L-90-413, Documents 901123 Request & Verbal Approval of Temporary Waiver of Compliance from Tech Spec 3.7.3, Ccws

Documents 901123 Request & Verbal Approval of Temporary Waiver of Compliance from Tech Spec 3.7.3, Ccws

ML17223B015
Person / Time
Site:	Saint Lucie
Issue date:	11/23/1990
From:	Sager D FLORIDA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
L-90-413, NUDOCS 9011280094
Download: ML17223B015 (5)

Text

ACCELERATED DISTRIBUTION DEMONSTRATION SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR: 9011280094 DOC. DATE: 90/11/23 NOTARIZED:

NO FACIL:50-389 St. Lucie Plant, Unit 2, Florida Power

& Light Co.

AUTH.NAME AUTHOR AFFILIATION SAGER,D.A.

Florida Power

& Light Co.

RECIP.NAME RECIPIENT AFFXLIATION Document Control Branch (Document Control Desk)

SUBJECT:

Documents 901123 request

& verbal approval of temporary waiver of compliance from Tech Spec 3.7.3, "CCWS."

DISTRIBUTION CODE:

AOOID COPIES RECEIVED:LTR

/

ENCL (J

SIZE:

TITLE: OR Submittal:

General Distribution NOTES DOCKET 05000389 RECXPIENT ID CODE/NAME PD2-2 LA NORRIS,J INTERNAL ACRS NRR/DET/ESGB NRR/DST 8E2 NRR/DST/SICB 7E NUDOCS-ABSTRACT OGC/HDS2 RES/DSIR/EIB EXTERNAL: NRC PDR COPIES LTTR ENCL RECIPIENT ID CODE/NAME PD2-2 PD NRR/DET/ECMB 9H NRR/DOEA/OTSB11 NRR/DST/SELB 8D NRR/DST/SRXB 8E OC/LFMB G=&PItE~

NSIC COPIES LTTR ENCL NOTE TO ALL"RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOM P 1-37 (EXT. 20079) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!

TOTAL NUMBER OF COPIES REQUIRED:

LTTR 24 ENCL

P.O. Box14000, Juno Beach, FL 33408-0420 November 23, 1990 L-90-4 13 10CFR50.36 U.

S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.

C.

20555 Gentlemen:

RE:

St. Lucie Unit 2 Docket No. 50-389 2B CCW Heat Exchanger Tem orar Waiver of Com liance This letter documents a request and verbal approval of a temporary waiver of compliance of Technical Specification 3.7.3, "Component Cooling Water System,"

Technical Specification 3.7.4, "Intake Cooling Water,"

and Technical Specification 3.0.4.

The verbal approval of the temporary waiver of compliance was transmitted to St. Lucie Plant by M., V. Sinkule (NRC Region II) on November 23, 1990.

On November 19,

1990, a small leak, about one drop every four

minutes, was detected on the 2B Component Cooling Water (CCW) Heat Exchanger.

The leak is located on the closed loop cooling water side of the tube sheet/shell weld joint.

The 2B CCW Heat Exchanger was taken out of service on November 20, 1990 to commence repair of the tube sheet/shell weld joint.

Technical Specification 3.7.3, "Component Cooling Water System,"

requires two independent component cooling water loops be operable during mode 1, 2, 3, and 4. Technical Specification 3.7.4, "Intake Cooling Water System,"

requires two independent intake cooling water loops be operable during mode 1,

2, 3,

and 4.

Technical Specification 3.0.4 prohibits entry into mode 1, 2,

3, and 4 with either one component cooling water loop or one intake cooling loop inoperable.

Florida Power and Light specifically requests a waiver of Technical Specification 3.0.4, to allow ascension to mode 3, a

waiver of Technical Specification 3.7.3, to allow one CCW heat exchanger to be out of service for 5

days, and a

waiver of Technical Specification 3.7.4 to allow one Intake Cooling Water train be out of service for 5 days.

If the 2B CCW Heat Exchanger is returned to operable status prior to 5 days, the temporary waiver of compliance will expire.

The waiver of Technical Specifications 3.0.4, 3.7.3, and 3.7.4 will enable St. Lucie Unit 2 to bring the Reactor Coolant System to full temperature and pressure while allowing the repair of the 2B CCW heat exchanger to be completed.

