ML17347A559

LER 87-014-00:on 870519,while Unit in Mode 6,determined That Design Discrepancy Existed in Containment Spray Sys.Caused by Flow Orifice in Discharge Line Not Incorporated in Field. Design Mods Will Be Implemented for correction.W/870618 Ltr

ML17347A559
Person / Time
Site:	Turkey Point
Issue date:	06/18/1987
From:	Hart R, Woody C FLORIDA POWER & LIGHT CO.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
L-87-249, LER-87-014, LER-87-14, NUDOCS 8706230415
Download: ML17347A559 (9)

Text

REGULATORY I,.ORMATION DISTRIBUTION SYSl,f (BIDS)ACCESSION NBR FAC I L: 50-250 AUTH.NAME HART>R.D.WOODY>C.O.REC IP.NAMF 8706230415 DOC.DATE: 87/06/18 NOTARIZED:

NO Turkey Point Plant>Uni t 3>Florida Power and Light C AUTHOR AFFILIATION Florida Pacer~~Light Co.Florida Poeer 5 Light Co.RECIP IENT AFFILIATION DOCKET 5.05000250

SUBJECT:

LER 87-0$4-00: on 870519>while unit in Mode 6 determined that design discrepancy existed in containment spray sos.Caused bg floe orifice in discharge line not incorporated in field.Design mods.eill be implemented for correction.

W/870618 ltr.DISTRIBUTION CODE: IE22D COPIES RECEIUED: LTR ENCL SIZE: TITLE: 50.73 Licensee Event Report (LER)>Incident Rpt>etc.NOTES: REC I P I ENT ID CODE/NAME PD2-2 LA Mc DONALD>D COPIES LTTR ENCL 1 1 1 REC IP I ENT ID CODE/NAME PD2-2 PD COPIES LTTR ENCL 1 1 INTERNAL: ACRS MICHELSQN AEQD/DQA AEOD/DSP/TPAB NRR/DEST/ADE NRR/DEBT/CEB NR R/DE ST/I C SB NRR/DEST/MTB NRR/DEBT/RSB NRR/DLPG/HFB

• ~NRR/DOEA/EAB NRR/DREP/RPB NRR/PMAS/PTSB RES DEPY GI 1 1 1 1 0 1 1 1 1 1 1.2 2 1 1 ACR 8 MOELLER AEQD/DSP/ROAB, DEDRO NRR/DEBT/ADS NRR/DEST/ELB NRR/DEST/MEB NRR/DEST/PSB NRR/DEST/SGB NRR/DLPG/GAB NRR/DREP/RAB NA RB REG FI 02 FILE 01 2 2 2 2 1 1 1 0 1 1 1 1 1 1 1 1 1 1 EXTERNAL: EGS(G GROH>M LPDR NSI C HARRIS>J 5 5 1 1 1 1 H'T LOBBY WARD NRC PDR NSIC MAYS>G 1 1 1 1 1TOTAL.NUMBER OF CQP IES REQUIRED: LTTR 42 ENCL 40 r l)I}

NRC Form 300 (943)LICENSEE EVENT REPORT (LER)UA.NUCLEAR REGULATORY COMMISSION APPROVED OMB NO.31500104 KXtlRES: S/31/BS FACILITY NAME (11 TITLE ICI EVENT DATE (SI MONTH DAY YEAR LER NUMBER (0)YEAR N":.i SSQVENT/AL NVMOCR RCVSION NUMBER REPORT DATE (7I~OAY YEAR MONTH Turkey Point 3 Design Basis Reconstitution Discovers a Pum s OTHER FACILITIES INVOLVED (S)DOCKET NUMBER(S)o so o o 251 FACILITY NAMES Turkey Point 4 DOCKET NUMBER (2)PA o s o o o25>pF04 0 5 1 9 8 7 8 7 0 1 4 0 0 0 6 8 7 N/A 0 5 0 0 0 OPERATINO 6 MODE (~)tOWER LEVEL p p p Q@~<<r(atr<<

20A02(OI 20AOS(~l(110)20AOS(~Ill)(EI 20AOS(~)ll I (/II I 20AOS (e I (I)Rr)20AOS(e I (I llrl 20AOS(cl BOM(el(II BO.SS(c)(2)S0.73(e I (21(ll 50.734)(2((N)

S0.7341(2)(IS I X X LICENSEE CONTACT FOR THIS LER l12)00.7341(2)

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IA)00.7$(e)(2)(r(N)(B) 00.73(e)(2)(cl THIS REPORT IS SUBMITTED PURSUANT 7 0 THE REOVIREMENTS OF 10 CFR (I: (Chectr Onc Ot mpre O/the/ollom'np/

(11 7$.71011 73.71(c)OTHER (Speclly in Ahttrect pelow cnr/ln Tent.H/IC Form JSPA/NAME Randall D.Hart, Licensing Engineer TELEPHONE NUMBER 30 524 6-13 00 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE OESCRI~ED IN THIS REPORT (1$)CAUSE SYSTEM COMPONENT MANVFAC TVRER REPORTABL'E TO NPRDS ,<gjgSNg@4a/)

