ML13247A338

Response to Request for Additional Information - Overall Integrated Plan to Commission Order Modifying License Requirements for Reliable Spent Fuel Pool Instrumentation (Order No. EA-12-051)

ML13247A338
Person / Time
Site:	Summer
Issue date:	08/28/2013
From:	Gatlin T D South Carolina Electric & Gas Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
EA-12-051, RC-13-0119
Download: ML13247A338 (21)

Text

Thomas D. Gatlin Vice-President Nuclear Operations (803) 345-4342 August 28, 2013 A SCANA COMPANY RC-13-0119 U. S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555-0001

Subject:

VIRGIL C. SUMMER NUCLEAR STATION (VCSNS) UNIT 1 DOCKET NO. 50-395 OPERATING LICENSE NO. NPF-12 SOUTH CAROLINA ELECTRIC & GAS COMPANY'S RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION

-OVERALL INTEGRATED PLAN IN REPONSE TO COMMISSION ORDER MODIFYING LICENSE REQUIREMENTS FOR RELIABLE SPENT FUEL POOL INSTRUMENTATION (Order No. EA-12-051)

References:

1. SCE&G's Overall Integrated Plan in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Reliable Spent Fuel Pool Instrumentation (Order Number EA-12-051)," dated February 28, 2013.RC-13-0031

2. NRC Order Number EA-12-051, Issuance of Order to Modify Licenses with Regard to Reliable Spent Fuel Pool Instrumentation, dated March 12, 2012 3. NRC Request for Additional Information

-Overall Integrated Plan in Response to the Commission Order Modifying Licenses with Regard to Requirements for Reliable Spent Fuel Pool Instrumentation (Order No. EA-12-051), dated July 29, 2013 In Reference 1, South Carolina Electric & Gas Company (SCE&G) provided the Virgil C.Summer Nuclear Station Unit 1 (VCSNS), Overall Integrated Plan in Response to the March 12, 2012 Commission Order Modifying Licenses with Regard to Requirements for Reliable Spent Fuel Pool Instrumentation, pursuant to NRC Order No. EA-12-051 (Reference 2).The purpose of this letter is to provide the response to the NRC request for additional information (Reference

3) regarding the VCSNS Overall Integrated Plan in (Reference 1).This letter contains no new regulatory commitments.

If you have any questions regarding this report, please contact Mr. Bruce L. Thompson at (803) 931-5042.g CoP Virgil C. Summer Station

• Post Office Box 88 -Jenkinsville, SC.- 29065

• F (803) 941-9776 o e Document Control Desk CR-12-01070 RC-13-01.19 Page 2 of 2 I certify under penalty of perjury that the foregoing is true and correct.Executed on Thomas D. Gatlin BQ/TDG/ts Attachments:

1. Virgil C. Summer Nuclear Station Unit 1 -Response to Request for Additional Information

-Overall Integrated Plan in Response to Commission Order Modifying License Requirements for Reliable Spent Fuel Pool Instrumentation (Order No. EA-12-051)

2. Figure 1 Longitudinal Section Through Fuel Pool 3. Figure 2 SFP Level Instrument Channel Layout c: K. B. Marsh S. A. Byrne J. B. Archie N. S. Carns J. H. Hamilton J. W. Williams W. M. Cherry E. J. Leeds V. M. McCree (w/attachments)

R. E. Martin (w/attachments)

NRC Resident Inspector K. M. Sutton NSRC RTS (CR-12-01070)

File (815.07)PRSF (RC-13-0119)

Document Control Desk Attachment I CR-12-01070 RC-13-0119 Page 1 of 19 VIRGIL C. SUMMER NUCLEAR STATION (VCSNS) UNIT I ATTACHMENT I Virgil C. Summer Nuclear Station Unit I -Response to Request for Additional Information

-Overall Integrated Plan in Response to Commission Order Modifying License Requirements for Reliable Spent Fuel Pool Instrumentation (Order No. EA-12-051)

1.0 INTRODUCTION

By letter dated February 28, 2013 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML13063A099), South Carolina Electric & Gas (SCE&G) 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 Virgil C.Summer Nuclear Station (VCSNS), Unit 1. The 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 date for this RAI, please provide the date this information will be submitted.

