ML15061A089
| ML15061A089 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 02/27/2015 |
| From: | Kaegi G Exelon Generation Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| EA-12-051, RS-15-028, TAC MF1050, TAC MF1051 | |
| Download: ML15061A089 (27) | |
Text
Exelon Generation Order No. EA-12-051 RS-15-028 February 27, 2015 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Dresden Nuclear Power Station, Units 2 and 3 Renewed Facility Operating License Nos. DPR-19 and DPR-25 NRC Docket Nos. 50-237 and 50-249
Subject:
Fourth 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-13-030)
- 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-13-118)
- 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 020)
- 8. Exelon Generation Company, LLC 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), dated August 28, 2014 (RS-14-198)
U.S. Nuclear Regulatory Commission Integrated Plan Report to EA-12-051 February 27, 2015 Page 2
- 9. NRC letter to Exelon Generation Company, LLC, 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), dated October 29, 2013 On March 12, 2012, the Nuclear Regulatory Commission ("NRC" or "Commission") issued an order (Reference 1) to Exelon Generation Company, LLC (EGC). Reference 1 was immediately effective and directs EGC 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 EGC initial status report regarding reliable spent fuel pool instrumentation. Reference 5 provided the Dresden Nuclear Power Station, Units 2 and 3 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, 7 and 8 provided the first, second, and third six-month status reports, respectively, pursuant to Section IV, Condition C.2, of Reference 1 for Dresden Nuclear Power Station. The purpose of this letter is to provide the fourth 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 NRC Interim Staff Evaluation Request for Additional Information Items contained in Reference 9.
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 271h day of February 2015.
Respectfully submitted, Glen T. Kaegi Director - Licensing & Regu atory Affairs Exelon Generation Company, LLC
Enclosure:
- 1. Dresden Nuclear Power Station, Units 2 and 3 Fourth 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 February 27, 2015 Page 3 cc: Director, Office of Nuclear Reactor Regulation NRC Regional Administrator - Region III NRC Senior Resident Inspector Dresden Nuclear Power Station, Units 2 and 3 NRC Project Manager, NRR Dresden Nuclear Power Station, Units 2 and 3 Ms. Jessica A. Kratchman, NRR/JLD/PMB, NRC Mr. Stephen R. Monarque, NRR/JLD/JPMB, NRC Mr. Robert L. Dennig, NRR/DSS/SCVB, NRC Mr. Blake Purnell, NRR/DORLJLPL3-2, NRC Mr. John Boska, NRR/JLD/MSD, NRC Illinois Emergency Management Agency - Division of Nuclear Safety
Enclosure Dresden Nuclear Power Station, Units 2 and 3 Fourth Six-Month Status Report for the Implementation of Order EA-12-051, Order Modifying Licenses with Regard to Reliable Spent Fuel Pool Instrumentation (23 pages)
Dresden Nuclear Power Station, Units 2 and 3 Fourth Six-Month Status Report for the Implementation of SFP LI February 27, 2015 Dresden Nuclear Power Station, Units 2 and 3 Fourth 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 Dresden Nuclear Power Station, Units 2 and 3, developed an Overall Integrated Plan (Reference 1), documenting the requirements to install reliable spent fuel pool level instrumentation (SFPLI), in response to NRC Order EA-12-051 (Reference 2). This enclosure provides an update of milestone accomplishments since submittal of the third 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 development of the third six month status report (Reference 8), and are current as of February 27, 2015.
None 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.
Milestone Target Completion Date Activity Status Revised Target Completion Date Submit 60 Day Status Report October 25, 2012 Complete Submit Overall Integrated Plan February 28, 2013 Complete Submit Response to RAls July 18, 2013 Complete Submit 6 Month Updates:
Update 1 August 28, 2013 Complete Update 2 February 28, 2014 Complete Update 3 August 28, 2014 Complete Update 4 February 27, 2015 Complete with this submittal Page 1 of 23
Dresden Nuclear Power Station, Units 2 and 3 Fourth Six-Month Status Report for the Implementation of SFP LI February 27, 2015 Milestone Target Completion Date Activity Status Revised Target Completion Date Provide Final Safety Evaluation (SE) Info April 30, 2015 Complete Update 5 August 28, 2015 Not Started Update 6 February 28, 2016 Not Started Update 7 August 28, 2016 Not Started Modifications:
Conceptual Design 302012 Complete Issue Exelon Fleet contract to procure SFPI Equipment 102015 Complete Begin Detailed Engineering Design for Unit 2 302014 Complete Complete and Issue SFPI Modification Package for Unit 2 402014 Not Started 102015 Begin Detailed Engineering Design for Unit 3 302014 Complete Complete and Issue SFPI Modification Package for Unit 3 402014 Not Started 102015 Begin SFPI Installation for Unit 2 302015 Not Started Complete SFPI Installation for Unit 2 and Put Into Service 402015 Not Started Begin SFPI Installation for Unit 3 302016 Not Started Complete SFPI Installation for Unit 3 and Put Into Service 402016 Not Started 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 Dresden Nuclear Power Station, Units 2 and 3, expects to comply with the order implementation date and no relief/relaxation is required at this time.
