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 8706230415 DOC. DATE: 87/06/18 NOTARIZED: NO DOCKET 5.

FAC I L: 50-250 Turkey Point Plant> Uni t 3> Florida Power and Light C 05000250 AUTH. NAME AUTHOR AFFILIATION HART> R. D. Florida Pacer ~~ Light Co.

WOODY> C. O. Florida Poeer 5 Light Co.

REC IP. NAMF RECIP IENT AFFILIATION

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 COPIES REC IP I ENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD2-2 LA 1 1 PD2-2 PD 1 1 Mc DONALD> D 1 INTERNAL: ACRS MICHELSQN 1 ACR 8 MOELLER 2 2 AEQD/DQA AEQD/DSP/ROAB, 2 2 AEOD/DSP/TPAB 1 1 DEDRO 1 1 NRR/DEST/ADE 1 0 NRR/DEBT/ADS 1 0 NRR/DEBT/CEB 1 NRR/DEST/ELB 1 NR R /DE ST/ I C SB 1 NRR/DEST/MEB 1 NRR/DEST/MTB NRR/DEST/PSB 1 NRR/DEBT/RSB NRR/DEST/SGB NRR/DLPG/HFB 1 1 NRR/DLPG/GAB 1

• ~

NRR/DOEA/EAB 1 1 NRR/DREP/RAB 1 NRR/DREP/RPB .2 2 NA RB 1 1 NRR/PMAS/PTSB 1 1 REG FI 02 1 RES DEPY GI FILE 01 1 1 EXTERNAL: EGS(G GROH> M 5 5 H'T LOBBY WARD 1 1 LPDR 1 1 NRC PDR 1 1 NSI C HARRIS> J 1 1 NSIC MAYS> G 1 TOTAL. NUMBER OF CQP IES REQUIRED: LTTR 42 ENCL 40

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NRC Form 300 UA. NUCLEAR REGULATORY COMMISSION (943)

APPROVED OMB NO. 31500104 LICENSEE EVENT REPORT (LER) KXtlRES: S/31/BS FACILITY NAME (11 DOCKET NUMBER (2) PA Turkey Point 3 o s o o o25 >pF04 TITLE ICI Design Basis Reconstitution Discovers a Pum s EVENT DATE (SI LER NUMBER (0) REPORT DATE (7I OTHER FACILITIES INVOLVED (S)

MONTH DAY YEAR YEAR N":.i SSQVENT/AL RCVSION OAY YEAR FACILITYNAMES DOCKET NUMBER(S)

NUMBER MONTH

~

NVMOCR Turkey Point 4 o so o o 251 0 5 1 9 8 7 8 7 0 1 4 0 0 0 6 8 7 N/A 0 5 0 0 0 THIS REPORT IS SUBMITTED PURSUANT 7 0 THE REOVIREMENTS OF 10 CFR (I: (Chectr Onc Ot mpre O/ the /ollom'np/ (11 OPERATINO MODE ( ~ ) 6 20A02(OI 20AOS(cl 00.7341(2) I /el 7$ .71011 tOWER LEVEL 20AOS( ~ l(110) BOM(el(II X $ 0.7$ (e I (2) (el 73.71(c) p p p 20AOS( ~ Ill)(EI BO.SS(c) (2) X S0.7$ (el(2)(rBI OTHER (Speclly in Ahttrect pelow cnr/ln Tent. H/IC Form 20AOS( ~ ) llI (/III S0.73(e I (21(ll 00.7341(21(rIS) IA) JSPA/

Q@~<<r(atr<< 20AOS (e I (I)Rr ) 50.734)(2((N) 00.7$ (e) (2)(r(N)(B) 20AOS(e I (I llrl S0.7341(2) (IS I 00.73(e) (2)(cl LICENSEE CONTACT FOR THIS LER l12)

NAME TELEPHONE NUMBER Randall D. Hart, Licensing Engineer 30 524 6- 13 00 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE OESCRI ~ ED IN THIS REPORT (1$ )

MANVFAC REPORTABL'E MANUFAC EPO/(TABLE CAUSE SYSTEM COMPONENT TO NPRDS ,<gjgSNg@4a/) CAUSE SYSTEM COMPONENT TVRER TURER TC NeROS

~Fwk&5:.. <<+3::

SVtPLEMENTAL REPORT EXPECTED lle) MONTH DAY rEAR EXPECTED SUBMISSION DATE (16)

YES (I/ yet, complete EXPECTED SVSMISSIOH DATE/

X tro AssTR AcT (Limit to /cod tpecet, / A, op pro rimetely /I(teen ti epic /pete typenr(Iten IinN/ Il~ I 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.

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

NRC Form 355A US. NUCLEAR REOULATORY COMMISSION (943)

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION APPROVED OMS NO. 3150W105 EXPIRES: 8/31/88 FACILITY NAME (1) DOCKET NUMSER (2) LER NUMSER (5) PACE (3)

YEAR 5ECUENT/AL QQy REYISroN NUMEN/l "Vd NUM Erl Turkey Point 3 0 5 0 0 0 2 50 87 014 0 0 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 shutdown).

for the respective unit prior to that unit entering mode 4 (hot

'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) canorifice be achieved even at the containment design pressure of 60 psig. This design, however, does not restrict flow sufficiently to completelylow.eliminate pump runout concerns when the containment pressure is relatively The runout concerns exist only when both CS pumps are operating during where the the injection phase and the level'n the RWST has dropped tosufficient the point to provide static head provided by water in the RWST is no longer an NPSH greater gr than that specified as being required by the CS pumps. It has b d termined that a RWST level of at least 40 feet above the plant datum iss required to satisfy NPSH requirements for containment pressures above 14 pssi g.

NRC FOIIM 555A (983)

NRC Form 358A (9831 US. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT (LER) TEXT CONTINUATlON APPROVED OMB NO. 3150W105 ENrI8 ES: 8/31/88 PACILITY NAME (11 DOCKET NUMBER (? I LER NUMBER (81 PACE (3)

YEAR SEOVENTIAL REVISION (N NVM ER NVM Erl Turkey Point 3 2 5 0 8 7 0 1 4 00 03 0 4 0 5 0 0 0 OF TEXT /// moro opoce /5 oeO/rirer/, ooo or/r//I/orro/HRC Fomr 3(E(AB/ (Ill 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 UN. NUCLEAR REGULATORY COMMISSION

)943)

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION APPROVEO OMB NO. 3150M)04 EXPIRES: E/31/EE FACILITY NAME I'l DOCKET NUMBER )3) LER NUMSER )S) PAGE 13)

YEAR SEOVENTIAL 45VISION NVM 54 NVM554 Turkey Point 3 8 7 0 1 4 0 0 0 4

/e'er/v/rerL 0 5 0 0 0 OF 0 4 TEXT //Imore Z>>ce Iree ///re@ 'o>>//VRC Form 3/54'5/ I)T)

4) As a part of the confirmatory order associated with EA 86-20 issued August 12, 1986, Turkey Point is currently performing a Selected tq assure that the Turkey Point Plant as built condition isSafety System Review consistent the current licensing basis and has the capability within with mitigate any of the design basis accidents and/or shutdown the the systems to 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