ML030870874
| ML030870874 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 11/21/2002 |
| From: | Dresche C, Harper R, Hoefert N Nuclear Management Co |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| FOIA/PA-2003-0094 PBF-1553, Rev 9 | |
| Download: ML030870874 (8) | |
Text
Point Beach Nuclear Plant OPERABILITY DETER-MINATION PART I OPR 000031 CAP 029952 / 030040 /030209 REV 4 ENGFNEERING TO COMPLETE THiS BOX WHEN OD ACCEPTED BY DSS SYNOPSIS FOR NIM INFORMATION ONLY CHAMPS Unit(s) 0, 1, 2 System AF Equipment ID Various
[] Inoperable - does not meet the minimum level ofperformance.
F- Operable - fully meets performance requirements. No further action required.
Operable But Degraded - or Operable But Nonconforming - meets the minimum required level of
[ performances, compensatory measures ARE required.
Operable But Degraded - or Operable But Nonconforming - meets the minimum required level of 0 performances, compensatory measures are NOT required. ,
Potential for simultaneous failure of all AFW pumps due to insufficient minimum pump flow TITLE (toQEMmfTNur UBmEx A*34o neeOprioN oP issu) 4 Revision 4 of this OD incorporates CAP 030209. The power to the AFP minimum-recirculaton s noid valves for I P-29 and 2P-29 and the control circuitry for motor driven pump P-38A (including the rolni recirculation valve for P-38A) ae all derived from 125VDC bus D-01. Evaluating this situation facda design basis accident or event combined with a single failure of equipment important to safety, coul#
challenge the operability of IP-29, 2P-29 and P-38A since the recirculation valves use a "fail closoe"I design. This issue would also result in essentially the same result as plugging the mini-recirculatiotif orifices.
Revision 3 of this 01 incorporates CAP 030040. The power to the AFP minimum-rccirculation soa noid valves is fed from a Safety Related DC power supply. This circuit's actuation is from a Non-Safety lated AC power source, Vital Instrunent Panel 1/2Y-06. The loss of the I20VAC power supply will cau : the mini-recirc valves to fail closed. Effectively the same result as plugging the mini-recirc orifice.
1 Revision 2 of this OD restored the original Revision 0 wording. The OD was reworded in Revision on Operations request to describe the problem in terms of loss of flow through the AF recirculation iio for any of the problem statement to be a loss of flow throý h the reason. Revision 2 restores the original wording AF recirculation line due to potential blockage of the orifice with material in the supply water.
Describe the condition.
Duringa plant transient,a combinationof the existing plant design and operating-if proceduresmay result irtafailuremode of one or more AFWpumps.
When steam generator(SG) levels have been restoredto desired levels following a
,uld transient,manual action is requiredto maintainthose levels. This manual action to match; he be accomplishedby securingthe associatedpump(s), or by reducingflow to onel r both steaming rate. It could also be accomplished by completely closing offflow d to SGs if desired: this is likely to be the case if the desiredlevel has been exceeded flow thr' gh a discharge flow to the SGs, could result in no overfill, swell, etc. Isolating susceptible toi runningAFWpump since the recirculationline orificepassages are his blockage particularlywhen the safety relatedSW is alignedas the suction source, would cause very rapidfailure of these multi-stage high pressure pumps Page 1 of 9 aecre
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As described in CAP 030040. a loss of l20V.4Cpowerfron Ltdl Insrrnmen:pane, Y-06 can result in noflow through a running AFtTpump dute to the recirculationline vcfve failing closed j In addition, CAP 030209 describes a condition where a loss of 125VDC bus D-OI ould alsofail the recirculationvalves closed on IP-29. 2P-29 and P-38A I
- 2. Identify the Current Licensing Basis (CLB) functions and performance requirements including Tech Spec Reference 3.7.5 !
FSAR Reference 10.2. 7.3.3 4 NRC Commitment Reference Other 50 59 EVAL 2002-005, FCR 02-027, FCR 02 019 If no CLB function, requirement or commitment is affected, no further action is required. NIA Stej 3.4 and 5 and proceed with Step 6.
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11/21/2002 18:23 9207554374 POINTEEACH PA:GE 412 TS31/00 182727534PONBAHPG 5
I!The AFWSystem shall be OPERABLE with one turbine driven AFW pump system <per Unit> and two motor driven AFWpump systems when in modes 1. 2. and 3 The bases
-or this Technical Specification states that "The AFWSystem automaticallysupplies Veedwarer to the steam generatorsto remove decay hearfrom the Reacto- Coolant Syvstem t.upon the loss of normalfeedwater supply'".