2.0 LEVELS

OF REQUIRED MONITORING The OIP states, in part, that Key spent fuel pool water levels will be identified as follows: 1. Level adequate to support operation of the normal fuel pool cooling system -Indicated level on either the primary or backup instrument channel of greater than elevation 460 feet and 3 inches (based on the design level of the anti-siphoning holes that prevent pool drainage below this water level). The low water level alarm is at the 461 foot elevation for the present spent fuel pool (SFP) level monitoring system.2. Level adequate to provide substantial radiation shielding for a person standing on the spent fuel pool operating deck -Indicated level on either the primary or backup instrument channel of greater than elevation 447.5 feet. This elevation is approximately Document Control Desk Attachment I CR-12-01070 RC-13-0119 Page 2 of 19 11 feet above the top of the fuel assemblies stored in the racks. This level would allow radiation shielding protection for personnel on the spent fuel operating deck by limiting the dose rates to approximately 210 mrem/hr. However, it is desirable to limit the dose rates to less than 100 mrem/hr which would require the level to be maintained at greater than elevation 455.5 feet or approximately 19 feet above the top of the fuel assemblies stored in the racks. This monitoring level ensures there is adequate margin in the water level to provide substantial radiation shielding for personnel to respond to Beyond-Design-Basis External Events and to initiate SFP makeup strategies.

3. Level where fuel remains covered -Monitoring level on either the primary or backup instrument channel of greater than elevation 436 feet and 8 inches, plus the accuracy of the SFP level instrument channel, assures there is adequate water level above the stored fuel seated in the rack.RAI-1 Please provide the following:

a) For level 1, 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 the 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.RAI #1 Response a) The normal SFP water level to support SFP cooling pump operation is the 461.5 feet Elevation.

Abnormal Operating Procedures for a decreasing SFP water level requires restoration to the 460.5 feet elevation before returning to normal operation.

The NEI 12-02 "Level 1" datum is considered to be 461.5 feet Elevation.

Per existing design basis calculations, Net Positive Suction Head (NPSH) margin exists with the SFP level at a Technical Specification minimum level, with the pool at saturated conditions, and a bounding high pump-flow-rate.

Therefore, the chosen Level 1 datum of 461.5 feet is greater than a SFP level that would cause loss of NPSH at saturated conditions and also greater than the elevation where the anti-siphoning holes are located.b) An elevation view of the SFP, showing the required NEI 12-02 levels and the monitoring-range sensitivities, is provided in FIGURE 1. The primary and back-up SFP level channel lay-outs are provided in FIGURE 2.

Document Control Desk Attachment I CR-12-01070 RC-13-0119 Page 3 of 19 3.0 INSTRUMENTATION DESIGN FEATURES 3.2 Arrangement The OIP states, in part, that SFP level horn antenna and wave guide will be installed at the southwest corner of the SFP for the primary channel. The sensor and display for the primary channel will be located outside of the fuel handling building, in the vicinity of the south wall at the 463 foot elevation of the auxiliary building, adjacent to the southwest corner of the spent fuel pool. The auxiliary building is a Seismic Class 1 safety related structure meeting the requirements of NEI 12-02 Section 3.9 for protection of the sensor and display against extreme external events. The back-up channel horn antenna and wave guide would be stored in the east stairwell of the auxiliary building at approximately the 463 foot elevation.

The backup channel sensor and display will be permanently installed at a location that is readily accessible to the operator, in the vicinity of the 463 foot elevation of the east stairwell of the auxiliary building.Separation of the primary and backup channel locations will meet the guidance of NEI 12-02 Section 3.2 by being located at opposite corners of the pool area, and separated by a distance comparable to the shortest length of a side of the pool. The portable components of the backup channel (i.e. the horn antenna and wave guide pipe) will be capable of a deployment time of 30 minutes from the identification of the need for the backup channel to be placed in service. The sensor and display will be permanently installed.

Installation of the horn antenna and wave guide piping will require no more than two trained personnel for deployment.

The supports for the horn antenna and wave guide piping will be part of the portable components and will allow for flexibility of location of the antenna if the predetermined location is inaccessible.

