ML13171A274

Request for Additional Information Overall Integrated Plan in Response to Order EA-12-051, Reliable Spent Fuel Pool Instrumentation,

ML13171A274
Person / Time
Site:	Catawba
Issue date:	06/24/2013
From:	James Kim Plant Licensing Branch II
To:	Henderson K Duke Energy Carolinas
Kim J
References
EA-12-051, TAC MF1060, TAC MF1061
Download: ML13171A274 (11)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 June 24, 2013 Mr. K. Henderson Site Vice President Catawba Nuclear Station Duke Energy Carolinas, LLC 4800 Concord Road York, SC 29745

SUBJECT:

CATAWBA NUCLEAR STATION, UNITS 1 AND 2- REQUEST FOR ADDITIONAL INFORMATION RE: OVERALL INTEGRATED PLAN IN RESPONSE TO ORDER EA-12-051, "RELIABLE SPENT FUEL POOL INSTRUMENTATION" (TAG NOS. MF1060 AND MF1061)

Dear Mr. Henderson:

By 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) for Catawba Nuclear Station, Units 1 and 2. The 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 SFP lnstrumentation,n 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 SFP Instrumentation," Revision 0, dated August 29, 2012 (ADAMS Accession No. ML12221A339).

The NRC staff has determined that the additional information, as requested in the enclosure, is needed to complete its review. Please provide a response to the questions within 30 days of the date of this letter. If any part of this information is not available within 30 days of this request, please provide the date that this information will be provided.

K. Henderson If you have any questions regarding this request, please contact me at 301-415-4125 or via e-mail at James.Kim@nrc.gov.

Sincerely, James Kim, Project Manager Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-413 and 50-414

Enclosure:

As stated cc w/encl: Distribution via Listserv

REQUEST FOR ADDITIONAL INFORMATION OVERALL INTEGRATED PLAN IN RESPONSE TO ORDER EA-12-051 "RELIABLE SPENT FUEL POOL INSTRUMENTATION" DUKE ENERGY CATAWBA NUCLEAR STATION UNITS 1 AND 2 DOCKET NOS. 50-369 AND 50-370

1.0 INTRODUCTION

By 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) for Catawba Nuclear Station, Units 1 and 2. The NRC staff endorsed Nuclear Energy Institute (NE1)12-02 "Industry Guidance for Compliance with NRC Order EA-12-051, to Modify Licenses with Regard to Reliable SFP Instrumentation," Revision 1, dated August 2012 (ADAMS Accession No. ML12240A307), with exceptions, as documented in Interim Staff Guidance (ISG) 2012-03uCompliance with Order EA-12-051, Reliable SFP 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 30 days of this request, please provide the date this information will be submitted.

2.0 LEVELS OF REQUIRED MONITORING The OIP states, in part, that Indication of SFP level will be provided from approximately normal pool water level (Et. 598'-6") down to approximately the top of irradiated fuel assemblies seated in the storage racks (Et. 573'). In particular, the system will be capable of continuously monitoring SFP level at three distinct water levels described in the Order.

• Level 1 - Level that is adequate to support operation of the normal fuel pool cooling system - indicated level on either channel greater than the point at which pump suction is presumed to be lost (EI. 597' - 4").

• Level 2 - Level adequate to provide substantial radiation shielding for a person standing on the spent fuel pool operating deck- indicated level on either channel greater than 10' above the highest point of any fuel racks, or >Et. 583'. This monitoring Enclosure

level ensures there is adequate water level to provide substantial radiation shielding for personnel responding to beyond design-basis external events and to initiate SFP makeup strategies.

• Level 3 - Level where fuel remains covered but actions to implement make-up water addition should no longer be deferred - Indicated level on either channel less than 12 inches above the highest point of any fuel storage rack. This monitoring level ensures there is adequate water level above the stored fuel seated in the storage racks.

RAI-1

Please provide the following:

a) For level1, specify how the identified location represents the HIGHER of the two points described in the NEI 12-02 guidance for this level.

b) A clearly labeled sketch depicting the elevation view of the proposed typical mounting arrangement for the portions of instrument channel consisting of permanent measurement channel equipment (e.g., fixed level sensors and/or stilling wells, and mounting brackets). Indicate on this sketch the datum values representing Level1, Level 2, and Level 3 as well as the top of the fuel. 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.

3.0 Instrumentation Design Features 3.2 Arrangement The OIP states, in part, that The two SFP level instrument channels will be installed in spatially separated locations and 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 external events.

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/placement of the primary and back-up SFP level sensor and mounting brackets, and the proposed routing of the cables that will extend from the sensors toward the location of the read-out/display device.

3.3 Mounting The OIP states, in part, that Each permanently installed instrument channel will be mounted to retain design configuration during and following the maximum seismic ground motion considered in the design of the spent fuel pool structure.

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, 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 description of the manner in which the level sensor (and stilling well, if appropriate) will be attached to the refueling floor and/or other support structures for each planned point of attachment of the probe assembly. Indicate in a schematic the portions of the level sensor that will serve as points of attachment for mechanical/mounting or 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.

3.4 Qualification The OIP states, in part, that Both instrument channels for each pool will be specified to be reliable at the maximum temperature, humidity, and radiation levels predicted during an extended loss of AC power (ELAP) event at their installed locations.

The instrumentation reliability will be demonstrated by appropriate combination of design, analysis, operating experience and/or testing as outlined by NEI 12-02.

This reliability will be established through vendor qualification documents procured under an augmented quality assurance process defined by Duke Energy.

The level instrumentation is to be designed to remain functional following a Safe Shutdown Earthquake.

