ML13206A384

Catawba Nuclear Station, Units 1 and 2, Response to Request for Additional Information Regarding Overall Integrated Plan in Response to Order EA-12-051, Reliable Spent Fuel Pool Instrumentation (TAC Numbers MF1060 and MF1061)

ML13206A384
Person / Time
Site:	Catawba
Issue date:	07/23/2013
From:	Henderson K Duke Energy Carolinas
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
EA-12-051, TAC MF1060, TAC MF1061
Download: ML13206A384 (14)

Text

Kelvin HendersonDUKE Vice PresidentENERGY. Catawba Nuclear Station803-701-4251Duke EnergyCNO1VP 1 4800 Concord Rd.York, SC 29745July 23, 2013U.S. Nuclear Regulatory CommissionAttention: Document Control DeskWashington, D.C. 20555-0001Subject: Duke Energy Carolinas, LLC (Duke Energy)Catawba Nuclear Station, Units 1 and 2Docket Numbers 50-413 and 50-414Response to Request for Additional Information Regarding OverallIntegrated Plan in Response to Order EA-1 2-051, "Reliable Spent FuelPool Instrumentation"(TAC Numbers MF1060 and MF1061)References: 1. Letter from Duke Energy to NRC, "Overall Integrated Plans inResponse to March 12, 2012, Commission Order ModifyingLicenses With Regard to Requirements for Reliable Spent FuelPool Instrumentation (Order Number EA-12-051)", dated February28, 20132. Letter from NRC to Duke Energy, "Request for AdditionalInformation Re: Overall Integrated Plan in Response to OrderEA-12-051, "Reliable Spent Fuel Pool Instrumentation"", datedJune 24, 2013In Reference 1, Duke Energy submitted an Overall Integrated Plan (OIP) in response to theMarch 12, 2012 NRC Order modifying licenses with regard to requirements for reliableSpent Fuel Pool (SFP) Instrumentation (Order Number EA-12-051).In Reference 2, the NRC transmitted Requests for Additional Information (RAIs) regardingthe OIP.The purpose of this letter is to respond to the Reference 2 RAIs. The attachment to thisletter constitutes Catawba's response. The format of the attachment is to restate each RAIquestion, followed by the appropriate response. At this time, only a response to RAI-1 canbe provided. The responses to the remaining RAIs will be provided in the February 2014six-month status report for the implementation of Order EA-12-051.There are no regulatory commitments contained in this letter or its attachment.www.duke-energy.com U.S. Nuclear Regulatory CommissionPage 2July 23, 2013If you have any questions on this letter or its attachment, please contact L.J. Rudy at (803)701-3084.I declare under penalty of perjury that the foregoing is true and correct.Executed on July 23, 2013.Very truly yours,Kelvin HendersonLJR/sAttachment U.S. Nuclear Regulatory CommissionPage 3July 23, 2013xc (with attachment):V.M. McCreeRegional AdministratorU.S. Nuclear Regulatory Commission -Region IIMarquis One Tower245 Peachtree Center Ave., NE Suite 1200Atlanta, GA 30303-1257G.A. Hutto, IIISenior Resident Inspector (Catawba)U.S. Nuclear Regulatory CommissionCatawba Nuclear StationJ.C. Paige (addressee only)NRC Project Manager (Catawba)U.S. Nuclear Regulatory CommissionOne White Flint North, Mail Stop 8 G9A11555 Rockville PikeRockville, MD 20852-2738E.J. LeedsDirector, Office of Nuclear Reactor RegulationU.S. Nuclear Regulatory CommissionOne White Flint North, Mail Stop 13 H1611555 Rockville PikeRockville, MD 20852-2738D.L. SkeenDirector, Japan Lessons Learned Project DirectorateU.S. Nuclear Regulatory CommissionOne White Flint North, Mail Stop 9 E311555 Rockville PikeRockville, MD 20852-2738M.R. JohnsonU.S. Nuclear Regulatory CommissionOne White Flint North, Mail Stop 16 E1511555 Rockville PikeRockville, MD 20852-2738R.M. TaylorU.S. Nuclear Regulatory CommissionOne White Flint North, Mail Stop 9 E311555 Rockville PikeRockville, MD 20852-2738 REQUEST FOR ADDITIONAL INFORMATIONOVERALL INTEGRATED PLAN IN RESPONSE TOORDER EA-12-051, "RELIABLE SPENT FUEL POOL INSTRUMENTATION"DUKE ENERGYCATAWBA NUCLEAR STATION, UNITS 1 AND 2DOCKET NOS. 50-369 AND 50-3701.0 INTRODUCTIONBy letter dated February 28, 2013 (Agencywide Documents Access and Management System(ADAMS) Accession No. ML13086A095), Duke Energy submitted an Overall Integrated Plan(OIP) in response to the March 12, 2012, U.S. Nuclear Regulatory Commission (NRC),Commission Order modifying licenses with regard to requirements for Reliable Spent Fuel Pool(SFP) Instrumentation (Order Number EA-12-051; ADAMS Accession No. ML12054A679) forCatawba Nuclear Station, Units 1 and 2. The NRC staff endorsed Nuclear Energy Institute(NEI)12-02 "Industry Guidance for Compliance with NRC Order EA-12-051, to Modify LicenseswithRegard to Reliable SFP Instrumentation," Revision 1, dated August 2012 (ADAMSAccessionNo. ML12240A307), with exceptions, as documented in Interim Staff Guidance (ISG)2012-03"Compliance with Order EA-12-051, Reliable SFP Instrumentation," Revision 0, datedAugust 29, 2012 (ADAMS Accession No. ML12221A339).The NRC staff has reviewed the February 28, 2013, response by the licensee and determinedthat the following Request for Additional Information (RAI) is needed to complete its TechnicalReview. If any part of this information is not available within 30 days of this request, pleaseprovide the date this information will be submitted.2.0 LEVELS OF REQUIRED MONITORINGThe OIP states, in part, thatIndication of SFP level will be provided from approximately normal pool water level (El. 598'-6") down to approximately the top of irradiated fuel assemblies seated in the storage racks(El. 573'). In particular, the system will be capable of continuously monitoring SFP level atthree distinct water levels described in the Order.