Page 2 of 23
Dresden Nuclear Power Station, Units 2 and 3 Fourth Six-Month Status Report for the Implementation of SFP LI February 27, 2015 6
Open Items from Overall Integrated Plan and Draft Safety Evaluation The following tables provide a summary of the open items documented in the Overall Integrated Plan or the Draft Safety Evaluation (SE) and the status of each item.
Overall Integrated Plan Open Items 01#
Description Status 1
Open Item:
Complete.
(Addressed in Reference 6)
Continuous level indication will be provided by a guided wave radar system, submersible pressure transducer, or other appropriate level sensing technology that will be determined during the detailed engineering phase of the project.
2 (RAI-1, Ref. 3)
RAI Question:
Complete.
(Addressed in Reference 4)
Please provide the following:
a) For Level 1, specify how the identified location represents the higher of the two points described in the NE) 12-02 guidance for this level.
b) A clearly labeled sketch depicting the elevation view of the proposed typical mounting arrangement for the portions of the instrument channel consisting of permanent measurement channel equipment (e.g., fixed level sensors and/or stilling wells, and mounting brackets).
Indicate on this sketch the datum values representing Level 1, Level 2, and Level 3 as well as the top of the fuel.
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.
Page 3 of 23
Dresden Nuclear Power Station, Units 2 and 3 Fourth Six-Month Status Report for the Implementation of SFP LI February 27, 2015 3
RAI Question:
Started - Planned completion date is March 20, (RAI-2, Please provide a clearly labeled 2015.
Ref. 3) sketch or marked-up plant Please see attachment 1 for the preliminary sketch.
drawing of the plan view of the The cable routing has been updated since the prior 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.
update.
4 RAI Question:
Started - Planned completion date is March 20, (RAI-3, Ref. 3)
Please provide the following:
a) The design criteria that will 2015.
be used to estimate the total a)
All SFPIS equipment will be designed in loading on the mounting accordance with the Dresden Station Safe device(s), including static weight loads and dynamic Shutdown Earthquake (SSE) design requirements.
loads. Describe the The vendor, Westinghouse, will evaluate the methodology that will be used structural integrity of the mounting brackets in a to estimate the total loading, inclusive of design basis calculation. The GTSTRUDL model, proposed by Westinghouse to calculate the stresses in the maximum seismic loads and bracket assembly, considers load combinations for the hydrodynamic loads that the dead load, live load and seismic load on the could result from pool sloshing bracket. The reactionary forces calculated from or other effects that could these loads will become the design inputs to design accompany such seismic the mounting bracket anchorage to the refuel floor forces.
to withstand a Safe Shutdown Earthquake (SSE).
b) A description of the manner in which the level sensor (and Seismic stilling well, if appropriate) will The seismic loads will be obtained from Dresden be attached to the refueling Station's response spectra curves (Reference floor and/or other support structures for each planned TDBD-DQ-1 for Dresden Nuclear Generating point of attachment of the probe Station). The following methodology will be used in assembly.
determining the stresses on the bracket assembly:
Indicate in a schematic the portions of the level sensor that Frequency analysis, taking into account the will serve as points of dead weight and the hydrodynamic mass of the attachment for structure, is performed to obtain the natural mechanical/mounting or frequencies of the structure in all three directions.
electrical connections.
c) A description of the manner SSE (Safe Shutdown Earthquake) response spectra analysis is performed to obtain member by which the mechanical stresses and support reactions.
connections will attach the level Modal responses are combined using the Ten Percent Method per U.S. NRC Regulatory Page 4 of 23
Dresden Nuclear Power Station, Units 2 and 3 Fourth Six-Month Status Report for the Implementation of SFP LI February 27, 2015 instrument to permanent SFP
Guide 1.92, Revision 1, "Combining Modal structures so as to support the
Responses and Spatial Components in Seismic level sensor assembly. Response Analysis".
The seismic loads for each of the three directions are combined by the Square Root of the Sum of Squares (SASS) Method.
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 will be obtained by analysis. The TID-7024, Nuclear Reactors and Earthquakes, 1963, by the US Atomic Energy Commission, approach will be used to estimate the wave height and natural frequency. Horizontal and vertical impact force on the bracket components will be calculated using the wave height and natural frequency obtained using the TID-7024 approach.
Using this methodology, sloshing forces will be calculated and added to the total reactionary forces that would be applicable for bracket anchorage design. The analysis will also confirm that the level probe can withstand a credible design basis seismic event.
