ML13323B443

Interim Staff Evaluation and Request for Additional Information Regarding the Overall Integrated Plan for Implementation of Order EA-12-051, Reliable Spent Fuel Pool Instrumentation

ML13323B443
Person / Time
Site:	Duane Arnold
Issue date:	11/26/2013
From:	Mahesh Chawla Plant Licensing Branch III
To:	Richard Anderson NextEra Energy Duane Arnold
Chawla M
References
EA-12-051, TAC MF1001
Download: ML13323B443 (25)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 November 26, 2013 Mr. Richard L. Anderson Vice President NextEra Energy Duane Arnold Energy Center 3277 DAEC Road Palo, lA 52324-9785

SUBJECT:

DUANE ARNOLD ENERGY CENTER -INTERIM STAFF EVALUATION AND REQUEST FOR ADDITIONAL INFORMATION REGARDING THE OVERALL INTEGRATED PLAN FOR IMPLEMENTATION OF ORDER EA 12 051, RELIABLE SPENT FUEL POOL INSTRUMENTATION (TAC NO. MF1001)

Dear Mr. Anderson:

On March 12, 2012, the U.S. Nuclear Regulatory Commission (NRC) issued Order EA 12 051, "Order Modifying Licenses with Regard to Reliable Spent Fuel Pool Instrumentation" (Agencywide, Documents Access and Management System (ADAMS) Accession No. ML12054A679), to all power reactor licensees and holders of construction permits in active or deferred status. This order requires the licensee to have a reliable indication of the water level in associated spent fuel storage pools capable of supporting identification of the following pool water level conditions by trained personnel: (1) level that is adequate to support operation of the normal fuel pool cooling system, (2) level that is adequate to provide substantial radiation shielding for a person standing on the spent fuel pool operating deck, and (3) level where fuel remains covered and actions to implement make-up water addition should no longer be deferred.

By letter dated February 28, 2013 (ADAMS Accession No. ML13063A014), NextEra Energy Duane Arnold, LLC, (the licensee) provided the Overall Integrated Plan (OIP) for Duane Arnold Energy Center describing how it will achieve compliance with Attachment 2 of Order EA 12 051 by the fall of 2016. By letter dated September 16, 2013 (ADAMS Accession No. ML13255A198), the NRC staff sent a request for additional information (RAI) to the licensee. The licensee provided supplemental information by letters dated August 27, 2013 (ADAMS Accession No. ML13242A008), and October 10, 2013 (ADAMS Accession No. ML13284A122).

The NRC staff has reviewed these submittals with the understanding that the licensee will update its OIP as implementation of the Order progresses. With this in mind, the staff has included an interim staff evaluation with this letter to provide feedback on the OIP. The staff's findings in the interim staff evaluation are considered preliminary and will be revised as the OIP is updated. As such, none of the staff's conclusions are to be considered final. A final NRC staff evaluation will be issued after the licensee has provided the information requested.

R. Anderson The interim staff evaluation also includes RAis, response to which the NRC staff needs to complete its review. The licensee should provide the information requested in the 6-month status updates, as the information becomes available. However, the staff requests that all information be provided by March 31, 2016, to ensure that any issues are resolved prior to the date by which the licensee must complete full implementation of Order EA 12 051. The licensee should adjust its schedule for providing information to ensure that all this information is provided by the requested date.

If you have any questions regarding this letter, please contact me at 301-415-8371 or via e-mail at mahesh.chawla@nrc.gov.

Sincerely, Mahesh Chawla, Project Manager Plant Licensing Branch 111-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-331

Enclosure:

Interim Staff Evaluation and Request for Additional Information cc w/encl: Distribution via Listserv

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 INTERIM STAFF EVALUATION AND REQUEST FOR ADDITIONAL INFORMATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO THE OVERALL INTEGRATED PLAN IN RESPONSE TO ORDER EA 12 051, RELIABLE SPENT FUEL POOL INSTRUMENTATION NEXTERA ENERGY DUANE ARNOLD, LLC DUANE ARNOLD ENERGY CENTER DOCKET NO. 50-331

1.0 INTRODUCTION

On March 12, 2012, the U.S. Nuclear Regulatory Commission (NRC) issued Order EA 12 051, "Issuance of Order to Modify Licenses with Regard to Reliable Spent Fuel Pool Instrumentation" (Agencywide Documents Access and Management System (ADAMS) Accession No. ML12054A679), to all power reactor licensees and holders of construction permits in active or deferred status. This order requires, in part, that all operating reactor sites have a reliable means of remotely monitoring wide-range spent fuel pool (SFP) levels to support effective prioritization of event mitigation and recovery actions in the event of a beyond-design-basis (BOB) external event. The order required all holders of operating licenses issued under Title 10 of the Code ofFederal Regulations (1 0 CFR) Part 50, "Domestic Licensing of Production and Utilization Facilities," to submit to the NRC an Overall Integrated Plan (OIP) by February 28, 2013. .

