RS-14-200, Third Six-Month Status Report in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Reliable Spent Fuel Pool Instrumentation (Order Number EA-12-051)

Third Six-Month Status Report in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Reliable Spent Fuel Pool Instrumentation (Order Number EA-12-051)

ML14241A291
Person / Time
Site:	Limerick
Issue date:	08/28/2014
From:	Jim Barstow Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
EA-12-051, RS-14-200
Download: ML14241A291 (32)

Text

Exelon Generation Order No. EA-12-051 RS-14-200 August 28, 2014 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Limerick Generating Station, Units 1 and 2 Facility Operating License Nos. NPF-39 and NPF-85 NRC Docket Nos. 50-352 and 50-353

Subject:

Third Six-Month Status Report in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Reliable Spent Fuel Pool Instrumentation (Order Number EA-12-051)

References:

1. NRC Order Number EA-12-051," Issuance of Order to Modify Licenses with Regard to Reliable Spent Fuel Pool Instrumentation," dated March 12, 2012

2. NRC Interim Staff Guidance JLD-ISG-2012-03, "Compliance with Order EA-12-051, Order Modifying Licenses with Regard to Reliable Spent Fuel Pool Instrumentation,"

Revision 0, dated August 29, 2012

3. NEI 12-02, Industry Guidance for Compliance with NRC Order EA-12-051, "To Modify Licenses with Regard to Reliable Spent Fuel Pool Instrumentation," Revision 1, dated August 2012

4. Exelon Generation Company, LLC's Initial Status Report in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Requirements for Reliable Spent Fuel Pool Instrumentation (Order Number EA-12-051), dated October 25, 2012

5. Exelon Generation Company, LLC Overall Integrated Plan in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Reliable Spent Fuel Pool Instrumentation (Order Number EA-12-051 ), dated February 28, 2013 (RS-13-032)

6. Exelon Generation Company, LLC First Six-Month Status Report in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Reliable Spent Fuel Pool Instrumentation (Order Number EA-12-051 ), dated August 28, 2013 (RS-13-122)

7. Exelon Generation Company, LLC Second Six-Month Status Report in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Reliable Spent Fuel Pool Instrumentation (Order Number EA-12-051), dated February 28, 2014 (RS 022)

8. NRC letter to Exelon Generation Company, LLC, Limerick Generating Station, Units 1 and 2 - Interim Staff Evaluation and Request for Additional Information Regarding the Overall Integrated Plan for Implementation of Order EA-1 2-051, Reliable Spent Fuel Pool Instrumentation (TAC Nos. MF0854 and MF0855), dated October 23, 2013

U.S. Nuclear Regulatory Commission Integrated Plan Report to EA-12-051 August 28, 2014 Page2 On March 12, 2012, the Nuclear Regulatory Commission ("NRG" or "Commission") issued an order (Reference 1) to Exelon Generation Company, LLC (EGG). Reference 1 was immediately effective and directs EGG to install reliable spent fuel pool level instrumentation. Specific requirements are outlined in Attachment 2 of Reference 1.

Reference 1 required submission of an initial status report 60 days following issuance of the final interim staff guidance (Reference 2) and an overall integrated plan pursuant to Section IV, Condition C. Reference 2 endorses industry guidance document NEI 12-02, Revision 1 (Reference 3) with clarifications and exceptions identified in Reference 2. Reference 4 provided the EGG initial status report regarding reliable spent fuel pool instrumentation. Reference 5 provided the Limerick Generating Station, Units 1 and 2 overall integrated plan.

Reference 1 requires submission of a status report at six-month intervals following submittal of the overall integrated plan. Reference 3 provides direction regarding the content of the status reports. References 6 and 7 provided the first and second six-month status reports, respectively, pursuant to Section IV, Condition C.2, of Reference 1 for Limerick Generating Station. The purpose of this letter is to provide the third six-month status report pursuant to Section IV, Condition C.2, of Reference 1, that delineates progress made in implementing the requirements of Reference 1. The enclosed report provides an update of milestone accomplishments since the last status report, including any changes to the compliance method, schedule, or need for relief and the basis, if any. The enclosed report also addresses the NRG Interim Staff Evaluation Request for Additional Information Items contained in Reference 8.

This letter contains no new regulatory commitments. If you have any questions regarding this report, please contact David P. Helker at 610-765-5525.

I declare under penalty of perjury that the foregoing is true and correct. Executed on the 281h day of August 2014.

Respectfully submitted, ct~~

James Barstow Director - Licensing & Regulatory Affairs Exelon Generation Company, LLC

Enclosure:

1. Limerick Generating Station, Units 1 and 2 Third Six-Month Status Report for the Implementation of Order EA-12-051, Order Modifying Licenses with Regard to Reliable Spent Fuel Pool Instrumentation

U.S. Nuclear Regulatory Commission Integrated Plan Report to EA-12-051 August 28, 2014 Page3 cc: Director, Office of Nuclear Reactor Regulation NRG Regional Administrator - Region I NRG Senior Resident Inspector - Limerick Generating Station, Units 1 and 2 NRG Project Manager, NRR - Limerick Generating Station, Units 1 and 2 Ms. Jessica A. Kratchman, NRR/JLD/PMB, NRG Mr. Stephen R. Monarque, NRR/JLD/JPMB, NRG Mr. Robert L. Dennig, NRR/DSS/SCVB, NRG Mr. Richard B. Ennis, NRR/DORULPL3-2, NRG Director, Bureau of Radiation Protection - Pennsylvania Department of Environmental Resources R. R. Janati, Chief, Division of Nuclear Safety, Pennsylvania Department of Environmental Protection, Bureau of Radiation Protection

U.S. Nuclear Regulatory Commission Integrated Plan Report to EA-12-051 August 28, 2014 Page4 bee: Site Vice President - Limerick Generating Station, Units 1 and 2 Vice President Operations Support Plant Manager, Limerick Generating Station, Units 1 and 2 Site Engineering Director - Limerick Generating Station, Units 1 and 2 Regulatory Affairs Manager Regulatory Assurance Manager - Limerick Generating Station, Units 1 and 2 Severe Accident Management Director Site Operations Director - Limerick Generating Station, Units 1 and 2 Corporate Licensing Manager - East Corporate Licensing Director - East Exelon Records Management PA DEP BRP Inspector - LGS Vinod Aggarwal Sailaja Mokkapati Abiola Olayiwola Craig Nichols

Enclosure Limerick Generating Station, Units 1 and 2 Third Six-Month Status Report for the Implementation of Order EA-12-051, Order Modifying Licenses with Regard to Reliable Spent Fuel Pool Instrumentation (27 pages)

Limerick Generating Station, Units 1 and 2 Third Six-Month Status Report for the Implementation of Order EA-12-051, Order Modifying Licenses with Regard to Reliable Spent Fuel Pool Instrumentation 1 Introduction Limerick Generating Station, Units 1 and 2, developed an Overall Integrated Plan (Reference 1 in Section 8), documenting the requirements to install Reliable Spent Fuel Pool Level Instrumentation (SFPLI), in response to Reference 2. This enclosure provides an update of milestone accomplishments since submittal of the second six month status report including any changes to the compliance method, schedule, or need for relief/relaxation and the basis, if any.