FSAR Lhapter 10.2.1 The AFW system shall automaticallystart and deliver adequate AF system flow to
[maintainadequate generatorlevels during accidents which may result in main steam
.safery valve opening including: Loss of Normal Feedwater (LONF)and Loss ofAll AC
- Power to the Station Auxiliaries (LOAC) These accidentsare evaluated in detail in sections 14.1.10 and 141.11 respectively
.The AFsystem is creditedwith automaticallystartingand deliveringsufficient AFflow to
'Imaintainadequate steam generatorlevels during accidents which require rapidreactor
'coolantsystem cooldown to achieve cold shutdown condition within the limits of the hanalysis,includingSteam GeneratorTube Rupture (SGTR; FSAR Chapter 14.2.4), and
),Mfain Steam Line Break (,VSLB: FSAR Chapter 14.2.5).
The AF system shall be capable of isolating the AF steam andfeedwatersupply lines from the rupturedgeneratorfollowinga SGTR event.
',The AF system also is capable of automaticallysupplying sufficient feedwater to remove iWeecay heatfrom both units without any reliance on ACpowerfor one hour (station btackout).
In the event ofplantfires, including those that requireevacuation of the control room, the AF system shall be capable of manual initiationto providefeedwater to a minimum of "onesteam generatorper unit at sufficient flow andpressureto remove decay and hot shutdown to cold Sshutdown
.sensible heat from the reactorcoolantsystem over the rangefrom conditions.
FSAR 10.2.2
- This section states that each pump has an AOV controlledrecirculationline back to the
- ,condensatestorage tanks to ensure minimum flow to prevent hydraulic instabilitiesand 4, dissipatepump heat.
FSAR MO.2.3 1Based on the operating characteristicsof the minimum recirculationflowcontrol 4scheme, a portiona AFpumps discharge will be automaticallyrecirculatedback to the CSTs for approximately45 seconds after the pump starts.The 45 second time delay in i closingthe recirculationline control valves is incorporatedin the design to providefor jpump stability and cooling during coastdown.
FSAR .3.3.4 ifa loss of instrument air occurs or an Auxiliary Feedwater Pump minimum flow urecirculationvalve fails closed, manualoperatoraction is requiredto prevent the
',potentialfailureof the pump(s). By procedure, the operator will eithersecure the running
- pump(s) or maintainforwardflow through the still runningpump(s) to preventpump damage that could be caused by overheating Backuppneumatic supplies are providedto all AFpump minimum recirculationvalves.
These backup supplies are sized to provide adequatetime for operatorsto either
.maintain minimumflow through the runningpump(s) to secure the unneededpump(s) if
,necessaryto restore instrument air,or to use the manualgag on each valve to provide I minimum recirculationflow.
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11/ Z1, 2OUU 1b: 2/ 9207554374 POINTBEACH PAGE Fii1 Sggregate Re*i ew: ldentify related issues by review of active ODs for the same system including as licable their compensatory measures. Historical ODs can also be included in this review at the discretioii rfthe Engineer. The reiew of the active ODs and their compensatory measures is to ensure there is no f.0nflfct between the related conditions, i.e . conflicting assumptions or compensatory measures I
No related issues euXst lated AR Number CR 01-3648 ntpact eview of the condition describedin section I of this OD indicatesa potentialfor the loss ifaflowpathfor the MDAFWPs mirroringthat describedin OD CR 01-3648. OD CR
ý1-3648 describes a condition where an Appendix Rfire in Fire Areas AO1-B, A02. A23N Ind A23S, could result in the loss ofMDAFPfiowpath due to afire initiatedauto-startof m MDAFP with a coincidentloss of off-site power and instrument air. In each of the fire reas listed above, a MDAFP is reliedupon as the means of deliveringAux Feedwaterto i least one Steam Generatorfor at least one or both Units to support decay heat removal aom the RCS. This condition occurs due to afire initiatedtrip of the Main Feedwater Pumps or startsignal to the credited MDAF'. This auto-startsignalgeneratedby this rondition opens the associatedrecirculationvalve and motor operateddischargevalve(s) polr the steam generatorto be suppliedAF. Due tofire damage, the motor driven Jischarge valve may fail to open and the mini-recirc valve mayfail closed due to a loss of strument air supply.