By letter dated February 28, 2013 (ADAMS Accession No. ML13063A014), NextEra Energy O_uane Arnold, LLC (the licensee) provided the OIP for Duane Arnold Energy Center describing how it will achieve compliance with Attachment 2 of Order EA 12 051 by the fall of 2016. By letter dated September 16, 2013 (ADAMS Accession No. ML13255A198), the NRC staff sent a request for additional information (RAI) to the licensee. The licensee provided supplemental information by letters dated August 27, 2013 (ADAMS Accession No. ML13242A008), and October 10, 2013 (ADAMS Accession No. ML13284A122).

2.0 REGULATORY EVALUATION

Order EA 12 051 requires all holders of operating licenses issued under 10 CFR Part 50, notwithstanding the provisions of any Commission regulation or license to the contrary, to comply with the requirements described in Attachment 2 to the Order except to the extent that a more stringent requirement is set forth in the license. Licensees shall promptly start implementation of the requirements in Attachment 2 to the Order and shall complete full implementation no later than two refueling cycles after submittal of the OIP or December 31, 2016, whichever comes first.

Enclosure

Order EA 12 051 required the licensees, by February 28, 2013, to submit to the Commission an OIP, including a description of how compliance with the requirements described in Attachment 2 of the Order will be achieved. of Order EA 12 051 requires the licensees to have a reliable indication of the water level in associated spent fuel storage pools capable of supporting identification of the following pool water level conditions by trained personnel: (1) level that is adequate to support operation of the normal fuel pool cooling system, (2) level that is adequate to provide substantial radiation shielding for a person standing on the SFP operating deck, and (3) level where fuel remains covered and actions to implement make-up water addition should no longer be deferred. of Order EA 12 051, states that the SFP level instrumentation shall include the following design features:

1.1 Instruments

The instrumentation shall consist of a permanent, fixed primary instrument channel and a backup instrument channel. The

.backup instrument channel may be fixed or portable. Portable instruments shall have capabilities that enhance the ability of trained personnel to monitor spent fuel pool water level under conditions that' restrict direct personnel access to the pool, such as partial structural damage, high radiation levels, or heat and humidity from a boiling pool.

1.2 Arrangement

The spent fuel pool level instrument channels shall be 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 spent fuel pool. This protection may be provided by locating the primary instrument channel and fixed portions of the backup instrument channel, if applicable, to maintain instrument channel separation within the spent fuel pool area, and to utilize inherent shielding from missiles provided by existing recesses and corners in the spent fuel pool structure.

1.3 Mounting

Installed instrument channel equipment within the spent fuel pool shall be mounted to retain its design configuration during and following the maximum seismic ground motion considered in the design of the spent fuel pool structure.

1.4 Qualification

The primary and backup instrument channels shall be reliable at temperature, humidity, and radiation levels consistent with the spent fuel pool water at saturation conditions for an extended period.

This reliability shall be established through use of an augmented quality assurance process (e.g., a process similar to that applied tothe site fire protection program).

1.5 Independence

The primary instrument channel shall be independent of the backup instrument channel.

1.6 Power supplies: Permanently installed instrumentation channels shall each be powered by a separate power supply. Permanently installed and portable instrumentation channels shall provide for power connections from sources independent of the plant [alternating current (ac)] and [direct current (de)] power distribution systems, such as portable generators or replaceable batteries. Onsite generators used as an alternate power source and replaceable batteries used for instrument channel power shall have sufficient capacity to maintain the level indication function until offsite resource availability is reasonably assured.

1. 7 Accuracy: The instrument channels shall maintain their designed accuracy following a power interruption or change in power source without recalibration.

1.8 Testing:* The instrument channel design shall provide for routine testing and calibration.

1.9 Display

Trained personnel shall be able to monitor the spent fuel pool water level from the control room, alternate shutdown panel, or other appropriate and accessible location. The display shall provide on-demand or continuous indication of spent fuel pool water level. of Order EA 12 051, states that the SFP instrumentation shall be maintained available and reliable through appropriate development and implementation of the following programs:

2.1 Training

Personnel shall be trained in the use and the provision of alternate power to the primary and backup instrument channels.

2.2 Procedures

Procedures shall be established and maintained for the testing, calibration, and use of the primary and backup spent fuel pool instrument channels.

2.3 Testing and Calibration: Processes shall be established and maintained for scheduling and implementing necessary testing and calibration of the primary and backup spent fuel pool level instrument channels to maintain*

the instrument channels at the design accuracy.

On August 29, 2012, the NRC 'issued an Interim Staff Guidance document (the ISG),

JLD~ISG-2012-03, "Compliance with Order EA 12 051, Reliable Spent Fuel Pool Instrumentation" (ADAMS Accession No. ML12221A339), to describe methods acceptable to the NRC staff for complying with Order EA 12 051. The ISG endorses, with exceptions and clarifications, the methods described in the Nuclear Energy Institute (NEI) guidance document NEI 12-02, Revision 1, "Industry Guidance for Compliance with NRC Order EA 12 051, to Modify Licenses with Regard to* Reliable Spent Fuel Po() I Instrumentation," dated August 2012 (ADAMS Accession No. ML 12~40A307). Specifically, the ISG states:

The NRC staff considers that the methodologies and guidance in conformance with the guidelines provided in NEI 12-02, Revision 1, subject to the clarifications and exceptions in Attachment 1 to this ISG, are an acceptable means of meeting the requirements of Order EA 12 051.