The personnel access pathways for the display readout are located in the auxiliary building, which is Seismic Class 1 safety-related structure, meeting the requirements of NEI 12-02 Section 3.9.The horn antenna and wave guide piping supports for the primary channel will be seismically designed with shielding to protect the horn antenna and wave guide piping from event generated missiles such as light fixtures, ductwork and roofing panels. The design of the antenna and antenna support will allow the spent fuel pool bridge to be utilized without interference.

The sensors and displays are located outside of the area of concern with respect to event generated missiles.RAI-2 Please provide the following:

a) 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 sensing electronics, and the proposed routing of the Document Control Desk Attachment I CR-12-01070 RC-13-0119 Page 4 of 19 cables that will extend from the sensing electronics toward the location of the read-out/display device.b) A description of how the backup channel waveguide and horn is to be attached to the electronics assembly when needed. Provide clarification on whether the waveguides are run through wall penetrations to the sensing electronics or whether any electronics are within the environment of the spent fuel pool area.c) A description of the installation process for the backup level channel from the identification of the need for the backup channel to be placed in service, to subsequent communication with plant decision makers, final installation and verification of proper functioning of the equipment.

d) A copy of the analysis performed to determine a deployment time of 30 minutes for the backup channel from the identification of the need for this channel to be placed in service. Include primary and alternate access route evaluation, habitability at installation location, and resource availability for personnel responsible to install instrumentation for the various SFP drain down scenarios and external events.e) A description of the shielding design to protect the horn antenna and wave guide piping from event generated missiles.RAI #2 Response a) 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 sensing electronics, and the proposed routing of the cables that will extend from the sensing electronics toward the location of the read-out/display device is provided in FIGURE 2.b) The plan has been changed for the back-up channel which was previously to be portable with respect to the waveguide and horn assembly.

The entire back-up channel will be permanently installed meeting all of the requirements of the primary channel.c) The back-up channel will be permanently installed to the same standards of the primary channel. The power supply and sensing device will be located outside of the Fuel Handling Building on the exterior west side wall (441 foot elevation) near the north bay entrance to the Auxiliary Building.

The read-out device location will be exterior to the building and protected from the elements.d) No additional analysis will be performed for deployment since the back-up channel will now be permanently installed.

Access routes to the readout device and power supply are provided through the Auxiliary Building and alternatively around the exterior of the station's power block. The location of both the primary and back-up channel readouts will be outside of the spent fuel pool area. Personnel performing Document Control Desk Attachment I CR-12-01070 RC-13-0119 Page 5 of 19 level monitoring activities will have ready access to the spent fuel pool makeup valve from the FLEX feed header.e) The shielding design has not been completed.

This information will be provided in a six-month update report as it becomes available.

3.3 Mounting

The OIP states, in part, that All permanently installed equipment associated with the level monitoring system will be mounted in accordance with Seismic Class I requirements.

Installed equipment will be seismically qualified to withstand the maximum seismic ground motion considered in the design of the plant area in which it is installed and will be consistent with the highest seismic and safety classification applied to the Spent Fuel Pool original design. Should the plant seismic design basis change, changes to the seismic design mountings for the installed level monitoring system will be processed in accordance with station procedures.

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 sensing/waveguide assembly.

Indicate in a schematic the portions of the level sensor/waveguide 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 wall or floor structures so as to support the waveguide/level sensor assembly.RAI #3 Response The seismic design of the mounting has not been completed.

This information will be provided in a six-month update report as it becomes available.

Document Control Desk Attachment I CR-12-01070 RC-13-0119 Page 6 of 19 3.4 Qualification The OIP states, in part, that Both channels will be reliable at temperature, humidity, and radiation levels consistent with the spent fuel pool water at saturation conditions for an extended period. Sensors and displays are located outside of the area of the pool and are not subject to the radiation, temperature and humidity conditions that are postulated for the areas in the vicinity of the pool during post event conditions.

Post event humidity in the Auxiliary Building near and above the SFP is assumed to be 100% with condensing steam.Equipment will be qualified for expected conditions at the installed location assuming that normal power is unavailable and that the SFP has been at saturation for an extended period. Equipment located in the vicinity of the SFP will be qualified to withstand peak and total integrated dose radiation levels for its installed location assuming that post event SFP water level remains above the fuel for an extended period of time. The horn antenna and wave guide piping are insensitive to temperature.