* Level 1 -Level that is adequate to support operation of the normal fuel pool coolingsystem -indicated level on either channel greater than the point at which pump suctionis presumed to be lost (El. 597' -4").* Level 2 -Level adequate to provide substantial radiation shielding for a person standingon the spent fuel pool operating deck -indicated level on either channel greater than 10'above the highest point of any fuel racks, or > El. 583'. This monitoring level ensures1 there is adequate water level to provide substantial radiation shielding for personnelresponding to beyond design-basis external events and to initiate SFP makeupstrategies.Level 3 -Level where fuel remains covered but actions to implement make-up wateraddition should no longer be deferred -Indicated level on either channel less than 12inches above the highest point of any fuel storage rack. This monitoring level ensuresthere is adequate water level above the stored fuel seated in the storage racks.RAI-1Please provide the following:a) For level 1, specify how the identified location represents the HIGHER of the two pointsdescribed in the NEI 12-02 guidance for this level.b) A clearly labeled sketch depicting the elevation view of the proposed typical mountingarrangement for the portions of instrument channel consisting of permanentmeasurement channel equipment (e.g., fixed level sensors and/or stilling wells, andmounting brackets). Indicate on this sketch the datum values representing Level 1,Level 2, and Level 3 as well as the top of the fuel. Indicate on this sketch the portion ofthe level sensor measurement range that is sensitive to measurement of the fuel poollevel, with respect to the Level 1, Level 2, and Level 3 datum points.Catawba Response:Instrument Channel Design Overview/BackgroundThe new Catawba Nuclear Station Wide Range (WR) Spent Fuel Pool (SFP) levelinstrumentation will consist of a primary and a backup channel for each SFP (i.e., Unit ISFP and Unit 2 SFP). Both the primary and backup channels will be permanentlyinstalled. Per NEI 12-02 guidance, neither of these channels requires access to the SFParea during a Beyond Design Basis (BDB) event.The primary SFP level channel will utilize wave guided radar technology, which will havea wave guided pipe and receiving horn located in the SFP area. The wave guided pipeand horn will contain no organic materials and will not be susceptible to degradationdue to exposure to radiation, heat, or steam. The associated primary channelelectronics will be remotely located from the SFP inside the Seismic Category I AuxiliaryBuilding. This channel will have battery backup capacity and will provide remote controlroom level monitoring capability.The backup SFP level channel will consist of a pressure transmitter that senses SFPhead (level) based on a process connection to the SFP transfer tube. The SFP isnormally aligned to the fuel transfer canal to support the Standby Shutdown Facility that2 has provisions for primary system makeup with pump suction supply from the SFPduring various fire, security, and station blackout events. The backup level instrumentreadout will be located in the main control room. The backup level instrument will bepowered from the unit vital batteries.a) The normal SFP water level is 598'-6" elevation (reference drawing CN-1680-0123,Revision 6). The SFP cooling pump suction piping submergence is lost whenwater level decreases below 597'-4" elevation (reference calculation CNC-1223.20-00-0008, Revision 0). Abnormal procedures secure the SFP cooling pump whenwater level decreases to 1' below normal (reference procedures API11AI55001026,Revision 15 and API21A/55001026, Revision 16). Thus, the NEI 12-02 "Level 1"datum is considered to be 597'-6" elevation.b) The radar level instrument design will locate components in the SFP area suchthat they will remain above the maximum water level in the SFP, and theequipment mounts will not require any connections to be made to the pool liner.The mounting brackets for the wave guided assemblies and receiving horns willbe secured to the SFP operating deck which is at 605'-10" elevation (referencedrawing CN-1680-0123, Revision 