3.0 TECHNICAL EVALUATION

3.1 Background and Schedule Duane Arnold Energy Center has one SFP located in the reactor building.

The licensee's OIP was submitted on February 28, 2013. The OIP states that installation of the SFP* level instrumentation at Duane Arnold Energy Center will be completed by the fall of 2016, based on the end of the second refueling outage following submittal of their OIP.

The NRC staff has reviewed the licensee's schedule for implementation of SFP level instrumentation. If the licensee completes implementation in accordance with this schedule, it would appear to achieve compliance with Order EA 12 051 within two refueling cycles after submittal of the OIP and before December 31, 2016.

3.2 Spent Fuel Pool Water Levels of Order EA 12 051 states, in part, that All licensees identified in Attachment 1 to this Order shall have a reliable indication of the water level in associated spent fuel storage pools capable of supporting identification of the following pool water level conditions by trained personnel: (1) level that is adequate to support operation of the normal fuel pool cooling system [Level 1], (2) level that is adequate to provide substantial radiation shielding for a person standing on the SFP operating deck [Level 2],

and (3) level where fuel remains covered and actions to implement make-up water addition should no longer be deferred [Level 3].

NEI 12-02 states, in part, that Level 1 represents the HIGHER of the following two points:

• The level at which reliable suction loss occurs due to uncovering of the coolant inlet pipe, weir or vacuum breaker (depending on the design), or

• The level at which the water height, assuming saturated conditions, above the centerline of the cooling pump suction provides the required net positive suction head specified by the pump manufacturer or engineering analysis.

In its OIP, the licensee stated that Level 1 would be set at an elevation of 853 feet (ft.) 8 inches (in.). The licensee also stated that this water level is above the SFP weir wall elevation that is needed to ensure adequate SFP cooling flow.

In its letter dated October 10, 2013, the licensee provided a sketch depicting the SFP elevations identified as Levels 1, 2 and 3 and the SFP instrument channel measurement range. The NRC staff notes that Level 1, at an elevation of 853ft. 8 in. is adequate for normal SFP cooling system operation and it is also adequate to ensure the required fuel pool cooling pump Net Positive Suction Head (NPSH) as the skimmer surge tanks supply the SFP cooling pumps. This level represents the higher of the two points described in NEI 12-02 for Level 1, for both units.

NEI 12-02 states, in part, that Level 2 represents the range of water level where any necessary operations iri the vicinity of the spent fuel pool can be completed without significant dose consequences from direct gamma radiation from the stored spent fuel. Level 2 is based on either of the following:

• 10 feet (+/- 1 foot) above the highest point of any fuel rack seated in the spent fuel pools, or

• a designated level that provides adequate radiation shielding to maintain personnel radiological dose levels within acceptable limits while performing local operations in the vicinity of the pool. This level shall be based on either plant-specific or appropriate generic shielding calculations, considering the emergency conditions that may apply at the time and the scope of necessary local operations, including installation of portable SFP instrument channel components.

In its OIP, the licensee stated that Level 2 would be set at an elevation of 841 ft. 5 in. The licensee also stated that this elevation is approximately 10 ft. above the top of the fuel racks.

In its letter dated October 10, 2013, the licensee provided a sketch depicting the SFP elevations identified as Levels 1, 2 and 3 and the SFP instrument channel measurement range. The NRC staff reviewed this sketch and notes that Level 2 is identified at an elevation 10 ft. above the top of the storage racks. The staff also notes that the licensee designated Level 2 using the first of the two options described in NEI 12-02 for Level 2.

NEI 12-02 states, in part, that Level 3 corresponds nominally (i.e., +/- 1 foot) to the highest point of any fuel rack seated in the spent fuel pool. Level 3 is defined in this manner to provide the maximum range of information to operators, decision makers and emergency response personnel.

In its OIP, the licensee stated that Level 3 would be set at an elevation of 831 ft. 5 in. which is the nominal level of the highest fuel rac.k.

In its letter dated October 10, 2013, the licensee provided a sketch depicting the SFP elevations identified as Levels 1, 2 and 3 and the SFP instrument channel measurement range. The NRC staff reviewed this sketch and notes that Level 3 at an elevation of 831ft. 5 in. is the highest point of any spent fuel storage rack seated in the SFP.

The licensee's proposed plan, with respect to identification of Levels 1, 2, and 3, appears to be consistent with NEI 12-02, as endorsed by the ISG.

3.3 Design Features: Instruments of Order EA 12 051, states, in part, that The instrumentation shall consist of a permanent, fixed primary instrument channel and a backup instrument channel. The backup instrument channel may be fixed or portable. Portable instruments shall have capabilities that enhance the ability of trained personnel to monitor spent fuel pool water level under conditions that restrict direct personnel access to the pool, such as partial structural damage, high radiation levels, or heat and humidity from a boiling pool.

NEI 12-02 states, in part, that A spent fuel pool level instrument channel is considered reliable when the instrument channel satisfies the design elements listed in Section 3

[Instrumentation Design Features) of this guidance and the plant operator has fully implemented the programmatic features listed in Section 4 [Program

• Features).

