ML13275A111

Dresden Nuclear Power Station, Units 2 and 3 - 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

ML13275A111
Person / Time
Site:	Dresden
Issue date:	10/29/2013
From:	Purnell B A Division of Operating Reactor Licensing
To:	Pacilio M J Exelon Generation Co
Blake Purnell, NRR/DORL 415-1380
References
EA-12-051, TAC MF1050, TAC MF1051
Download: ML13275A111 (24)

Text

Mr. Michael J. Pacilio Senior Vice President UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 October 29, 2013 Exelon Generation Company, LLC President and Chief Nuclear Officer (CNO) Exelon Nuclear 4300 Winfield Road Warrenville, IL 60555 SUBJECT: DRESDEN NUCLEAR POWER STATION, UNITS 2 AND 3-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 NOS. MF1050 AND MF1051) Dear Mr. Pacilio: 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. ML 12054A679), 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. ML 13060A125), Exelon Generation Company, LLC (the licensee) provided the Overall Integrated Plan (OIP) for Dresden Nuclear Power Station, Units 2 and 3, describing how it will achieve compliance with Attachment 2 of Order EA-12-51 by fall 2015 for Unit 2 and fall 2016 for Unit 3. By letter dated June 26, 2013 (ADAMS Accession No. ML 13177 A064 ), the NRC staff sent a request for additional information (RAJ) to the licensee. The licensee provided supplemental information by letters dated July 18, 2013 (ADAMS Accession No. ML 13200A 125), and August 28, 2013 (ADAMS Accession No. ML 13241 A242). 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 staff evaluation will be issued after the licensee has provided the information requested.

M. Pacilio -2-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 April 30, 2015, 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 301-415-1380 or via e-mail at Blake.Purnell@nrc.gov. Docket Nos. 50-237 and 50-249 Enclosure: Interim Staff Evaluation and Request for Additional Information cc w/encl: Distribution via Listserv Blake Purnell, Project Manager Plant Licensing Branch 111-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation 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 EXELON GENERATION COMPANY. LLC DRESDEN NUCLEAR POWER STATION, UNITS 2 AND 3 DOCKET NOS. 50-237 AND 50-249 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 [SFP] Instrumentation" (Agencywide Documents Access and Management System (ADAMS) Accession No. ML 12054A679), 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 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 of Federal 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. ML 13060A 125), Exelon Generation Company, LLC (the licensee) provided the OIP for Dresden Nuclear Power Station, Units 2 and 3, describing how it will achieve compliance with Attachment 2 of Order EA-12-051 by fall 2015 for Unit 2 and fall 2016 for Unit 3. By letter dated June 26, 2013 (ADAMS Accession No. ML 13177 A064), the NRC staff sent a request for additional information (RAI) to the licensee. The licensee provided supplemental information by letters dated July 18, 2013 (ADAMS Accession No. ML 13200A 125), and August 28, 2013 (ADAMS Accession No. ML 13241A242). 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 NRC 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 ENCLOSURE

-2-than two refueling cycles after submittal of the OIP or December 31, 2016, whichever comes first. Order EA-12-051 required the licensee, by February 28, 2013, to submit to the NRC an OIP, including a description of how compliance with the requirements described in Attachment 2 of the Order will be achieved. Attachment 2 of Order EA-12-051 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 SFP operating deck, and (3) level where fuel remains covered and actions to implement make-up water addition should no longer be deferred. Attachment 2 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 to the site fire protection program).

