ML030800438

Operability Determination 000031, CR 029952, Rev 1

ML030800438
Person / Time
Site:	Point Beach
Issue date:	11/07/2002
From:	Branam T, Ted Carter, Schroeder J, Weber D Nuclear Management Co
To:	Office of Nuclear Reactor Regulation
References
FOIA/PA-2003-0094 PBF-1553, Rev 9
Download: ML030800438 (8)

Text

Poin: Beach "-,c-ear PNant OPER.-ABILITY DETERMINATION PART I OPR IŽ0001 C.AP 029952 REVP ENGINEERING TO COMPLETE THIS BOX WHEN OD ACCEPTED BY DSS SYNOPSIS FOR NIM IFORL-ATION ONLY Unit(s) 0, 1,2 System AF C-HANMPS Equipment ID Vancus

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Inoperable - does not meet the rmnirmum level of performance.

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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 rminmum required level of E]

performances, compensatory measures are NOT required.

Potential for simultaneous failure of all AFW pumps due to insufficient nmmunum pump flow TITLE (EQUIPMEN-t NUMBER AND DESCRIPTION OF ISSU-E)

Describe the condition.

During a plant transient, a combination of the existing plant design and operating procedures may result in a failure mode of one or more AFW pumps.

When steam generator (SG) levels have been restored to desired levels following a transient, manual action is required to maintain those levels. This manual action could be accomplished by securing the associated pump(s), or by reducing flow to match the steaming rate. It could also be accomplished by completely closing offflow to one or both SGs if desired; this is likely to be the case if the desired level has been exceeded due to overfill, swell, etc. Isolating discharge flow to the SGs, could result in AFW pump damage due to the potential inability of the recirculation line to pass the required flow to maintain pump operability. This may cause very rapid failure of these multi-stage high pressure pumps.

2.

Identify the Current Licensing Basis (CLB) functions and performance requirements including.

Tech Spec Reference FSAR Reference 375 10.2. 7.3.3.4

'NRC Comrrmtment 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. N/A Steps 3, 4 and 5 and proceed with Step 6.

PBF-1553 Rcvis=on 9 t0/16102 Page 1 of 8 Reterenct NP

_z37 7

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TS3 7.5 Th7e AFWIStstem shall be OPERABLE -t'vth one turbine drite-z AFW pump system <per Unit> and r.ýo motor drz'en AF.VF u:mp systems when in modes 1. '. and 3 The bases for this Technical Specificanon stares that "The AFWS~stem autom-,nzcall, supplies f'eeddtater to the steam generators to remove decay heat f-om :ze Reactor Coolant System upon the loss of normalfeedwater supply".

FSAR Chapter 10 2.1 The AFW svstem shall automaticalli start and deliver adequate AF system flow to maintain adequate generator levels during accidents which may resuhd in main steam safety valve ovening including: Loss of Normal Feedwater (LONF) and Loss ofAll AC Power to the Station Auxiliaries (LOA). These accidents are evaluated in detail in sections 14 1. 10 and 14.1.11 respectively.

The AF system is credited vith automatically starting and delivering sufficient AFflow to maintain adequate steam generator levels during accidents which require rapid reactor coolant system cooldown to achieve cold shutdown condition within the limits of the analysis, including Steam Generator Tube Rupture (SGTR; FSAR Chapter 14.2.4), and Main Steam Line Break (MSLB: FSAR Chapter 14.2.5).

The AF system shall be capable of isolating the AF steam and feedwater supply lines from the ruptured generator following a SGTR event.

The AF system also is capable of automatically supplying sufficient feedwater to remove decay heat from both units without any reliance on ACpowerfor one hour (station blackout).

In the event ofplant fires, including those that require evacuation of the control room, the AF system shall be capable of manual initiation to provide feedwater to a minimum of one steam generator per unit at sufficient flow and pressure to remove decay and sensible heat from the reactor coolant system over the range from hot shutdown to cold shutdown conditions.

FSAR 10.2.2 This section states that each pump has an AOVcontrolled recirculation line back to the condensate storage tanks to ensure minimum flow to prevent hydraulic instabilities and dissipate pump heat.