In its OIP, the licensee stated that both the primary and backup instrument channels will consist of fixed components and that the measured range will be continuous from the normal pool level elevation of 853ft. 8 in. to the top of the spent fuel racks at elevation 831 ft. 5 in.

In its letter dated October 10, 2013, the licensee provided a sketch depicting the SFP elevations identified as Levels 1, 2 and 3 and the SFP instrument channel measurement range. The NRC staff notes that this sketch showed that level indication would be provided from the normal pool level elevation of 854ft. 0 in. to the top of the spent fuel racks at elevation 831 ft. 5 in. The staff also notes that the normal pool elevation provided in this letter is 4 in. above the normal pool elevation provided in the licensee's OIP. However, both elevations cover the identified Level 1.

The NRC staff notes that the range specified for the licensee's instrumentation will cover Levels 1, 2, and 3 as described in Section 3.2 above. The licensee's proposed plan, with respect to the number of channels and the range of the instrumentation for both of its SFPs, appears to be consistent with NEI 12-02, as endorsed by the ISG.

3.4 Design Features: Arrangement of Order EA 12 051, states, in part, that The spent fuel pool level instrument channels shall be 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 spent fuel pool. This protection may be provided by locating the primary instrument channel and the fixed portions of the backup instrument channel, if applicable, to maintain instrument channel separation within the spent fuel pool area, and to utilize

inherent shielding from missiles provided by existing recesses and corners in the spent fuel pool structure.

NEI 12-02 states, in part, that The intent of the arrangement requirement is to specify reasonable separation and missile protection requirements for permanently installed instrumentation used to meet this order. Although additional missile barriers are not required to be installed, separation and shielding can help minimize the probability that damage due to an explosion or extreme natural phenomena (e.g., falling or wind-driven missiles) will render fixed channels of SFP instrumentation unavailable.

Installation of the SFP instrument channels shall be consistent with the plant-specific SFP design requirements and should not impair normal SFP function.

Channel separation should be maintained by locating the installed sensors in different places in the SFP area. )

In its OIP, the license stated that the primary and backup instrument channel level sensing components will be located in the north side of the SFP and that the distance between the primary and backup instrument level sensing components will be approximately 20 feet. The licensee also stated that the cabling for power supplies and indications for each channel will be routed in separate conduits from the cabling for the adjacent channel and the sensor conditioning electronics and battery backup will be located in the Control Building which is a Class 1 structure.

In NRC's letter dated September 16, 2013, the staff requested a modified marked-up plant drawing of the plan view of the SFP area, to depict the SFP inside dimensions, the planned locations/placement of the primary and back-up SFP level sensors, and the proposed routing of the cables that will extend from the sensors toward the location of the local electronics cabinets and read-out/display devices in the main control room (MCR) or alternate accessible location.

In its letter dated October 10, 2013, the licensee stated, in part, that The answer to this request requires design information that is under development. The information will be provided in a six (6) month update after it has been obtained, no later than August 2015.

The NRC staff notes that the OIP includes a drawing showing the location of the level channel instruments, and the proposed cable routing from the SFP in the reactor building to the transmitters in the control building. However, this drawing does not show the cable routing from the transmitters to the credited displays. The staff also notes that further information regarding the arrangement of the SFP level instrumentation is not currently available for review and that in its letter dated October 10, 2012, the licensee indicated that the information will be provided to th.e staff in a six-month update, no later than August 2015. The staff has identified this request as:

RAI #1 Please modify the marked-up plant drawing of the plan view (in Section XVIII, Page 10 of

10) of the SFP area, to depict the SFP inside dimensions, the planned locations/

placement of the primary and back-up SFP level sensors, and the proposed routing of the cables that will extend from the sensors toward the location of the local electronics cabinets and read-out/display devices in the main control room or alternate accessible location.

(This information was previously requested as RAI-2 in the NRC letter dated September 16, 2013.)

3.5 Design Features: Mounting of Order EA 12 051 states, in part, that Installed instrument channel equipment within the spent fuel pool shall be mounted to retain its design configuration during and following the maximum seismic ground motion considered in the design of the spent fuel pool structure.

NEI 12-02 states, in part, that The mounting shall be designed to be consistent with the highest seismic or safety classification of the SFP. An evaluation of other hardware stored in the SFP shall be conducted to ensure it will not create adverse interaction with the fixed instrument location(s).

The basis for the seismic design for mountings in the SFP shall be the plant seismic design basis at the time of submittal of the Integrated Plan for implementing NRC Order EA 12 051.

In its OIP, the licensee stated that the mounting of the SFP level instrumentation will be Seismic Class I and that the 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.

In NRC's letter dated September 16, 2013, the staff requested information regarding mounting of the SFP level instrumentation.

In its letter dated October 10, 2013, the licensee stated, in part, that The answer to this request requires design information that is under development. The information will be provided in a six (6) month update after it has been obtained, no later than August 2015.

The NRC staff notes that the information regarding mounting for the SFP level instrumentation is not currently available for review and that in its letter dated October 10, 2012, the licensee indicated that the information will be provided to the staff in a six-month update, no later than August 2015. The staff has identified these requests as:

RAI#2

• 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, to support the level sensor assembly.