The"Through Air Radar" system performance is unaffected by vapor, gas composition, pressure and temperature changes at the surface of the pool. The sensor is able to penetrate foam, saturated steam and smoke without any adverse affect on the accuracy of the pool level measurement.

Antenna location will not be subject to pool overflow and the mounting of the antenna to the sensor at the wall penetration will be qualified to the SFP area post event environment.

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 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/waveguide mounted in the spent fuel pool 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/waveguide, to the electronics assembly, and then 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, including primary and back-up electronics assemblies, such that following a seismic event each instrument will maintain its required accuracy.

Document Control Desk Attachment I CR-12-01070 RC-13-0119 Page 7 of 19 RAI #4 Response a) The primary and back-up SFP level channel instrumentation reliability will be established based on a combination of similarity analyses, testing, and operating experience, as described below.Temperature The postulated temperature in the spent fuel pool area that results from a boiling pool is 100 degrees Celsius (212 degree Fahrenheit).

The radar sensor electronics will be located outside of the spent fuel pool room in an area where the temperature will not exceed the radar sensor electronics rated design temperature.

Humidity The maximum humidity postulated for the spent fuel pool area is 100 percent relative humidity, saturated steam. The radar sensor electronics will be located outside of the spent fuel pool room in an area away from the steam atmosphere.

The waveguide pipe can tolerate condensation formation on the inner wall surface, provided condensate pooling does not occur within the waveguide pipe.Condensate pooling is prevented by installing a weep hole(s) at the low point(s)in the wave guide pipe.Steam The ability of the radar wave to propagate through steam has been demonstrated by vendor testing. In addition, "Through Air Radar" has been used in numerous applications that involve measuring the level of boiling liquids. The vendor manual contains a table that provides accuracy correction factors for superimposed gas or vapor including saturated steam at various pressures.

Therefore successful operating experience has demonstrated that the through air radar functions at high levels of steam saturation.

Shock and Vibration The "Through Air Radar" sensor was shock and vibration tested in accordance with MIL-S-901D and MIL-STD-167-1.

This shock and vibration testing only applies to the sensor. The waveguide piping is 3 inch diameter Schedule 40 piping and is seismically anchored to the floor. Thus the waveguide piping is not considered to be sensitive to shock or vibration.

The power supply panel contains components that are part of the standard VEGA Mobile Remote Display. In addition, the readout portion of the display panel (PLICSCOM), was installed in the sensor during the shock and vibration testing. The Mobile Remote Display is designed for truck-mounted mobile applications subject to shock and vibration from normal handling, after transportation and setup on the job. Per NEI 12-02, designing instruments for operation in environments where significant shock and Document Control Desk Attachment I CR-12-01070 RC-13-0119 Page 8 of 19 vibration loadings are common, such as for portable hand-held devices or transportation applications, is an acceptable measure for verifying that the design is adequate to withstand shock and vibration.

This panel is therefore considered to have an acceptable resistance to shock and vibration.

Radiation The area above and around the pool will be subject to large amounts of radiation in the event water level decreases near the top of the fuel racks. The only parts of the measurement channel in the pool radiation environment are the metallic waveguide and horn, which are not susceptible to the expected levels of radiation.

The sensor electronics will be located in an area that does not exceed their lxlO 3 Rad design limit for the required operating time, or the design will provide shielding as required.b) A seismic shake test will be performed to the requirements of IEEE 344-2004 for elements of the "Through Air Radar" to levels anticipated that will envelope most if not all plants in the United States. The equipment to be tested includes the sensor, readout and power control panel, horn end of the waveguide, pool end and sensor end mounting brackets, and waveguide piping. The items will be tested to the Required Response Spectra (RRS) contained in EPRI TR-107330 to account for the potentially high seismic motion that could occur to the cabinet-mounted readout and the power control panel. This RRS will also envelop the seismic ground motion for items mounted to the building structure, pool edge, etc.c) The seismic testing described in RAI #4 b) includes testing the system for functionality prior to and post seismic testing, which include verification of the instrument accuracy.3.5 Independence The OIP states, in part, that The primary instrument channel will be redundant to and independent of the backup instrument channel. The power sources for the primary and backup channels will be independent through the utilization of standalone battery power. The channels will be separated by a distance commensurate with the shortest length of a side of the spent fuel pool as defined by NEI 12-02 Section 3.2.

