L-2013-223, Florida Power & Light/St. Lucie'S Response to Request for Additional Information Regarding Overall Integrated Plan in Response to Order EA-12-051, Reliable Spent Fuel Pool Instrumentation

Florida Power & Light/St. Lucie'S Response to Request for Additional Information Regarding Overall Integrated Plan in Response to Order EA-12-051, Reliable Spent Fuel Pool Instrumentation

ML13219A838
Person / Time
Site:	Saint Lucie
Issue date:	07/26/2013
From:	Jensen J Florida Power & Light Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
EA-12-051, L-2013-223
Download: ML13219A838 (16)

Text

0 July 26, 2013 L-2013-223 F=PL. 10 CFR 2.202 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 St. Lucie Units 1 and 2 Docket Nos. 50-335 and 50-389 Florida Power & Light/St. Lucie's Response To Request For Additional Information Regarding Overall Integrated Plan In Response To Order EA-12-051, "Reliable Spent Fuel Pool Instrumentation"

References:

1. NRC Order Number EA-12-051, Order to Modify Licenses with Regard to Reliable Spent Fuel Pool Instrumentation, dated March 12, 2012, Accession No. ML12056A044.

2. NRC Interim Staff Guidance JLD-ISG-2012-03, "Compliance with Order EA-12-051, Reliable Spent Fuel Pool Instrumentation," Revision 0, dated August 29, 2012, Accession No. ML12221A339.

3. NEI 12-02, "Industry Guidance for Compliance with NRC Order EA-12-051, 'To Modify Licenses with Regard to Reliable Spent Fuel Pool Instrumentation," Revision 1, dated August 24, 2012, Accession No. ML12240A307.

4. FPL Letter L-2012-384, dated October 25, 2012, "Florida Power & Light (FPL)'s Initial Status Report in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Reliable Spent Fuel Pool Instrumentation (Order Number EA-12-051)," Accession No. ML12300A420.

5. FPL Letter L-2013-079, dated February 28, 2013, "Florida Power & Light/St. Lucie's Overall Integrated Plan in Response to March 12, 2012 Commission Order to Modify Licenses with Regard to Reliable Spent Fuel Pool Instrumentation (Order Number EA 05 1)," Accession No. ML13063A026.

6. NRC Letter to FPL dated July 16, 2013, "St. Lucie Nuclear Power Plant, Units I and 2 -

Request For Additional Information Regarding Overall Integrated Plan For Reliable Spent Fuel Pool Instrumentation (TAC Nos. MF0990 AND MF0991)," Accession No. ML13196A079.

On March 12, 2012, the Nuclear Regulatory Commission (NRC) issued an order (Reference 1) to FPL/St. Lucie. Reference (1) was immediately effective and directed FPL to implement and maintain reliable spent fuel pool water level instrumentation. Specific requirements are outlined in Attachment 2 of Reference (1).

Reference (1) required submission of an Overall Integrated Plan by February 28, 2013. The NRC Interim Staff Guidance (ISG) (Reference 2) was issued August 29, 2012, which endorsed industry guidance document NEI 12-02, Revision I (Reference 3), with clarifications and exceptions identified in Reference (2). Reference (3) provided direction regarding the content of this Overall Integrated Plan.

Florida Power & Ught Company 6501 S. Ocean Drive, Jensen Beach, FL 34957

L-2013-223 Page 2 Reference (4) provided the FPL/St. Lucie initial status report regarding reliable spent fuel pool instrumentation, as required by Reference (1). Reference (5) provided FPL/St. Lucie's Overall Integrated Plan in Response to March 12, 2012 Commission Order to Modify Licenses with Regard to Reliable Spent Fuel Pool Instrumentation (Order Number EA-12-05 1).

The responses to the request for additional information contained in Reference (6) are contained in the Attachment to this letter.

This letter contains no new Regulatory Commitments and no revisions to existing Regulatory Commitments.

If you have any questions please contact Mr. Eric Katzman, Licensing Manager, at (772) 467-7734.

I declare under penalty of perjury that the foregoing is true and correct.

Executed on Z14 10 2013.