(This information was previously requested as RAI-3 in the NRC letter dated September 16, 2013.) '

In addition, the staff plans to verify the results of the licensee's seismic testing and analysis when it is completed based on the licensee's response to the following RAI.

RAI#3 For RAI 2(a) above, please provide the analyses used to verify the design criteria and methodology for seismic testing of the SFP instrumentation and the electronics units, including design basis maximum seismic loads and the hydrodynamic loads that could result from pool sloshing or other effects that could accompany such seismic forces.

RAI#4 For each of the mounting attachments required to attach SFP level equipment to plant structures, please describe the design inputs, and the methodology that will be used to qualify the structural integrity of the affected structures/equipment.

3.6 Design Features: Qualification Attachment 2 of Order EA 12 051 states, in part, that The primary and backup instrument channels shall be reliable at temperature, humidity, and radiation levels consistent with the spent fuel pool water at saturation conditions for an extended period. This reliability shall be established

through use of an augmented quality assurance process (e.g. a process similar to that applied to the site fire protection program).

NEI 12-02 states, in part, that The instrument channel reliability shall be demonstrated via an appropriate combination of design, analyses, operating experience, and/or testing of channel components for the following sets of parameters, as described in the paragraphs below:

• conditions in the area of instrument channel component use for all instrument components,

• effects of shock and vibration on instrument channel components used during any applicable event for only installed components, and

• seismic effects on instrument channel components used during and following a potential seismic event for only installed components ...

The NRC staff's assessment of the instrument qualification is discussed in the following

.subsections: (3.6.1) Augmented Quality Process and (3.6.2) Qualification and Reliability.

3.6.1 Augmented Quality Process Appendix A-1 of the guidance in NEI 12-02 describes a quality assurance process for non-safety systems and equipment that is not already covered by existing quality assurance requirements. Within the ISG, the NRC staff found the use of this quality assurance process to be an acceptable means of meeting the augmented quality requirements of Order EA 12 051.

In its OIP, the licensee stated that augmented quality requirements, similar to those applied to fire protection, will be applied to this project.

The licensee's proposed augmented quality assurance process appears to be consistent with NEI 12-02, as endorsed by the ISG.

3.6.2 Qualification and Reliability NEI 12-02 states, in part, that The temperature, humidity and radiation levels consistent with conditions in the vicinity of the [SFP] and the area of use considering normal operational, event and post-event conditions for no fewer than seven days post-event or until off-site resources can be deployed by the mitigating strategies resulting from Order EA-12-049 should be considered. Examples of post-event (beyond-design-basis) conditions to be considered are:

• radiological conditions for a normal refueling quantity of freshly discharged (1 00 hours0 days <br />0 hours <br />0 weeks <br />0 months <br />) fuel with the SFP water Level 3 as described in this order,

• temperatures of 212 degrees F and 100% relative humidity environment,

• boiling water and/or steam environment

• a concentrated borated water environment.

In its OIP, the licensee stated, consistentwith NEI 12-02, in part, that The temperature, humidity and radiation levels consistent with conditions in the vicinity of the SFP and the area of use, considering normal operational, event and post-event conditions for no fewer than seven days post-event or until off-site resources can be deployed by the mitigating strategies resulting from Order EA-12-049 (Reference 2), will be addressed in the engineering and design .

phase. Examples of post-event (beyond-design-basis) conditions that will be considered are:

• radiological conditions for a normal refueling quantity of freshly discharged (1 00 hours0 days <br />0 hours <br />0 weeks <br />0 months <br />) fuel with the SFP water Level 3 as described in this order,

• temperatures of 212 degrees F and 100% relative humidity environment,

• boiling water and/or steam environment, and ...

In NRCs letter dated September 16, 2013, the staff requested information regarding the qualification and reliability of the SFP level instrumentation.

In its letter dated October 10, 2013, the licensee stated, in part, that The answer to this request requires design information that is under development. The information will be provided in a six (6) month update after it has been obtained, no later than August 2015.

• The NRC staff notes that the information regarding qualification and reliability of the SFP level instrumentation is not currently available for review and that in its letter dated October 10, 2012, the licensee indicated that the information will be provided to the staff in a six-month update, no later than August 2015. The staff has identified these requests as:

RAI#S 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 such that following a seismic event the instrument will maintain its required accuracy.

(This information was previously requested as RAI-4 in the NRC letter dated September 16, 2013.)

In addition, the staff plans to verify the results of the licensee's testing and analysis used to demonstrate the qualification and reliability of the. installed equipment when it is completed based on the licensee's response to the following RAI.

RAI#6 For RAI #5 above, please provide the results for the selected methods, tests and analyses used to demonstrate the qualification and reliability of the instailed equipment in accordance with the Order requirements.

3. 6. 3 Qualification Evaluation Summary Upon acceptable resolution of the RAis in Section 3.6, the NRC staff will be able to make a conclusion regarding the instrument qualification.

3.7 Design Features: Independence of Order EA 12 051 states, in part, that The primary instrument channel shall be independent of the backup instrument channel.

NEI 12-02 states, in part, that Independence of permanently installed instrumentation, and primary and backup channels, is obtained by physical and power separation commensurate with the hazard and electrical isolation needs .. If plant AC or DC power sources are used, then the power sources shall be from different buses and preferably different divisions/channels depending on available sources of power.