The following Westinghouse documents will 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.
To be provided by Westinhouse during detailed design phase - Pool-side Bracket Seismic Analysis
- b.
LTA-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 Dresden Station specific calculations will be developed to address the seismic qualification of the readout display in the Turbine Building. The design criteria in this calculation will meet the Page 5 of 23
Dresden Nuclear Power Station, Units 2 and 3 Fourth Six-Month Status Report for the Implementation of SFP LI February 27, 2015 requirements to withstand a SSE. The methods that will be used in the calculation follow IEEE Standard 344-2004 and IEEE Standard 323-2003 for seismic qualification of the instrument.
b)
The level sensor, which is one long probe, will be suspended from the launch plate via a coupler/connector assembly. The launch plate is a subcomponent of the bracket assembly, which will be mounted to the refuel floor via anchors or welded to existing embedded plates on the refuel floor. A sketch of the portions of the level sensor that will serve as points of attachment for mechanical/mounting or electrical connections will be provided later.
c)
The bracket assembly that supports the sensor probe and launch plate will be mechanically connected to the SFP structure. One type of mechanical connection that will be used consists of four concrete expansion anchors that will bolt the bracket assembly to the SFP structure via the base plate. The other type of mechanical connection is a welded connection between the base plate and existing embedded plates on the SFP structure.
The concrete expansion anchors and welds will be designed to withstand an SSE and will meet the Dresden Station safety related installation requirements. The qualification details of the bracket will be provided in a Pool-side bracket Seismic Analysis and the qualification of the anchorage to the floor will be provided in a Dresden Station specific calculation Evaluation of SFPI Sensor Mounting Detail Anchorage and Mounting.
5 (RAI-4, RAI Question:
Started - Planned completion date is March 20, 2015.
Please provide the following:
Ref. 3) a) A description of the specific method or combination of a)
Beyond Design Basis Environment methods you intend to apply to demonstrate the reliability of the permanently installed equipment under beyond-design-basis ambient temperature, humidity, shock, vibration, and radiation conditions, b) A description of the testing Westinghouse will qualify the components (probe, connector, cable) of the SFPIS located in the SFP area to the beyond design basis environment.
Components of the system will be subjected to beyond design basis conditions of heat and humidity, thermal and radiation aging mechanisms.
This testing will confirm the functionality of these system components under beyond design basis environmental conditions. Westinghouse will perform testing to ensure aging of the components and/or analyses that will be in the SFP area will not have a significant effect on conducted to provide the ability of the equipment to perform following a Page 6 of 23
Dresden Nuclear Power Station, Units 2 and 3 Fourth Six-Month Status Report for the Implementation of SFP LI February 27, 2015 plant design basis earthquake.
Mild Environment Westinghouse will qualify the system components (display panel, sensor) that reside in the mild environment conditions to determine that the components can satisfactorily perform to those conditions. Westinghouse will confirm that aging does not have a significant effect on the ability of the equipment to perform following a plant design basis earthquake.
Display The methods to be used by the vendor to qualify the readout display follow IEEE Standard 344-2004 and IEEE Standard 323-2003 for seismic qualification of the instrument. For temperature and humidity qualification of the displays IEEE 344-2004, IEEE 323-2003, NRC Regulatory Guides 1.100, Revision 3; 1.209, March 2007; and EPRI TR-107330 guidance will be followed. The readout display will be located in the Turbine Building and is not expected to be subject to harsh environmental or radiological conditions seen in the Reactor Building.
Shock and Vibration SFPIS pool side brackets will be 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.
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 the level sensor and its bracket, display enclosure and its bracket, will be subjected to seismic testing, including shock and vibration test requirements.
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 assurance that the equipment will perform reliably under the worst-case credible design basis loading at the location where the equipment will be mounted. Include a discussion of this seismic reliability demonstration as it applies to a) the level sensor mounted in the SFP area, and b) any control boxes, electronics, or read-out and re-transmitting devices that will be employed to convey the level information from the level sensor to the plant operators or emergency responders.
c) A description of the specific method or combination of methods that will be used to confirm the reliability of the permanently installed equipment such that following a seismic event the instrument will maintain its required accuracy.
Page 7 of 23
Dresden Nuclear Power Station, Units 2 and 3 Fourth Six-Month Status Report for the Implementation of SFP LI February 27, 2015 components from vibration induced damage.
b)
The seismic adequacy of the SFPIS (all components) will be demonstrated by vendor testing and analysis in accordance with the below listed standards:
IEEE 344-2004, IEEE Recommended Practice for Seismic Qualification of Class lE Electrical Equipment for Nuclear Power Generating Stations IEEE-323-1974, Standard for Qualifying Class lE Equipment for Nuclear Power Generating Stations USNRC Regulatory Guide 1.100, Rev. 3 USNRC Regulatory Guide 1.92, Rev. 1 Dresden Calculation - Seismic Qualification of the SFPIS Indicator Seismic adequacy of the level sensor probe supporting bracket within the SFP area will be demonstrated by analysis as discussed in the response to RAI-2.
c)
Westinghouse will seismically qualify the SFPI instrument and its components. With the instrument to be seismically qualified and installed as described in RAI 5b response, including the readout display in the Turbine Building, the instrument is assured to maintain reliable and accurate indication when required.