"hedifference in the conditions describedin OD CR 01-3648 andthis OD is the failure echanism ofthe MDAFP recirculationline, however the failuremechanismfor the
- DAFPs is the same. The condition describedin this OD, as itpertainsto Appendix R, is jounded by that describedin OD CR 01-3648 because the initiatingevent is essentially fhe samefor both conditions, i.e., auto-startof the MDAFP andloss of control ofthe Imotor operateddischargevalve(s)for the steam generatordue to fire damage. The loss instrument airdescribedin OD CR 01-3648 is equivalent to the recirculationline ilure mechanism describedin this OD because loss of instrument air is assumedfor all 1ppendix Rfires and the failure mechanism describedin this OD could appy to allfire itiated'startsof the MDAFPs. Therefore,failure of the MDAFPs as describedin OD R 01-3648 is the samefor this condition andAppendix R operabilityconclusion of 10perableBut Nonconforming also remains the same.
ielated AR Number CR 01-3595 Olmpact:
.*losed. Concerns postulated failure of the recirculation line AOV. This is a related issue but it does not
,Irnpact this OPR.
felated AR Number lrmpact:
Ikeview additionally. as applicable, these items to help clarify current plant conditions.
]these items may have impact on the SSC performance.
lctive Temporary Operating Procedure Changes None Applicable P B F - 1 53 Rcvision 10116/02 Pa ge 4 of 9 Reference NP 5 3 7 i.
+/-+/-zi+/- _.Uz _ . 132U7554374 POINTBEACH PAGE 02
!Active Temporary Modifications None Applicable Iodifications currently being installed None Applicable Recent Work Orders None Applicable Ikpproved DCNs None Applicable Recently Performed Inservice Testing IT-10 p
4 evaluate the CLB functions and performance requirements identified in Step 2 against the as-found tondition and the related issues identified in Step 3. The evaluation must identify the extent to which the ESC is capable of performing its identified CLB function. Document the evaluation:
f4fter the automatic initiationofAF in response to an analyzed event, operatorsare
- -equired to manually controlAFflow based on SG levels (FSAR 7 3.3.4). Manual control (nay include shuttingpump dischargevalves resultingin pump operationstrictly on fecirculationflow. Due to the potential debris blockage ofthe recirculationline striction orifices (1/2R0-4003, RO-4008, RO-4015). sufficientflow topreventpump lmamage may not be achieved
- Iso, as describedin CAP 030040, a loss of 120 VACpowerfrom Vital Instrumentpanel
"-06can result in loss of recirculationflow due to the recirculationline valve failing losed. CAP 030209 describes a thirdcondition where the loss ofl25VDC bus D-01 tould result in the loss of IP-29, 2P-29 and P-38A due to the closure ofthe recirculation Ine valves.
ýIeasures taken include heightened Operatorawareness ofthe potentialfor pump
- Iamage (briefings with on-comingshifi personnel), temporary information tagsposted
ýn the AFW pump flow controls.Revisions to operatingproceduresthat will alert the peratorto the limitations of the AFW system with respect to minimum AFW pumpflow Ppre in progress. The revisions will ensure that AFW Minimum Flow Requirements are Ii aintainedor the affected AFWpump is secured kJ.EAMIA guidelinesstates that motor driven pumps may be started twicefrom an initial
- 4. andby condition with no restrictions.After the initialstarts,NEMA MG-i recommends sequent startsafter "allconditions affecting operationhave been thoroughly estigatedand the apparatushas been examinedfor evidence ofexcessive heating.
is guidance encompasses situations where the load or prime mover may have experienceda fault which causes afailure to start or run; excessive temperaturesare not
.xpecredwith the equitmentfunctioning normally.Additional startstherefore are Ollowed andnot expected to cause machinefailure.It shouldbe recognized minimum of
$ starts ofa motor driven AFpump are allowed in thefirst 15 minutes of operation.An 4dditionalone or two starts is allowedprovided the run time is at least 15 minutes 4etween these laterstarts.Motor startingnameplate information directsthat after initial Iarts the motor may be restartedif run time has exceeded 15 minutes or it has been curedfor 60 minutes. Excessive consecutive startingwill decrease overall motor life.
$tartingduty limitationsare provided by the manufacturerto provide the longest k~ossible motor life.
? e AOlP SG control band is 29% to 65% This representsan approximate volume of O0 gallons.At a steaming rate f/SO gpm, a motor driven pump atart would be ALequired every 50 minutes to control level within halfofthe control band At marimum PBF-15531 Revi*ion d110/16(02 Page 5 of 9 Pefemn.- NP 5 3 7
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,.mnpflow rate of 2 0 0 gpm. the pump would be operatedfor 16 n:nutes to recover the vel lost while the pump was secured Since the operationof the pumps will meet the EMA criteria established,the pump motor will not fail as a result of repetitive starts Vie pump motors are suppliedfrom Westinghouse DB-50 Air CircuitBreakers. Vendor Wiformation indicates an in-rush, non-fault ditty cycle of 750 breaker operations The Aecommended operatingconditions are a frequency of operation not to exceed 20 per 10 4inutes or 30 per hour. Since the MDAFPs are only used during startup,shutdown includingSG chemical additions)and requiredsystem testing, the number of breaker kperations are well below these operating limits If an operatoris requiredto secure and
ýstartpumps during a transient, the actions would be performed at afrequency of 4perationmuch less than the recommended valuefor the entire transient.
r7here are no startingcycle limitations on the turbine driven AFW pumps. The turbine tendor was contactedand verified that no duty cycle concerns existfor this pump
.ssembly. The steam supply MOVs are ratedfor 5 minutes of operation every hour which torrespondsto five open/shut cycles With a maximum steaming rate of 75 gpm, it would take approximately 33 minutes to steam off halfof the control band (2500 gallons). The hameplate guidancefor motors and valves is based on manufacturers"recommendations or long life and are consideredconservative. Therefore, operationof the valve will not Ve degraded.