2 Milestone Accomplishments The following milestones have been completed since the submittal of the Second Six Month Status Report, (Ref. 7) and are current as of August 28, 2014.

• Provided responses to all RAis via ePortal on 06/30/14

• SFPI Modification Package is at 50% completion 3 Milestone Schedule Status The following provides an update to the milestone schedule to support the Overall Integrated Plan. This section provides the activity status of each item, and the expected completion date noting any change.

The dates are planning dates subject to change as design and implementation details are developed.

The revised milestone target completion dates do not impact the order implementation date.

Revised Target Target Completion Milestone Activity Status Completion Date Date Submit 60 Day Status Report October 25, 2012 Complete Submit Overall Integrated Plan February 28, 2013 Complete Submit Responses to RAis July 18, 2013 Complete Submit 6 Month Updates:

Update 1 August 28, 2013 Complete Update 2 February 28, 2014 Complete Complete with Update 3 August 28, 2014 this submittal Provide Final Safety Evaluation September 30, 2014 Complete (SE) Information Page 1of27

Limerick Generating Station, Units 1 and 2 Third Six-Month Status Report for the Implementation of SFPLI August28,2014 Revised Target Target Completion Milestone Activity Status Completion Date Date Update 4 February 28, 2015 Not Started Modifications:

Conceptual Design 3Q2012 Complete Issue Exelon Fleet contract to 1Q2015 Complete procure SFPI Equipment Begin Detailed Engineering Design 3Q2013 Complete Complete and Issue SFPI 3Q2014 Started Modification Package Begin Installation 1Q2015 Not Started Complete SFPI Installation and Put 1Q2015 Not Started Into Service 4 Changes to Compliance Method There are no changes to the compliance method as documented in the Overall Integrated Plan (Reference 1).

5 Need for Relief/Relaxation and Basis for the Relief/Relaxation Limerick Generating Station, Units 1 and 2 expects to comply with the order implementation date and no relief/relaxation is required at this time.

6 Open Items from Overall Integrated Plan and Interim Staff Evaluation The following tables provide a summary of the open items documented in the Overall Integrated Plan (OIP) or the Interim Staff Evaluation (ISE) and the status of each item.

Overall Integrated Plan Open Items OIP# Description Status 1 Open Item: Complete Continuous level indication will be (Addressed in Reference 6) provided by a guided wave radar system, submersible pressure transducer, or other appropriate level sensing technology that will be determined durine the detailed Page 2of27

Limerick Generating Station, Units 1 and 2 Third Six-Month Status Report for the Implementation of SFPLI August28,2014 engineering phase of the project.

2 RAI Question: Complete

.(RAI-1, Please provide the following: (Addressed in Reference 4)

Ref. 3) a) For level 1, specify how the identified location represents the HIGHER of the two points described in the NEI 12-02 guidance for this level.

b) A clearly labeled sketch depicting the elevation view of the proposed typical mounting arrangement for the portions of instrument channel consisting of permanent measurement channel equipment (e.g., fixed level sensors and/or stilling wells, and mounting brackets). Indicate on this sketch the datum values representing Level 1 , Level 2, and Level 3, as well as the top of the fuel racks.

Indicate on this sketch the portion of the level sensor measurement range that is sensitive to measurement of the fuel pool level, with respect to the Level 1 , Level 2, and Level 3 datum points.

Indicate on this sketch the elevation of the bottom opening of the gates that connect the two pools.

3 RAI Question: Com12lete with this submittal (RAl-2, Please provide a clearly labeled The marked-up sketch is provided in Attachment 1.

Ref.3) sketch or marked-up plant drawing of the plan view of the SFP area, depicting the SFP inside dimensions, the planned locations/placement of the primary and backup SFP level sensor, and the proposed routing of the cables that will extend from the sensors toward the location of the read-out/display device.

4 RAI Question: Com12lete with this submittal (RAl-3, Please provide the following: a) All SFPIS equipment will be designed in Ref.3) a) The design criteria that will be accordance with the Limerick Generating Station used to estimate the total loading (LGS) Safe Shutdown Earthquake (SSE) design on the mounting device(s),

requirements.

including static weight loads and dynamic loads. Describe the methodoloav that will be used to The vendor, Westinghouse, has evaluated the Page 3of27

Limerick Generating Station, Units 1 and 2 Third Six-Month Status Report for the Implementation of SFPLI August28,2014 estimate the total loading, inclusive structural integrity of the mounting brackets in of design basis maximum seismic calculation CN-PEUS-14-10. The GTSTRUDL loads and the hydrodynamic loads model, used by Westinghouse to calculate the that could result from pool stresses in the bracket assembly, considers load sloshing or other effects that could combinations for the dead load, live load and accompany such seismic forces.

b) A description of the manner in seismic load on the bracket. The reactionary forces which the level sensor (and stilling calculated from these loads become the design well, if appropriate) will be inputs to design the mounting bracket anchorage to attached to the refueling floor the refuel floor to withstand a Safe Shutdown and/or other support structures Earthquake (SSE).

for each planned point of attachment of the probe assembly. Seismic Indicate in a schematic the portions of the level sensor that The seismic loads are obtained from LGS response will serve as points of attachment for mechanical/mounting or spectra curves (Specification-8031-G-19) for LGS.

electrical connections. The following methodology was used in c) A description of the manner by determining the stresses on the bracket assembly:

which the mechanical connections will attach the level instrument to

• Frequency analysis, taking into account the dead permanent SFP structures so as to weight and the hydrodynamic mass of the structure, support the level sensor assembly. is performed to obtain the natural frequencies of the structure in all three directions.