CAUSE SYSTEM COMPONENT MANUFAC TURER EPO/(TABLE TC NeROS~Fwk&5:..<<+3:: SVtPLEMENTAL REPORT EXPECTED lle)X tro YES (I/yet, complete EXPECTED SVSMISSIOH DATE/AssTR AcT (Limit to/cod tpecet,/A, op pro rimetely/I(teen ti epic/pete typenr(Iten IinN/Il~I EXPECTED SUBMISSION DATE (16)MONTH DAY rEAR I On May 19, 1987, while Unit 3 was in mode 6 (Refueling) and Unit 4 was in mode 5 (cold shutdown), it was determined that a design discrepancy existed in the containment spray system.During the design basis reconstitution of the Containment Spray (CS)system, it was discovered that the system piping resistance was such that pump runout flow will exist'review of the original calculations indicated that a restricting orifice was assumed to be present in the calculation.

Upon discovery of this apparent discrepancy, a walkdown of the CS system discharge lines for both units was done which disclosed that the orifices assumed in the original calculation were not identified in the design documents or installed in the field.This results in the as built discharge piping for the CS pumps allowing flow in excess of the current analyses assumptions.

This high flow-rate cannot be accommodated by the suction piping'due to the CS pump net positive suction head (NPSH)requirements at elevated flows.A review of the original CS system flow calculations discovered that the original assumed flow orifice in the discharge line was not installed in the field.Design modifications will be implemented to correct this discrepancy prior to each unit entering mode 4 (hot shutdown)along with appropriate procedure changes.Also engineering will continue to evaluate the as found condition to determine its safety significance.

NRC Form 3CS (9 83I 8706230415 870618 PDR ADDCI(, 05000250 S PDR

NRC Form 355A (943)LICENSEE EVENT REPORT (LER)TEXT CONTINUATION US.NUCLEAR REOULATORY COMMISSION APPROVED OMS NO.3150W105 EXPIRES: 8/31/88 FACILITY NAME (1)Turkey Point 3 DOCKET NUMSER (2)YEAR 0 5 0 0 0 2 50 87 014 0 0 LER NUMSER (5)5ECUENT/AL QQy REYISroN NUMEN/l"Vd NUM Erl PACE (3)0 4 TEXT///moro EOoco/I roovirod, voo Odd/rrorro/HRC Frvrn 3(SEES/(IT)EVENT: On May 19, 1987, while Unit 3 was in mode 6 (Refueling) and Unit 4 was in mode 5 (cold shutdown), it was determined that a design discrepancy existed in the containment spray, system.During the design basis reconstitution of the Containment Spray (CS)system, it was discovered that the system piping resistance was such that pump runout flow could occur.A review of the original calculations indicated that a restricting orifice was assumed to be present in the calculation.

Upon discovery of this apparent discrepancy, a walkdown of the CS system discharge lines for Unit 3 and 4 was done which disclosed that the orifice(s) assumed in the original calculation were not identified in the design documents or installed in the field.This results in the as built dis-charge piping for the CS pumps allowing flow in excess of the analyses assump-tions.This high flow rate cannot be accommodated by the suction piping due to the CS pump net positive suction head (NPSH)requirements at elevated flows when the CS pumps are taking suction from the refueling water storage tank (RWST).During the recirculation phase there is no concern since the CS pump takes its suction from the discharge of the residual heat removal system pump which is at a sufficiently high pressure to satisfy the required NPSH of the CS pumps even at maximum runout flow they could achieve.CAUSE OP EVENT: A review the original CS system flow calculations discovered that the original assumption of a flow orifice in the discharge line was not incorporated in the field.ANALYSIS OP EVENT: This condition was discovered when Unit 3 was in a refueling outage and Unit 4 was in an extended maintenance outage., At that, time, the CS system was not required to be operable on either unit..Permanent changes to the discharge lines for the CS pumps to install flow orifices will be completed for the respective unit prior to that unit entering mode 4 (hot shutdown).

'he CS system design is being modified to add a flow reduction orifice in the discharge line of each CS pump.The orifices have been sized to assure that the minimum required spray flow of 1450 gallons per minute (GPM)can be achieved even at the containment design pressure of 60 psig.This orifice design, however, does not restrict flow sufficiently to completely eliminate pump runout concerns when the containment pressure is relatively low.The runout concerns exist only when both CS pumps are operating during the injection phase and the level'n the RWST has dropped to the point where the static head provided by water in the RWST is no longer sufficient to provide an gr NPSH greater than that specified as being required by the CS pumps.It has is b d termined that a RWST level of at least 40 feet above the plant datum s 14 si required to satisfy NPSH requirements for containment pressures above ps g.NRC FOIIM 555A (983)