Document Control Desk Attachment I CR-12-01070 RC-13-0119 Page 9 of 19 RAI-5 Please provide the following:

a) A description of how 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 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 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.RAI #5 Response a) NEI 12-02 Section 3.2 provides the guidance for separation of the primary and back -up channels.

The guidance is to be "separated by a distance commensurate with the shortest length of a side of the spent fuel pool." The primary horn will be located at the southwest corner of the pool and the back-up horn will be located at the northwest corner of the pool. The horn, waveguide, sensor, readout devices and power supply panels are all separated by this distance.b) The primary and back-up channels have completely independent power supplies and as described in the response to RAI #5 a) above, all of the components for each channel are "separated by a distance commensurate with the shortest length of a side of the spent fuel pool." In addition, the primary and back-up channel electronics will also be located at different plant elevations.

The approximate locations will be at the 468 foot elevation for the primary channel and at the 441 foot elevation for the back-up channel.3.6 Power Supplies The OIP states, in part, that Both the primary and back-up channels will be powered from dual selectable power supplies utilizing dedicated lithium ion batteries with backup batteries available for easy replacement.

Minimum expected battery life each battery supply provides for 7 days of continuous service. The battery systems will include provision for battery replacement should the installed battery be non-functional following the event. Spare batteries will be readily available to maintain power to the system for the entire period of the FLEX response.

Document Control Desk Attachment I CR-12-01070 RC-13-0119 Page 10 of 19 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)), 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 the minimum duration needed, consistent with the plant mitigation strategies for BDB external events (Order EA-12-049).

c) If it is expected that battery changes will be necessary prior to restoration of power using the FLEX mitigation strategies, provide a description of the ease of access to the point at which batteries are attached, and the minimum time requirements needed to restore level indication.

RAI #6 Response a) No electrical AC power source is required for either the primary or back-up channel.b) Both the primary and back-up channels will be powered from dual selectable power supplies utilizing dedicated lithium ion batteries.

The battery systems will include provision for battery replacement should the installed battery be non-functional following the event. The primary and back-up SFP level channel dedicated battery capacity is based on ability of the sensor to supply full load (20 mA) for the duration specified in the plant FLEX mitigation strategy with built-in safety margin.The battery capacity will be verified by analyses and/or test prior to installation.

The preliminary estimate of battery capacity is expected to be approximately 6-7 days. It is estimated that a minimum battery capacity of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> is required to align with the FLEX mitigation plan. Battery replacement provisions will be included in the FLEX Phase III strategy to provide continued SFP level monitoring capability.

c) Spare batteries will be readily available to maintain power to the system for the entire period of the FLEX response.

Batteries can be replaced within 15 minutes. Tools, spare batteries and instructions that are required will be maintained at the location of the power supply panel. SFP Level Channel can be returned to service within 30 minutes.

Document Control Desk Attachment I CR-12-01070 RC-13-0119 Page 11 of 19 3.7 Accuracy The OIP states, in part, that Instrument channels will be designed such that they will maintain their design accuracy following a power interruption or change in power source without recalibration.

Accuracy will consider SFP 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 lower level of each indicating range (levels 1, 2 and 3) without conflicting or ambiguous indication.

The Through Air Radar system has accuracy equal to or better than +/- 3 inches.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 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 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.RAI #7 Response a) The manufacturer reference accuracy for the primary SFP level channel is no greater than +/-1 inch based on tests performed by vendor This is the design accuracy value that will be specified for the primary SFP level instrument channel. This value is subject to change dependent on the actual performance with the installed waveguide.

The accuracy of the primary SFP level channel is minimally affected by postulated BDB conditions (i.e., radiation, temperature, humidity, post-seismic and post- shock conditions).

The stainless steel horn antenna and waveguide pipe that is exposed to Beyond Design Basis (BDB)conditions is unaffected by radiation, temperature and humidity other than a minor effect of condensation forming on the waveguide inner walls. This minor effect will have a slight slowing effect on the radar pulse velocity.