Respectfully submitted, Joseph Jensen Site Vice President St. Lucie Plant Attachment Response to Request for Additional Information Regarding Overall Integrated Plan in Response to Order EA- 12-051 cc: Director, Office of Nuclear Reactor Regulation NRC Regional Administrator NRC Resident Inspector

L-2013-223 Attachment Page 1 of 14 Response to Request for Additional Information Regarding Overall Integrated Plan in Response to Order EA-12-051

1.0 INTRODUCTION

By letter dated February 28, 2013 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML13063A026), Florida Power & Light Company submitted an Overall Integrated Plan (OIP) in response to the March 12, 2012, Commission Order modifying licenses with regard to requirements for Reliable Spent Fuel Pool Instrumentation (Order Number EA-12-051; ADAMS Accession No. ML12054A679) for St. Lucie Nuclear Power Plant, Units 1 and 2. The U.S. Nuclear Regulatory Commission (NRC) staff endorsed Nuclear Energy Institute (NEI) 12-02 "Industry Guidance for Compliance with NRC Order EA-12-051, to Modify Licenses with Regard to Reliable Spent Fuel Pool Instrumentation," Revision 1, dated August 2012 (ADAMS Accession No. ML12240A307), with exceptions, as documented in Interim Staff Guidance (ISG) 2012-03 "Compliance with Order EA-12-051, Reliable Spent Fuel Pool Instrumentation," Revision 0, dated August 29, 2012 (ADAMS Accession No. ML12221A339).

The NRC staff has reviewed the February 28, 2013 response by the licensee and determined that the following Request for Additional Information (RAI) is needed to complete its Technical Review. If any part of this information is not available within the 30 day response period for this RAI, please provide the date this information will be submitted.

L-2013-223 Attachment Page 2 of 14 2.0 LEVELS OF REQUIRED MONITORING The O/P states, in part, that Key spent fuel pool water levels:

1. Level adequate to support operation of the normal fuel pool cooling system Elevation 56'-0" for both Units land 2. This elevation is derived from Unit I UFSAR Section 9.1 and is shown on isometric drawings 8770-G-125 Sheet FS-W-3 and 2998-G-125 Sheet FS-W-6 (References 10, 11 & 12 respectively).

2. Level adequate to provide substantialradiationshielding for a person standing on the spent fuel pool operatingdeck- An elevation approximately 10' above the highest fuel rack is utilized, with specific elevations as follows:

Unit 1: El. 46"'3" based on Unit I FSAR Fig. 1.2-19 (Reference 17) in conjunction with plant drawings 8770-11884, 8770-11885 & 8770-11890 (References 13 thru 15 respectively).

Unit 2: El. 46"-5" based on Unit 2 FSAR Fig. 1.2-17 (Reference 18) and plant drawing 2998-18511 (Reference 16).

These elevations are approximately 10'above the top of the fuel racks (see level 3 elevations below).

3. Level where fuel remains covered -

Unit 1: El. 36'-3", based on Unit IFSAR Fig. 1.2-19 (Reference 17) in conjunction with plant drawings 8770-11884, 8770-11885 & 8770-11890 (References 13 thru 15 respectively).

Unit 2: El. 36'-5", based on Unit 2 FSAR Fig. 1.2-17 (Reference 18) and plant drawing 2998-18511 (Reference 16).

RAI-1

Pleaseprovide the following:

a) For level 1, specify how the identified location representsthe HIGHER of the two points describedin the NEI 12-02 guidance for this level.

b) A clearly labeled sketch depicting the elevation view of the proposed typical mounting arrangementfor the portions of instrument channel consisting of permanentmeasurement channel equipment (e.g., fixed level sensors and/or stilling wells, and mounting brackets). Indicate on this sketch the datum values

L-2013-223 Attachment Page 3 of 14 representingLevel 1, Level 2, and Level 3 as well as the top of the fuel racks.

Indicate on this sketch the portion of the level sensor measurement range that is sensitive to measurement of the fuel pool level, with respect to the Level 1, Level 2, and Level 3 datum points.