-3-1.5 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 demand or continuous indication of spent fuel pool water level. Attachment 2 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. ML 12221A339), 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

-4 -Modify Licenses with Regard to Reliable Spent Fuel Pool Instrumentation' "dated August 2012 (ADAMS Accession No. ML 12240A307). 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 Dresden Nuclear Power Station, Units 2 and 3, has two independent SFPs located in the reactor building. The pools for both units are essentially identical and are not interconnected in any way. The OIP states that installation of the SFP level instrumentation at Dresden Nuclear Power Station will be completed by the end of the fall 2015 refueling outage for Unit 2 and the fall 2016 refueling outage for Unit 3. These dates are based on the end of the second refueling outage for each unit following submittal of the 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 Attachment 2 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 spent fuel pool 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

-5-* 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 for Level 1, for both units, the indicated level on either primary or backup instrument channel must be greater than 23 feet (ft.) (elevation 612 ft.) plus instrument accuracy above the top of the storage racks. The licensee stated that this elevation is based on the height of the SFP weirs, demonstrating a water level above 23ft. is adequate for normal fuel pool cooling system operation. In its letter dated, July 18, 2013, the licensee stated, in part, that The Spent Fuel Pool at Dresden Station has skimmers and scuppers located at an approximate [611 ft. 3 inch (in.)] elevation that water must flow into. From there the water is routed to surge tanks from which the Fuel Pool Cooling Pumps draw suction. The suction trip is at an approximate 595ft. 0 in. elevation. Thus the 611 ft. 3 in. elevation reflects the higher of the two points noted in NEI 12-02, Section 2.3.1. The NRC staff notes that Level 1 at elevation 611 ft. 3 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. The staff also notes that this level represents the higher of the two points described in NEI 12-02 for Level 1. NEI 12-02 states, in part, that Level 2 represents the range of water level where any necessary operations in 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, for both units, is the indicated level on either the primary or backup instrument channel of greater than 10 ft. (elevation 599 ft.) plus instrument channel accuracy above the top of the storage racks. In its letter dated July 18, 2013, the licensee provided a sketch depicting the SFP elevations and levels. The NRC staff reviewed this sketch and notes that Level 2 is identified at an elevation

-6-10 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 OJP, the licensee stated that Level 3, for both units, is the indicated level on either the primary or backup instrument channel of greater than 0 ft. (elevation 589ft.) plus instrument channel accuracy above the top of the storage racks. In its letter dated July 18, 2013, the licensee provided a sketch depicting the SFP elevations and levels. The NRC staff reviewed this sketch and notes that the elevation provided for Level 3 is above 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 Attachment 2 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 OJP, the licensee stated that both the primary and backup instrument channels would be located and permanently mounted in each unit's dedicated SFP. In its Jetter dated July 18, 2013, the licensee provided a sketch showing the level sensor instrument range for both the primary and backup instrument channels is 23ft. 0 in. from the normal water level elevation of 612ft. 0 in. to the top of the spent fuel racks at elevation 589ft. 0 in. The sketch also depicts the location of Levels 1, 2, and 3.

-7 -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 Attachment 2 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 driven missiles) will render fixed channels of SFP instrumentation unavailable. Installation of the SFP instrument channels shall be consistent with the 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, in part, that The current plan is to install SFP level sensors in the northeast and southeast areas of the Unit 2 SFP separated by a distance in excess of 20 feet and in the northwest and southwest areas of the Unit 3 SFP separated by a distance in excess of 20 feet. The sensors themselves will be mounted, to the extent practical, near the pool walls and below the pool curb to minimize their exposure to damaging debris and not interfere with SFP activities. Instrument channel electronics and power supplies will be located in seismic and missile protected areas either below the SFP operating floor or in buildings other than the [reactor building]. The areas to be selected will provide suitable radiation shielding and environmental conditions for the equipment consistent with instrument manufacturer's recommendations. Equipment and cabling for power supplies and indication for each channel will be separated equivalent to that provided for redundant safety related services.