Condensation is prevented from pooling in the waveguide and thus blocking the radar signal by placement of weep holes at low points in the waveguide pipe. A minor effect on the accuracy is the length of the overall measurement path can change due to temperature related expansion of the waveguide pipe. The waveguide pipe permits the sensor Document Control Desk Attachment I CR-12-01070 RC-13-0119 Page 12 of 19 electronics to be located in mild environment conditions so that the effect of elevated temperature on accuracy is also limited. Based on vendor operating instructions for the system, a small correction factor is applied to account for the impact of saturated steam at atmospheric pressure on the radar beam velocity.

Testing performed by vendor using saturated steam and saturated steam combined with smoke indicate that the overall effect on the instrument accuracy is minimal. The overall accuracy due to BDB conditions described above is estimated to not exceed+/-3 inches. As part of the engineering change process, the overall level channel uncertainties will be formally documented by an instrument uncertainty calculation.

b) Operational surveillance procedures will perform periodic channel checks (monthly)for the primary and back-up SFP level instrumentation to verify proper operation.

The channel checks will be accomplished by comparison between the presently installed wide-range channel indications, or by comparison to the known SFP physical level elevation reference markings.

The acceptance criteria will consider the respective overall channel uncertainty contributions for accuracy, calibration setting tolerance, resolution, and drift as applicable.

The back-up channel will be verified during the 12-month functional testing and will also be checked against a known physical level elevation reference marking as part of the deployment Flex Support Guideline for the installation of the back-up channel waveguide and horn during a BDB event.3.8 Testing The OIP states, in part, that Instrument channel design will provide for routine testing and in-situ calibration consistent with Order EA-12-051 and the guidance in NEI 12-02. The backup portable channel will not require additional calibration or testing at the time of deployment.

Details will be determined during the engineering and design phase for PM Program requirements, testing and calibration frequencies.

It is expected that the batteries will be changed annually at the recommended frequency suggested by the OEM. Calibration of the instrument itself is not required.

The recommended surveillance testing will be performed within 60 days of a refueling outage and not more than once in a 12 month period to verify channel operability for both the primary channel and the back-up.RAI-8 Please provide the following:

a) It is not clear to the staff which instrument does not need to be calibrated, as suggested in your submittal.

Provide clarification on whether one or both instruments will be periodically calibrated.

Document Control Desk Attachment I CR-12-01070 RC-13-0119 Page 13 of 19 b) A description of the capability and provisions the proposed mounted and portable level sensing equipment will have to enable periodic testing and calibration, including how this capability enables the equipment to be tested in-situ.c) 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.

d) A description of how calibration tests and functional 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.e) A description of the preventive maintenance tasks 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.RAI #8 Response a) Both the primary and back-up (portable) channels will be functionally tested with a calibration check performed on a 12-month periodicity.

There will be no difference in the testing requirements for the back-up channel since the plan has changed to make the entire channel permanently installed.

b) The back-up channel waveguide tube and horn will now be permanently installed and the channel will receive the same 12-month functional testing with calibration check as the primary channel.c) Operational surveillance procedures will perform periodic channel checks (monthly)for the primary and back-up SFP level instrumentation to verify proper operation.

The channel checks will be accomplished by comparison between the presently installed wide-range channel indications, or by comparison to the known SFP physical level elevation reference markings.

The acceptance criteria will consider the respective overall channel uncertainty contributions for accuracy, calibration setting tolerance, resolution, and drift as applicable.

d) Periodic channel checks will be established for the primary and back-up SFP level channels to verify proper instrument operation, as described in the response to RAI #7 b). The frequency of the channel checks is expected to be at least monthly (+/- 25% grace period). This frequency will readily satisfy NEI 12-02 (section 4.3)requirements.

Periodic calibration checks will be performed as described in the response to RAI #8 a). Instrument channel calibration check frequency will be 12 months and performed in accordance with the manufacture recommendations, and/or as established based on operating experience within the preventive maintenance program. As part of the periodic calibration check surveillance for the primary and Document Control Desk Attachment I CR-12-01070 RC-13-0119 Page 14 of 19 back-up SFP level channel, further functional verifications will be performed to verify proper operation of the battery back-up feature.The channel checks will be performed by Operations surveillance procedures, and the instrument calibrations checks will be performed by Maintenance instrumentation calibration surveillance procedures.