FSAR 10.2.3 Based on the operating characteristics of the minimum recirculation flow control scheme, a portion of the AFpumps discharge will be automatically recirculated backlto the CSTs for approximately 45 seconds after the pump starts. The 45 second time delay in closing the recirculation line control valves is incorporated in the design to provide for pump stability and cooling during coastdown.

FSAR 7.3.3.4 If a loss of instrument air occurs or an Auxiliary Feedwater Pump minimum flow recirculation valve fails closed, manual operator action is required to prevent the potential failure of the pump(s). By procedure, the operator will either secure the running pump(s) or maintain forward flow through the still running pump(s) to prevent pump damage that could be caused by overheating.

Backup pneumatic supplies are provided to all AFpump minimum recirculation valves.

These backup supplies are sized to provide adequate time for operators to either maintain minimum flow through the running pump(s) to secure the unneeded pump(s) if necessary to restore instrument ab; or to use the manual gag on each valve to provide minimum recirculation flow.

PBF-1553 Revisio g 10/16i02 Page 2 of 8 RP::rcnc" NP 5 3 7

Aggregate Reiei*: [dent:uf related issues b', re,,,e,, otfactx'e ODs for the same p':stem inciudng as apphcable their comrpensatoqy measures Historical ODs can also be mciuced in this re.e, at the discreton of the Engineer. The re', iewv of the act,% e ODs and their compensator: measures is to ensure there is no conflhct between the related conditions.

e., conflicmig assumptiors or cormensatorv measures H

No related issues exist Related AR Number CR 01-.3,648 impact Review of the condition described in section I of this OD indicates a potentialfor the loss of aflowpath for the MDAFWPs mirroring that described in OD CR 01-3648. OD CR 01-3648 describes a condition where an Appendix Rfire in Fire Areas A01-B, A02, A23N and A23S, could result in the loss of MDAFPflowpath due to afire initiated auto-start of an MDAFP with a coincident loss of off-site power and instrument air. In each of the fire areas listed above, a MDAFP is relied upon as the means of delivering Aux Feedwater to at least one Steam Generator for at least one or both Units to support decay heat removal from the RCS. This condition occurs due to afire initiated trip of the Main Feedwater Pumps or start signal to the credited MDAFP. This auto-start signal generated by this condition opens the associated recirculation valve and motor operated discharge valve(s) for the steam generator to be supplied AF. Due to fire damage, the motor driven discharge valve may fail to open and the mini-recirc valve may fail closed due to a loss of instrument air supply.

The difference in the conditions described in OD CR 01-3648 and this OD is the failure mechanism of the MQDAFP recirculation line, however the failure mechanism for the MDAFPs is the same. The condition described in this OD, as it pertains to Appendix R, is bounded by that described in OD CR 01-3648 because the initiating event is essentially the same for both conditions, i.e., auto-start of the MWDAFP and loss of control of the motor operated discharge valve(s) for the steam generator due to fire damage. The loss of instrument air described in OD CR 01-3648 is equivalent to the recirculation line failure described in this OD because loss of instrument air is assumed for all Appendix R fires and the failure described by this OD could appy to allfire initiated starts of the MDAFPs. Therefore, failure of the MDAFPs as described in OD CR 01-3648 is the same for this condition and Appendix R operability conclusion of Operable But Nonconforming also remains the same.

Related AR Number CR 01-3595 Impact:

Closed. Concerns postulated failure of the recirculation line AOV. This is a related issue but it does not unpact this OPR.

Related AR Number Impact:

Review additionally, as applicable, these items to help clarify current plant conditions These items may have impact on the SSC performance.

Active Temporary Operating Procedure Changes None Applicable PBF.1553 Revision9 10/16&02 Page 3 of 8 R.-'erence-NP 5 3 7

Ac::ve Terporar. Modifications None Aohlicabie Modifications cu-entty being installed None Apnhcable Recent Work Orders None Apolicable A poroved DC",ý's None Applicable Recently Performed Inservice Testing IT-10 4

Evaluate the CLB functions and performance requirements identified in Step 2 against the as-found condition and the related issues identified in Step 3. The evaluation must identify the extent to which the SSC is capable of performing its identified CLB funcnon. Document the evaluation After the automatic initiation of AF in response to an analyzed event, operators are required to manually cqontrol AFflow based on SG levels (FSAR 7.3.3.4). Manual control may include shutting pump discharge valves resulting in pump operation strictly on recirculation flow. Due to the potential inability of the recirculation line to pass the required flow to maintain pump operability, the AF system may not be able to perform its CLB functions.

