald A. Ross Manager, Nuclear Generating Stations i pk

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