FPL Response RAI-1.a For Level 1, the two points described in the NEI 12-02 guidance are; the level at which reliable suction loss occurs due to uncovering of the coolant inlet pipe, weir or vacuum breaker (depending on the design), or the level at which the water height, assuming saturated conditions, above the centerline of the cooling pump suction provides the required net positive suction head (NPSH) specified by the pump manufacturer or engineering analysis. To determine the higher of the two levels the following was taken into consideration:

1. The level at which reliable suction loss occurs due to uncovering the coolant inlet pipe or any weirs or vacuum breakers associated with suction loss is established based on nominal coolant inlet pipe elevation. There are no siphon breakers in the suction lines at either unit at St. Lucie. The elevation of the suction line centerline is 56'-0" for both St. Lucie Units 1 and 2.

2. The level at which the normal SFP cooling pumps lose required NPSH assuming saturated conditions in the pool is below the elevation that defines Level 1 per (1) above. The centerline of the cooling pump suctions is at plant elevation 21'-7 '/2 inches. The required NPSH at pump runout at saturated conditions is 12'. This corresponds to an NPSHR value of plant elevation 33'-7 Y2", which is lower than the 56'-0" stated in (1) above.

The higher of the above levels is (1). Therefore, Level 1 elevation is established at 56'-

0" for both the primary and backup instrumentation channels.

The SFP level instrument upper range will be at least 6 inches above Level 1 to account for channel accuracy and instrument loop uncertainty. From a practical perspective, the upper range capability will extend even higher (e.g., approximately 4 feet up to the normal operating level at elevation 60'-0".)

FPL Response RAI-1.b The following sketch contains the information requested in RAI-1.b. Instrument uncertainty, which is to be determined, is not included in the elevation values for Levels 1 and 3.

L-2013-223 Attachment Page 4 of 14 Seismic I Mounting Bracket

. .f ) To Electronics 0 )erating Deck 62' Normal Water L -Level 60' Nominal top of Measurement Range (Value above normal will be established in Level 1 56'-0" detailed design phase) (Both Units)

Level 2 Sensor Active Unit 1 46'-3" Measurement Range Unit 2 46'-5" Bottom of Measurement Level 3 Range (Approximately 6" Unit 1 37'-3" Below Level 3) Unit 2 37'-5" 0

6____ Top of Fuel Racks Unit 1 36*-3" Unit 2 36'-5" Fuel Transfer Canal Note that FPL is modifying the previously provided elevation for Level 3 based on subsequent industry and regulatory discussions that have occurred since submittal of the OIP.

NEI 12-02 describes Level 3 as the level where fuel remains covered and actions to implement make-up water addition should no longer be deferred. Level 3 corresponds nominally (i.e., +/- 1 foot) to the highest point of any fuel rack seated in the spent fuel pool. Level 3 is defined in this manner to provide the maximum range of information to operators, decision makers and emergency response personnel.

St. Lucie previously designated Level 3 as the actual top of the fuel storage racks. St.

Lucie is now designating Level 3 as the water level greater than 1 foot above the top of the fuel storage racks plus the accuracy of the SFP level instrument channel, which is yet to be determined. Designation of this level as Level 3 is conservative; its selection assures that the fuel will remain covered, and at that point there would be no functional or operational reason to defer action to implement the addition of make-up water to the pool.

Accordingly, the previous Level 3 elevation of 36'-3" for St. Lucie Unit 1 is being revised to 37'-3" and 36'-5" for St. Lucie Unit 2 is being revised to 37'-5".

L-2013-223 Attachment Page 5 of 14 3.0 INSTRUMENTATION DESIGN FEATURES 3.1 Arrangement The OIP states, in part, that The two SFP level instrument channels will be installed in diverse locations, arrangedin a manner that provides reasonableprotection of the level indication function against missiles that may result from damage to the structure over the SFP.

As indicatedabove, the primary and backup SFPlevel sensors will be installedin the South side of each unit's SFP, as close to the opposite corners as practicalto maintain maximum attainableseparation. Sensor conditioningelectronics and battery backup will be mounted in a remote location separatedfrom the SFP by a reinforced concrete wall(s) which will provide suitable radiationshielding for the electronics.

RAI-2

Please provide a clearly labeled sketch or marked-up plant drawing of the plan view of the SFP area, depicting the SFP inside dimensions, the planned locations/placementof the primary and back-up SFP level sensors, and the proposed routing of the cables that will extend from the sensors toward the location of the local electronicscabinets and read-out/displaydevices in the main control room or alternate accessible location.