• SSE (Safe Shutdown Earthquake) response spectra analysis is performed to obtain member stresses and support reactions.

• Modal responses are combined using the Ten Percent Method per U.S. NRC Regulatory Guide 1.92, Revision 1, "Combining Modal Responses and Spatial Components in Seismic Response Analysis.

• The seismic loads for each of the three directions are combined by the Square Root of the Sum of Squares (SRSS) Method. This method is endorsed per Specification-8031-G- l 9 for LGS.

• Sloshing analysis is performed to obtain liquid pressure and its impact on bracket design.

• The seismic results are combined with the dead load results and the hydrodynamic pressure results in absolute sum. These combined results are compared with the allowable stress values.

Sloshing Sloshing forces were obtained by analysis. The TID-7024, Nuclear Reactors and Earthquakes, 1963, by the US Atomic Energy Commission, approach has been used to estimate the wave height and natural frequency. Horizontal and vertical impact Page 4 of 27

Limerick Generating Station, Units 1 and 2 Third Six-Month Status Report for the Implementation of SFPLI August28,2014 force on the bracket components was calculated using the wave height and natural frequency obtained using TID-7024 approach. Using this methodology, sloshing forces have been calculated and added to the total reactionary forces that would be applicable for bracket anchorage design. The analysis also determined that the level probe can withstand a credible design basis seismic event.

The load impact due to the rising water and submergence of the bracket components has also been considered for the overall sloshing impact.

Reliable operation of the level measurement sensor with a submerged interconnecting cable has been demonstrated by analysis of previous Westinghouse testing of the cable, and the vendor's cable qualification.

The following Westinghouse documents provide information with respect to the design criteria used, and a description of the methodology used to estimate the total loading on the device.

a. CN-PEUS-14 Seismic Analysis of the SFP Mounting Bracket for Limerick Generating Station Units 1 & 2

b. LTR-SEE-II-13-47, WNA-TR-03149-GEN -

Sloshing Analysis

c. EQ-QR-269, WNA-TR-03149-GEN, EQ-TP-353

- Seismic Qualification of Other Components of SFPI b) The level sensor, which is one long probe, will be suspended from the launch plate via coupler/connector assembly. The launch plate is a subcomponent of the bracket assembly, which is mounted to the refuel floor via anchors. Attachment 1 shows a schematic of the level sensor with mechanical attachment points.

c) The bracket assembly that supports the sensor probe and launch plate will be mechanically connected to the SFP structure. The mechanical connection consists of concrete expansion anchors that will bolt the bracket assembly to the SFP structure via the base plate. The concrete expansion anchors will be designed to withstand SSE and will meet the LOS safety related installation requirements. The qualification details of the bracket are provided in Westinghouse's Pool-Side Bracket Page 5 of 27

Limerick Generating Station, Units 1 and 2 Third Six-Month Status Report tor the Implementation of SFPLI August28,2014 Seismic Analysis CN-PEUS-14-10 and the qualification of the anchorage to the floor will be provided in LGS specific calculation.

5 RAI Question: Com12lete with this submittal (RAI-4, Please provide the following: a) Beyond Design Basis Environment -

Ref.3) a) A description of the specific Westinghouse qualified the components (probe, method or combination of methods connector, cable) of the SFPIS located in the SFP that will be applied to demonstrate the reliability of the permanently area to the beyond design basis environment.

installed equipment under BDB Components of the system were subjected to beyond ambient temperature, humidity, design basis conditions of heat and humidity, shock, vibration, and radiation thermal and radiation aging mechanisms. This conditions. testing confirmed functionality of these system b) A description of the testing components under these beyond design basis and/or analyses that will be conducted to provide assurance that environmental conditions. Westinghouse performed the equipment will perform reliably testing to ensure aging of the components in the SFP under the worst-case credible design area will not have a significant effect on the ability basis loading at the location where of the equipment to perform following a plant the equipment will be mounted. design basis earthquake. Exelon has reviewed the Include a discussion of this seismic documents and found acceptable. Reference reliability demonstration as it Westinghouse documents EQ-TP-351, WNA-TR-applies to a) the level sensor mounted in t.he SFP area, 03149-GEN, and EQ-TP-354 for description of and b) any control boxes, specific qualification methods.

electronics, or read-out and re- Mild Environment- Westinghouse qualified the transmitting devices that will be system components (display panel, sensor) that employed to convey the level reside in the mild environment conditions to information from the level sensor to determine that the components can satisfactorily the plant operators or emergency responders. perform to those conditions. Westinghouse has c) A description of the specific determined that aging does not have a significant method or combination of methods effect on the ability of the equipment to perform that will be used to confirm the following a plant design basis earthquake. Exelon reliability of the permanently has reviewed the documents and found acceptable.

installed equipment such Reference Westinghouse documents EQ-QR-269, that following a seismic event the instrument will maintain its WNA-TR-03149-GEN for description of specific required accuracy. methods.

Shock and Vibration - SFPIS pool side brackets were analyzed for Safe Shutdown Earthquake design requirements per NRC order EA-12-051 and NEI 12-02 guidance. As provided by the NRC Order EA-12-051, the NEI 12-02 guidance and as clarified by the NRC interim staff guidance, the probe, coaxial cable, and the mounting brackets are "inherently resistant to shock and vibration loadings." As a result, no additional shock and vibration testing is required for these components.

Page 6of27

Limerick Generating Station, Units 1 and 2 Third Six-Month Status Report for the Implementation of SFPLI August28,2014 SFPIS pool side brackets for both the primary and backup Westinghouse SFP measurement channels will be permanently installed and fixed to rigid refuel floors, which are Seismic Category 1 structures. The SFPI system components, such as level sensor and its bracket, display enclosure and its bracket, were subjected to seismic testing, including shock and vibration test requirements. The results for shock and vibration tests were consistent with the anticipated shock and vibration expected to be seen by mounted equipment. The level sensor electronics are enclosed in a NEMA-4X housing.

The display electronics panel utilizes a NEMA-4X rated stainless steel housing as well. These housings will be mounted to a seismically qualified wall and will contain the active electronics, and aid in protecting the internal components from vibration induced damage.