In its OIP, the licensee stated that the primary instrument channel will be redundant to and independent of the backup instrument channel and that independence will be obtained through separation of the sensors, indication, backup battery power supplies, associated cabling and channel feeds.

In NRCs letter dated September 16, 2013, the staff requested information regarding SFP level instrumentation* channel independence.

In its October 10, 2013, letter, the licensee stated, in part, that The answer to this request requires design information that is under development. The information will be provided in a six (6) month update after it has been obtained, no later than August 2015.

The NRC staff notes that the information regarding the SFP level instrumentation channel independence is not currently available for review and that in its letter dated October 10, 2012, the licensee indicated that the information will be provided to the staff in a six-month update, no later than August 2015. The staff has identified this request as:

RAI#7 Please provide the following:

a) A description of the manner in which the proposed level measurement system meets the independence requirement, to minimize, to the extent practicable, the potential for a common cause event to adversely affect both channels.

b) Further information describing how each level measurement system, consisting of level sensor electronics, cabling, and readout devices will be designed and installed to address independence through the application and selection of independent power sources, the use of physical and spatial separation, independence of signals sent to the location(s) of the readout devices, and the independence of the displays.

(This information was previously requested as RAI-5 in the NRC letter dated September 16, 2013.)

3.8 Design Features: Power Supplies of Order EA 12 051, states in part, that Permanently installed instrumentation channels shall each be powered by a separate power supply. Permanently installed and portable instrumentation channels shall provide for power connections from sources independent of the plant AC and DC power distribution systems, such as portable generators or replaceable batteries. Onsite generators used as an alternate power source and replaceable batteries used for instrument channel power shall have sufficient

capacity to maintain the level indication function until offsite resource availability is reasonably assured.

NEI 12-02 states, in part, that The normal electrical power supply for each channel shall be provided by different sources such that the loss of one of the channels primary power supply will not result in a loss of power supply function to both channels of SFP level instrumentation.

All channels of SFP level instrumentation shall provide the capability of connecting the channel to a source of power (e.g., portable generators or replaceable batteries) independent of the normal plant AC and DC power systems. For fixed channels this alternate capability shall include the ability to isolate the installed channel from its normal power supply or supplies. The portable power sources for the portable and installed channels shall be stored at separate locations, consistent with the reasonable protection requirements associated with NEI 12-06 (Order EA-12-049.) The portable generator or replaceable batteries should be accessible and have sufficient capacity to support reliable instrument channel operation until off-site resources can be deployed by the mitigating strategies resulting from Ord~r EA-12-049.

If adequate power supply for either an installed or portable level instrument credits intermittent operation, then the provisions shall be made for quickly and reliably taking the channel out of service and restoring it to service. For example, a switch on the power supply to the channel is adequate provided the power can be periodically interrupted without significantly affecting the accuracy and reliability of the instrument reading. Continuous indication "Of SFP level is acceptable only if the power for such indication is demonstrably adequate for the time duration specified in section 3.1 [.]

In its OIP the licensee stated in part, that, Both channels will be powered from dedicated batteries and local battery chargers. The battery chargers for both channels will normally be powered from separate sources of 120V AC power. Minimum battery life of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> will be provided. The battery systems will include provision for battery replacement should the battery charger be unavailable following the event. Spare batteries will be readily available. In the event of a loss of normal power, the battery chargers will be connected to a backup power source.

In NRC letter dated September 16, 2013, the staff requested information regarding the total power supply configuration and characteristics for the SFP level instrumentation.

In its letter dated October 10, 2013, the licensee stated, in part, that, The answer to this request requires design information that is under development. The information will be provided in a six (6) month update after it has been obtained, no later than August 2015.

The NRC staff notes that the information regarding total power supply configuration and characteristics for the SFP level instrumentation is not currently available for review and that in its letter dated October 10, 2012, the licensee indicated that the information will be provided to the staff in a six-month update, no later than August 2015. The staff has identified this request as:

RAI#8 Please provide the following:

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

b) The results of the calculation depicting battery backup duty cycle requirements, demonstrating battery capacity is sufficient to maintain the level indication function until offsite resource availability is reasonably assured.

(This information was previously requested as RAI-6 in the NRC letter dated September 16, 2013. However, based on feedback from the licensees, it has been revised as above.)

3.9 Design Features: Accuracy of Order EA 12 051 states, in part, that The instrument channels shall maintain their designed accuracy following a power interruption or change in power source without recalibration.

NEI 12-02 states, in part, that Accuracy should consider operations while under SFP conditions, e.g., saturated water, steam environment, or concentrated borated water. Additionally, instrument accuracy should 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.

In its OIP, the licensee stated that the instrument channels will be designed such that they will maintain their design accuracy following a power interruption or change in power source without recalibration.

In NRCs letter dated September 16, 2013, the staff requested information regarding the SFP level instrumentation accuracy and the instrument channels capacity to maintain their designed accuracy following a power interruption or change in power source without recalibration.

In its letter dated October 10, 2013, the licensee stated, in part, that The answer to this request requires design information that is under development. The information will be provided in a six (6) month update after it has been obtained, no later than August 2015.