Recurring work orders will be established within the periodic maintenance program to govern the scheduling and performance of the periodic calibration checks.e) Routine preventive maintenance required during normal operation is limited to periodic channel calibration check, and/or battery replacement.

The preventive maintenance frequency will be established as outlined in the response to RAI #8 d).3.9 Display The OIP states, in part, that Remote indication will be provided in two "appropriate and accessible locations" in the Auxiliary Building.

The primary channel display will provide a read-out in the vicinity of the north wall 463 foot elevation adjacent to and outside of the southwest corner of the Spent Fuel Pool and Fuel Handling Building.

The backup channel will provide a readout in the northeast stairwell of the Auxiliary Building in the vicinity of the 463 foot elevation and adjacent to the northwest corner of the Spent Fuel Pool and west wall of the Fuel Handling Building.RAI-9 Please provide the following:

a) Since both the primary and backup display locations are not in the main control room, provide a description of the display locations that address primary and alternate access route evaluation, continuous habitability at display locations, continual resource availability for personnel responsible to promptly read displays, and provisions for verbal communications with decision makers for the various SFP drain down scenarios and external events.b) 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.

RAI #9 Response a) The primary and back-up SFP channel displays are located outside of the main control room and remote from the SFP area and in two separate areas; the primary in the Auxiliary Building north stairwell 468 feet elevation and the back-up on the west exterior wall of the Fuel Handing Building at the 441 feet elevation (FIGURE 2).

Document Control Desk Attachment I CR-12-01070 RC-13-0119 Page 15 of 19 The display locations are outside of any locked high radiation areas, and are accessible by operations personnel during a postulated BDB event through at least two paths through the Auxiliary Building.

One path is on the west side of the building and the second is on the north end of the building.

The primary level channel read-out display is located in a Seismic Category I structure, which is protected from potential threats posed by external natural phenomena events, such as flooding, seismic and tornado missiles.

Personnel access to the display locations relies upon the stairwells within the Auxiliary Building north side and west side for alternate access. The back-up channel readout display is located at the 441 foot elevation on the exterior west wall of the Fuel Handling Building.

Access to the back-up channel can be through the Auxiliary Building or from paths outside of the station's power block. The back-up channel read-out display will be protected from seismic, flooding and high wind external events. During a postulated Extended Loss of AC Power (ELAP) event, ambient temperatures at both locations would not be expected to prohibit periodic personnel access to monitor SFP levels. The estimated time for personnel to access the primary or back-up channel display is 10-15 minutes, after personnel dispatch.

Personnel accessing this area would rely on portable hand-held lighting, and hand-held radio communication with the main control room, and/or SFP inventory control personnel.

The location of both read-out displays will allow easy access to the spent fuel pool makeup valve should it be necessary to utilize the same personnel for monitoring spent fuel pool level as well as controlling SFP inventory.

This location is considered to be promptly accessible for the purposes of monitoring SFP level during a postulated BDB event.b) The primary and back-up SFP level read-out displays are remotely located outside the SFP area and are readily accessible by operational personnel.

The primary SFP level channel read-out display is located in Seismic Category I structures, which are protected from potential threats posed by external natural phenomena events, such as flooding, seismic and tornado missiles.

The back-up channel readout display is located at the 441 foot elevation on the exterior west wall of the Fuel Handling Building.

Access to the back-up channel can be through the Auxiliary Building or from paths outside of the station's power block. The back-up channel read-out display will be protected from seismic, flooding and high wind external events. The estimated time for personnel to access the primary or back-up SFP level display is 10-15 minutes, afterpersonnel dispatch.

The location of the primary and back-up SFP level display is in close proximity to the areas that Operations personnel would potentially be dispatched to as part of the FLEX strategy for providing makeup to the spent fuel pool. If a drain-down event is determined to be in progress, operators for monitoring level will be assigned for continuous level monitoring as a priority, response until such time as the drain-down event is terminated and periodic monitoring for evaporative losses is resumed.