6 (RAI-5, RAI Question:
Started - Planned completion date is March 20, 2015.
Please provide the following:
Ref. 3)
The two channels of the proposed level a) A description of how the two channels of the proposed level measurement system will be installed such that:
measurement system meet this a)
The level probes will be mounted on the east requirement so that the and west side of each SFP and will be separated potential for a common cause by a distance greater than the span of the shortest event to adversely affect both side of the pool. This meets the NEI 12-02 revision channels is minimized to the 1 guidance for channel separation.
extent practicable.
b)
The information related to physical separation, is depicted in attachment 1, which b)Further information shows the location of the probe and mounting describing the design and brackets and cable routing to the two individual installation of each level transmitters. Dresden's primary and backup measurement system, consisting of level sensor instrument channel displays will be located on the Main Floor of the Turbine Building along the electronics, cabling, and Reactor Building wall and will have physical and readout devices. Please spatial separation between the displays. Each Page 8 of 23
Dresden Nuclear Power Station, Units 2 and 3 Fourth Six-Month Status Report for the Implementation of SFP LI February 27, 2015 address how independence of these components of the primary and back-up channels is achieved through the application of independent power sources, physical and spatial separation, independence of signals sent to the location(s) of the readout devices, and the independence of the displays.
system's cables will be spatially separated using Dresden's divisional spatial separation criteria. The independent power sources will consist of powering each train from a separate Motor Control Center.
7 (RAI-6, Ref. 3)
RAI Question:
Started - Planned completion date is March 20, 2015.
a)
The primary and backup SFPLI instrument channels will be normally powered from 120 VAC.
Upon loss of normal AC power, individual batteries installed in each channel's electronics / UPS enclosure will automatically maintain continuous channel operation for at least (3) days. The power cables will be routed so that spatial and physical separation is maintained between the primary and backup channels. Additionally, a receptacle and a selector switch are installed in each channel electronics / UPS enclosure to directly connect emergency 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 Turbine Building.
The calculation also determines that the battery will last for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. Dresden will review this calculation during the detailed design phase. Based on preliminary assessment, the Dresden readout display of level indication in the Turbine Building will be available for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> of operation.
Therefore, the results of the calculation meet the NEI 12-02 requirements.
Please provide the following:
a) A description of the electrical ac power sources and capacities for the primary and backup channels, b) If the level measurement channels are to be powered through a battery system (either directly or through an Un interruptible Power Supply),
please provide the design criteria that will be applied to size the battery in a manner that ensures, with margin, that the channel will be available to run reliably and continuously following the onset of the beyond-design-basis event for the minimum duration needed, consistent with the plant mitigation strategies for beyond-design-basis external events (Order EA-12-049).
8 (RAI-7, Ref. 3)
RAI Question:
Started - Planned completion date is March 20, 2015.
c) The Westinghouse documents WNA-CN-00301-GEN and WNA-DS-02957-GEN describe the channel accuracy under both (a) normal SFP level conditions and (b) at the Beyond Design Basis (BDB) conditions that would be present if SFP level were at Level 2 and Level 3 datum points. Each Please provide the following:
c) An estimate of the expected instrument channel accuracy performance (e.g., in percent of span) under both a) normal SFP level conditions Page 9 of 23
Dresden Nuclear Power Station, Units 2 and 3 Fourth Six-Month Status Report for the Implementation of SFP LI February 27, 2015 (approximately Level 1 or instrument channel will be accurate to within +/-3" higher) and b) at the beyond-during normal spent fuel pool level conditions. The design-basis conditions (i.e.,
radiation, temperature, humidity, post-seismic and instrument channels will retain this accuracy after BDB conditions, in accordance with the above Westinghouse documents. The same channel post-shock conditions) that accuracy requirements are applicable to the would be present if the SFP readout display in the turbine building. The level were at the Level 2 and accuracy is within the channel accuracy Level 3 datum points, d) A description of the requirements of the Order (+/-1 foot) for BDB conditions and meets the NEI 12-02 requirements.
methodology that will be used d) Westinghouse will provide a document regarding for determining the maximum the methodology for routine testing/calibration allowed deviation from the verification and calibration methodology. This instrument channel design document will also specify the required accuracy accuracy that will be employed criteria under normal operating conditions.
under normal operating Dresden Station calibration and channel verification conditions as an acceptance procedures will follow the guidance and criteria criterion for a calibration procedure to flag to operators and to technicians that the channel requires adjustment to within the normal condition design accuracy.
provided in this document.
