ML13189A056

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

ML13189A056
Person / Time
Site:	Robinson
Issue date:	07/11/2013
From:	Billoch-Colon A Plant Licensing Branch II
To:	William Gideon Carolina Power & Light Co
Billoch-Colon A
References
TAC MF0793
Download: ML13189A056 (10)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 July 11, 2013 Mr. William G. Gideon, Vice President H. B. Robinson Steam Electric Plant Carolina Power & Light Company 3581 West Entrance Road Hartsville, SC 29550

SUBJECT:

H. B. ROBINSON STEAM ELECTRIC PLANT, UNIT NO.2 - REQUEST FOR ADDITIONAL INFORMATION REGARDING OVERALL INTEGRATED PLAN FOR RELIABLE SPENT FUEL POOL INSTRUMENTATION (ORDER NUMBER EA-12-051) (TAC. NO. MF0793)

Dear Mr. Gideon:

By letter to the U.S. Nuclear Regulatory Commission (NRC) dated February 28,2013 (Agencywide Documents Access and Management System Accession No. ML13086A096),

Carolina Power & Light Company (the licensee), doing business as Duke Energy, Inc.,

submitted an Overall Integrated Plan in response to the March 12, 2012, Commission Order to modify licenses with regard to requirements for Reliable Spent Fuel Pool Instrumentation (Order Number EA-12-051) for H.B. Robinson Steam Electric Plant, Unit No.2.

The NRC staff is reviewing your submittal and has determined that additional information is required to complete the review. The specific information requested is addressed in the enclosure to this letter. During a discussion with your staff on July 9, 2013, it was agreed that you would provide a response 30 days from the date of this letter.

The NRC considers that timely responses to requests for additional information help ensure sufficient time is available for the NRC staff review and contribute toward the NRC's goal of efficient and effective use of staff resources.

Please contact me at (301) 415-3302, if you have any questions.

Sincerely, Araceli T. Billoch Colon, Project Manager Plant Licensing Branch 11-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-261

Enclosure:

Request for Additional Information cc w/encl: ListServ

REQUEST FOR ADDITIONAL INFORMATION REGARDING H. B. ROBINSON STEAM ELECTRIC PLANT UNIT 2 OVERALL INTEGRATED PLAN IN RESPONSE TO ORDER EA-12-0S1 "RELIABLE SPENT FUEL POOL INSTRUMENTATION" DOCKET NO. SO-261

1.0 INTRODUCTION

By letter dated February 28, 2013 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML13086A096), Carolina Power & Light Company (the licensee),

doing business as Duke Energy, Inc., 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 (SFP) Instrumentation (Order Number EA-12-0S1; ADAMS Accession No. ML 120S4A679) for H. B. Robinson Steam Electric Plant Unit 2. The Nuclear Regulatory Commission (NRC) staff endorsed Nuclear Energy Institute (NEI) 12-02 "Industry Guidance for Compliance with NRC Order EA-12-0S1, 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 No. 2012-03 "Compliance with Order EA-12-0S1, 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.

2.0 LEVELS OF REQUIRED MONITORING The OIP states, in part, that:

In accordance with the guidance in NEI 12-02, the SFP water level instrumentation system will be capable of continuously monitoring three distinct water levels:

Level 1 - The water level adequate to support operation of the normal fuel pool cooling system is approximately 273 feet plant elevation.

Level 2 - The water level adequate to provide substantial radiation shielding for a person standing on the SFP operating deck (i.e., greater than 10 feet above the highest point of any fuel racks) is approximately 262 feet plant elevation.

Enclosure

-2 Level 3 - The water level where fuel remains covered but actions to implement make-up water addition should no longer be deferred will be established based on the accuracy of the chosen instrumentation and the highest point of any fuel racks at approximately 252 feet plant elevation.

RAI-1

Provide the following:

a. For Level 1, specify how the identified elevation 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 Level 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.

3.0 INSTRUMENTATION DESIGN FEATURES 3.2 Arrangement The OIP states, in part, that:

In accordance with the guidance in NEI 12-02, the level instrument channels will be installed in diverse locations and physically arranged in a manner that provides reasonable protection of the level indication function against missiles that may result from damage to the structure over the SFP.

The sensing component of each level instrument channel will be installed separately within the SFP in order to reduce common susceptibility to missiles and other external events. The final location and mounting will be determined by the detailed design.

RAI-2

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 backup SFP level sensors, and the proposed routing of the cables that will extend from the sensors toward the location of the local electronics cabinets and read-ouUdisplay devices in the main control room or alternate accessible location.

- 3 3.3 Mounting The OIP states, in part, that:

Each permanently installed instrument channel will be mounted to retain its design configuration during and following the maximum seismic ground motion considered in the design of the SFP structure in accordance with the guidance in NRC JLD-ISG-2012-03 and NEI 12-02.

RAI-3

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:

Sensing components and cables for the channels will be reliable at temperature, humidity, and radiation levels consistent with the SFP water at saturation conditions over an extended period of time.

Sensing components and cables will be qualified for expected conditions at the installed location assuming the SFP has been at saturation for an extended period.

Sensing components and cables located at the SFP will be qualified to withstand peak and total integrated dose radiation levels for their installed location based on post-event SFP water level equal to Level 3 for an extended period of time.

Additionally, the instrument channels will be tested, where possible, and analytically evaluated to remain functional after a potential seismic event with the exception of the battery charger and replacement batteries.

-4 Augmented Quality provisions will be applied to ensure that rigor of the qualification documentation reviews and in-plant modification installation oversight is sufficient to ensure compliance with the qualification requirements described above. This approach to quality assurance is consistent with the guidance in NRC JLD-ISG-2012-03 and NEI 12-02.