-8 -By letter dated June 26, 2013, the NRC staff requested additional information regarding instrument channel arrangement (RAI-2). The NRC staff notes that the information regarding final sensor locations and cable routings for the SFP instrumentation has not been provided. In its letter dated July 18, 2013, the licensee indicated that the requested information was not yet available, but it will be provided with the February 2015 (Unit 2) and February 2016 (Unit 3), 6-month status reports. The staff has identified this request as: RAI #1 Please provide a clearly labeled sketch or marked-up plant drawing of the plan view of the SFP area, depicting the SFP inside dimensions, the planned locations/placement of the primary and back-up SFP level sensor, and the proposed routing of the cables that will extend from the sensors toward the location of the read-out/display device. (This information was previously requested as RA/-2 in the NRC Jetter dated June 26, 2013) 3.5 Design Features: Mounting Attachment 2 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, in part, that Design of the mounting of the sensors in the SFP shall be consistent with the seismic Class I criteria. Installed equipment will be verified to be seismically adequate for the seismic motions associated with the maximum seismic ground motion considered in the design of the plant area in which it is installed. By letter dated June 26, 2013, the NRC staff requested additional information regarding instrument channel mounting (RAI-3). In its letter dated July 18, 2013, the licensee indicated that the requested information was not yet available, but it will be provided with the February 2015 (Unit 2) and February 2016 (Unit 3), 6-month status reports. The staff has identified this request as:

-9-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 so as to support the level sensor assembly. (This information was previously requested as RA/-3 in the NRC Jetter dated June 26, 2013) In addition, the NRC staff plans to verify the results of the licensee's seismic testing and analysis when it is completed. The staff has identified these requests as: 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 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 was 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).

-10-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 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 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 the reliability of the instrumentation would be established through the use of an augmented quality assurance process (e.g., a process similar to that applied to the site fire protection program). 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 site resources can be deployed by the mitigating strategies resulting from Order EA-12-049 should be considered. Examples of post-event basis) conditions to be considered are:

• radiological conditions for a normal refueling quantity of freshly discharged (100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br />) fuel with the SFP water level 3 as described in this Order,

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

-11 -* boiling water and/or steam environment

• a concentrated borated water environment ... In its OIP, the licensee stated, consistent with NEI 12-02, in part, that Temperature, humidity and radiation levels consistent with the conditions in the vicinity of the SFP and the area of use considering normal operation, event and post-event conditions for no fewer than seven days post-event or until site resources can be deployed by the mitigating strategies resulting from Order EA-12-049 will be addressed in the detailed design engineering phase of the project. Examples of post-event (beyond-design-basis) conditions to be considered are:

• radiological conditions for a normal refueling quantity of freshly discharged (100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br />) fuel with the SFP water level3 as described in Order EA-12-051,

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

• boiling water and/or steam environment

• a concentrated borated water environment ... By letter dated June 26, 2013, the NRC staff requested additional information regarding instrument channel qualification (RAI-4 ). In its letter dated July 18, 2013, the licensee indicated that the requested information was not yet available, but it will be provided with the February 2015 (Unit 2) and February 2016 (Unit 3), 6-month status reports. The staff has identified this request 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.

-12-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 June 26, 2013) In addition, the NRC 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. The staff has identified this request as: 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 installed 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 Attachment 2 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 independent of the backup instrument channel and that independence will be achieved through physical and electrical separation of each channels' components commensurate with hazard and electrical isolation needs. By letter dated June 26, 2013, the NRC staff requested additional information regarding instrument channel independence (RAI-5). In its letter dated July 18, 2013, the licensee indicated that the requested information was not yet available, but it will be provided with the February 2015 (Unit 2) and February 2016 (Unit 3), 6-month status reports. The staff has identified this request as:

-13-RAI#7 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 on 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 RA/-5 in the NRC Jetter dated June 26, 2013) 3.8 Design Features: Power Supplies Attachment 2 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 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. 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 Order EA-12-049.

