ML20084D016

AO 250-74-2:on 740205,safety Injection Pump 3A Failed to Start.Caused by Closing Spring Mechanical Indicator of Safety Injection Pump 3A Motor Circuit Breaker Being in Intermediate Position & Not Closed.Spring Mechanism Tested

ML20084D016
Person / Time
Site:	Turkey Point
Issue date:	02/15/1974
From:	Schmidt A FLORIDA POWER & LIGHT CO.
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
References
AO-250-74-2, NUDOCS 8304080447
Download: ML20084D016 (3)

Text

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! Mr. John F. O' Leary, Director Directorate of Licensing fgM3y @ .

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Dear Mr. O' Leary:

ABNORMAL OCCURRENCE NO. 250-74-2 l FEBRUARY 15, 1974 q OCCURRENCE DATE: FEBRUARY 5, 1974 ,

a TURKEY POINT UNIT NO. 3 1

FAILURE OF NO. 3A SAFETY INJECTION PUMP TO START 1 i A. Conditions Prior to Occurrence 1

l- Unit No. 3 Reactor was operating at steady-state con-l ditions of approximately 60% reactor power.

1 j B. Description of the Occurrence

At approximately 3:35 PM on February 5, 1974, the reactor

). operator noted that No. 3B accumulator level was approaching

the lower end of the desired operating band. He selected j No. 3A Safety Injection Pump to add borated water to the i accumulators. When he turned the control switch to the

, ON position, to start the pump, the control room indicaters i of motor current, system flow, and system pressure remained

! at zero, indicating that No. 3A Safety Injection Pump did i not start. Immediate investigation by plant personnel re-

! vealed that No. 3A Safety Injection pump motor circuit '

i breaker,was in an intermediate position and was not closed.

j^ C. Cause of the Occurrence Visual inspection of No. 3A Safety Injection Pump motor

< ' circuit breaker showed that the closing spring mechanical j j indicator was in an intermediate position. No other ,

abnormal conditions were found. ,

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.The circuit breaker was then placed in the racked out position. The circuit breaker' closing spring charging ,

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'notor mance. was- tested and. demonstrated satisfactory perfq' cal 3 results were This.testwasrepeatedfivetipes-apf0 obtained.

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Page 2 February 15, 1974 l

I The circuit breaker was placed in the racked in position and No. 3A Safety Injection Pump was then started and demonstrated satisfactory performance.

Evaluation of the results of the visual inspection, the tests of the closing sprin,g charging motor, and the sucessful start of No. 3A Safety Injection Pump con-cluded that the failure to start was caused by an in-sufficient charge on the circuit breaker closing spring.

D. Analysis of Occurrence At the time of the occurrence, the accumulator levels were within specified operating limits. Manual starting of No. 3A Safety Injection Pump was acceptable and there were no safety related requirements for operation of a safety injection pump when this incident occurred.

If operation of the Engineered Safeguards System had required automatic operation of safety injection pumps during the time No. 3A Safety Injection Pump was in-operable, the other three safety injection pumps were operabic. The Safety Analyses presented in the Turkey Point Unit Nos. 3 and 4 Final Safety Analysis Report assume that only two safety injection pumps operate during the incident analyzed.

Technical Specifications for the facility provide for continuing to operate at power with three safety in-jection pumps operabic for periods up to 30 days.

Therefore, the failure of No. 3A Safety Injection Pump did not adversely affect the safe operation of Turkey Point Unit No. 3 and did not present any danger

.to the public health or safety.

E. Corrective Action The immediate corrective action taken was to test No. 3A Safety Injection Pump motor circuit breaker closing spring charging mechanism, demonstrate satisfactory. circuit

. breaker operation, and return the circuit breaker to service.

To prevent repetition of this and similar instances in the future, procedures have been established which pro-vide for a daily visual inspection of Engineered Safe-guards System equipment circuit breakers. This inspec-tion will include verification that electrical power is availabic to operate the circuit breaker closing spring charging motor and that the mechanical indicator shows that the closing spring is fully charged.

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Mr. John F. ' Leary O Page 3 February 15, 1974 F. Failure-Data This is the first failure of this type _ experienced on Turkey Point Unit Nos. 3 and 4 circuit breakers.

No. 3A Safety Injection Pump motor circuit breaker was manufactured by General Electric Company. The air circuit breaker is type AM-4,16-350, rated at 1200 A.

Very truly yours,

'f

. D. Schmidt Director of Power Resources .

VTC:df cc: Mr. Norman C. Moseley, Director Region II Directorate of Regulatory Operation U.S. Atomic Energy Commission Suite 818

'230 Peachtree Street, N.W.

Atlanta, Georgia 30303 m

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