ML17221A641

Responds to 880107 Supplemental Safety Evaluation Re Alternate Shutdown Capability.Util Will Add General Note in Procedure to Permit Restoration of Essential Equipment Should Bus Feeder Breaker Trip Due to Fire

ML17221A641
Person / Time
Site:	Saint Lucie
Issue date:	02/22/1988
From:	Conway W FLORIDA POWER & LIGHT CO.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
GL-81-12, GL-86-10, L-88-89, NUDOCS 8802260198
Download: ML17221A641 (7)

Text

REGULATORY INFORMATION DISTRIBUTION S TEM (RIDS)

VQ 4 ACCEEEION,PIBR: 8802260198 DOC. DATE: 88/02/22 NOTARIZED: NO DOCKET I FACIL: 50-335 St. Lucie Planti Unit ii Florida Power 8c Light Co. 05000335 AUTH. NAME AUTHOR AFFILIATION CONWAYe W. F. Florida Poeer & Light Co.

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

SUBJECT:

Responds to 880107 supplemental safety evaluation re alternate shutdoen capability. Util will add general note in procedure to permit restoration of essential equip should bus feeder breaker trip due to fire.

DISTRIBUTION CODE: A006D COPIES RECEIVED: LTR ENCL SIZE:

TITLE: OR/Licensing Submittal: Fire Protection NOTES:

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TOUR QNYr E 1 1 INTERNAL'CRS 3 3 ARM/DAF/LFMB 1 0 NRR WERMEILn J 1 0 NRR/DEBT/ADB7E4 1 1 NRR/DES PSBBD1 1 1 OQC 15-B-18 1 0 QF E 01 1 EXTERNAL'PDR 1 1 NRC PDR 1 1 NSIC 1 1 TOTAL NUMBER OF COP IEB REQUIRED: LTTR 19 ENCL 15

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~/Pl>)'6 FEBRUNY 2 2 f988 L-88-89 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555 Gentlemen:

Re: St. Lucie Unit 1 Docket No. 50-335 Alternate Shutdown Ca abilit By letter dated January 7, 1988 (E. G. Tourigny to C. 0.

Woody) NRC transmitted the Supplemental Safety Evaluation (SSE) for St. Lucie Unit 1 Alternate Shutdown Capability.

The SSE supplemented the original safety evaluation dated July 17, 1984 to address a fire in the Cable Spread Room.

The SSE concluded that except for two open items, the Florida Power & Light Company methodology for assuring safe shutdown for a fire in the Control Room or Cable Spread Room conforms to the criteria delineated in Sections III.G.3 and III.L. of 10 CFR 50 Appendix R and Generic Letter 81-12 and 86-10.

As requested by the above letter, attached please find FPL's plans to address the following two open items.

The absences of Thot indication on the alternate shutdown panel, and 2 ~ The lack of an analysis of multiple high impedance faults.

pools 8802260198 880222 ADOCN, 05000335, PDR PDR an FPL Group company

U. S. Nuclear Regulatory Commission L-88-89 Page two Based on discussions with the NRC Project Manager for St.

Lucie Plant and the age of the issue, FPL feels beneficial to meet and discuss the resolution of it the would be open items. The meeting arrangements will be discussed with the NRC Project Manager.

Should you have any additional questions, please contact us.

Very truly yours, Senior Vice President-Nuclear WFC/GRM/gp Attachment cc: Dr. J. Nelson Grace, Regional Administrator, Region II, USNRC Senior Resident Inspector, USNRC, St. Lucie Plant

ATTACHMENT ST. LUCIE UNIT 1 ALTERNATE SHUTDOWN CAPABILITY SUPPLEMENTAL SAFETY EVALUATION OPEN ITEMS alternate shutdown panel.

During the NRC's 1985 special fire protection inspection review of alternate shutdown instrumentation, both I&E and NRR confirmed the use of Tcold. NRC letter dated 4/22/85 Transmittal Inspection Report 85-06 which stated:

"EOP 2-0030144, Alternate Shutdown-Instrumentation for monitoring reactor coolant hot leg temperature was not installed at the hot shutdown panel or any other remote station. IE Notice 84-09 identifies this system process variable as being required.

The licensee provided information indicating that this issue was discussed with NRR and not having Thot indication was acceptable to the NRC as documented in NRC meeting minutes of May 7, 1982.

The licensee formally submitted letter L-82-208 dated May 17, 1982 which describes the analyses (see FSAR Section 15.3 and 15.C.4) that natural circulation maintains a close relationship between reactor coolant hot and cold leg temperatures.

Several natural circulation cooldowns on Unit 1 have verified the accuracy of the above results; thus, an operator can monitor primary system conditions from the hot shutdown panel using Tcold. The inspector discussed these issues with NRR, Auxiliary Systems Branch, who confirmed that the licensee's approach is satisfactory."

St. Lucie Unit 2 Safety Evaluation Report NUREG Supplement 0843 (SER) references FPL letter L-82-208 dated May 17, 1982 which responds to the use of Tcqld on Unit 2 Section 9.5.1.6 of SER Supplement 3 identifies the use of TE-,1115 and TE-1125 which provide Tcold indication. It states that:

"Based on the above, we conclude that the instrumentation outside of the control room, and, therefore, the alternative shutdown capability, complies with the guidelines of Section III.L of Appendix R and is therefore, acceptable."

GRM/016. ASD

Based on the above, the information submitted to NRR in 1982 for Unit 2 and incorporated in the 1983 submittal for Unit 1 was satisfactory. Furthermore, the Unit 2 SER Supplement 3 reflects NRC acceptance. FPL, therefore, considers this issue to be resolved.

faults. 'mpedance Postulating multiple high impedance faults simultaneously for branch circuits goes beyond the scope of electrical distribution system design. For the multiple high impedance fault scenario to take place, multiple branch circuit cables would have to fail along their length in such a manner as to result in a unique insulation resistance that would produce a leakage current to ground, or conductor to conductor, which when added to the conductor load would result in a current just below the branch circuit protective device rating.

These fault currents would then have to be sustained long enough to cause the supply breaker to trip. Thus, an improbable combination of temporary leakage current in multiple cables would have to occur simultaneously to trip the supply breaker. Due to the low probability of the above described specific fault condition of the cables, an analysis of multiple high impedance faults was not deemed necessary.

However, FPL will add a general note in the Alternate Shutdown procedure to permit restoration of essential equipment should a bus feeder breaker trip due to fire. The note will alert plant personnel to trip all bus loads prior to restoration of power to the bus, and to restart only necessary loads.

GRM/016. ASD