-14-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 Each channel will be normally powered from a different 120Vac [120 alternating current] bus. Upon loss of normal ac power, individual channel installed batteries will automatically maintain continuous channel operation. The batteries will be replaceable and be sized to maintain channel operation until site resources can be deployed by the mitigating strategies resulting from Order EA-12-049. Additionally, each channel will have provisions for connection to another suitable power source. By letter dated June 26, 2013, the NRC staff requested additional information regarding instrument channel power supplies (RAI-6). In its letter dated July 18, 2013, the licensee indicated that the requested information was not yet available, but it will be provided with the February 2015 (Unit 2) and February 2016 (Unit 3), 6-month status reports. Based on feedback from licensees, the staff has revised this RAI as follows: RAI#8 Please provide the following: a) A description of the electrical ac power sources and capabilities for the primary and backup channels. b) Please provide the results of the calculation depicting the battery backup duty cycle requirements demonstrating that its capacity is sufficient to maintain the level indication function until offsite resource availability is reasonably assured. 3.9 Design Features: Accuracy Attachment 2 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

-15-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, in part, that The instrument channels will be designed to maintain their design accuracy following a power interruption or change in power source without recalibration. Instrument channel accuracy, to be determined during detailed design, will consider Spent Fuel Pool conditions (e.g., saturated water, steam environment, concentrated borated water), as well as, other applicable radiological and environmental conditions and include display accuracy. Instrument channel 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 or 3) without conflicting or ambiguous indications. By letter dated June 26, 2013, the NRC staff requested additional information regarding instrument channel accuracy (RAI-7). In its letter dated July 18, 2013, the licensee indicated that the requested information was not yet available, but it will be provided with the February 2015 (Unit 2) and February 2016 (Unit 3), 6-month status reports. The staff has identified this request as: RAI#9 Please provide the following: a) An estimate of the expected instrument channel accuracy performance (e.g., in percent of span) under both (a) normal SFP level conditions (approximately Level1 or higher) and (b) at the BOB conditions (i.e., radiation, temperature, humidity, post-seismic and post-shock conditions) that would be present if the SFP level were at the Level 2 and Level 3 datum points. b) A description of the methodology that will be used for determining the maximum allowed deviation from the instrument channel design accuracy that will be employed under normal operating conditions as an acceptance criterion for a calibration procedure to flag to operators and to technicians that the channel requires adjustment to within the normal condition design accuracy. (This information was previously requested as RA/-7 in the NRC Jetter dated June 26, 2013) 3.10 Design Features: Testing Attachment 2 of Order EA-12-051 states, in part, that The instrument channel design shall provide for routine testing and calibration.

-16-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 the guidelines of NRC JLD-ISG-2012-03 and NEI 12-02. By letter dated June 26, 2013, the NRC staff requested additional information regarding instrument channel testing (RAI-8). In its letter dated July 18, 2013, the licensee indicated that the requested information was not yet available, but it will be provided with the August 2015 (Unit 2) and August 2016 (Unit 3), 6-month status reports. 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 how such testing and calibration will enable the conduct of regular channel checks of each independent channel against the other, and against any other permanently-installed SFP level instrumentation. c) A description of how functional checks will be performed, and the frequency at which they will be conducted. Describe how calibration tests will be performed, and the frequency at which they will be conducted. Provide a discussion as to how these surveillances will be incorporated into the plant surveillance program. d) A description of what preventive maintenance tasks are required to be performed during normal operation, and the planned maximum surveillance interval that is necessary to ensure that the channels are fully conditioned to accurately and reliably perform their functions when needed. (This information was previously requested as RAI-8 in the NRC Jetter dated June 26, 2013) 3.11 Design Features: Display Attachment 2 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

-17-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 the primary and backup instrument displays would be located at the control room, alternate shutdown panel, or other appropriate and accessible location. The specific location would be determined during detailed design. By letter dated June 26, 2013, the NRC staff requested additional information regarding instrument channel displays (RAI-9). In its letter dated July 18, 2013, the licensee indicated that the requested information was not yet available, but it will be provided with the February 2015 (Unit 2) and February 2016 (Unit 3), 6-month status reports. Based on feedback from licensees, the staff has revised this RAI as follows:

-18-RAI #11 Please provide the following: a} The specific location for each of the primary and backup instrument channel displays. b) If a display will be located somewhere other than the control room or alternate shutdown panel, please describe the evaluation used to validate that the display location can 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, please 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. 3.12 Programmatic Controls: Training Attachment 2 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 Personnel performing functions associated with these SFP level instrumentation channels will be trained to perform the job specific functions necessary for their assigned tasks (maintenance, calibration, surveillance, etc.). This training will be consistent with equipment vendor guidelines, instructions and recommendations. The Systematic Approach to Training (SAT) will be used to identify the population to be trained and to determine the initial and continuing elements of the required training. Training will be completed prior to placing the instrumentation in service.

-19-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 Attachment 2 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. By letter dated June 26, 2013, the NRC staff requested additional information regarding procedures for the instrumentation (RAI-1 0). In its letter dated July 18, 2013, the licensee indicated that the requested information was not yet available, but it will be provided with the August 2015 (Unit 2) and August 2016 (Unit 3), 6-month status reports. Based on feedback from licensees, the staff has revised this RAI as follows: RAI #12 Please provide a list of the procedures addressing operation {both normal and abnormal response}, calibration, test, maintenance, and inspection procedures that will be developed for use of the spent SFP instrumentation. Please provide a brief description of the specific technical objectives to be achieved within each procedure. 3.14 Programmatic Controls: Testing and Calibration Attachment 2 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

-20-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 would be consistent with vendor recommendations or other documented basis. The licensee also stated that calibration would be specific to the mounted instruments and the displays. By letter dated June 26, 2013, the NRC staff requested additional information regarding instrument channel testing and calibration {RAI-11 ). In its letter dated July 18, 2013, the licensee indicated that the requested information was not yet available, but it will be provided with the August 2015 (Unit 2) and August 2016 (Unit 3), 6-month status reports. The staff has identified this request as: RAI #13 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 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 NEI12-02, Section 4.3 regarding compensatory actions for one or both non-functioning channels will be addressed. c) A description of what compensatory actions are planned in the event that one of the instrument channels cannot be restored to functional status within 90 days. (This information was previously requested as RAI-11 in the NRC letter dated June 26, 2013) 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.

-21 -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 staff will issue an evaluation with its conclusion after the licensee has provided the requested information.

M. Pacilio -2 -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 April 30, 2015, 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 301-415-1380 or via e-mail at Blake.Purnell@nrc.gov. Docket Nos. 50-237 and 50-249 Enclosure: Interim Staff Evaluation and Request for Additional Information cc wlencl: Distribution via Listserv DISTRIBUTION: PUBLIC LPL3-2 Reading RidsAcrsAcnw_MaiiCTR Resource RidsNrrDeEicb Resource RidsNrrDorllpl3-2 Resource RidsNrrDssSbpb Resource RidsNrrLASRohrer Resource RidsNrrPMDresden Resource ADAMS Accession No ML13275A111 OFFICE NRR/DORLILPL3-2/PM NAME BPurnell DATE 10/2/13 OFFICE NRR/DE/EICB/BC NAME JThorp* DATE 10/1/13 OFFICE NRR/DORL/LPL3-2/BC NAME TTate DATE 10/25/13 Sincerely, IRA I Blake Purnell, Project Manager Plant Licensing Branch 111-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation RidsRgn3MaiiCenter Resource CRoque-Cruz, NRR DRahn, NRR GCasto, NRR MMitchell, NRR RKuntz, NRR BPurnell, NRR CHunt, NRR *via memo NRR/DORLILPL3-2/LA NRR/DSS/SBPB/BC SRohrer GCasto* 10/2/13 10/1/13 OGC BKiuklan 10/21/13 NRR/DORL/LPL3-2/PM BPurnell 10/29/13 OFFICIAL RECORD COPY