Reference Westinghouse reports WNA-DS-02957, WNA-TR-03149-GEN for shock and vibration.

b) The seismic adequacy of the SFPIS (all components) is demonstrated by vendor testing and analysis in accordance with below listed standards:

• IEEE 344-2004, IEEE Recommended Practice for Seismic Qualification of Class IE Electrical Equipment for Nuclear Power Generating Stations

• IEEE-323-1974, Standard for Qualifying Class IE Equipment for Nuclear Power Generating Stations

• USNRC Regulatory Guide 1.100, Rev. 3

• USNRC Regulatory Guide 1.92, Rev. 1 c) Westinghouse has seismically qualified the SFPI instrument and its components. CN-PEUS-14-10 describes Pool-Side Bracket Seismic Analysis, EQ-QR-269, WNA-TR-03149-GEN, EQ-TP-353 describe remaining seismic qualifications of the instrument components. With the instrument being seismically qualified and installed as described in RAI 4b, the instrument is assured to maintain reliable and accurate indication when required.

Westinghouse report WNA-CN-00301-GEN and LGS Engineering Change 13-00414 will provide the channel accuracy from measurement to display.

6 RAI Question: Com12lete with this submittal Page 7of27

Limerick Generating Station, Units 1 and 2 Third Six-Month Status Report for the Implementation of SFPLI August28,2014 (RAI-5, Please provide the following: The two channels of the proposed level Ref.3) a) A description of how the two measurement system will be installed such that:

channels of the proposed level a) The level probes will be mounted on the east and measurement system meet this requirement so that the potential for west walls of the SFP and will be separated by a a common cause event to adversely distance greater than the span of the shortest side of affect both channels is minimized to the pool. This meets the NEI 12-02 revision 1 the extent practicable. guidance for channel separation.

b) Further information on how each b) The level sensor enclosure and the electronics/

level measurement system, UPS enclosure for the both the primary and back up consisting of level sensor electronics, cabling, and readout devices will be instrument channel will be installed in the Auxiliary designed and installed to address Equiment Room (AER). Independence, physical and independence through the spatial separation of the level sensors and application and selection of electronics/UPS enclosures for primary and backup independent power sources, the use instrument channels is maintained by routing the of physical and spatial separation, associated instrument channel cables separately.

independence of signals sent to the The 120 VAC power to the primary instrument will location(s) of the readout devices, and the independence of the be provided from a Unit 1 10Y161 distribution panel displays. and the backup instrument in the Unit 2 pool will be powered from 2L29 lighting panel.

The 120VAC distribution panels for the primary and backup instruments are powered by different 480V buses. Therefore the loss of any one bus will not result in the loss of ac power to both instrument channels. Attachment 1 (page 2 of 2) demonstrates the physical separation between the primary and backup power sources.

The primary and backup channel indicators will be located on the wall of the AER. These level indicators will be credited as the level indications used by operators to satisfy the NRC Order EA 051 requirements. Providing the 120VAC power to primary and backup instrument channels from separate power sources will address the concerns regarding power supply independence.

All power and instrument cables associated with both the primary and backup channels will be routed in different conduits in the AER.

7 RAI Question: Com12Iete with this submittal (RAI-6, Please provide the following: a) The primary and backup SFPLI instrument Ref.3) a) A description of the electrical ac channels will be normally powered from power sources and capabilities for 120 VAC 10Y161 distribution panel and the primary and backup channels.

b) Please provide the results of the 2L29 lighting distribution panel calculation depictin2 the battery respectively. These are on different buses, Page 8 of 27

Limerick Generating Station, Units 1 and 2 Third Six-Month Status Report for the Implementation of SFPLI August28,2014 backup duty cycle requirements which maintain power source independence.

demonstrating that its capacity is Upon loss of normal AC power, individual sufficient to maintain the level batteries installed in each channel's indication function until offsite resource availability is reasonably electronics/ UPS enclosure will assured. automatically maintain continuous channel operation for at least three (3) days. The power cables will be routed separately for both the primary and backup channels so that spatial and physical separation is maintained. Additionally, a receptacle and a selector switch are installed in each channel electronics/ UPS enclosure to directly connect emergency FLEX power to the SFPLI.

b) The Westinghouse Report, WNA-CN-00300-GEN, provides the results of the calculation depicting the battery backup duty cycle. This calculation demonstrates that battery capacity is 4.22 days to maintain the level indicating function to the display location, located in the AER at LGS. The calculation also determines that the battery will last greater than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. Therefore, the LGS readout display of level indication in the AER will be available for greater than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> of operation. The results of the calculation meet the NEI 12-02 requirements.

8 RAI Question: Com12lete with this submittal (RAI-7, Please provide the following: a) The Westinghouse documents WNA-CN-00301 Ref.3) a) An estimate of the expected and WNA-DS-02957-GEN describe the channel instrument channel accuracy accuracy under both (a) normal SFP level conditions performance under both (a) and (b) at the Beyond Design Basis (BDB) normal SFP level conditions conditions that would be present if SFP level were at (approximately Level 1 or higher) and (b) at the BDB conditions (i.e., Level 2 and Level 3 datum points. Each instrument radiation, temperature, humidity, channel will be accurate to within +/-3" during post-seismic and post-shock normal spent fuel pool level conditions. The conditions) that would be present instrument channels will retain this accuracy after if the SFP level were at the Level 2 BDB conditions, in accordance with the above and Level 3 datum points. Westinghouse documents. The same channel b) A description of the accuracy requirements are applicable to both the methodology that will be used for primary and backup readout display in the in the determining the maximum allowed AER. This value is within the channel accuracy Page 9of27

Limerick Generating Station, Units 1 and 2 Third Six-Month Status Report for the Implementation of SFPLI August 28, 2014 deviation from the instrument requirements of the Order (+/-1 foot).

channel design accuracy that will b) The Westinghouse document WNA-TP-04709-be employed under normal GEN describes the methodology for routine operating conditions as an testing/calibration verification and calibration acceptance criterion for a methodology. This document also specifies the calibration procedure to flag to operators and to technicians that required accuracy criteria under normal operating the channel requires adjustment to conditions. LGS calibration and channel within the normal condition design verification procedures will follow the guidance and accuracy. criteria provided in this document.

Instrument channel calibration will be performed if the level indication reflects a value that is outside the acceptance band established in the LGS calibration and channel verification procedures.

Calibration will be performed once per refueling cycle for LGS. Per Westinghouse document WNA-TP-04709-GEN calibration on a SFP level channel is to be completed within 60 days of a planned refueling outage considering normal testing scheduling allowances (e.g. 25%). This is in compliance with the NEI 12-02 guidance for Spent Fuel Pool Instrumentation.