Instrument channel calibration will be performed if the level indication reflects a value that is outside the acceptance band that will be established in the Dresden Station calibration and channel verification procedures. Calibration will be performed once per refueling cycle for Dresden Station. 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 - Planned completion date is November 21, (RAI-8, Ref. 3)
Please provide the following:
a) A description of the 2015.
a)
During the detailed design phase, Westinghouse will provide the calibration procedure capability and provisions the and functional test procedure describing the proposed level sensing capabilities and provisions of SFPI periodic testing equipment will have to enable and calibration, including in-situ testing. Dresden periodic testing and calibration, including how this capability will review the procedures to ensure the instrument can be calibrated/functionally tested/in-situ testing enables the equipment to be tested in-situ.
can be performed per the Order requirements.
b)
The level displayed by the channels will be b) A description of how such verified per the Dresden Station administrative and testing and calibration will operating procedures. If the level is not within the enable the conduct of regular required accuracy per Westinghouse channel checks of each recommended tolerances, channel calibration will independent channel against be performed.
the other, and against any other c)
Functional checks will be performed per a permanently-installed SFP level future Westinghouse functionality test procedure at instrumentation.
the Westinghouse recommended frequency.
Calibration tests will be performed per a future Page 10 of 23
Dresden Nuclear Power Station, Units 2 and 3 Fourth Six-Month Status Report for the Implementation of SFP LI February 27, 2015 c) A description of how Westinghouse calibration procedure at the calibration tests and functional Westinghouse recommended frequency. In checks will be performed, and accordance with Dresden Station maintenance and the frequency at which they will operating programs, Dresden Station will develop be conducted. Discuss how calibration, functional test, channel verification these surveillances will be procedures per future Westinghouse incorporated into the plant surveillance program.
recommendations to ensure reliable, accurate and continuous SFPI functionality.
d) A description of what d)
Dresden Station will develop preventive maintenance tasks for the SFPI per Westinghouse preventive maintenance tasks recommendation identified in the technical manual are required to be performed WNA-G0-00127-GEN to assure that the channels during normal operation, and are fully conditioned to accurately and reliably 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.
perform their functions when needed.
10 RAI Question:
Replaced by Interim SE RAI #11 (ref. 5).
(RAI-9, Please provide the following:
Ref. 3) a) The specific location for each of the primary and backup instrument channel displays.
b) If the primary and backup display location is other than the main control room, provide justification for prompt accessibility to displays including primary and alternate route evaluation, habitability at display location(s), continual resource availability for personnel responsible to promptly read displays, and provisions for communications with decision makers for the various SFP drain down scenarios and external events.
c) The reasons justifying why the locations selected enable the information from these instruments to be considered "promptly accessible." Include consideration of various drain-down scenarios.
Page II of 23
Dresden Nuclear Power Station, Units 2 and 3 Fourth Six-Month Status Report for the Implementation of SFP LI February 27, 2015 11 RAI Question:
Replaced by Interim SE RAI #12 (ref. 5).
(RAI-Please provide the following:
10, Ref. 3) a) A list of the operating (both normal and abnormal response) procedures, calibration/test procedures, maintenance procedures, and inspection procedures that will be developed for use of the SFP instrumentation in a manner that addresses the order requirements.
b) A brief description of the specific technical objectives to be achieved within each procedure. If your plan incorporates the use of portable spent fuel level monitoring components, please include a description of the objectives to be achieved with regard to the storage location and provisions for installation of the portable components when needed.
12 RAI Question:
Started - Planned completion date is March 20, (RAI-Please provide the following:
2015. Dresden Station revised the compensatory 11,
a) Further information action plan requirements applicable to conditions where the instrument channel(s) are not restored to Ref. 3) describing the maintenance functional status within the specified time, as and testing program the specified in the Note. The condition will be entered licensee will establish and into the corrective action program in lieu of a report implement to ensure that regular testing and calibration is to PORC.
performed and Response for a,b:
b)verified by inspection and Performance tests (functional checks) and Operator audit to demonstrate performance checks will be described in detail in the conformance with design and vendor operator's manual, and the applicable system readiness information is planned to be contained in plant requirements. Include a description of your plans for operating procedures.
ensuring that necessary Operator performance tests are planned to be channel checks, functional performed periodically as recommended by the tests, periodic calibration, and maintenance will be conducted for the level measurement equipment vendor.
Channel functional tests per operations procedures, system and its supporting with limits established in consideration of vendor equipment.
c) A description of how the equipment specifications, are planned to be performed at appropriate frequencies established Page 12 of 23
Dresden Nuclear Power Station, Units 2 and 3 Fourth Six-Month Status Report for the Implementation of SFP LI February 27, 2015 guidance in NEI12-02, Section equivalent to or more frequently than existing SFPI.