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 BOB ambient temperature, humidity, shock, vibration, and radiation conditions.

b) A description of the testing and/or analyses 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 reliability demonstration as it applies to a) the level sensor mounted in the SFP area, and b) any control boxes, electronics, or read-out and re-transmitting devices that will be employed to convey the level information from the level sensor to the plant operators or emergency responders.

c) A description of the specific method or combination of methods that will be used to confirm the reliability of the permanently installed equipment during and following seismic conditions to maintain its required accuracy.

3.5 Independence The OIP states, in part, that The two SFP level instrument channels for each pool will be physically and electrically independent of one another. The associated cabling, power supplies and indication for each level instrument channel will be routed separately from each other.

RAI-5

Please provide the following:

a) A description of the two channels of the proposed level measurement system meet this requirement so that the potential for a common cause event to adversely affect both channels is minimized to the extent practicable.

b) Further information on the planned design and installation of each level measurement system, consisting of level sensor electronics, cabling, and readout devices, in order to address independence through independent power sources, physical and spatial separation, independence of signals sent to the location(s) of the readout devices, and the independence of the displays.

3.6 Power Supplies The OIP states, in part, that The two instrumentation channels for each unit will be powered normally by separate power supplies backed up by rechargeable or replaceable batteries.

The backup power sources will have sufficient capacity to maintain the level indication function until offsite power or other emergency resource availability is reasonably assured.

RAI-6

Please provide the following:

a) A description of the electrical AC power sources and capacities for the primary and backup channels.

b) If the level measurement channels are to be powered through a battery system (either directly or through an Uninterruptible Power Supply (UPS)), 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 BOB event for the minimum duration needed, consistent with the plant Mitigation strategies for BOB external events (Order EA-12-049).

3. 7 Accuracy The OIP slates, in part, that The instrument accuracy will be consistent with the guidelines of NRC JLO-ISG-2012-03 and NEI12-02. The new SFP level instrumentation will be designed to maintain their design accuracy without recalibration following a power interruption or change in power source. Additionally, instrument accuracy will be designed to allow trained personnel to determine when the actual level exceeds the specified lower level of each indicating range (water levels 1, 2, 3 as identified by NEI 12-02 guidance) without conflicting or ambiguous indication.

RAI-7

Please provide the following:

a) An estimate of the expected instrument channel accuracy performance (e.g., in% of span) under both a) normal SFP level conditions (approximately Level 1 or higher) and b) at the BOB 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 instrument channel design accuracy that will be employed under normal operating conditions as an acceptance criterion for a calibration procedure to flag to operators and to technicians that the channel requires adjustment to within the normal condition design accuracy.

3.8 Testing The OIP states, in part, that The instrument channel design shall provide for routine testing and calibration.

Testing will be consistent with the guidelines of NRC JLD-ISG-2012-03 and NEI 12w02. The standard CNS processes for scheduling and implementing testing and calibration will ensure that the SFP level instruments are maintained by trained technicians using approved test procedures.

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 calibration will enable the conduct of regular channel checks of each independent channel against the other, and against any other permanently-installed SFP level instrumentation.

c) A description of how functional checks will be performed and the frequency at which they will be conducted. Describe how calibration tests will be performed, and the frequency at which they will be conducted. Discuss how these surveillances will be incorporated into the plant surveillance program.

d) A description of what preventive 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 accurately and reliably perform their functions when needed.

3.9 Display The OIP states. in part, that The instrument displays for each SFP level instrument will be provided in the main control room or other accessible location. The displays will be consistent with the guidelines of NRC JLDISG-2012-03 and NEI12-02.

RAI-9

Please provide the following:

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

b) If the primary and backup location is other than the main control room, then provide justification for prompt accessibility to displays including primary and alternate route evaluation, habitability at display location(s), continual resource availability for personnel responsible to promptly read displays, and provisions for communications with decision makers for the various SFP drain down scenarios and external events.

c) The reasons justifying the locations selected enable the information from these instruments to be considered "promptly accessible". Include with consideration of various drain-down scenarios.

4.0 PROGRAM FEATURES 4.2 Procedures The OIP states, in part, thai Procedures will be developed using guidelines and vendor instructions to address the maintenance, operation and abnormal response issues associated with the SFP level instrumentation.

Procedures will also address strategy to ensure SFP water addition is initiated at an appropriate time consistent with implementation of NEI12-06, Diverse and Flexible Coping Strategies (FLEX) Implementation Guide.

RAI-10

Please provide a description of the standards, guidelines and/or criteria that will be used to develop procedures for inspection, maintenance, repair, operation, abnormal response, and administrative controls associated with the SFP level instrumentation.

4.3 Testing and Calibration The OlP states, in part, that Testing and calibration of the instrumentation will be consistent with vendor recommendations or other documented basis. Calibration will be specific to the mounted instrument(s) and the display(s). Existing station work control processes will be used to control maintenance and testing.

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RAI-11

Please provide the following:

a) Further information describing the maintenance and testing program the licensee will establish and implement to ensure that regular testing and calibration is performed and verified by inspection and audit to demonstrate conformance with design and system readiness requirements. Include a description of licensee plans for ensuring that necessary channel checks, functional tests, periodic calibration, and maintenance will be conducted for the level measurement system and its supporting equipment.

b) A description of how licensee will implement the guidance in NEI12-02 Section 4.3 regarding 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 the instrument channels cannot be restored to functional status within 90 days.

ML13171A274 *memo dated June 15' 2013 OFFICE DORULPL2-1/PM DORULPL2-1/LA DSSISBPBIBC DORULPL2-1/BC DORULPL2-1/PM NAME JKim SF1gueroa GCasto* RPascarelli JKim DATE 6124/13 6/24113 6/15/13 6/24/13 6/24/13