9 RAI Question: Started (RAl-8, Please provide the following: a) Westinghouse calibration procedure WNA-TP-Ref.3) a) A description of the capability 04709-GEN and functional test procedure WNA-and provisions the proposed level TP-04613-GEN describe the capabilities and sensing equipment will have to provisions of SFPI periodic testing and calibration, enable periodic testing and including in-situ testing.

calibration, including how this capability enables the equipment b) The level displayed by the channels will be to be tested in-situ. verified per the LGS administrative and operating b) A description of how such procedures, as recommended by Westinghouse testing and calibration will enable vendor technical manual WNA-G0-00127-GEN. If the conduct of regular channel the level is not within the required accuracy per checks of each independent Westinghouse recommended tolerance in WNA-TP-channel against the other, and 04709-GEN, channel calibration will be performed.

against any other permanently- c) Functional checks will be performed per installed SFP level Westinghouse functionality test procedure WNA-instrumentation.

c) A description of how functional TP-04613-GEN at the Westinghouse recommended checks will be performed, and the frequency. Calibration tests will be performed per frequency at which they will be Westinghouse calibration procedure WNA-TP-conducted. Describe how 04709-GEN at the Westinghouse recommended calibration tests will be performed, frequency.

and the frequency at which they In accordance with LGS maintenance and operating will be conducted. Provide a programs, LGS will develop calibration, functional discussion as to how these test, channel verification procedures per surveillances will be incorporated Westinghouse recommendations to ensure reliable, Page 10of27

Limerick Generating Station, Units 1 and 2 Third Six-Month Status Report for the Implementation of SFPLI August 28, 2014 into the plant surveillance accurate and continuous SFPI functionality by program. February 15, 2015.

d) A description of what preventive maintenance tasks are d) LGS will develop preventive maintenance tasks required to be performed during for the SFPI per Westinghouse recommendation normal operation, and the planned identified in the technical manual WNA-G0-00127-maximum surveillance interval GEN to assure that the channels are fully that is necessary to ensure that the conditioned to accurately and reliably perform their channels are fully conditioned to functions when needed by February 15, 2015.

accurately and reliably perform their functions when needed.

10 RAI Question: Com11lete with this submittal (RAI-9, Please provide the following: a) LGS primary and backup instrument Ref.3) a) The specific location for the channel displays are located in AER.

primary and backup instrument channel display. b) LGS's primary and backup instrument b) If the primary or backup display channel displays are located outside of the location is other than the main control room, then provide control room and alternate shutdown panel.

justification for prompt accessibility As described above, they are located in the to displays including primary and AER. This location was selected due to the alternate route evaluation, display location proximity to the main habitability at display location(s), control room.

continual resource availability for personnel responsible to promptly read displays, and provisions for Radiological habitability at the display communications with decision location in the AER (plant generator control makers for the various SFP drain- center) has been evaluated against drawings down scenarios and external events. M-171 (Specification for Environmental c) The reasons justifying why the Service Conditions Limerick Generating locations selected enable the Station) for core melt scenario estimated information from these instruments radiological conditions as well as estimated to be considered "promptly accessible" to various drain-down dose rates from SFP draindown conditions scenarios and external events. to Level 3 (calculation BYRB-0187, this is Exelon generic calculation and LGS is bounded by this calculation), and exposure to personnel monitoring SFP levels would remain less than emergency exposure limits allowable for emergency responders to perform this action, per the LGS M-171.

Heat and humidity from SFP boildown conditions have been evaluated for this location, and the location is at an elevation below the SFP operating floor and physically separated by building and closed fire doors from the SFP such that heat and humidity from a boiling SFP would not Page 11of27

Limerick Generating Station, Units 1 and 2 Third Six-Month Status Report for the Implementation of SFPLI August 28, 2014 compromise habitability at this location.

Both primary and backup instrument channel displays are located in seismic category I structures such that they are inherently protected for missile hazards.

c) Spent fuel pool level control and level display monitoring will be the responsibility of the Equipment Operators to collect data as required and report to the Control Room decision makers. Travel time from the Control Room to the primary display is approximately 6 minutes based on walkdowns . Radiological habitability for the transit routes to both displays has been evaluated with drawing M-171 (Specification for Environmental Service Conditions Limerick Generating Station) for core melt scenario conditions as well as estimated dose rates from SFP draindown conditions to Level 3, (calculation BYR13-0187) and exposure to personnel monitoring SFP levels would remain less than emergency exposure limits allowable for emergency responders to perform this action, per the LGS M-171 document. Heat and humidity from SFP boildown conditions have been evaluated for access to this

-location, and the access routes are below the SFP operating floor and physically

. separated by closed fire doors from the SFP such that heat and humidity from a boiling SFP would not compromise habitability concerns with accessing these displays. The access routes to the display locations are within seismic category I structures.

Radio communications will be available in areas near the display locations.

11 RAI Question:

Complete with this submittal (RAI-10, Please provide the following:

Ref.3) a) A list of the operating (both Replaced by Interim SE RAI#l5 normal and abnormal response) procedures, calibration/test procedures, maintenance Page 12of27

Limerick Generating Station, Units 1 and 2 Third Six-Month Status Report for the Implementation of SFPLI August28,2014 procedures, and inspection procedures that will be developed for use of the SFP instrumentation in a manner that addresses the order requirements.

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

12 RAI Question: Com12lete with this submittal (RAI-11, Please provide the following: Response for a:

Ref.3) a) Further information describing Performance tests (functional checks) and Operator the maintenance and testing performance checks will be described in detail in the program the licensee will establish vendor operator's manual, and the applicable and implement to ensure that information is planned to be contained in plant regular testing and calibration is performed and verified by operating procedures.

inspection and audit to Operator performance tests are planned to be demonstrate conformance with performed periodically as recommended by the design and system readiness equipment vendor.

requirements. Please include Channel functional tests per operations procedures a description of your plans for with limits established in consideration of vendor ensuring that necessary channel equipment specifications are planned to be checks, functional tests, periodic performed at appropriate frequencies.

calibration, and maintenance will Manual calibration and operator performance checks be conducted for the level measurement system and its are planned to be performed in a periodic scheduled supporting equipment. fashion with additional maintenance on an as-b) A description of how the needed basis when flagged by the system's guidance in NEI12-02 section 4.3 automated diagnostic testing features .

regarding compensatory actions Channel calibration tests per maintenance for one or both non-functioning procedures with limits established in consideration channels will be addressed. of vendor equipment specifications are planned to be c) A description of what performed at frequencies established in compensatory actions are planned consideration of vendor recommendations.

in the event that one of the SFPI channel/equipment maintenance/preventative instrument channels cannot be restored to functional status within maintenance and testing program requirements to 90 days. ensure design and system readiness are planned to be established in accordance with Exelon's processes and procedures and in consideration of vendor recommendations to ensure that aooropriate regular Page 13of27

Limerick Generating Station, Units 1 and 2 Third Six-Month Status Report for the Implementation of SFPLI August 28, 2014 I I Required I Compensatory Action if I testing, channel checks, functional tests, periodic calibration, and maintenance is performed (and available for inspection and audit). Subject maintenance and testing program requirements are planned to be developed during the SFPI modification design process.