4.3 regarding compensatory actions for one or both non-Manual calibration and operator performance functioning channels will be checks are planned to be performed in a periodic addressed.
scheduled fashion with additional maintenance on d) A description of what an as-needed basis when flagged by the system's compensatory actions are automated diagnostic testing features.
planned in the event that one of Channel calibration tests per maintenance the instrument channels cannot procedures with limits established in consideration be restored to functional status within 90 days.
of vendor equipment specifications are planned to be performed at frequencies established in consideration of vendor recommendations.
SFPI channel/equipment maintenance/preventative maintenance and testing program requirements to 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 appropriate regular 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 c, d:
Both primary and backup SFPI channels will 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:
- Channel(s) Required Compensatory Out-of-Restoration Action if Service Action Required Restoration Action not completed within Specified Time Page 13 of 23
Dresden Nuclear Power Station, Units 2 and 3 Fourth Six-Month Status Report for the Implementation of SFP LI February 27, 2015 Restore Immediately channel to initiate action in functional status accordance with within 90 days Note below (or if channel restoration not expected within 90 days, then proceed to Compensatory Action)
Initiate action Immediately within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> initiate action in to restore one accordance with 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: Initiate an Issue Report to enter the condition into the Corrective Action Program. Identify the equipment out of service time is greater than the specified allowed out of service time, develop and implement an alternate method of monitoring, determine the cause of the non-functionality, and the plans and schedule for restoring the instrumentation channel(s) to functional status.
Draft Safety Evaluation Open Items 01#
Description Status 1
(RAI-3, Ref. 5)
RAI Question:
Started - Planned completion date is March 20, 2015.
The following Westinghouse documents will provide the analyses used to verify the design criteria and describe the methodology for seismic testing of the SFP instrumentation and electronics units, inclusive of design basis maximum seismic loads and hydrodynamic loads that could result from pool sloshing and other effects that could accompany For RAI 2(a) above, please provide the analyses used to verify the design criteria and Page 14 of 23
Dresden Nuclear Power Station, Units 2 and 3 Fourth Six-Month Status Report for the Implementation of SFP LI February 27, 2015 methodology for seismic testing of the and the electronics units, including sis design-baismic maximum se such seismic forces:
- a.
To be provided by Westinghouse during detailed design phase -
Pool-side Bracket Seismic Analysis
- b.
LTR-SEE-II-13-47, WNA-TR-03149-GEN - Sloshing Analysis
- c.
EQ-QR-269, WNA-TR-03149-GEN, EQ-TP-353 - Seismic loads and Qualification of other components of SFPI hydrodynamic loads Dresden Station specific calculations will address the seismic that could result from qualification of the turbine building indicators. The design criteria that pool sloshing or will be used in this calculation will satisfy the requirements to withstand other effects that could accompany such seismic forces.
a SSE and will meet the Dresden Station safety related installation requirements for mounting the readout displays in the turbine building.
2 RAI Question:
Started - Planned completion date is March 20, 2015.
(RAI-4, For each of the The structural integrity and mounting of SFP level equipment will be Ref. 5) mounting based on formal calculations, plant drawings, and approved work plans attachments required per Exelon procedures and processes.
to attach SFP level Design Inputs will include, but not limited to, the following:
equipment to plant structures, please
- 1.
Component weights and dimensions, core hole locations and describe the design support details.
inputs and the methodology that was used to qualify
- 2. The capability of concrete expansion anchors.
- 3. The loads (dynamic and static) for the probe mounting bracket.
the structural
- 4. Concrete properties integrity of the affected
- 5. Seismic accelerations requirements for electrical equipment structur es/equipment 6. Allowable stresses for structural bolts.
Methodology to qualify the safety related structural integrity will include, 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.
Page 15 of 23
Dresden Nuclear Power Station, Units 2 and 3 Fourth Six-Month Status Report for the Implementation of SFP LI February 27, 2015 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, 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, HVAC 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 allowables.
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.
Cable Tray Loading Violations (CTLVs) - The structural evaluation of cable tray supports for potential increase in design basis loading will be performed by identifying the hangers affected by the routing point. For each affected hanger controlling routing point will be determined. Then actual load associated with the routing point will be computed. Then the actual load will be compared to the load used in the hanger design. An evaluation of cable tray hanger for any increased load will be performed.
- 7. 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, then 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.
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Dresden Nuclear Power Station, Units 2 and 3 Fourth Six-Month Status Report for the Implementation of SFP LI February 27, 2015 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.
3 (RAI-6, Ref. 5)
RAI Question:
Started Below SFPIS during anchor stainless withstand Environmental Area Level and qualified conditions.