FPL Response RAI 2 The answer to this request requires design information that is under development. The information will be provided at the 6 month update after it has been obtained.

3.2 Mounting The OIP states, in part, that Mounting will be Seismic Class I. Installed equipment will be seismically qualified to withstand the maximum seismic ground motion consideredin the design of the plant area in which it is installed.

RAI-3

Please provide the following:

a) The design criteria that will be used to estimate the total loading on the mounting device(s), including static weight loads and dynamic loads.

Describe the methodology that will be used to estimate the total loading,

L-2013-223 Attachment Page 6 of 14 inclusive of design basis maximum seismic loads and the hydrodynamic loads that could result from pool sloshing or other effects that could accompany such seismic forces.

b) A descriptionof the manner in which the level sensor (andstilling well, if appropriate)will be attached to the refueling floor and/or other support structures for each planned point of attachmentof the probe assembly.

Indicate in a schematic the portions of the level sensor that will serve as points of attachment for mechanical/mountingor electrical connections.

c) A description of the manner by which the mechanical connections will attach the level instrument to permanent SFP structures so as to support the level sensor assembly.

FPL Response RAI-3.a, b, c The answer to this request requires design information that is under development. The information will be provided at the 6 month update after it has been obtained.

3.3 Qualification The OIP states, in part, that Components of the instrument channels will be qualified for shock and vibration using one or more of the following methods:

• Components are supplied by manufactures using commercial quality programs (such as IS09001, Quality management systems - Requirements (Reference 8)) with shock and vibration requirements included in the purchase specification at levels commensurate with portable hand-held device or transportationapplications;

" Components have a substantialhistory of operationalreliabilityin environments with significantshock and vibration loadings, such as transportationapplications;or

• Components are inherently resistantto shock and vibration loadings, such as cables.

The effects of postulated seismic events on installedinstrument channel components (with the exception of battery chargersand replaceable batteries), will be verified to ensure that the equipment design and installation is robust. Applicable components of the instrument channels will be qualified by the manufacturer(or otherwise tested) for seismic effects at response levels commensurate with the equipment mounting location. Instrument channel qualification will be basedon the

L-2013-223 Attachment Page 7 of 14 guidanceprovided in Sections 7, 8, 9, and 10 of IEEE Standard 344-2004, IEEE Recommended Practicefor Seismic Qualification of Class 1E Equipment for Nuclear Power GeneratingStations, (Reference 9) or a substantiallysimilarindustrial standard.

RAI-4

Please provide the following:

a) A description of the specific method or combination of methods you intend to apply to demonstrate the reliability of the permanently installed equipment under Beyond-Design-Basis(BDB) ambient temperature,humidity, shock, vibration, and radiationconditions.

b) A description of the testing and/oranalyses that will be conducted to provide assurance that the equipment will perform reliably under the worst-case credible design basis loading at the location where the equipment will be mounted. Include a discussion of this seismic reliabilitydemonstration as it applies to a) the level sensor mounted in the SFP area, and b) any control boxes, electronics, or read-out and re-transmittingdevices that will be employed to convey the level information from the level sensor to the plant operatorsor emergency responders.

c) A description of the specific method or combination of methods that will be used to confirm the reliabilityof the permanently installedequipment such that following a seismic event the instrument will maintain its required accuracy.

FPL Response RAI-4.a, b, c The answer to this request requires design information that is under development. The information will be provided at the 6 month update after it has been obtained.

3.4 Independence The OIP states, in part, that The primary instrument channel will be redundant to and independent of the backup instrument channel. Independence will be obtained through separationof the sensors, indication, backup battery power supplies, associatedcabling and channel power feeds.

L-2013-223 Attachment Page 8 of 14

RAI-5

Please provide the following:

a) A descriptionof how the two channels of the proposed level measurement system in each pool meet this requirementso that the potentialfor a common cause event to adversely affect both channels is minimized to the extent practicable.

b) Furtherinformation describing the design and installation of each level measurement system, consisting of level sensor electronics, cabling, and readout devices. Please address how independence of these components of the primary and back-up channels is achieved through the application of independentpower sources, physical and spatial separation,independence of signals sent to the location(s) of the readout devices, and the independence of the displays.