Response for b, c:

Both primary and backup SFPI channels incorporate permanent installation (with no reliance on portable, post-event installation) of relatively simple and robust augmented quality equipment. Permanent installation coupled with stocking of adequate spare parts reasonably diminishes the likelihood that a single channel (and greatly diminishes the likelihood that both channels) is (are) out-of-service for an extended period of time. Planned compensatory actions for unlikely extended out-of-service events are summarized as follows:

Page 14 of 27

Limerick Generating Station, Units 1 and 2 Third Six-Month Status Report for the Implementation of SFPLI August28,2014 Channel(s) Restoration Required Restoration Out-of- Action Action not completed Service within Specified Time 1 Restore Channel Immediately initiate to functional action in accordance with status within 90 note below days (or if channel restoration not expected within 90 days, then proceed to Compensatory Action 2 Initiate action Immediately initiate within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to action in accordance with restore one note below channel to functional status and restore one channel to functional status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

Note below Note: Present a report to the on-site Plant Operations Review Committee (PORC) within the following 14 days. The report shall outline the planned alternate method of monitoring, the cause of the non-functionality, and the plans and schedule for restoring the instrumentation channel(s) to functional status.

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Limerick Generating Station, Units 1 and 2 Third Six-Month Status Report tor the Implementation of SFPLI August28,2014 Interim Staff Evaluation Open Items 01# Description Status 1 RAI Question: Started (revised)

(RAI- Please provide the following: a) Complete redundant monitoring of the pools will 1, a) A description of the operational not be available when the gates are installed. The Ref. circumstances under which the gates gates are not normally installed. There is an are expected to be installed, and

5) describe how continuous back-up existing procedure M-097-009 (Cask Pit Gate monitoring (e.g., direct visual Removal, Installation, Maintenance and Movement observation) is available when the of Fuel Pool Gates Between Storage/ Repair gates are installed. Locations) to remove and install the gates. To b) The elevation for the bottom of the address the concern when the gates may be gate opening to demonstrate that both installed, the procedure M-097-009 will be revised the primary and backup SFP instrument channels can to establish administrative guidance/controls to simultaneously measure the same follow the NEI 12-02 Rev. 1 guidance for the 90 Level 3 elevation. day out of service criterion. Limerick Generating Station (LGS) will complete the procedure revision by Febmary 2015.

b) The elevation for the bottom of the transfer pit for LGS is 327'-8.75". Level 3 for LGS is revised to elevation 327' -11.32", which is slightly above the bottom of the transfer pit, rather than, the top of the Fuel rack elevation 327 .5ft. This will provide assurance that both the primary and backup SFP level instrument channels can measure the same Level 3 elevation in both SFPs.

2 RAI Question: Complete (RAI- Please describe the impact of the (Addressed in Reference 7) 2, installation of the gate on the Ref. reliability of the SFP level instrumentation for each SFP, and

5) what compensatory measures would be taken to ensure reliable level indication in each SFP when the gate is installed.

3 RAI Question: Complete with this submittal (RAI- Please provide additional information The two channels will be mounted in different locations 4, describing how the final arrangement of the SFP and separated at least by a distance Ref. of the SFP instrumentation and comparable to the shortest side of the pool. The coaxial routing of the cabling between the

5) level instruments, the electronics and cables that extend from the two channels toward the the displays, meets the Order location of the transmitters (sensor electronics) will be requirement to arrange the SFP level installed using separate routes and separate conduits.

instrument channels in a manner that The existing embedded conduits in the concrete floor provides reasonable protection of the provide a physical barrier to protect the coax cable from level indication function against potential missile hazards. The rest of the conduit is Page 16 of 27

Limerick Generating Station, Units 1 and 2 Third Six-Month Status Report for the Implementation of SFPLI August28,2014 missiles that may result from damage within the reactor enclosure and control structure which to the structure over the SFP. are missile protected. The conduits (in which the coax cables are installed) will be separated in accordance with current plant licensing bases criteria for electrical separation (E-1412) to protect against plant hazards.

The 4-20mA cables that extend from the transmitter to the electronics enclosure (display) location will also be installed in separate conduits and will be routed separately in accordance with current plant licensing bases criteria for electrical separation to protect against plant hazards.

4 RAI Question: Complete with this submittal (RAI- For RAJ S(a) above (please refer to The following Westinghouse documents provide the 6, RAI-3(a) in the Overall Integrated analyses used to verify the design criteria and describe Ref. Plan Open Items Table), please the methodology for seismic testing of the SFP

5) provide the analyses used to verify instrumentation and electronics units, inclusive of the design criteria and methodology design basis maximum seismic loads and for seismic testing of the SFP instrumentation and the electronics hydrodynamic loads that could result from pool units, including, design basis sloshing and other effects that could accompany such maximum seismic loads and the seismic forces:

hydrodynamic loads that could a. CN-PEUS-14 Seismic Analysis of the SFP result from pool sloshing or other Mounting Bracket for Limerick Generating Station effects that could accompany such seismic forces. Units 1 & 2.

b. LTR-SEE-II-13-47, WNA-TR-03149-GEN -

Sloshing Analysis

c. EQ-QR-269, WNA-TR-03149-GEN, EQ-TP-353-Seismic Qualification of Other Components of SFPI No equipment failures were noted as a result of seismic test runs. Seismic test data has been documented in the seismic test reports, referenced above.