- Planned completion date is March 20, 2015.
is a summary of the test conditions that will be used by Westinghouse to qualify the SFPIS.
Environmental Conditions for Components installed in the Spent Fuel Pool Area will be verified detailed design. The materials with which the probe and the are manufactured are to be resistant to radiation effects. The steel anchor and stainless steel probe are to be designed to 40 year dose.
Conditions for SFPIS Components in the Spent Fuel Pool sensor probe, coax coupler and connector assembly, launch plate pool side bracket assembly, coax cable are to be designed and to operate reliably in the below specified environmental 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.
Parameter Normal BDB Temperature 50-140°F 212°F Pressure Atmospheric Atmospheric Humidity 0-95% RH 100% (saturated steam)
Radiation TID y (above pool) 1E03 Rads 1E07 Rads Radiation TID y (12" above top of fuel rack) 1E09 Rads (probe and weight only) 1E07 Rads and below Environmental The level bracket specified Conditions Outside of the Spent Fuel Pool Area sensor transmitter and bracket, electronics display enclosure are to be designed and qualified to operate reliably in the environmental conditions.
Parameter Normal BDB BDB (Level Sensor Electronics Page 17 of 23
Dresden Nuclear Power Station, Units 2 and 3 Fourth Six-Month Status Report for the Implementation of SFP LI February 27, 2015 Only)
Temperature 50-120°F 140°F 140°F Pressure Atmosp heric Atmospheric Atmospheric Humidity 0-95%
RH 0-95%
(non-condensing) 0-95%
(non-condensing)
Duration 3 days 3 days 3 days Radiation TID y 1E03 R y 1E03 R 5 1E03 R Dresden specific calculations which support the seismic installation and environmental analysis of the display enclosures and transmitters will be included in the detailed design.
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 them acceptable.
Additionally, Westinghouse has completed their aging tests to age the system components to 10 years. The tests were completed satisfactorily and the final test reports were reviewed and found acceptable by Exelon.
Seismic Category I Testing Seismic qualification testing will be performed by Westinghouse along with the technical evaluations being performed by Westinghouse during detailed design.
Vibration Justification Components of the system (i.e., bracket, transmitter, display enclosure) will be permanently installed to meet the requirements to withstand a SSE and will meet Dresden's seismic installation requirements.
Westinghouse will analyze the pool side bracket to withstand design basis SSE. Other components of the SFPIS will be subjected to shock and vibration during the seismic testing.
Sloshing Justification Page 18 of 23
Dresden Nuclear Power Station, Units 2 and 3 Fourth Six-Month Status Report for the Implementation of SFP LI February 27, 2015 A sloshing calculation will be performed by Westinghouse during detailed design. Sloshing forces will be taken into consideration for the anchorage design of the pool side bracket to ensure the bracket is rigidly mounted to include sloshing affects.
4 RAI Question:
Started - Planned completion date is March 20, 2015.
(RAI-8, Please provide the a)
The primary and backup SFPLI instrument channels will be Ref. 5) following:
a) A description of normally powered from 120 VAC. Upon loss of normal AC power, individual batteries installed in each channel's electronics / UPS the electrical ac enclosure will automatically maintain continuous channel operation for power sources and at least three (3) days. The power cables will be routed so that spatial capabilities for the and physical separation is maintained between the primary and backup primary and backup channels. Additionally, a receptacle and a selector switch are installed channels.
in each channel electronics / UPS enclosure to directly connect b) Please provide emergency power to the SFPLI.
the results of the b)
The Westinghouse Report, WNA-CN-00300-GEN, provides the calculation depicting results of the calculation depicting the battery backup duty cycle. This the battery backup calculation demonstrates that battery capacity is 4.22 days to maintain duty cycle the level indicating function to the display location, located in the Turbine requirements Building. The calculation also determines that the battery will last for 72 demonstrating that hours. Dresden will review this calculation during the detailed design its capacity is phase. Based on preliminary assessment, the Dresden readout display sufficient to maintain of level indication in the Turbine Building will be available for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> of the level indication operation. Therefore, the results of the calculation meet the NEI 12-02 function until offsite resource availability is reasonably assured.
requirements.
5 RAI Question:
Started - Planned completion date is March 20, 2015.
(RAI-Please provide the a)
Dresden's primary and backup instrument channel displays will be located on the Main Floor of the Turbine Building along the Reactor 11, Ref. 5) following:
a) The specific Building wall.
location for each of b)
Dresden's primary and backup instrument channel displays are the primary and located outside of the control room. As described above, they are backup instrument located in the Turbine Building. This location was selected due to the channel display location proximity to the main control room.
displays.