Whe recommendationsof this OperabilityDeterminationis to consider the AF system QPERA BLE but NON-CONFORMING. The potentialNon-Conformancepertains to the AR statement ofthe minimum recirculationflow path ensuringminimumflow is izvoilable V
ýiote: If the SSC is determined to be inoperable based on this evaluatiou, mark Step 5 N/A and continue
.iith step 6.
- 5. Evaluate the need for compensatory measures. Complete with input from DSS.
j] Degraded or nonconforming, however, no compensatory measures are required.
Degraded or nonconforming. The following compensatory measures are REQUIRED in order to maintain operability.
If Compensatory Measures are not required go to Step 6.
SCompensatory measures must be in place prior to OD final approval by the DSS Affecte Unit (I OR2 ORO) 0
!.Describe the Compensatory Measure (what needs to be performed) ks an immediate compensatory measure, a briefing of all responsible on-shift Reactor 4Operationsstaffshould be conducted describingthe concern and appropriateresponses:
I"
- J. if dischargeflow cannot be maintainedper the applicable operatingprocedure(s) without exceeding desiredSG level, secure the associatedpump(s) and re-startagain later when (i.9 needed POF-ISSii Page 6 of 9 Refetence NP 53 7 Rcvi-0Ort9 10116f02
11/21/2002 18:27 9207554374 POINTEEACH PAGE 0 4
the controls (In 4 Install tags. placards.or otherwise post the pertinent njbrinattonat Sthe Control Room and locally)for the associatedAFIf pumps (turbine) 11 Emphasize verifying a minimum of 50 (75) gpm flow through a motor Sdriven pump when reducingflow as stated in the operatingprocedures.
,a sis which indicates the Compensatory Measure maintains operability ky verifying minimum pumpflow requirements, the continued availabilityof the AFW pump heat Rumps is ensured. Minimum pump flow maintainshydraulic stability, removes ind increase the life of the pump Ifthe minimum flow requirement cannot be
- isaintained, then the pump will be secured to prevent damage. Repetitive operation of a been determined to be
ijs an additionalaction,revise operatingprocedures as appropriateto prevent reducing 4orw ofoperatingAFW pumps below the minimum flow requirements.
.nplementation Mechanism (Procedure number, Temp Mod number, etc):
is determinedappropriateby Operations.
flant condition(s) or mode(s) of operation wbich require the Compensatory Measure:
1?dodes 1, 2, and 3 (modes in which decay heat removalfrom the SGs is necessaryand requiredcapabilityper MTS.
Under what conditions may the Compeasatory Measure be terminated?
lines.
ýFEngineeringevaluation or modification to restore the function of the recirculation
- 6. flrpared By:
CU,;.,r £:tsL- / C.. ,,L Date/Time: 160,
- Name (Print) / Signature Measure (if applicable)
.Engineering Manager Approval of Evaluation and Proposed Compensatory
~~- ~ yv.Ait2 ýA~
~ Date/Time:Y/
Name (Print) / Signature
- 7. 1SRO Review of Operabilitq Documentation:
3FJ Inoperable - does not meet the minimum level of performance.
No further action required.
iU] Operable - fully meets performance requirements.
minimum required level of Operable But Degraded - or Operable But Nonconforming - meets the
, performances, compensatory measures ARE required Page 7 of 9 Ftef'rence: 1JP 5 3 7 FBF-10I R~t,,sio,9 10116/02
11,21 " 18:IU:27 9207554374 PO INTBEA--CH P4GE A5 Operable But Dcu.raded - or Operaole But Nonconforming - meets the minimum requ'red level of performances. compensator. measures are NOT required D Evaluation Accepted Evaluation and Compensatory Measures Accepted
[]
Compensatory Measures Verified in Place.
NP 10 I., LCO Tracking Log updated to include new items bSS- >-/ R -Nam (RPent) Date/Time: 7_jZ _ 1 Name (Print) / Sig~nature Route dD package to in-box in WCC for processing Package includes originalPartI, allattachments. and relatedbonditzon report.
I.
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