6). The specific installation locations for thewave guided assemblies and receiving horns have not been finalized. Additionalinformation on equipment elevation, equipment orientation, and mounting forboth the primary and the backup channel devices will be included in the responseto RAI-2. Figure 1 at the end of this attachment provides the elevationsrepresenting Level 1, Level 2, and Level 3, the top of the fuel storage racks, andthe level monitoring range.3.0 Instrumentation Design Features3.2 ArrangementThe OIP states, in part, thatThe two SFP level instrument channels will be installed in spatially separated locationsand arranged in a manner to reduce the potential for common damage to both channels.Each channel will be installed within or adjacent to the Spent Fuel Buildings on Unit 1 &2, which are Category I structures capable of withstanding missiles and other externalevents.RAI-2Please provide a clearly labeled sketch or marked-up plant drawing of the plan view of the SFParea, depicting the SFP inside dimensions, the planned locations/placement of the primary andback-up SFP level sensor and mounting brackets, and the proposed routing of the cables thatwill extend from the sensors toward the location of the read-out/display device.3 Catawba Response:Information is not available within the 30-day response period for this RAI. Duke Energyanticipates submitting a response to this RAI for Catawba in the February 2014 six-month status report for the implementation of Order EA-12-051.3.3 MountingThe 0IP states, in part, thatEach permanently installed instrument channel will be mounted to retain designconfiguration during and following the maximum seismic ground motion considered inthe design of the spent fuel pool structure.RAI-3Please provide the following:a) The design criteria that will be used to estimate the total loading on the mountingdevice(s), including static weight loads and dynamic loads. Descriibe the methodologythat will be used to estimate the total loading, inclusive of design basis maximumseismic loads and the hydrodynamic loads that could result from pool sloshing or othereffects that could accompany such seismic forces.b) A description of the manner in which the level sensor (and stilling well, if appropriate) willbe attached to the refueling floor and/or other support structures for each planned pointof attachment of the probe assembly. Indicate in a schematic the portions of the levelsensor that will serve as points of attachment for mechanical/mounting or electricalconnections.c) A description of the manner by which the mechanical connections will attach the levelinstrument to permanent SFP structures so as to support the level sensor assembly.Catawba Response:Information is not available within the 30-day response period for this RAI. Duke Energyanticipates submitting a response to this RAI for Catawba in the February 2014 six-month status report for the implementation of Order EA-12-051.3.4 QualificationThe 0IP states, in part, thatBoth instrument channels for each pool will be specified to be reliable at the maximumtemperature, humidity, and radiation levels predicted during an extended loss of ACpower (ELAP) event at their installed locations.4 The instrumentation reliability will be demonstrated by appropriate combination ofdesign, analysis, operating experience and/or testing as outlined by NEI 12-02.This reliability will be established through vendor qualification documents procuredunder an augmented quality assurance process defined by Duke Energy.The level instrumentation is to be designed to remain functional following a SafeShutdown Earthquake.RAI-4Please provide the following:a) A description of the specific method or combination of methods you intend to apply todemonstrate the reliability of the permanently installed equipment under BDB ambienttemperature, humidity, shock, vibration, and radiation conditions.b) A description of the testing and/or analyses that will be conducted to provide assurancethat the equipment will perform reliably under the worst-case credible design basisloading at the location where the equipment will be mounted. Include a discussion ofthis seismic reliability demonstration as it applies to a) the level sensor mounted in theSFP area, and b) any control boxes, electronics, or read-out and re-transmitting devicesthat will be employed to convey the level information from the level sensor to the plantoperators or emergency responders.c) A description of the specific method or combination of methods that will be used toconfirm the reliability of the permanently installed equipment during and followingseismic conditions to maintain its required accuracy.Catawba Response:Information is not available within the 30-day response period for this RAI. Duke Energyanticipates submitting a response to this RAI for Catawba in the