Measures taken include heightened Operator awareness of the potential for pump damage (briefings with on-coming shift personnel), temporary information tags posted on the AFWpump flow controls. Revisions to operating procedures that will alert the Operator to the limitations of the AFWsystem with respect to minimum AFWpump flow are completed. The revisions will ensure that AFW Minimum Flow Requirements are maintained or the affected AFWpump is secured.

NEMA guidelines states that motor driven pumps may be started twice from an initial standby condition with no restrictions. After the initial starts, NEMIA MG-1 recommends subsequent starts after "all conditions affecting operation have been thoroughly investigated and the apparatus has been examined for evidence of excessive heating."

This guidance encompasses situations where the load or prime mover may have experienced a fault which causes a failure to start or run; excessive temperatures are not expected with the equipment functioning normally. Additional starts therefore are allowed and not expected to cause machine failure. It should be recognized that a minimum of 3 starts of a motor driven AFpump are allowed in the first 15 minutes of operation. An additional one or two starts is allowed provided the run time is at least 15 minutes between these later starts. Motor starting nameplate information directs that after initial starts the motor may be restarted if run time has exceeded 15 minutes or it has been secured for 60 minutes. Excessive consecutive starting will decrease overall motor life. Starting duty limitations are provided by the manufacturer to provide the longest possible motor life.

The AOP SG control band is 29% to 65%. This represents an approximate volume of 5000 gallons. At a steaming rate of50 gpm, a motor driven pump start would be required every 50 minutes to control level within half of the control band. At maximum pump flow rate of 200 gpm, the pump would be operated for 16 minutes to recover the level lost while the pump was secured. Since the operation of the pumps will meet the NEMA criteria established, the pump motor will not fail as a result of repetitive starts.

The pump motors are supplied from Westinghouse DB-50 Air Circuit Breakers. Vendor information indicates an in-rush, non-fault duty cycle of 750 breaker operations. The recommended operating conditions are a frequency of operation not to exceed 20 per 10 PBF-1 553 Revsion 9 10/16W02 Page 4 of 8 Reference NP 5 3 7

minutes or 30 per hour. Since the MDAFPs are only used during startup, shutdo;rn (including SG chemical additions) and required system test ng, the number of breaker operations are well below these operating limits 1fan operator is required to secure and restart pumps during a transient, the actuons would be performed at a frequency of operation much less than the recommended valuefor the entire transient.

There are no starting c;cle limitations on the turbine driven AFW pumps The turbine vendor was contacted and verified that no duty cycle concerns existfor this pump assembly. The steam supply MOVs are rated/or 5 minutes of operation every hour which corresponds to five open/shut cycles. With a maximum steaming rate of 75 gpm, it would take approximately 33 minutes to steam off half of the control band (2500 gallons). The nameplate guidancefor motors and valves is based on manufacturers' recommendations for long life and are considered conservative. Therefore, operation of the valve will not be degraded.

The recommendations of this Operabilty Determination is to consider the AF system OPERABLE but NON-CONFORMiTNG. The potential Non-Conformance pertains to the FSAR statement of the minimum recirculation flow path ensuring minimum flow is available.

Note. If the SSC is determined to be inoperable based on this evaluation, mark Step 5 N/A and continue with Step 6.

5.

Evaluate the need for compensatory measures. Complete with input from DSS.

D Degraded or nonconforming, however, no compensatory measures are required.

Degraded or nonconformng The folowmg compensatory measures are REQUIRED in order to maintain operability.

If Compensatory Measures are not required go to Step 6.

Compensatory measures must be in place prior to OD final approval by the DSS Affected Unit (I OR 2 OR 0) 0 Describe the Compensatory Measure (what needs to be performed):

As an immediate compensatory measure, a briefing of all responsible on-shift Reactor Operations staff should be conducted describing the concern and appropriate responses:

1. If discharge flow cannot be maintained per the applicable operating procedure(s) without exceeding desired SG level, secure the associated pump(s) and re-start again later when (if) needed.