FPL Response RAI-5.a The permanently installed primary and backup instrument channels will be fully redundant to and independent of each other with respect to physical separation and the normal electrical power sources are from separate channel sources. The physical and electrical separation minimizes the potential for a single electrical fault or common cause event to adversely affect both channels.

The level sensors, located near the south-east and south-west corners of the SFP, will be physically separated to the extent practical by a distance equal to the shortest length of a pool side as allowed per NEI 12-02 Section 3.2. The length of the shortest side of the SFP at St. Lucie is approximately 33 feet. This horizontal separation minimizes a common cause event in the area of the SFP from adversely affecting both channels.

This spatial separation will be maintained for the sensor cable within the SFP area.

Once outside the SFP area, conduit and cable separation between the channels will be maintained to meet or exceed the current plant design and licensing basis separation criteria.

The level transmitters, one per channel, will be physically separated from each other and are located one elevation below the level sensors in the new fuel storage area directly outside the SFP room.

The third component, the level processor cabinets, one per channel, which includes the display and uninterruptible power supply (UPS), will be physically separated from each other by a distance meeting or exceeding current plant design basis separation for channels. The cabling for each channel will be located in physically independent conduits or raceways installed to seismic 1 criteria.

L-2013-223 Attachment Page 9 of 14 FPL Response RAI-5.b As stated in the response to RAI-5.a, each channel is fully redundant and independent of each other. Equipment and associated cabling located in the pool area will be physically separated by a distance equal to the length of the shortest side of the pool.

Plant separation criteria will be maintained for instrument locations and associated cabling outside the SFP area. The level indication signals sent to each respective channel's readout device is completely independent of the other channel. No power sources or signals are shared between the two channels.

Each channel will be powered from separate lighting panels that are each fed from separate and independent MCCs that are fed from separate and independent 6.9 KV switchgear. Each channel is equipped with its own UPS and battery backup system.

3.5 Power supplies The OIP states, in part, that Both channels will be powered from dedicated batteries and local battery chargers.

The battery chargersfor both channels will normally be powered from separate sources of 120V AC power. Minimum battery life of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> will be provided. The battery systems will include provision for battery replacementshould the battery chargerbe unavailable following the event. Spare batteries will be readily available.

In the event of a loss of normal power the battery chargerscould be connected to another suitable power source.

RAI-6

a) A description of the electricalAC power sources and capacitiesfor the primary and backup channels battery charger.

b) If the level measurement channels are to be powered through a battery system (eitherdirectly or through an UninterruptiblePower Supply (UPS)), please provide the design criteria that will be applied to size the battery in a manner that ensures, with margin, that the channel will be available to run reliably and continuously following the onset of the BDB event for, b the minimum duration needed, consistent with the plant mitigation strategiesfor BDB external events (OrderEA- 12-049).

FPL Response RAI-6.a, b The answer to this request requires design information that is under development. The information will be provided at the 6 month update after it has been obtained.

L-2013-223 Attachment Page 10 of 14 3.6 Accuracy The OIP states, in part, that Instrument channels will be designed such that they will maintain theirdesign accuracyfollowing a power interruption or change in power source without recalibration.

Accuracy will consider SFP conditions, e.g., saturatedwater, steam environment, or concentratedborated water. Additionally, instrument accuracywill be sufficient to allow trainedpersonnel to determine when the actual level exceeds the specified lower level of each indicatingrange (levels 1, 2 and 3) without conflicting or ambiguous indication. The accuracy will be within the resolution requirements of Figure 1 of NEI 12-02.

RAI.7 Please provide the following:

a) An estimate of the expected instrument channel accuracyperformance (e.g., in

% of span) under both a) normal SFPlevel conditions (approximatelyLevel I or higher) and at the BDB conditions (i.e., radiation,temperature,humidity, post-seismic and post-shock conditions) that would be present if the SFP level were at the Level 2 and Level 3 datum points.

b) A description of the methodology that will be used for determining the maximum allowed deviation from the instrumentchannel design accuracythat will be employed under normal operatingconditions as an acceptance criterion for a calibrationprocedure to flag to operatorsand to technicians that the channel requiresadjustment to within the normal condition design accuracy.