NRC Form 358A (9831 LICENSEE EVENT REPORT (LER)TEXT CONTINUATlON US.NUCLEAR REGULATORY COMMISSION APPROVED OMB NO.3150W105 ENrI8 ES: 8/31/88 PACILITY NAME (11 DOCKET NUMBER (?I LER NUMBER (81 PACE (3)Turkey Point 3 TEXT///moro opoce/5 oeO/rirer/, ooo or/r//I/orro/HRC Fomr 3(E(AB/(Ill 2 5 0 0 5 0 0 0 YEAR (N 8 7 SEOVENTIAL NVM ER 0 1 4 REVISION NVM Erl 00 03 OF 0 4 This was chosen because the plant s emergency operating procedures direct the operators to shut off the CS pumps if the containment pressure drops below 14 psig, so the pump runout and NPSH calculations assumed that operation of the CS pumps with containment pressure less than 14 psig has been precluded by operator action to stop the CS pumps.In addition, the emergency operating procedures direct the operators to restrict the operation of the CS system to 1 pump when the level in the RWST reaches the low alarm setpoint.With only 1 CS pump in operation there is no longer any concern regarding available NPSH since, with the reduction in overall CS flow rate, there is commensurate reduction in the pressure drop in the CS pump suction line and increase in NPSH available.

Therefore, the addition of the orifice in the CS pump discharge lines and the increase in the low level alarm setpoint for the RWST will ensure that adequate NPSH will be available for the CS pumps.The FSAR states in section 6.4, Containment Spray System, that adequate heat=removal capability for the containment is provided by two separate, full capacity, engineered safety systems.These are the Containment Spray System, whose components operate in the sequential modes described in FSAR section 6.4.2, and the Emergency Containment Cooling and Filtering System which is discussed in FSAR section 6.3.The design basis for containment heat removal considers simultaneous operation of one spray pump and 2 of 3 emergency containment coolers.This is the basis for containment pressure transient calculations in FSAR section 14.Since this discrepancy represents a condition which is not analyzed for either Turkey Point unit, additional evaluation is being done by our engineering department to determine the safety significance of this condition.

Should this evaluation significantly change this LER, a LER update will be sent accordingly.

Based on the above, the health and safety of the public was not affected.CORRECTIVE ACTIONS: 1)Plant change/modifications (PC/Ms)have been developed for each unit to install a flow orifice in the discharge piping of the CS pumps and revise the low level alarm setpoint for the RWST.The flow orifices along with the increase in the low level alarm setpoint for th'e RWST will ensure adequate NPSH for the CS pumps in compliance with current analyses assumptions.

2)Upon completion of the PC/Ms and change in RWST low level setpoint, appropriate plant procedures will be revised and training requirements will be determined and implemented as necessary.

3)Engineering will continue to evaluate this discrepancy to determine the safety significance of the as found condition.

NRC FORM 355A (WOl NRC Form 354A)943)LICENSEE EVENT REPORT (LER)TEXT CONTINUATION UN.NUCLEAR REGULATORY COMMISSION APPROVEO OMB NO.3150M)04 EXPIRES: E/31/EE FACILITY NAME I'l DOCKET NUMBER)3)YEAR LER NUMSER)S)SEOVENTIAL NVM 54 45VISION NVM554 PAGE 13)Turkey Point 3 TEXT//I more Z>>ce/e'er/v/rerL Iree///re@'o>>//VRC Form 3/54'5/I)T)0 5 0 0 0 8 7 0 1 4 0 0 0 4 OF 0 4 4)As a part of the confirmatory order associated with EA 86-20 issued August 12, 1986, Turkey Point is currently performing a Selected Safety System Review tq assure that the Turkey Point Plant as built condition is consistent with the current licensing basis and has the capability within the systems to mitigate any of the design basis accidents and/or shutdown the plant.ADDITIONAL DETAILS: The CS pumps are horizontally mounted, centrifugal pumps and are constructed out of austenitic stainless steel.Each is rated at design flow conditions of 1450 gallons per minute (GPM)at a 470 foot discharge head.The CS pumps are a model 3736 4X6-13 pump manufactured by Goulds Pumps Inc.Similar occurrences:

None NRC FORM 355A I94)31 P.O.BO 0, JUNO BEACH, FL 33408 FLORIDA POWER&LIGHT COMPANY~ONE 18 lest L-87-249 l0 CFR 50.73 U.S.Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C.20555 Gent I emen: Re: Turkey Point Unit 3 Docket No.50-250 Reportable Event: 87-I4 Date of Event: May l9, l987 Design Basis Reconstitution Discovers Discrepancy in Desi n Flow Rates for the Containment S ra Pum s The attached Licensee Event Report is being submitted pursuant to the requirements of l0 CFR 50.73 to provide notification of the subject event.Very truly yours, C.Woody, G up Vice President Nuclear Energy COW/SDF/gp Attachment cc: Dr.J.Nelson Grace, Regional Administrator, Region II, USNRC Senior Resident inspection, USNRC, Turkey Point Plant SDF I/027/I PEOPLE...SERVING PEOPLE