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Limerick Generating Station, Units 1 and 2 Third Six-Month Status Report for the Implementation of SFPLI August28,2014 5 RAI Question: Com12lete with this submittal (RAI- For each of the mounting The structural integrity and mounting of SFP level 7, attachments required to attach SFP equipment is based on formal calculations, plant Ref. level equipment to plant structures, drawings, and approved work plans per Exelon

5) please describe the design inputs, procedures and processes.

and the methodology that was used to qualify the structural integrity of Design Inputs include, but not limited to, the following :

the affected structures /equipment. 1. Component weights and dimensions, core hole locations and support details.

2. The capability of concrete expansion anchors.

3. The loads (dynamic and static) for the probe mounting bracket.

4. Concrete properties.

5. Seismic accelerations requirements for electrical equipment.

6. Allowable stresses for structural bolts.

Methodology to qualify the safety related structural integrity includes, but not limited to, the following:

1. Structural Weldments -Qualifying the weld design entails the selection of a weld's physical attributes, such as type, configuration and size, which will make it suitable for transferring the prescribed loads within appropriate limits. This process involves determining the maximum unit forces on the weld and comparing them with the weld capacity. The methodology determines weld design forces by assuming nominal linear stress/strain distribution. For each design, the engineer must confirm that the distribution of stiffness within the joint is consistent with this assumption. In some cases more refined techniques may be required to predict appropriate distribution of weld forces.

2. Concrete Expansions - The design methodology of concrete expansion anchor assemblies involves 1) application of component attachment loads to the plate,

2) analysis of the assembly to determine the resultant tension and shear forces on individual anchors, 3) evaluation of the anchor forces relative to anchor allowables, and 4) computation and evaluation of bending stresses in the CEA plate. Reactions for the attached component (applied to the plate at the centroid of the attachment weld) shall be resolved into moments, shears and axial loads (about the major axes of the expansion anchor plate).

3. Local Stress Effects -The member local stresses for open sections are computed according to specific procedures for flange attachments, web attachments, Page 18 of 27

Limerick Generating Station, Units 1 and 2 Third Six-Month Status Report for the Implementation of SFPLI August28,2014 attachments to flanges of beams supporting concrete, and attachments to webs of beams supporting concrete.

4. Existing Embedment Plate Evaluation - Embedment plates for mechanical/electrical component support attachments (i.e., pipe supports, conduit supports, HV AC supports, etc.) are evaluated as follows:

• Determine embedment plate detail based on the component support design drawing and appropriate structural drawings.

• Determine an allowable load for the embedment plate detail per plant design tables.

• Ensure that the attachment location satisfies the location tolerances used in determining the embedment plate is allowable.

• Calculate reactions at face of embedment plate.

• Determine if the embedment plate can be qualified per criteria.

5. Conduit and Conduit Supports - Structural adequacy of rigid conduit is evaluated by determining the critical span condition, loads, checking conduit stresses and verifying structural adequacy of conduit clamps.

Structural adequacy of Conduit, Junction Boxes, and Junction Box Supports is evaluated by determining loads, calculating member forces and joint reactions, checking member stresses, checking connections, checking expansion anchor assemblies, checking attachments to structure and resolving overstresses.

6. Category I Partition Walls - When qualifying a wall for a new/revised attachment, the following method is utilized:

• If the loads on the existing critical design strip are larger in magnitude than the loads on the design strip containing the new attachment, then the wall can be qualified by this comparison.

• If the wall cannot be qualified by comparison of loading, moment and shear due to the attachment shall be calculated and their effects added to the critical design strip. New stresses or moment and shear will be compared to the allowable stresses/capacities.

• If this results in an unacceptable overstress condition, detailed evaluation of the design strip containing the attachment is required. All existing attachments and core holes in the strip will be accounted for in this evaluation.

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Limerick Generating Station, Units 1 and 2 Third Six-Month Status Report for the Implementation of SFPLI August28,2014 6 RAI Question: Started (RAI- For RAI #8 above, please provide the Below is a summary of the test conditions used by 9, results for the selected methods, tests Westinghouse to qualify the SFPIS. Environmental and analyses utilized to demonstrate Ref. Conditions for SFPIS Components installed in the the qualification and reliability of the

5) installed equipment in accordance Spent Fuel Pool Area at LGS are bounded by below test with the Order requirements. conditions, except for radiation TID 12" above top of fuel rack for beyond design basis conditions (BDB).

The BDB radiation TID, 12" above top of fuel rack for LGS is 4 .E07 R y, per calculation B YR 13-051 - NEI 12-02 Spent Fuel Pool Doses. The BDB radiation value to which the Westinghouse equipment is qualified to is 1.E07 Ry, per Section 5.1.l of WNA-TR-03149-GEN.

The radiation value of 4.E07 Ry is higher than 1.E07 R y to which Westinghouse qualified the instrument to.

However, this value of 4.E07 Ry is applicable only when the water is at Level 3. At Level 2 the TID reduces to 2.E07 Ry and it further reduces to 8.E06 at Level 1 and above. With SFP water level at Level 3 the only components of SFPI that are exposed to high radiation are the stainless steel probe and the stainless steel anchor. The materials with which the probe and the anchor are manufactured are resistant to radiation effects. The stainless steel anchor and stainless steel probe can withstand 40 year dose. Westinghouse updated the design specification (WNA-DS-02957-GEN) and LTR-SFPIS-13-35, Revision 1 documentation to include the above technical justification.

Environmental Conditions for SFPIS Components in the Spent Fuel Pool Area Level sensor probe, coax coupler and connector assembly, launch plate and pool side bracket assembly, coax cable are designed and qualified to operate reliably in the below specified environmental conditions.

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Limerick Generating Station, Units 1 and 2 Third Six-Month Status Report for the Implementation of SFPLI August28,2014 Parameter Normal BDB Temperature 50-140°F 212°F Pressure Atmospheric Atmospheric 100%

Humidity 0-95% RH (saturated steam)

Radiation TID y 1E03 Rads 1E07 Rads (above pool)

Radiation TID y 1E09 Rads (12" above top of (probe and 1E07 Rads fuel rack) weight only)

Environmental Conditions Outside of the Spent Fuel Pool Area The level sensor transmitter and bracket, electronics display enclosure and bracket are designed and qualified to operate reliably in the below specified environmental conditions.