February 2014 six-month status report for the implementation of Order EA-12-051.3.5 IndependenceThe OIP states, in part, thatThe two SFP level instrument channels for each pool will be physically and electricallyindependent of one another. The associated cabling, power supplies and indication foreach level instrument channel will be routed separately from each other.5 RAI-5Please provide the following:a) A description of the two channels of the proposed level measurement system meet thisrequirement so that the potential for a common cause event to adversely affect bothchannels is minimized to the extent practicable.b) Further information on the planned design and installation of each level measurementsystem, consisting of level sensor electronics, cabling, and readout devices, in order toaddress independence through independent power sources, physical and spatialseparation, independence of signals sent to the location(s) of the readout devices, andthe independence of the displays.Catawba Response:Information is not available within the 30-day response period for this RAI. Duke Energyanticipates submitting a response to this RAI for Catawba in the February 2014 six-month status report for the implementation of Order EA-12-051.3.6 Power SuppliesThe OIP states, in part, thatThe two instrumentation channels for each unit will be powered normally by separatepower supplies backed up by rechargeable or replaceable batteries. The backup powersources will have sufficient capacity to maintain the level indication function until offsitepower or other emergency resource availability is reasonably assured.RAI-6Please provide the following:a) A description of the electrical AC power sources and capacities for the primary andbackup channels.b) If the level measurement channels are to be powered through a battery system (eitherdirectly or through an Uninterruptible Power Supply (UPS)), provide the design criteriathat will be applied to size the battery in a manner that ensures, with margin, that thechannel will be available to run reliably and continuously following the onset of the BDBevent for the minimum duration needed, consistent with the plant Mitigation strategiesfor BDB external events (Order EA-12-049).6 Catawba Response:Information is not available within the 30-day response period for this RAI. Duke Energyanticipates submitting a response to this RAI for Catawba in the February 2014 six-month status report for the implementation of Order EA-12-051.3.7 AccuracyThe OIP states, in part, thatThe instrument accuracy will be consistent with the guidelines of NRC JLD-ISG-2012-03and NEI 12-02. The new SFP level instrumentation will be designed to maintain theirdesign accuracy without recalibration following a power interruption or change in powersource. Additionally, instrument accuracy will be designed to allow trained personnel todetermine when the actual level exceeds the specified lower level of each indicatingrange (water levels 1, 2, 3 as identified by NEI 12-02 guidance) without conflicting orambiguous indication.RAI-7Please provide the following:a) An estimate of the expected instrument channel accuracy performance (e.g., in % ofspan) under both a) normal SFP level conditions (approximately Level 1 or higher) andb) 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 3datum points.b) A description of the methodology that will be used for determining the maximum alloweddeviation from the instrument channel design accuracy that will be employed undernormal operating conditions as an acceptance criterion for a calibration procedure toflag to operators and to technicians that the channel requires adjustment to within thenormal condition design accuracy.Catawba Response:Information is not available within the 30-day response period for this RAI. Duke Energyanticipates submitting a response to this RAI for Catawba in the February 2014 six-month status report for the implementation of Order EA-12-051.3.8 TestingThe OIP states, in part, thatThe instrument channel design shall provide for routine testing and calibration. Testingwill be consistent with the guidelines of NRC JLD-ISG-2012-03 and NEI 12-02. The7 standard CNS processes for scheduling and implementing testing and calibration willensure that the SFP level instruments are maintained by trained technicians usingapproved test procedures.RAI-8Please provide the following:a) A description of the capability and provisions the proposed level sensing equipment willhave to enable periodic testing and calibration, including how this capability enables theequipment to be tested in-situ.b) A description of how such testing and calibration will enable the conduct of regularchannel checks of each independent channel against the other, and against any otherpermanently-installed SFP level instrumentation.c) A description of how functional checks will be