RAI-4

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 (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 such that following a seismic event the instrument will maintain its required accuracy.

3.5 Independence The OIP states, in part. that:

Independence will be established in accordance with the guidance in NRC JLD-ISG-2012-03 and NEI12-02. The instrument channels for the SFPs will be of the same technology, permanently installed, separated by distance, and electrically independent of one another.

The channels will have their own sensing components reasonably separated in accordance with NEI 12-02, separate cable routes, and separate electronics.

RAI-5

Provide the following:

a. A description of how the two channels of the proposed level measurement system in each pool meet this requirement so that the potential for a common

-5 cause event to adversely affect both channels is minimized to the extent practicable.

b. Further information describing the design and installation of each level measurement system, consisting of level sensor electronics, cabling, and readout devices. Address how independence of these components of the primary and back-up channels is achieved through the application of 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 DIP states, in part, that:

Instrument channels will each be powered normally by a separate station power source and will have rechargeable or replaceable batteries with sufficient capacity to maintain the level indication function until the normal power is restored, consistent with the guidance in NEI 12-02.

RAI-6

Provide the following:

a. A description of the electrical alternate current 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), 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 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 DIP states, in part, that:

Instrument channels will be designed such that they will maintain their design accuracy without recalibration following a power interruption or change in power source.

Accuracy will consider SFP post-event conditions, e.g., saturated water, steam environment, or concentrated borated water. Additionally, instrument accuracy will be sufficient to allow trained personnel to determine when the actual level exceeds the specified level of each indicating range (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.

- 6

RAI-7

Provide the following:

a. An estimate of the expected instrument channel accuracy performance (e.g., in percentage 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:

Testing and calibration will be consistent with the guidelines of NRC JLD-ISG-2012-03, NEI 12-02 guidance and vendor recommendations.

Channel degradation due to age or corrosion is not expected but can be identified by monitoring trends.

Station procedures and preventive maintenance tasks will be developed to perform required surveillance testing, calibration, backup battery maintenance, functional checks, and visual inspections of the sensing components.

RAI-8

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 calibration tests and functioned checks 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 preventative maintenance tasks are required to be performed during normal operation, and the planned maximum surveillance

-7 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 the channels will be located in a mild environment under normal and expected beyond design basis conditions that are accessible to plant personnel properly trained in the use of the equipment. The display will be consistent with the guidelines of NRC JLD-ISG-2012-03 and NEI 12-02.

RAI-9

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 description of the location for the primary and backup 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 why the locations selected will enable the information from these instruments to be considered "promptly accessible." Include consideration of various drain-down scenarios.

4.0 PROGRAM FEATURES 4.2 Procedures The OIP states, in part, that:

Procedures will be developed using guidelines and vendor instructions to address the maintenance, operation and abnormal response issues associated with the SFP level instrumentation.

In addition, a procedure will be developed to describe what actions must be taken following the installation of a normally removed gate(s) since the impacted SFP would no longer be monitored with two redundant instrumentation channels.

Procedures will also address strategy to ensure SFP water addition is initiated at an appropriate time consistent with implementation of NEI 12-06, Diverse and Flexible Coping Strategies Implementation Guide.

-8

RAI-10

Provide the following:

a. A list of the operating (both normal and abnormal response) procedures, calibration/test procedures, maintenance procedures, and inspection procedures that will be developed for use of the SFP instrumentation in a manner that addresses the order requirements.

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

4.3 Testing and Calibration The OIP 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 instruments and the displays. A maintenance procedure will be written to direct calibration and repair of the instruments.

RAI-11 :

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 your 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 the guidance in NEI 12-02 Section 4.3 regarding compensatory actions for one or both nonfunctioning 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.

July 11, 2013 Mr. William G. Gideon, Vice President H. B. Robinson Steam Electric Plant Carolina Power & Light Company 3581 West Entrance Road Hartsville, SC 29550

SUBJECT:

H. B. ROBINSON STEAM ELECTRIC PLANT, UNIT NO.2 - REQUEST FOR ADDITIONAL INFORMATION REGARDING OVERALL INTEGRATED PLAN FOR RELIABLE SPENT FUEL POOL INSTRUMENTATION (ORDER NUMBER EA-12-051) (TAC. NO. MF0793)

Dear Mr. Gideon:

By letter to the U.S. Nuclear Regulatory Commission (NRC) dated February 28,2013 (Agencywide Documents Access and Management System Accession No. ML13086A096),

Carolina Power & Light Company (the licensee), doing business as Duke Energy, Inc.,

submitted an Overall Integrated Plan in response to the March 12,2012, Commission Order to modify licenses with regard to requirements for Reliable Spent Fuel Pool Instrumentation (Order Number EA-12-051) for H.B. Robinson Steam Electric Plant, Unit No.2.

The NRC staff is reviewing your submittal and has determined that additional information is required to complete the review. The specific information requested is addressed in the enclosure to this letter. During a discussion with your staff on July 9,2013, it was agreed that you would provide a response 30 days from the date of this letter.

The NRC considers that timely responses to requests for additional information help ensure sufficient time is available for the NRC staff review and contribute toward the NRC's goal of efficient and effective use of staff resources.

Please contact me at (301) 415-3302, if you have any questions.

Sincerely, IRAJ Araceli T. Billoch Colon, Project Manager Plant Licensing Branch 11-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-261

Enclosure:

Request for Additional Information cc w/encl: ListServ DISTRIBUTION:

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