FPL Response RAI-7.a, b The answer to this request requires design information that is under development. The information will be provided at the 6 month update after it has been obtained.

3.7 Testing The OIP states, in part, that Instrument channel design will provide for routine testing and calibrationconsistent with Order EA-12-051and the guidance in NEI 12-02. Details will be determined during the engineering and design phase. Instrument channel testing and calibration will be performed using existing plant work control processes.

L-2013-223 Attachment Page 11 of 14 RAI- 8 Please provide the following:

a) A description of the capability and provisions the proposed level sensing equipment will have to enable periodic testing and calibration,including how this capability enables the equipment to be tested in-situ.

b) A description of how such testing and calibrationwill enable the conduct of regularchannel checks of each independent channel against the other, and against any other permanently-installedSFP level instrumentation.

c) A description of how calibrationtests and functional checks will be performed and the frequency at which they will be conducted. Discuss how these surveillances will be incorporatedinto the plant surveillance program.

d) A description of what preventative maintenance tasks are required to be performed during normal operation, and the planned maximum surveillance interval that is necessary to ensure that the channels are fully conditioned to accuratelyand reliably perform their functions when needed.

FPL Response RAI-8.a, b, c, d The answer to this request requires design information that is under development. The information will be provided at the 6 month update after it has been obtained.

3.8 Display The OIP states, in part, that The design will include remote indication that will be accessible during post event conditions.

RAI-9

Please provide the following:

a) The specific location for the primary and backup instrument channel display.

b) Since both the primary and backup display locations are not in the main control room, please provide a descriptionof the location for the primary and back up displays, including primary and alternate route evaluation, habitabilityat display location(s), continualresource availabilityfor personnel responsible to promptly read displays, and provisions for communications with decision makers for the various SFP drain down scenariosand external events.

L-2013-223 Attachment Page 12 of 14 c) The reasonsjustifying why the locations selected will enable the information from these instruments to be considered "promptlyaccessible". Include consideration of various drain-down scenarios.

FPL Response RAI-9.a, b, c The answer to this request requires design information that is under development. The information will be provided at the 6 month update after it has been obtained.

L-2013-223 Attachment Page 13 of 14 4.0 PROGRAM FEATURES 4.1 Procedures The OIP states, in part, that Procedures will be developed using guidelines and vendor instructions to address the maintenance, operation, and abnormalresponse issues associatedwith the new SFPinstrumentation.

RAI-10

Pleaseprovide the following:

a) A list of the operating (both normal and abnormalresponse)procedures, calibration/testprocedures,maintenance procedures,and inspection procedures that will be developed for use of the SFPinstrumentation in a manner that addresses the orderrequirements.

b) A brief description of the specific technical objectives to be achieved within each procedure. If your plan incorporatesthe use of portable spent fuel level monitoring components, please include a description of the objectives to be achieved with regardto the storage location and provisions for installationof the portable components when needed.

FPL Response RAI 10.a, b The answer to this request requires design information that is under development. The information will be provided at the 6 month update after it has been obtained.

4.2 Testing and Calibration The OIP states, in part, that Processeswill be established and maintained for scheduling and implementing necessary testing and calibrationof the primary and backup spent fuel pool level instrument channels to maintain the instrumentchannels at the design accuracy.

Testing and calibrationof the instrumentation will be consistent with vendor recommendations and any other documented basis. Calibrationwill be specific to the mounted instrument and the monitor.

L-2013-223 Attachment Page 14 of 14

RAI-11

Please provide the following:

a) Furtherinformation describing the maintenance and testing program the licensee will establish and implement to ensure that regulartesting and calibrationis performed and verified by inspection and audit to demonstrate conformance with design and system readiness requirements. Include a description of your plans for ensuring that necessary channelchecks, functional tests, periodiccalibration, and maintenance will be conducted for the level measurement system and its supporting equipment.

b) A description of how the guidance in NEI 12-02 section 4.3 regarding compensatory actions for one or both non-functioning channels will be addressed.

c) A description of the compensatory actions to be taken in the event that one of the instrument channels cannot be restored to functional status within 90 days.

FPL Response RAI 11 .a, b, c The answer to this request requires design information that is under development. The information will be provided at the 6 month update after it has been obtained.