Dresden Station UFSAR section 3.8.4 states that the turbine building b) If a display will be portion of the structural complex is a Class II structure as explained in located somewhere Section 3.8.5. Section 3.8.5 states that Class II structures supporting other than the Class I structures, systems and components were designed to Class II control room or requirements and have been investigated to assure that the integrity of alternate the Class I items is not compromised. The instrument channel display shutdown panel, please describe the location will be investigated to assure that the integrity of the display items is not compromised.
Both primary and backup instrument evaluation used to validate that the channel display locations are selected to reduce the likelihood of missile damage to the displays.
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Dresden Nuclear Power Station, Units 2 and 3 Fourth Six-Month Status Report for the Implementation of SFP LI February 27, 2015 display location can Dresden Station UFSAR figure 3.11-4 shows the Main Floor of the be accessed without Turbine Building as zone 38 and would include the display location and unreasonable delay the access to the displays from the Control Room. UFSAR table 3.11-2 following a BDB shows zone 38 with a normal maximum temperature of 120°F which event. Include the would allow emergency responders to perform level display monitoring.
time available for Travel time from the Control Room to the primary and secondary display personnel to access is approximately 5 minutes based on walkdowns. There are alternate the display as credited in the paths if the primary path is blocked or is not habitable. The maximum time to reach the display locations via the alternate paths is 8 minutes.
evaluation, as well Per the preliminary evaluation, radiological habitability at the display as the actual time location and the path to the display location was evaluated against (e.g., based on walk-estimated dose rates from SFP draindown conditions to Level 3 and throughs) that it will exposure to personnel monitoring SFP levels are expected to remain take for personnel to less than emergency exposure limits allowable for emergency access the display.
responders to perform this action. Also, for severe accidents scenarios Additionally, please include a description of the involving core damage and increased radiological exposure levels, access to these SFP level displays for short term can be achieved (see UFSAR Appendix 12A). Exposure duration to personnel monitoring SFP levels would be limited to remain less than emergency exposure limits radiological and allowable for emergency responders to perform this action. The SFP environmental electronics and displays are not expected to take radiation dose higher conditions on the than the qualified TID 1.0E03 rads. This is because the location is paths outside secondary containment and not near any piping systems that personnel might could contain fission products. (see UFSAR Appendix 12A). Heat and take. Describe humidity from SFP boildown conditions was preliminarily evaluated for whether the display this location. The location is at an elevation below the SFP operating location remains floor and physically separated by secondary containment such that heat habitable for and humidity from a boiling SFP is not expected to compromise radiological, heat and humidity, and other environmental conditions following a BDB event.
habitability at this location and the path to the display locations.
Describe whether personnel are continuously stationed at the display or monitor the display periodically.
6 RAI Question:
Started - Planned completion date is March 20, 2015.
(RAI-Please
a list provide Appropriate quality measures will be selected for the SFPIS required by 12, of the procedures Order EA-12-051, consistent with Appendix A of NEI 12-02. Site procedures will be developed for system inspection, calibration and test, Ref. 5) addressing operation maintenance, repair, operation and normal and abnormal responses, in (both normal and accordance with Exelon's procedure control process. Technical abnormal response),
calibration, test, objectives to be achieved in each of the respective procedures are described below:
maintenance, and inspection Procedure Objectives to be achieved procedures that will
- 1.
System Inspection: To verify that system components are in be developed for use place, complete, and in the correct configuration, and that the sensor Page 20 of 23
Dresden Nuclear Power Station, Units 2 and 3 Fourth Six-Month Status Report for the Implementation of SFP LI February 27, 2015 of the spent SFP instrumentation.
Please provide a brief description of the specific technical objectives to be achieved within each procedure.
probe is free of significant deposits.
- 2.
Calibration and Test: To verify that the system is within the specified accuracy, is 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. We would not do this in a procedure.
- 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: RAls not included in the Interim Staff Evaluation Open Items Table are duplicate to the RAls in Reference 3 and are listed in the Overall Integrated Plan Open Items Table.
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 Generation Company, LLC, letter to USNRC, "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 030)
- 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. USNRC letter to Exelon Generation Company, LLC, "Request for Additional Information Regarding Overall Integrated Plan for Reliable Spent Fuel Pool Instrumentation", dated June 26, 2013.
- 4. Exelon Generation 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 051)", dated July 18, 2013 (RS-13-176).
Page 21 of 23
Dresden Nuclear Power Station, Units 2 and 3 Fourth Six-Month Status Report for the Implementation of SFP LI February 27, 2015
- 5. USNRC letter to Exelon Generation Company, LLC, "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", dated October 29, 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-13-118).
- 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-14-020).
- 8. Third 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, 2014 (RS-14-198).
Page 22 of 23
0 8
LI E.)
Dresden Nuclear Power Station, Units 2 and 3 Fourth Six-Month Status Report for the Implementation of SFP LI February 27, 2015 : Preliminary Plan View of Spent Fuel Pool Area Page 23 of 23