The NRC staff notes that information on SFP Level instrumentation accuracy is not currently available for review. In its letter dated October 10, 2012, the licensee indicated the information will be provided to the staff in a six-month update, no later than August 2015. The staff has identified this request as:

RAI#9 Please provide the following:

a) An estimate of the expected instrument channel accuracy performance under both .

(a) normal SFP level conditions (approximately Leve1*1 or higher) and (b) at the BOB (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 to be used for determining the maximum allowed deviation from the instrument channel design accuracy under normal operating conditions.

(This information was previously requested as RAI-:-7 in the NRC letter dated September 16, 2013.)

3.10 Design Features: Testing of Order EA 12 051 states, in part, that The instrument channel design shall provide for routine testing and calibration.

NEI 12-02 states, in part, that Static or non-active installed (fixed) sensors can be used and should be designed such that testing and/or calibration can be performed in-situ. For microprocessor based channels the instrument channel design shall be capable of testing while mounted in the pool.

In its OIP, the licensee stated that instrument channel design will provide for routine testing and calibration consistent with Order EA 12 051 and the guidance in NEI 12-02.

In NRCs letter dated September 16, 2013, the staff requested information regarding the design of the SFP level instrumentation to provide for routine testing and calibration.

I~ its October 10, 2013, letter the lic~nsee stated, in part, that The answer to this request requires design information that is under development. The information will be provided in a six (6) month update after it has been obtained, no later than August 2015.

The NRC staff notes that information on the design of SFP level instrumentation to support routine testing and calibration is not currently available for review. In its letter dated October 10, 2012, the licensee indicated the information will be provided to the staff in a six-month update, no later than August 2015. The staff has identified this request as:

RAI #10 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 the way 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 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.

(This information was previously requested as RAI-8 in the NRC letter dated September 16, 2013.)

3.11 Design Features: Display of Order EA 12 051 states, in part, that Trained personnel shall be able to monitor the spent fuel pool water level from the control room, alternate shutdown panel, or other appropriate and accessible location. The display shall provide on-demand or continuous indication of spent fuel pool water level.

NEI 12-02 states, in part, that The intent of this guidance is to ensure that information on SFP level is reasonably available to the plant staff and decision makers. Ideally there will be an indication from at least one channel of instrumentation in the control room.

While it is generally recognized (as demonstrated by the events at Fukushima Daiichi) that SFP level will not change rapidly during a loss of spent fuel pool cooling scenario more rapid SFP drain down cannot be entirely discounted.

Therefore, the fact that plant personnel are able to determine the SFP level will satisfy this requirement, provided the personnel are available and trained in the use of the SFP level instrumentation (see Section 4.1) and that they can accomplish the task when required without unreasonable delay.

SFP level indication from the installed channel shall be displayed in the control room, at the alternate shutdown panel, or another appropriate and accessible location (reference NEI 12-06). An appropriate and accessible location shall have the following characteristics:

• occupied or promptly accessible to the appropriate plant staff giving appropriate consideration to various drain down scenarios,

• outside of the area surrounding the SFP floor, e.g., an appropriate distance from the radiological sources resulting from an event impacting the SFP, .

• inside a structure providing protection against adverse weather, and

• outside of any very high radiation areas or LOCKED HIGH RAD AREA during normal operation.

If multiple display locations beyond the required "appropriate and accessible location" are desired, then the instrument channel shall be designed with the capability. to drive the multiple display locations without impacting* the primary "appropriate and accessible" display.

In its OIP, the licensee stated that design would include remote indication that would be accessible during and after post-event conditions.

In NRC letter dated September 16, 2013, the staff requested information regarding the location for the SFP level instrumentation displays ..

In its October 10, 2013, letter the licensee stated, in part, that The answer to this request requires design information that is under development. The information will be provided in a six (6) month update after it has been obtained, no later than August 2015.

The NRC staff notes that the information regarding the location of the SFP level instrumentation displays is not currently available for review. In its letter dated October 10, 2012, the licensee indicated that the information will be provided to the staff in a six-month update, no later than August 2015. The staff has identified this request as:

RAI #11 Please provide the following:

a) The specific location for each of the primary and backup instrument channel displays.

b) For any displays located outside the MCR, describe the evaluation used to validate the display location cari be accessed without unreasonable delay following a BOB event. Include the time available for personnel to access the display as credited in the evaluation, as well as the actual time (e.g., based on walk-throughs) that it will take for personnel to access the display. Additionally, include a description of the radiological and environmental conditions on the paths personnel might take. Describe whether the display location remains habitable for radiological, heat and humidity, and other environmental conditions following a BOB event. Describe whether personnel are continuously stationed at the display or monitor the display periodically.

(This information was previously requested as RAI-9) in the NRC letter dated September 16, 2013.)

3.. 12 Programmatic Controls: Training of Order EA 12 051 states, in part, that Personnel shall be trained in the use and the provision of alternate power to the primary and backup instrument channels.

NEI 12-02 states, in part, that The personnel performing functions associated with these SFP level instrumentation channels shall be trained to perform the job specific functions necessary for their assigned tasks (maintenance, calibration, surveillance, etc.).

SFP instrumentation should be installed via the normal modification processes.