2. Revise Operating Procedures as appropriate to prevent reducing flow of operating AFWpumps below the minimum requirements.

3. Install tags, placards, or otherwise post the pertinent information at the controls (in the Control Room and locally)for the associated AFW pumps.

4. Emphasize verifying a minimum of50 (75) gpm flow through a motor (turbine) driven PBF-1553 Revision 9 10/16,02 Referenc.

NP 5 3 7 Page 5 of 8

pump when reducIng flow as stated in the EOP foldout page Basis which indicates the Compensatory Measure maintains operability By verifying minimum pump flow requirements, the continued avazlability of the AFW pumps is ensured. Minimum pump flow maintains hydraulic stabiliýv, removes pump heat and increase the life of the pump If the minimum flow requirement cannot be maintained, then the pump will be secured to prevent damage. Repenitive operation of a motor driven or turbine drzien AFpumpfor SG level control has been determined to be acceptable.

Implementation Mechanism (Procedure number, Temp -Mod number. etc):

As determined appropriate by Operations.

Plant condition(s) or mode(s) of operation which require the Compensatory Measure:

Modes 1, 2, and 3 (modes in which decay heat removalfrom the SGs is necessary and required capability per ITS.

Under what conditons may the Compensatory Measure be terminated?

Engineering evaluation or modification to restore thefunction of the recirculation lines.

6.

Prepared By:

X.

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A Date/Time:

IJ Name (Print) / Signature Engineering Manager Approval of Evaluation and Proposed Compensatory Measure (if applicable) 7 7 1I -

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Date/Time:_

Name (Print) / Signature

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7.

SRO Review of Operability Documentation:

El Inoperable - does not meet the minimum level of performance.

El Operable - fully meets performance requirements. No further action required.

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Operable But Degraded - or Operable But Nonconforming - meets the minimum required level of performances, compensatory measures ARE required.

El Operable But Degraded - or Operable But Nonconforming - meets the minimum required level of performances, compensatory measures are NOT required.

Evaluation Accepted Evaluation and Compensatory Measures Accepted.

PBF-1553 Revision 9 10/16/02 Page 6 of 8 Reference NP 5 3 7

L-Compensatory Measures Verified m Place D

N-P 10.1 1. LCO Tracking Log updated to include new items Name (Prnt); S&,,ature Route OD package to in-box in WCC for processing. Package includes original Par: L all attachments, and related condition report PBF-1553 Revision 9 10/16/02 Page 7 of*8 Reference NP 5 3 7 t

OPERABILITY DETERMINATIO-N OPR Unit5()

CAP

__stem REV CHAMPS ID 1

SOBD condition which requires compensatory measures Li OBD condition which does NOT require compensator. measures.

Tidke (Eculcrenv ID and Descnotion of rssue PART [I CORRECTIVE ACTION PL.kN, SCHEDULE AND JUSTIFICATION (30 days to complete)

For those Operable But Degraded or Nonconforming items, what action(s) need to be done to restore the condinon to its "fully operable" or -fully qualified" status" Also consider any compensatory measures in place and what needs to be done for their removal.

2.

Provide a schedule for completion of the action(s) listed in question 1. This schedule represents the earliest available opportunity to perform the corrective actions, allowing reasonable time for planning, scheduling, design, procurement, etc.

3.

List the date of the next refueling outage for the affected Unit(s).

PBI:

PB2:

4.

Li All actions required to bring this degraded or non-conforming issue back to fully operable will be completed prior or concurrent with the next refueling outage as indicated in Step 3. N/A Step 5 and obtain approval.

Li All actions required to bring this degraded or non-conforming issue back to fully operable will NOT be completed prior or concurrent with the next refueling outage as indicated in Step 3. COMPLETE Step 5 and obtain approval.

5 Please provide justification for this schedule based on:

the amount of time required for design, review, and approval of the corrective action, procurement for replacement or repair, availability of specialized equipment to perform the repair, the need to be in hot or cold shutdown to implement the corrective action, or other factors that constrain the corrective action schedule.

Prepared by:

Date/Time:

Name (Print) / Signature Engineering Manager Approval:

Name (Print) / Signature Reference NP 5 3 7 PBF-1553 Revmston 9 10/16102 Date/Time:

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