Document Control Desk Attachment I CR-12-01070 RC-13-0119 Page 16 of 19 4.0 PROGRAM FEATURES 4.1 Training The OIP states, in part, that Training will consist of the use of the level instrumentation system as well as deployment of the portable components of the backup channel.RAI-10 Please provide a description of the training, and resources that are needed to ensure that sufficient plant personnel are available and trained to install the backup channel within 30 minutes of the loss of the operating channel.RAI #10 Response The back-up channel is no longer planned to have portable components requiring installation prior to being placed in service. The back-up channel will be permanently installed to the same requirements of the primary channel.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 new SFP instrumentation.

For the portable components of the backup channel, the procedures will also specify the storage location and the installation instructions.

RAI-1I Please 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 Document Control Desk Attachment I CR-12-01070 RC-13-0119 Page 17 of 19 regard to the storage location and provisions for installation of the portable components when needed.RAI #11 Response a) The operation procedure for the alignment and functional check of the system will be addressed in a FLEX Support Guideline (FSG). The calibration/test procedures for the 12-month functional testing and calibration check will be performed by /&C technicians in accordance with I&C Procedure.

The monthly channel check for the primary and back-up channels will be performed in accordance with plant operation logs under an Operation Administrative Procedure and will include as appropriate the acceptance criteria for channel check verification.

The FSG will be referenced from the appropriate Emergency Operating Procedure for placing the channels in service following an ELAP event.b) The FSG for Spent Fuel Pool Level Monitoring will require specific technical objectives to place the primary channel in service by turning on the power and performing a functional check of the system. If it is determined that the primary channel has been damaged or has failed to function as a result of the functional check, the FSG will direct the station personnel to place the back-up portable channel in service. The back-up channel is no longer planned to be a portable channel.4.3 Testing and Calibration The OIP states, in part, that Processes will be established for scheduling the necessary testing and calibration of all spent fuel pool level instrument channels.

This schedule will also be used to maintain the instrument channels at the design accuracy.

Testing and calibration of the instrumentation will be consistent with vendor recommendations and other documented basis during the design process. Calibration will be specific to the mounted sensor and the display and will include an in-situ check of the entire channel including the wave guide piping and horn antenna. Surveillance and testing will be performed at frequencies consistent with those specified in NEI-12-02 Section 4.3.RAI-12 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 your plans for ensuring that Document Control Desk Attachment I CR-12-01070 RC-13-0119 Page 18 of 19 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 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.RAI #12 Response a) Both the primary and back-up channels will be functionally tested with a calibration check performed on a 12-month periodicity.

The channel checks will be accomplished by comparison between the presently installed wide-range channel indications, or by comparison to the known SFP physical level elevation reference markings.

The acceptance criteria will consider the respective overall channel uncertainty contributions for accuracy, calibration setting tolerance, resolution, and drift as applicable.

Periodic channel checks will be established for the primary and back-up SFP level channels to verify proper instrument operation, as described in the response to RAI #7 b). The frequency of the channel checks is expected to be at least monthly (+/- 25 percent grace period). This frequency will readily satisfy NEl 12-02 (section 4.3) requirements.

Instrument channel calibration check frequency will be 12 months and performed in accordance with the manufacture recommendations, and/or as established based on operating experience within the preventive maintenance program. As part of the periodic calibration check surveillance for the primary SFP level channel, further functional verifications will be performed to verify proper operation of the battery back-up feature.The channel checks will be performed by Operations surveillance procedures, and the instrument calibrations checks will be performed by Maintenance instrumentation calibration surveillance procedures.

Recurring work orders will be established within the periodic maintenance program to govern the scheduling and performance of the periodic calibration checks.Routine preventive maintenance required during normal operation is limited to the periodic channel calibration check, and/or battery replacement.

The spent fuel pool level monitoring system maintenance and testing program will be inspected and audited in a manner consistent with the Appendix B requirements for safety and quality related instrumentation.

Document Control Desk Attachment I CR-12-01070 RC-13-0119 Page 19 of 19 b) If both channels are non-functional and at least one channel cannot be restored within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, a complete spare channel will be maintained at the site such that replacement of the primary channel can be initiated within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> and completed within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.c) If only one channel is non-functional and cannot be restored to functional status within 90 days the channel will be replaced with the complete spare channel available on site.