ML20137V052

Provides History & Status of Auxiliary Power Upgrade Implemented in Response to 840212 & 16 Events.Ser Concludes That Design of Upgrade Results in Overall Improvement in Electrical Sys Design & Safety of Plant

ML20137V052
Person / Time
Site:	Turkey Point
Issue date:	01/31/1986
From:	Woody C FLORIDA POWER & LIGHT CO.
To:	Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
NUDOCS 8602190414
Download: ML20137V052 (3)

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'I bk . FLORIDA POWER & LIGHT COMPANY

' O[ JAN 3 1 NBS L-86-40 ggg 24 W Dr. 3. Nelson Grace Regional Administrator, Region 11 U.S. Nuclear Regulatory Commission 101 Marietta Street NW, Suite 2900 Atlanta, G A 30323

Dear Dr. Grace:

h Re: Turkey Point Unit 3 and 4 Docket Nos. 50-250 and 50-251 Auxillary Power Upgrade This letter provides a brief history and status of the Auxillary Power Upgrade being implemented by the Turkey Point Plants.

Turkey Point Plant experienced a series of events on February 12 and February 16, 1984, which included reactor trips, unscheduled shutdowns, and loss of ofIsite power to Unit 3. These events were described in License Event Reports 250-84-06 & 250-34-07, respectively. Dy Confirmation of Action Letter (L-84-36) dated February 21, 1984 Florida Power and Light Company (FPL) identified interim actions which were completed prior to restart and long term actions which included a review of the offsite and onsite electrical power systems. FPL provided the results of their review and proposed design modification for the NRC to review and approve prior to completing the proposed changes. The above commitments were confirmed by NRC letter dated February 29,1984.

By letters L-84-157 dated June 22,1984 and L-84-ISO dated July 25,1984, FPl.

provided design details and analysis in support of the auxillary power upgrade. NRC issued an SER on September 17,198h with the conclusion that the design of the proposed auxillary power upgrade results in an overall improvement in the electrical system design and safety of the plant, and is therefore, acceptable.

The modified item 2 of FPL Confirmation of Action Letter (L-85-163) dated April 17,1985, stated:

"Pending long term design changes and modifications, Units 3 & 4 will not be operated at greater than 50% rated feedwater flow unless the associated unit's "C" bus is being powered from the opposite unit's "C" transformer. The feeder breaker from each unit's "C" transformer to its' respective bus will be maintained in a racked out configuration whenever the respective unit is operating at greater than 50% rated feedwater flow."

0602190414 PDR ADOCK 0 86 h PDR s ,p PEOPLE. . SERVING PEOPLE ygi

y y a O Dr. 3. Nelson Grace L-86-40 Page Two The basis for this change was provided and confirmed by NRC letter dated April 24, 1985.

In early February,1986, FPL plans to complete the modifications described in letters L-84-157 and L-84-180. The final implementation will be conducted in two phases:

Phase I will accomplish separating the power supply of the Unit 3 start up

-(S/U) transformer and the Unit 3 "C" bus transformer. At the completion of this phase, the Unit 3 "C" bus and S/U transformers will be in the . final configuration.

Phase 2 will accompi:sh separating the power supply of the Unit 4 S/U transformer and the Unit 4 "C" bus transformer. At the completion of Phase 2 Unit 4 "C" bus and S/U transformer will be in the final configuration.

Phase I will require de-energizing the Unit 3 start op transformer and the Unit 3-

"C" bus transformer for approximately 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. During this period Unit 3 will reduce ' power. to less than 50% rated feed flow and Unit 4 will be in a refueling outage.

Phase 2 will require de-energizing the Unit 4 start up transformer and the Unit 4 "C" bus transformer for approximately 10 days. During this period Unit 4 will be in the refueling outage. Since the Unit 3 "C" bus transformer and start up transformer are in the final confirguration with separate feeds from the switch yard, Unit 3 can remain at 100% power.

Completion of Phase 1 above, completes item 2 of the Confirmation of Action Letter as modified on April 17, 1985, and the long term design changes and modifications will be complete for Unit 3. Unit 3 may then operate at greater than 50% rated feed flow with the Unit 3 "C" bus powered from the Unit 3 "C" bus transformer. In addition, af ter completion of Phase 2 above Unit 4 may operate at greater than 50% rated feed flow with the Unit 4 "C" bus powered from the Unit 4 "C" bus transformer.

FPL engineering has reviewed the proposed implementation plan and determined that as long as the Unit 3 "C" transformer modification is completed first and Unit 4 is in a refueling outage, the Unit 3 "C" transformer can be used to power both "C" buses during the Unit 4 "C" transformer modification with Unit 3 at 100% feedwater flow.

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Dr. 3. Nelson Grace

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Should you'have any questions please contact us.

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I Very truly yours, i

&e' C. O. Woody l

Group Vice P ~ten  !

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