BOB (level Sensor Normal BOB Electronics Only)

Parameter 140°F 140°F Temperature 50-120°F Atmospheric Atmospheric Pressure Atmospheric 0-95%

0-95%

- (non-condensing) (non-condensing)

Humidity 0-95%RH 3days 3 days Duration 3days Radiation s 1E03Ry s 1E03 R s 1E03R TIDy Page 21 of27

Limerick Generating Station, Units 1 and 2 Third Six-Month Status Report for the Implementation of SFPLI August28,2014 Thermal and Radiation Aging - organic components in SFP area Westinghouse documents EQ-QR-269, EQ-TP-354, WNA-TR-03149-GEN provide thermal and radiation aging program details for the SFPI components.

Westinghouse completed their thermal and radiation aging testing programs to qualify the SFPI components to 1.25 years. Exelon has reviewed the documents and found acceptable.

Additionally, Westinghouse is continuing their aging tests to age the system components to 10 years. These tests are projected to be completed towards end of Summer 2014. Final test reports are scheduled to be provided to Exelon by September 4, 2014. Exelon will complete the test report reviews by September 30, 2014.

Seismic Category I Testing Seismic qualification testing performed by Westinghouse along with the technical evaluations performed by Westinghouse confirm that the SFPIS meets the seismic requirements of the vendor's design specification. Westinghouse's design specification satisfies the LGS installation requirements to withstand a SSE.

Vibration Justification As specified in RAI-4 Ref. 32, components of the system (i.e., bracket, transmitter enclosure, display enclosure, and readout display in the Auxiliary Equipment Room (AER)) will be permanently installed to meet the requirements to withstand a SSE and will meet the LGS safety related installation requirements.

Westinghouse has analyzed the pool side bracket to withstand design basis SSE. Other components of the SFPIS were subjected to shock and vibration during the seismic testing and met the requirements necessary for mounted equipment.

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Limerick Generating Station, Units 1 and 2 Third Six-Month Status Report for the Implementation of SFPLI August28,2014 Sloshing Justification The sloshing calculation performed by Westinghouse was reviewed for a design basis seismic event and found acceptable. Sloshing forces were taken into consideration for the anchorage design of the pool side bracket to ensure the bracket is rigidly mounted to include sloshing affects.

7 RAI Question: Complete with this submittal (RAI- Please provide the following: Please see response to RAI-9 (OIP #10 above).

14, a) The specific location for the Ref. primary and backup instrument

5) channel display.

b) For any display located outside the main control room, please describe the evaluation used to validate that the display location can be accessed without unreasonable delay following a BDB 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 BDB event. Describe whether personnel are continuously stationed at the display or monitor the display periodically.

8 RAI Question: Complete with this submittal (RAI- Please provide a list of the procedures a) Appropriate quality assurance measures will be 15, addressing operation (both normal selected for the SFPIS required by Order EA-Ref. and abnormal response), calibration,12-051, consistent with Appendix A-1 of NEI test, maintenance, and inspection

5) procedures that will be developed for 12-02. Site procedures will be developed for use of the SFP instrumentation. The system inspection, calibration and test, licensee is requested to include a brief maintenance, repair, operation, and normal and description of the specific technical abnormal responses, in accordance with objectives to be achieved within each Exelon's procedure control process.

procedure.

Page 23 of 27

Limerick Generating Station, Units 1 and 2 Third Six-Month Status Report for the Implementation of SFPLI August28,2014 Technical objectives to be achieved in each of the respective procedures are described below:

Procedure Objectives to be achieved

1. System Inspection: To verify that system components are in place, complete, and in the correct configuration.

2. Calibration and Test: To verify that the system is within the specified accuracy, functioning as designed, and is appropriately indicating SFP water level.

3. Maintenance: To establish and define scheduled and preventive maintenance requirements and activities necessary to minimize the possibility of system interruption.

4. Repair: To specify troubleshooting steps and component repair and replacement activities in the event of system malfunction.

5. Operation: To provide sufficient instructions for operation and use of the system by plant operation staff.

6. Responses: To define the actions to be taken upon observation of system level indications, including actions to be taken at the levels defined in NEI 12-02.

Note: RAis 3, 5, 8, 10,11,12,13 and 16 are not included in the Interim Staff Evaluation Open Items Table as they are duplicate to the RAis in Reference 3 and listed in the Overall Integrated Plan Open Item Table as RAis 2, 3, 4, 5, 6, 7, 8, and I I.respectively.

7 Potential Draft Safety Evaluation Impacts There are no potential impacts to the Draft Safety Evaluation identified at this time.

8 References The following references support the updates to the Overall Integrated Plan described in this enclosure.

1. Exelon Generating Company, LLC, letter to USNRC, "Overall Integrated Plan in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Requirements for Reliable Spent Fuel Pool Instrumentation (Order Number EA-12-051)", dated February 28, 2013 (RS 032).

2. NRC Order Number EA-12-051, "Issuance of Order Modifying Licenses with Regard to Reliable Spent Fuel Pool Instrumentation," dated March 12, 2012.

3. NRC letter to Exelon Generation Company, LLC, Limerick Generating Station, Units 1and2-Request For Additional Information RE: Overall Integrated Plan In Response to Order EA- 12-051, "Reliable Spent Fuel Pool Instrumentation" (TAC NOS. MF0854 and MF0855), dated June 24 2013.

Page 24of27

Limerick Generating Station, Units 1 and 2 Third Six-Month Status Report for the Implementation of SFPLI August28,2014

4. Exelon Generating Company, LLC, Letter to USNRC, "Response to Request for Additional Information - Overall Integrated Plan in Response to Commission Order Modifying License Requirements for Reliable Spent Fuel Pool Instrumentation (Order No. EA-12-051)", dated July 18, 2013, (RS-13-177).

5. NRC letter to Exelon Generation Company, LLC, "Limerick Generating Station, Units 1 and 2 -

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. MF0854 and MF0855)", dated October 23, 2013.

6. First Six-Month Status Report for the Implementation of Order EA-12-051, Order Modifying Licenses with Regard to Reliable Spent Fuel Pool Instrumentation, dated August 28, 2013 (RS 122)

7. Second Six-Month Status Report for the Implementation of Order EA-12-051, Order Modifying Licenses with Regard to Reliable Spent Fuel Pool Instrumentation, dated February 28, 2014 (RS-14- 22)

Page 25 of 27

Limerick Generating Station, Units 1 and 2 Third Six-Month Status Report for the Implementation of SFPLI August 28, 2014 Attachment 1 (Page 1 of 2)

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