90ii280094 90ii2 PDR ADOCK 05000389 p

PDC an FPL Group company

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Technical Specifications associated with High Pressure Safety Injection, Low Pressure Safety Injection, Containment

Spray, and Containment

Coolers, have been determined to be no more limiting than the Component Cooling Water and Intake Cooling Water Technical Specifications.

As compensatory

measures, Florida Power and Light will:

1.

not remove any equipment associated with core heat removal (Emergency Core Cooling, AuxiliaryFeedwater, Atmospheric Dump Valves, Emergency Power Systems) for planned maintenance while this temporary waiver of compliance is in effect.

2.

establish the Technical Specification required inventory for the Condensate Storage Tank (CST) prior to mode 4

(normally required in mode

3) to ensure inventory for core heat removal is available.

A preliminary evaluation of the safety significance and the potential consequences demonstrates that there are no potential consequences which have not been previously analyzed in the Safety Analysis Report (SAR).

The basis for this conclusion is that the only credible failure of the CCW system is a failure of a

CCW system active component.

The 2A CCW Heat Exchanger will be the only non-redundant component during the time the 2B CCW Heat Exchanger is out-of-service.

St. Lucie Unit 2 has been analyzed for a Station Blackout event.

The Station Blackout analysis is presented in FSAR section 15.10, and concludes that the unit can withstand a Blackout for a four (4) hour duration without any adverse consequences.

Since a Station Blackout assumes loss of both offsite and onsite emergency

power, there would be a corresponding loss of CCW due to the loss of power to the CCW pumps.

The analyzed station blackout event will envelope any postulated loss of CCW scenario, since the duration of the analyzed Station Blackout event is 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> and the estimated maximum duration of the loss of CCW is only 1/2 hour.

In the event of a CCW system failure the plant would be required to execute a Natural Circulation Cooldown (due to loss of CCW to the RCPs).

Based on the FSAR Appendix 5.2B this Cooldown takes 25.7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br /> to bring the RCS to Shutdown Cooling entry conditions (cooldown to 325 at 50 F/hr and a 20.4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> soak at 325 degrees F

to ensure that void formation in the head is prevented for a total cooldown time of 25.7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br />).

During this time no components requiring CCW are relied upon for RCS cooldown.

Within this time frame, it -is possible to restore one (1) train of CCW by aligning the "C"'ump to the "A" Heat Exchanger using the "B" electrical train to power the "C" pump.

This would provide redundancy to the normal alignment of the "A" pump to the "A" heat exchanger powered by the "A" electrical train.

One (1) train of the CCW is sufficient to remove the entire decay heat load of the Reactor.

An evaluation of the Design Basis Loss of Coolant Accident with Loss of Offsite Power considering the failure of an active

component (Diesel Generator, High Pressure Safety Injection pump, Intake Cooling Water train) while the 2B CCW heat exchanger is inoperable was conducted.

With the single failure of any active component, Component Cooling Water is still available to provide its intended function.

Florida Power and Light has performed an evaluation to determine the root cause of the weld defects identified in the 2B CCW heat exchanger tube sheet/shell welds.

The root cause was determined to be lack of fusion between weld material and the carbon steel shell resulting in sufficient voiding in the weld to allow an observable leak.

Stresses induced due to retubing the 2B CCW heat exchanger, including the removal and reinstallation of the channel

heads, as well as the subsequent hydrostatic testing is the reason for the small leaks indicated at each end of the heat exchanger.

The 2A CCW heat exchanger was not retubed, and therefore did not undergo these additional stresses.

In conclusion, the 2A CCW heat exchanger will perform as designed.

FPL plans to conduct non-destructive examination of the full circumference of the 2B CCW Heat Exchanger shell/tube sheet welds during the next refueling outage to better characterize the condition of these welds.

This request does not involve a significant hazards consideration since:

1)

The postulated loss of CCW is enveloped by the Station Blackout Analysis.

2)

Sufficient time exists during the Natural Circulation Cooldown to restore the CCW system prior to achieving Shutdown Cooling Entry conditions.

3)

An evaluation has been performed which demonstrates that the 2A CCW heat exchanger will function as designed during a Loss of Offsite Power concurrent with a design basis Loss of Coolant Accident.

This Temporary Waiver of Compliance was reviewed by the Facility Review Group on November 23, 1990.

Very truly yours, 4A'. A.

er Vice sident St.

Lu e Plant DAS/JWH cc:

Stewart D. Ebneter, Regional Administrator, Region II, USNRC Senior Resident Inspector, USNRC, St. Lucie Plant