performed and the frequency at whichthey will be conducted. Describe how calibration tests will be performed, and thefrequency at which they will be conducted. Discuss how these surveillances will beincorporated into the plant surveillance program.d) A description of what preventive maintenance tasks are required to be performed duringnormal operation, and the planned maximum surveillance interval that is necessary toensure that the channels are fully conditioned to accurately and reliably perform theirfunctions when needed.Catawba Response:Information is not available within the 30-day response period for this RAI. Duke Energyanticipates submitting a response to this RAI for Catawba in the February 2014 six-month status report for the implementation of Order EA-12-051.3.9 DisplayThe OIP states, in part, thatThe instrument displays for each SFP level instrument will be provided in the maincontrol room or other accessible location. The displays will be consistent with theguidelines of NRC JLDISG-2012-03 and NEI 12-02.RAI-9Please provide the following:a) The specific location for the primary and backup instrument channel display.8 b) If the primary and backup location is other than the main control room, then providejustification for prompt accessibility to displays including primary and alternate routeevaluation, habitability at display location(s), continual resource availability for personnelresponsible to promptly read displays, and provisions for communications with decisionmakers for the various SFP drain down scenarios and external events.c) The reasons justifying the locations selected enable the information from theseinstruments to be considered "promptly accessible". Include with consideration ofvarious drain-down scenarios.Catawba Response:Information is not available within the 30-day response period for this RAI. Duke Energyanticipates submitting a response to this RAI for Catawba in the February 2014 six-month status report for the implementation of Order EA-12-051.4.0 PROGRAM FEATURES4.2 ProceduresThe OIP states, in part, thatProcedures will be developed using guidelines and vendor instructions to address themaintenance, operation and abnormal response issues associated with the SFP levelinstrumentation.Procedures will also address strategy to ensure SFP water addition is initiated at anappropriate time consistent with implementation of NEI 12-06, Diverse and FlexibleCoping Strategies (FLEX) Implementation Guide.RAI-1 0Please provide a description of the standards, guidelines and/or criteria that will be used todevelop procedures for inspection, maintenance, repair, operation, abnormal response, andadministrative controls associated with the SFP level instrumentation.Catawba Response:Information is not available within the 30-day response period for this RAI. Duke Energyanticipates submitting a response to this RAI for Catawba in the February 2014 six-month status report for the implementation of Order EA-12-051.4.3 Testing and CalibrationThe OIP states, in part, that9 Testing and calibration of the instrumentation will be consistent with vendorrecommendations or other documented basis. Calibration will be specific to themounted instrument(s) and the display(s). Existing station work control processes willbe used to control maintenance and testing.RAI-11Please provide the following:a) Further information describing the maintenance and testing program the licensee willestablish and implement to ensure that regular testing and calibration is performed andverified by inspection and audit to demonstrate conformance with design and systemreadiness requirements. Include a description of licensee plans for ensuring thatnecessary channel checks, functional tests, periodic calibration, and maintenance will beconducted for the level measurement system and its supporting equipment.b) A description of how licensee will implement the guidance in NEI 12-02 Section 4.3regarding compensatory actions for one or both non-functioning channels.c) A description of the compensatory actions to be taken in the event that one of theinstrument channels cannot be restored to functional status within 90 days.Catawba Response:Information is not available within the 30-day response period for this RAI. Duke Energyanticipates submitting a response to this RAI for Catawba in the February 2014 six-month status report for the implementation of Order EA-12-051.10 FIGURE 1LEVEL RANGE MINIMUM EL. 573'+0 TO APPROXIMATELY EL. 599'+0EL. 605'+10i OPERATING DECKNOTE iMAX. WATER LEVEL RANGE (EL. 598'+ 1")NORMAL WATER LEVEL (EL. 598'+G") -----------LEVEL 1 (EL. 597'+" -)LEVEL 2 (EL. 583'+ 0")FUEL STORAGE RACKSLEVEL 3 (EL. 573'+0")EL. 558'+G".v ...1ý7 -NOTE 1:v7IFINAL LOCATION OF EOUIPMENT IS NOT DETERMINED, BUT THE RANGE WILL MEET OR EXCEEDELEVATIONS DEFINED BY THE MAXIMUM POOL LEVEL AND THE TOP OF THE FUEL RACKS.