In some cases, utilities may choose to utilize portable instrumentation as a portion of their SFP instrumentation response. In either case utilities should use the Systematic Approach to Training (SAT) to identify the population to be trained. The SAT process should also determine both the initial and continuing elements of the required training.

In its OIP, the licensee stated, in part, that The Systematic Approach to Training (SAT) will be used to identify the population to be trained and to determine both the initial and continuing elements of the required training. Training will be completed prior to placing the instrumentation in service.

The licensee's proposed plan to train personnel in the use and the provision of alternate power to the primary and backup instrument channels, including the approach to identify the population to be trained appears to be consistent with NEI 12-02, as endorsed by the ISG.

3.13 Programmatic Controls: Procedures of Order EA 12 051 states, in part, that Procedures shall be established and maintained for the testing, calibration, and use of the primary and backup spent fuel pool instrument channels.

NEI 12-02 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.

In its OIP, the licensee stated that procedures would be developed using guidelines and vendor instructions to address the maintenance, operation and abnormal response issues associated with the primary and backup channels of SFP instrumentation.

In NRC letter dated September 16, 2013, the staff requested information regarding the licensee's plan to establish and maintain procedures for the testing, calibration, and use of the primary and backup spent fuel pool instrument channels.

In its letter dated October 10, 2013, the licensee stated, in part, that The answer to this request requires design information that is under development. The information will be provided in a six (6) month update after it has been obtained, no later than August 2015.

The NRC staff notes that the information regarding procedural details for the SFP level instrumentation is not currently available for review. In its letter dated October 10, 2012, the licensee indicated the information will be provided to the staff in a six-month update, no later than August 2015. The staff has identified this request as:

RAI #12 a) Please provide a list of the procedures addressing operation (both normal and abnormal response), calibration, test, maintenance, and inspection that will be developed for use of the SFP instrumentation.

b) Please provide a brief description of the specific technical objectives to be achieved within each procedure.

(This information was previously requested as RAI-10 in the NRC letter dated September 16, 2013.)

3.14, Programmatic Controls: Testing and Calibration of Order EA 12 051 states, in part, that Processes shall be established and maintained for scheduling and implementing necessary testing and calibration of the primary and backup spent fuel pool level instrument channels to maintain the instrument channels at the design accuracy.

NEI 12-02 states, in part, that Processes shall be established and maintained for scheduling and implementing necessary testing and calibration of the primary and backup SFP level instrument channels to maintain the instrument channels at the design accuracy. The testing and calibration of the instrumentation shall be consistent with vendor recommendations or other documented basis.

In its OIP, the licensee stated that the testing and calibration of the instrumentation will be consistent with vendor recommendations or other documented basis. The licensee also stated that calibration will be specific to the mounted instruments and the displays.

In NRC letter dated September 16, 2013, the staff requested information regarding the processes for scheduling and implementation of testing and calibration of the primary and backup SFP level instrument channels.

In its letter dated October 10, 2013, the licensee stated, in part, that The answer to this request requires design information that is under development. The information will be provided in a six (6) month update after it has been obtained, no later than August 2015.

The NRC staff notes that the information regarding testing and calibration program requirements and compensatory actions for the SFP instrumentation is not currently available for review and that in its letter dated October 10, 2012, the licensee indicated that the information will be provided to the staff in a six-month update, no later than August 2015. The staff has identified these requests as:

RAI #15 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 plans to ensure 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 the NextEra/DAEC procedure/process to implement the guidance in NEI 12-02 section 4.3 regarding compensatory actions for one or both non-functioning channels.

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

(This information was previously requested as RAI-11 in the NRC letter dated September 16, 2013.)

RAI #16 Please provide a description of the in-situ calibration process at the SFP location that will result in the channel calibration being maintained at its design accuracy.

3.15 Instrument Reliability NEI 12-02 states, in part, that A spent fuel pool level instrument channel is considered reliable when the instrument channel satisfies the design elements listed in Section 3 [Instrument Design Features] of this guidance and the plant operator has fully implemented the programmatic features listed in Section 4 [Program Features].

In its OIP, the licensee stated that the reliability of the primary and backup instrument channels will be assured by conformance with the guidelines of NRC JLD-ISG-2012-03 and NEI 12-02.

Upon acceptable resolution of the RAis noted above, the NRC staff will be able to make a conclusion regarding the reliability of the SFP instrumentation.

4.0 CONCLUSION

The NRC staff is unable to complete its evaluation regarding the acceptability of the licensee's plans for implementing the requirements of Order EA 12 051 due to the need for additional information as described above. The NRC staff will issue an evaluation with its conclusion after the licensee has provided the requested information.

ML133238443 *via memo dates October 28 2013 OFFICE NRR/DORULPL3-1 /PM NRR/DORULPL3-1 /PM NRR/DORULPL3-1/LA NRR/DSS/SBPB/BC NAME CFaria MChawla (SWal/ for) MHenderson GCasto*

DATE 11/14/13 11/14/13 11/21/13 10/24/2013 OFFICE NRR/DE/EICB/BC NRR/DORULPL3-1/BC NRR/DORULPL3-1 /PM NAME JThorp* RCarlson MChawla DATE 10/28/2013 11/26/13 11/26/13