ML17338A980

Submits Proposed Amend to Licenses DPR-31 & DPR-41 to Increase Min low-low Steam Generator Water Level Reactor Trip Setpoint to 15% of Narrow Range Instrument Scale.Safety Evaluation Encl

ML17338A980
Person / Time
Site:	Turkey Point
Issue date:	08/09/1979
From:	Robert E. Uhrig FLORIDA POWER & LIGHT CO.
To:	Eisenhut D Office of Nuclear Reactor Regulation
References
L-79-217, NUDOCS 7908140435
Download: ML17338A980 (5)

Text

"'REGULATORY INFORMATION DISTRIBUTION

'SYSTEM (RIDS)ACCESSION NBR 7908140435'OC

~DATKt~79/08/09 NOTARI ZKO NO KE1T FACIL:50<<250 Turkey'Point PlantE-Unitt 3i Florida Power and Light'0 50 251 Turkey Point Planti Unit 4E Florida Power and Light C 05000251 AUTH BYNAME AUTHOR AFFILIATION UHRIG E R, K~Florida Power 8 Light Co, REC IP~NAME RECIPIENT AFFILIATION EISENHUTiD.G, Division of Operating Reactors

SUBJECT:

Submits proposed amend to L.icenses DPR 31 L DPR-41 to increase min low 1ow steam generator water level-reactor trip setpoint to 15/of narro'w range instrument scale.Safety evaluation encl'ISTRIBUTION CODE: ABOIS COPIES RECEIVED'LTR Q ENCL~SIZE: TITLE i GENERAL DISTRIBUTION FOR AFTER ISSUANCE OF OPERATING L'IC NOTES~Et'/CA DC@'K 4~0 at w Pter rf ta M at Stt&at M ta at at at at+aorta at a0 at as aS ta ta ta ta ta&Pa M 0a ea ae M w aR w at ta w w ta 0a at tf Ra Pa w~at w%'t at w aR w at a\at ta M ta&at M at&RECIPIENT IO CODE/NAME ACTIONS 05 BC 044 A/INTERNAL!01 12 ISK 15 CORE PERF BR 17 ENGR BR 19 PLANT SYS BR 21 KFLT TRT SYS OEL'D EXTFRNAL: 03 LPDR 23 ACRS COPIES LTTR ENCL 7 7 1 2 2 1 1 1 1 1 1 1 1 1 0 1 1 16 16 RECIPIENT ID CODE/NAME 02 NRC POR 14 TA/EDO 16 AD SYS/PROJ 18 REAC SFTY BR 20 EEB 22 BRINKMAN 04 NS'I C COPIES LTTR ENCL 1 1 1 1 1 1 1 1 1.1 1 1 1 1 TOTAL NUMBER OF COPIES REQUI'RED:

LTTR 39 ENCI 38 4 yh Ilz Director of Nuclear Reactor Regulation Attention:

Darrell'.Eisenhut,.Acting Dir.Division of Operating Reactors U.S.Nuclear Regulatory Commission Washington, D.C.20555

Dear Nr.Stello:

FLORIDA POWER&LIGHT COMPANY August 9, 1979 iL-79-217 Re: Turkey Point Units 3 and 4 Docket Nos.50-250 and 50-251 Proposed Amendment to Facil:ity 0 eratin Licenses DPR-31 and DPR-41.In accordance with 10 CFR 50.30, Fl'orida Power&Light Company submits herewith three (3)signed originals and forty (40)copies of a request to amend'ppendix A of.Facility Operating Licenses DPR-31 and DPR-41.This proposal addresses the potential for erroneous steam generator water level indication due to postulated events that could lead to heating of the water level instrumentation reference leg.The proposed amendment is described below and shown on the accompanying Technical Specification page bearing the date of this letter in the lower right corner.Pa e 2.3-3 The minimum setpoint for.the"low-low steam generator water level'" reactor trip is increased from 5/.to 15Ãof the nar-row range instrument scale.The, proposed'mendment has been reviewed by the Turkey Point Plant Nuclear Safety Committee and the Florida Power 8I Light Company Nucl,ear Review.Board.They have concluded that it does not invol.ve an unreviewed safety question.We have determined that since this request involves a single safety issue and a duplicate amendment, the request should be classified as a Class I and a Class III amendment pursuant to 10CFR 170.Accordingly, a check for$4,400 is attached.Very t u yours, Robert E.Uhrig Vice:Pres'ident Advanced Systems 8 Technology REU/t1AS/dlh Attachment M(Ch~e 8'4 4'c: J-..P.O'Reil:ly, Region II Robert Lowenstein, Esquire W50$14IIqg~PEOPLE...SERVING PEOPLE Over-power AT<dT~gjTp T T'l K2";111*K---K2 (T-T')-f (hq)1 dt Indicated bT at rated power, F Average temperature, F Indicated average temperature at nominal conditions and rated power, F 0 for decreasing average temperature, 0.2 sec./F for increasing average temperature 0.00068i'or T equal to or more than T';0 for T less than T d~=Rate-of change of temperature, F/sec dt f(iq)=As defined above Pressurizer Low Pressurizer pressure-equal to or.greater than 1835 psig.High Pressurizer pressure-equal to or less than 2385 psig.High Pressurizer water level-equal to or less than 925 of full scale.Reactor Coolant Flow Low reactor coolant flow-equal to or greater than 90K of normal indicated flow Low reactor coolant pump motor frequency-equal to or greater than 56.1 Hz Under voltage on reactor coolant pump motor bus-equal to or greater than 60/of normal voltage Steam'Generators Low-low steam generator water level-equal to or greater than 15/of narrow range instrument scale*This factor is l.11 for steam generator tube.plugging<15 percent This factor is 1.10 for steam generator tube plugging>15 percent and<19%This factor is, 1.08 for steam generator tube plugging>19Ãand<25/.this factor is 0.00106 for steam generator tube plugging>19!and<25%.2.3-3 SAFETY EYALUATION Re: Turkey Point Uni.ts 3&4 Docket Nos.50-250 8 50-251 Proposed Tech Spec Change SGlJL Tri Set oint I.Introduction This evaluation supports a proposed change in the"low-low steam generator water level" reactor trip setpoint.The minimum set-point wil'1 be conservatively increased from 5X to 15Ãof the nar-row range instrument scale.II.Evaluation High energy line breaks inside containment can result in heatup of the steam generator level measurement, reference leg.Increased reference leg water column temperature will result in a decrease of the water column density wi'th a consequent apparent increase in the indicated steam generator water level (i.,e., apparent level exceeding actual level).This potential level bias could result in delayed protection signals (reactor trip and auxiliary feedwater initiation) which are based on low-low steam generator water levels In case of a feedline rupture, this adverse environment could be present and could delay or prevent the, primary signal arising from declining steam generator water level (low-low steam generator level).Backup signals which may be available include the following:, over-temperature delta-T, high pressurizer pressure, containment pres-sure, and safety injection.

For other'high energy 1'ine breaks that could introduce a similar positive bias to the steam generator water level measurement, steam generator level does not provide the primary trip function and the potential bias would not interfere with needed protective system actuation.

Analysis of the problem by our NSSS vendor has shown that a 101.error (of narrow range span)could resul't from the temperature effect described above.Therefore, by increasing the minimum allowable low-low steam generator water level tri.p setting from 5/to 15K of narrow range instrument scale, we can ensure that the trip setpoint maintains conservati,sm and compensates for tbe potential 10%error..II'I.Conclusion Me have concluded, based on the considerations discussed above, that: (1)the amendment does not involve a signifi cant increase in the probability or consequences of accidents previously considered and does not involve a significant decrease in a safety margin;(2)there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner;and (3)such activities wil,l be conducted in compliance with the Com-mission's regulations and the issuance of, this amendment will not be inimical to the common defense and security or to the health and safety of the, public.

STATE Or rLORXDZ)))ss E.A.Adomat being first duly sworn, deposes and says=That he is Executive pic p p,g'm~Light Company r the Licensee herein;of, Florida Power 6 That he has executed, the foregoing document.-

'hat the state-ments made in this said, document are true and correct to the best of.his knowledge, information, and belief, and that.he is authorized to execute the document on behalf of said Licensee E.A.Adoma t Subscribed and sworn to before me this day of icAa~NOTARY PUBLIC, in and for the County of Dade, State of Florida , NOTARY PUBLIC STATE OF FLORIDA st LARGE MY COMMISSION EXPIRES AUGUST 24, l%l BONDED THBU NAYNARD BONOINQ AGENCY eely commission expires: