ML13063A012
| ML13063A012 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 02/28/2013 |
| From: | Heacock D Dominion, Dominion Nuclear Connecticut |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 12-165B, EA-12-051 | |
| Download: ML13063A012 (29) | |
Text
Dominion Nuclear Connecticut, Inc.
5,000 Dominion Boulevard, Glen Allen, VA 23060 jF~Dominion Web Address: www.dom.com 10 CFR 2.202 EA-12-051 February 28, 2013 Attention: Document Control Desk Serial No.: 12-165B U.S. Nuclear Regulatory Commission NL&OS/MAE: R2 Washington, D.C. 20555-0001 Docket Nos.: 50-336/423 License Nos.: DPR-65 NPF-49 DOMINION NUCLEAR CONNECTICUT, INC.
MILLSTONE POWER STATION UNITS 2 AND 3 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)
References:
- 1. NRC Order Number EA-12-051, Order Modifying Licenses with Regard to Requirements for Reliable Spent Fuel Pool Instrumentation, dated March 12, 2012 (ML12073A202)
- 2. NRC Interim Staff Guidance JLD-ISG-2012-03, Compliance with Order EA-12-051, Order Modifying Licenses with Regard to Requirements for Reliable Spent Fuel Pool Instrumentation, Revision 0, dated August 29, 2012 (ML12221A339)
On March 12, 2012, the Nuclear Regulatory Commission (NRC) issued an order (Reference 1) to Dominion Nuclear Connecticut, Inc. (DNC). Reference 1 (the Order) was immediately effective and directs DNC to have a reliable indication of the water level in associated spent fuel storage pools. Specific requirements are outlined in of the Order.
An answer to the Order was provided on March 26, 2012 (Serial No.12-165) and an Initial Status Report was provided within 60 days of the issuance of Reference 2, on October 25, 2012 (Serial No. 12-165A). This letter confirms that DNC has applied Reference 2 and developed Overall Integrated Plans in accordance with the guidance.
The Overall Integrated Plans as required by Section IV, Condition C.I.a of the Order are provided for Millstone Units 2 and 3 as Enclosures 1 and 2, respectively, to this letter.
The Overall Integrated Plans are based on conceptual design information. Finalized design details and associated procedural guidance as well as any modifications or clarifications to the information contained in the enclosures, will be provided in the 6-month Integrated Plan updates required by the Order.
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Serial No. 12-165B Order EA-12-051 Docket Nos. 50-336/423 Page 2 of 3 If you have any questions, please contact Ms. Margaret Earle at (804) 273-2768.
Sincerely, David A. Heacock President and Chief Nuclear Officer Dominion Nuclear Connecticut, Inc.
Enclosures Commitments made by this letter: No New Regulatory Commitments COMMONWEALTH OF VIRGINIA COUNTY OF HENRICO The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today by David A. Heacock who is President and Chief Nuclear Officer of Dominion Nuclear Connecticut, Inc. He has affirmed before me that he is duly authorized to execute and file the foregoing document in behalf of the Company, and that the statements in the document are true to the best of his knowledge and belief.
Acknowledged before me thilwd2ay oký,A ( 2013.
My Commission Expires. ., 3)
VCKI L.HULL dNotary Public INotary Public (SEAL) Commonwealth of Virginia My ComsinEprsMy3.21 140542 (SEALa 01
Serial No. 12-165B Order EA-12-051 Docket Nos. 50-336/423 Page 3 of 3 cc: Director of Office of Nuclear Reactor Regulation (w/o Enclosures)
U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 13H16M 11555 Rockville Pike Rockville, MD 20852-2738 U. S. Nuclear Regulatory Commission, Region I Regional Administrator 2100 Renaissance Blvd.
Suite 100 King of Prussia, PA 19406-2713 Mr. David H. Jaffe U. S. Nuclear Regulatory Commission Two White Flint North Mail Stop T6 D23 11545 Rockville Pike Rockville, MD 20852-2738 Mr. James S. Kim NRC Project Manager Millstone Units 2 and 3 U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 08 C 2A 11555 Rockville Pike Rockville, MD 20852-2738 NRC Senior Resident Inspector Millstone Power Station
Serial No. 12-165B Order EA-1 2-051 Docket No.:50-336 Enclosure 1 Millstone Unit 2 Overall Integrated Plan Reliable Spent Fuel Pool Instrumentation Millstone Power Station Dominion Nuclear Connecticut, Inc.
Serial No. 12-165B Order EA-12-051 Docket No. 50-336 Millstone Unit 2 Overall Integrated Plan Reliable Spent Fuel Pool Instrumentation I. Introduction The Nuclear Regulatory Commission (NRC) issued Order EA-12-051, Issuance of Order to Modify Licenses with Regard to Reliable Spent Fuel Pool Instrumentation, (Reference 1) on March 12, 2012. The Order requires licensees to have a reliable indication of the water level in spent fuel pools (SFPs) capable of supporting identification of the following pool water level conditions by trained personnel: (1) level that is adequate to support operation of the normal fuel pool cooling system, (2) level that is adequate to provide substantial radiation shielding for a person standing on the spent fuel pool operating deck, and (3) level where fuel remains covered and actions to implement make-up water addition should no longer be deferred. The Order also requires an overall integrated plan that provides a description of how the requirements of the Order will be achieved.
NEI 12-02, Industry Guidancefor Compliance with NRC OrderEA-12-051, 'To Modify Licenses with Regard to Reliable Spent Fuel Pool Instrumentation," (Reference 2) provides an approach for complying with Order EA-12-051. NRC Interim Staff Guidance (ISG) JLD-ISG-2012-03, Compliance with Order EA-12-051, Reliable Spent Fuel Pool Instrumentation,(Reference 3) considers that the methodologies and guidance in conformance with the guidelines provided in NEI 12-02, Revision 1, subject to the clarifications and exceptions specific to Section 3.4, Qualification, are an acceptable means of meeting the requirements of Order EA-12-051.
This integrated plan provides the Millstone Power Station Unit 2 (MPS2) approach for complying with Order EA-12-051 using the methods described in NRC ISG JLD-ISG-2012-03. The current revision of the MPS2 Integrated Plan is based on conceptual design information and will be revised as detailed design engineering proceeds. Consistent with the requirements of Order EA-12-051 and the guidance in NEI 12-02, six-month reports will delineate progress made, any proposed changes in compliance methods, updates to the schedule, and if needed, requests for relief and the bases.
Page 1 of 12
Serial No. 12-165B Order EA-12-051 Docket No. 50-336 II. Schedule The schedule for providing reliable SFP instrumentation at MPS2 is consistent with the requirements of Order EA-12-051 in that the new systems will be installed and functional no later than two refueling cycles following submittal of this overall integrated plan or December 2016, which ever occurs first. MPS2 will enter its next refueling outage (M2-R-22) in the spring of 2014; therefore, a functional system is required prior to completion of refueling cycle M2-R-23 in the fall of 2015. The current project milestones are:
" Commence Engineering and Design 1Q2013
" Complete Engineering and Design 3Q2013
- Complete Procurement of SFP Instruments 4Q2013
- Commence Installation of SFP Instruments 2Q2014
" Level Measurement System Functional 3Q2014 III. Identification of Spent Fuel Pool Water Levels The SFP is an L-shaped structure located in the Auxiliary Building adjacent to the Main Control Room. Two adjacent areas, which are accessible from the SFP by means of sealable gates, are the transfer canal and the spent fuel cask laydown pit. The SFP is designed to accommodate fuel racks that store new and spent fuel assemblies under water. Normal water level of the SFP is at elevation 36'-6".
- 1) Level 1 - This is indicated level on either the primary or back-up instrument channel of greater than approximate elevation 36'-0" plus the accuracy of the SFP level instrument channel, which is to be determined. This level is based on the elevation at which the top of the upper SFP cooling pump suction line penetrates the pool wall (Reference 4, Section 9.5.2.1).
- 2) Level 2 -This is indicated level on either the primary or back-up instrument channel of greater than approximate elevation 22'-5" plus the accuracy of the SFP level instrument channel, which is to be determined. This elevation is approximately 10' above the top of the fuel racks and ensures a minimum level of 10' above the top of the fuel (References 4). This water level ensures there is sufficient depth to provide radiation shielding for personnel to respond to Beyond-Design-Basis External Events and to initiate SFP makeup strategies.
Page 2 of 12
Serial No. 12-165B Order EA-12-051 Docket No. 50-336
- 3) Level 3 - This is indicated level on either the primary or back-up instrument channel of greater than approximate elevation 12'-5" plus the accuracy of the SFP level instrument channel, which is to be determined. This monitoring level assures that the fuel remains covered.
IV. Instruments Design of the instruments will be consistent with the guidelines of NRC ISG JLD-ISG-2012-03 and NEI 12-02 as discussed below.
The MPS2 SFP Primary and Back-up instrument channels will use Guided Wave Radar (GWR) based level measurement technology. GWR level measurement instruments work based on the Time Domain Reflectometry (TDR) principal. The device transmits low-intensity electromagnetic pulses along a rigid or flexible conductor where pulses move at the speed of light. When the pulses reach the surface of the medium to be measured, a portion of the signal is reflected back to the electronics. The instrument measures the time from when the pulse is transmitted to when it is received; half of the measured time will be equivalent to the distance from the reference point of the device to the surface of the measured process. The time value will be representative of the measured level and converted for use in displaying level information.
Attributes of a GWR/TDR system include:
" A sensor probe that is submerged in the process medium.
" Device performance that is not affected by dust, foam, agitated surfaces, boiling surfaces, changes in pressure, changes in temperature, changes in dielectric constant, or changes in density.
" The requirement to locate sensitive electronic equipment outside of the SFP area.
" Low power consumption.
" No mechanical moving parts which simplifies the installation and reduces maintenance.
- The ability to detect level with accuracy that meets the requirements of NEI 12-02.
The primary and back-up channels will use a fixed instrument providing continuous level measurement over the entire range. The measured range will be from approximately elevation 37'-0" to elevation 12'-5" - for a total indicated range of approximately 24'-7" (295 inches). SFP level is verified daily in accordance with existing procedures.
Page 3 of 12
Serial No. 12-165B Order EA-12-051 Docket No. 50-336 Primary instrument channel level sensing components will be located on the east wall of the SFP. Back-up instrument channel level sensing components will be located in the northwest corner of the SFP.
V. Reliability Reliability of the primary and back-up instrument channels will be assured by conformance with the guidelines of NRC ISG JLD-ISG-2012-03 and NEI 12-02, as discussed in Section IX, Qualification. Reliable level indication will be functional at all times consistent with Section XIII, Testing.
VI. Instrument Channel Design Criteria Instrument channel design criteria will be consistent with the guidelines of NRC ISG JLD-ISG-2012-03, Revision 0 and NEI 12-02, Revision 1.
Design criteria for both the primary and back-up channels will be consistent with the design criteria and basis associated with the SFP as described in the MPS2 UFSAR Section 9.5.1. Design requirements will be used as input to drive the detailed design, final equipment and vendor selection and final implementation.
VII. Arrangement The primary and back-up channel level sensor probes will be installed on opposite sides of the SFP to maintain adequate channel separation. In the conceptual design, the SFP probes bolt to a triangular mounting plate for installation at the corner of the SFP or a rectangular plate for mounting at the side of the SFP. The mounting options will allow the probe to be installed within a few inches of the SFP liner, minimizing the chances of interference with other structures, and occupying limited space on the SFP deck. Existing barriers and physical separation will be used to provide a level of protection for the sensor and interconnecting cable located along the SFP wall or on the refueling floor. These physical barriers will protect the instrument sensors and cables from potential missiles generated by an event. The final sensor mounting design and cable routing will maintain a low profile to ensure that there is no interference with the existing fuel handling equipment. Specific details will be developed during the detailed design phase.
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Serial No. 12-165B Order EA-12-051 Docket No. 50-336 Vendor electronics will be located in a mild environment of the Main Control Room providing adequate protection from temperature, humidity, and radiation. Level indicators will be located in the Main Control Room. Specific details will be developed during the detailed design phase.
The cables associated with a channel's sensor, power supply and indicator will be independently routed in separate raceways from cables associated with the other channel.
VIII. Mounting Both the primary and backup systems will be installedas Seismic Category I to meet the NRC ISG JLD-ISG-2012-03 and NEI 12-02 guidance requirements.
IX. Qualification General The sensors and cables for both channels will be reliable at temperature, humidity, and radiation levels consistent with the spent fuel pool water at saturation conditions over an extended period of time. Post event temperature at sensors and for cables located above the SFP is assumed to be 212°F. Post event humidity in the SFP floor area near and above the SFP is assumed to be 100% with condensing steam. The sensors and cables located in the vicinity of the SFP will be qualified to withstand peak and total integrated dose radiation levels for their installed location based on post event SFP water level equal to Level 3 for an extended period of time.
Sensor cable terminations will not be subject to pool overflow. The mounting and cable connecting the sensors will be qualified to the SFP environment described above. Conduit design in the SFP area will be installed to Seismic Class I criteria. Both existing and new barriers will be used to provide a level of protection for the exposed cable located on or near the refueling floor from missiles that may be generated by an event. The existing and new raceways used to route the sensor cable to the indicating transmitters (electronics) enclosures will be installed to Seismic Class I criteria.
Page 5 of 12
Serial No. 12-165B Order EA-12-051 Docket No. 50-336 Instrument channel reliability will be demonstrated via a combination of design, analyses, operating experience, and/or testing of channel components for the following sets of parameters:
- Conditions in the area of instrument channel components,
- Effects of shock and vibration on the instrument channel components, and
- Seismic effects on instrument channel components used during and following a potential seismic event.
Augmented quality requirements consistent with NEI 12-02, Appendix A-1 will be applied to this project.
Conditions Temperature, humidity and radiation levels consistent with conditions in the vicinity of the SFP and the area of use considering normal operational, event and post-event conditions will be addressed in the engineering and design phase. These conditions will be considered for no fewer than seven days post-event or until off-site resources can be deployed by the mitigating strategies resulting from Order EA-12-049 (Reference 5). Examples of post-event (beyond-design-basis) conditions that will be considered are:
- Radiological conditions for a normal refueling quantity of freshly discharged (100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br />) fuel with Level 3 SFP water level as described in Section III,
" Temperatures of 212 degrees F and 100% relative humidity environment,
" Boiling water and/or steam environment,
" A concentrated borated water environment, and
- The impact of FLEX mitigating strategies.
Shock and Vibration Components of the instrument channels will be qualified for shock and vibration using one or more of the following methods:
- Components are supplied by manufacturers using commercial quality programs (such as IS09001, Quality managementsystems - Requirements (Reference 6)) with shock and vibration requirements included in the purchase specification at levels commensurate with portable hand-held device or transportation applications; Page 6 of 12
Serial No. 12-165B Order EA-12-051 Docket No. 50-336
- Components have a substantial history of operational reliability in environments with significant shock and vibration loading, such as portable hand-held device or transportation applications; or
" Components are inherently resistant to shock and vibration loadings, such as cables.
Seismic For seismic effects on the installed instrument channel components, the following measures will be used to verify that the design and installation is adequate. Applicable components of the instrument channels are rated by the manufacturer (or otherwise tested) for seismic effects at levels commensurate with those of postulated design basis event conditions at the location of the instrument channel component using one or more of the following methods:
" Substantial history of operational reliability in environments with significant vibration, such as for portable hand-held devices or transportation applications. Such a vibration design envelope will be inclusive of the effects of seismic motion imparted to the components proposed at the location of the proposed installation;
" Adequacy of seismic design and installation is demonstrated based on the guidance in Sections 7, 8, 9, and 10 of IEEE Standard 344-2004, IEEE Recommended Practicefor Seismic Qualificationof Class 1E Equipmentfor Nuclear Power GeneratingStations, (Reference 7) or a substantially similar industrial standard; or
" Demonstration that proposed devices are substantially similar in design to models that have been previously tested for seismic effects in excess of the plant design basis at the location where the instrument is to be installed (g-levels and frequency ranges).
These requirements will be used as design input for the detailed design, vendor selection, and final implementation.
X. Independence The primary instrument channel will be redundant to and independent of the back-up instrument channel. Both the primary and back-up instrument channels will be of the same technology, manufacturer, and model.
Independence will be achieved through physical separation of the final installed instruments.
The two (2) permanently installed instrument sensors will be separated by a distance Page 7 of 12
Serial No. 12-165B Order EA-12-051 Docket No. 50-336 comparable to the shortest length of a side of the pool, to the extent practical, based on the existing SFP geometry and construction. The cables associated with each channel will follow separate and independent routes from the instruments to each electronic's enclosure and from the enclosures to the displays. The normal AC or DC power source for each channel will be provided from independent and separate sources.
XI. Power Supplies The normal power supply for each channel will be provided by different power sources such that loss of one power source will not result in the loss of both channels. In addition to the normal plant AC and/or DC power supply to each channel, a back-up power source will also be provided to each channel in the form of a back-up battery independent of the normal AC or DC power sources.
Specific details will be developed during the detailed design phase.
XIl. Accuracy The instrument channels will maintain their design accuracy following a power interruption or change in power source without requiring recalibration. Since the instrumentation is generally commercial off the shelf supplied components, the vendor published instrument accuracies will be verified as acceptable and will be used as a basis for final configuration and calibration procedures.
Accuracy requirements will consider SFP conditions, e.g., saturated water, steam environment, and concentrated borated water. Additionally, instrument accuracy will be sufficient to allow trained personnel to determine when the actual level exceeds the specified lower level of each indicating range (levels 1, 2 and 3) without conflicting or ambiguous indication. The GWR/TDR equipment selected will have accuracy within the resolution requirements of NEI 12-02, Figure 1.
Specific details regarding accuracy will be obtained from the supplier during the detailed design phase.
Page 8 of 12
Serial No. 12-165B Order EA-12-051 Docket No. 50-336 XIII. Testing Instrument channel design will provide for routine testing and calibration consistent with Order EA-12-051 and the guidance in NEI 12-02. The installed sensors will be designed to allow testing and/or calibration via in-situ methods while mounted in the pool. Removal of the sensor from the pool will not be required for calibration or testing.
Specific details regarding testing procedures and calibration requirements will be reviewed and determined with the supplier during the detailed design phase.
XIV. Display Trained personnel must be capable of monitoring the SFP water level from a location remote to that of the SFP area (e.g. control room, remote shutdown panel or other appropriate and accessible location). To that end, the selected location for the display(s) will ensure SFP level information is promptly made available to plant staff and key decision makers.
Since final indicator location will be based on the detailed design package, the distance between the sensing element and the display is currently not fully defined. However, it is expected that the display will be located at a distance within 500 feet from the sensing element in an appropriate and accessible area with the following characteristics:
" Occupied or promptly accessible to the appropriate plant staff giving appropriate consideration to various drain down scenarios,
- Outside the area surrounding the SFP floor, e.g., an appropriate distance from the radiological sources resulting from an event impacting the SFP,
- Inside a structure providing protection against adverse weather, and
- Outside any very high radiation area or locked high radiation area during normal operation.
The conceptual design locates the electronic enclosure and primary display in the Main Control Room. Specific details regarding the display and display location(s) will be finalized during the detailed design phase.
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Serial No. 12-165B Order EA-12-051 Docket No. 50-336 XV. Instrument Channel Program Criteria Training The Systematic Approach to Training (SAT) will be used to identify the population to be trained and to determine both the initial and continuing elements of the required training. Training will be completed prior to placing the instrumentation in service.
Specific details regarding training will be reviewed and determined between the plant and the supplier as part of the procurement process for the new instruments.
Procedures Procedures will be developed using guidelines and vendor instructions to address the maintenance, operation, and abnormal response issues associated with the new SFP instrumentation.
Procedures will address a strategy to ensure SFP water level addition is initiated at an appropriate time consistent with implementation of NEI 12-06, Diverse and Flexible Coping Strategies (FLEX) Implementation Guide (Reference 8).
Procedures will also address the following situations:
- If, at the time of an event or thereafter until the unit is returned to normal service, an instrument channel ceases to function, its function will be recovered within a period of time consistent with the emergency conditions that may apply at the time.
" If, at the time of an event or thereafter until the unit is returned to normal service, an instrument channel component must be replaced, we may use commercially available components that may or may not meet all of the qualifications (Section VII) to maintain the instrument channel functionality.
Testing and Calibration Processes will be established and maintained for scheduling and implementing necessary testing and calibration of the primary and back-up spent fuel pool level instrument channels to maintain the instrument channels at the design accuracy. Testing and calibration of the Page 10 of 12
Serial No. 12-165B Order EA-12-051 Docket No. 50-336 instrumentation will be consistent with vendor recommendations and any other documented basis. Calibration will be specific to the mounted instrument and the monitor.
XVI. Need for Relief and Basis Dominion Nuclear Connecticut Inc. is not requesting relief from the requirements of Order EA-12-051 or the guidance in NRC ISG JLD-ISG-2012-03 at this time.
Consistent with the requirements of Order EA-12-051 and the guidance in NEI 12-02, six-month reports will delineate progress made, any proposed changes in compliance methods, updates to the schedule, and if needed, requests for relief and their bases.
XVII. References
- 1) US Nuclear Regulatory Commission Order EA-12-051, "Issuance of Order to Modify Licenses with Regard to Reliable Spent Fuel Pool Instrumentation," March 12, 2012
- 2) 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, August 2012
- 3) NRC Interim Staff Guidance JLD-ISG-2012-03, "Compliance with Order EA-12-051, Reliable Spent Fuel Pool Instrumentation," Revision 0, August 29, 2012
- 4) Millstone Power Station Unit 2 Updated Final Safety Analysis Report
- 5) US Nuclear Regulatory Commission Order EA-12-049, "Issuance of Order to Modify Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events," March 12, 2012
- 6) 1509001, "Quality management systems - Requirements," Fourth Edition
- 7) IEEE Standard 344-2004, "IEEE Recommended Practice for Seismic Qualification of Class 1E Equipment for Nuclear Power Generating Stations" Page 11 of 12
Serial No. 12-165B Order EA-12-051 Docket No. 50-336
Revision 0, August 2012 Page 12 of 12
Serial No. 12-165B Order EA-12-051 Docket No.:50-336 Enclosure 2 Millstone Unit 3 Overall Integrated Plan Reliable Spent Fuel Pool Instrumentation Millstone Power Station Dominion Nuclear Connecticut, Inc.
Serial No. 12-165B Order EA-12-051 Docket No. 50-423 Millstone Unit 3 Overall Integrated Plan Reliable Spent Fuel Pool Instrumentation I. Introduction The Nuclear Regulatory Commission (NRC) issued Order EA-12-051, Issuance of Order to Modify Licenses with Regard to Reliable Spent Fuel Pool Instrumentation,(Reference 1) on March 12, 2012. The Order requires licensees to have a reliable indication of the water level in spent fuel pools (SFPs) capable of supporting identification of the following pool water level conditions by trained personnel: (1) level that is adequate to support operation of the normal fuel pool cooling system, (2) level that is adequate to provide substantial radiation shielding for a person standing on the spent fuel pool operating deck, and (3) level where fuel remains covered and actions to implement make-up water addition should no longer be deferred. The Order also requires an overall integrated plan that provides a description of how the requirements of the Order will be achieved.
NEI 12-02, Industry Guidancefor Compliance with NRC Order EA-12-051, "'To Modify Licenses with Regard to Reliable Spent Fuel Pool Instrumentation," (Reference 2) provides an approach for complying with Order EA-12-051. NRC Interim Staff Guidance (ISG) JLD-ISG-2012-03, Compliance with OrderEA-12-051, Reliable Spent Fuel Pool Instrumentation,(Reference 3) considers that the methodologies and guidance in conformance with the guidelines provided in NEI 12-02, Revision 1, subject to the clarifications and exceptions specific to Section 3.4, Qualification, are an acceptable means of meeting the requirements of Order EA-12-051.
This integrated plan provides the Millstone Power Station Unit 3 (MPS3) approach for complying with Order EA-12-051 using the methods described in NRC ISG JLD-ISG-2012-03. The current revision of the MPS3 Integrated Plan is based on conceptual design information and will be revised as detailed design engineering proceeds. Consistent with the requirements of Order EA-12-051 and the guidance in NEI 12-02, six-month reports will delineate progress made, any proposed changes in compliance methods, updates to the schedule, and if needed, requests for relief and the bases.
Page 1 of 12
Serial No. 12-165B Order EA-12-051 Docket No. 50-423 II. Schedule The schedule for providing reliable SFP instrumentation at MPS3 is consistent with the requirements of Order EA-12-051 in that the new systems will be installed and functional no later than two refueling cycles following submittal of this overall integrated plan or December 2016, which ever occurs first. MPS3 will enter its next refueling outage (M3-R-15) in the spring of 2013; therefore, a functional system is required prior to completion of refueling cycle M3-R-16 in the fall of 2014. The current project milestones are:
- Commence Engineering and Design 1Q2013
" Complete Engineering and Design 3Q2013
" Complete Procurement of SFP Instruments 4Q2013
" Commence Installation of SFP Instruments 2Q2014
- Level Measurement System Functional 3Q2014 III. Identification of Spent Fuel Pool Water Levels The SFP is an L-shaped structure located in the southwestern quadrant of the fuel building. Two adjacent areas, which are accessible from the SFP by means of sealable gates, are the transfer canal and the spent fuel shipping cask pit. The SFP is designed to accommodate fuel racks that store new and spent fuel assemblies under water. Normal water level of the SFP is at elevation 49'-10".
- 1) Level 1 -This is indicated level on either the primary or back-up instrument channel of greater than approximate elevation 46'-10" plus the accuracy of the SFP level instrument channel, which is to be determined. This level is based on the elevation at which the top of the SFP cooling pump suction lines penetrate the pool walls.
- 2) Level 2 - This is indicated level on either the primary or back-up instrument channel of greater than approximate elevation 35'-4" plus the accuracy of the SFP level instrument channel, which is to be determined. This elevation is approximately 10' above the top of the fuel racks and ensures a minimum level of 10' above the top of the fuel (Reference 4). This water level ensures there is sufficient depth to provide radiation shielding for personnel to respond to Beyond-Design-Basis External Events and to initiate SFP makeup strategies.
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Serial No. 12-165B Order EA-12-051 Docket No. 50-423
- 3) Level 3 - This is indicated level on either the primary or back-up instrument channel of greater than approximate elevation 25'-4" plus the accuracy of the SFP level instrument channel, which is to be determined. This monitoring level assures that the fuel remains covered (Reference 4).
IV. Instruments Design of the instruments will be consistent with the guidelines of NRC ISG JLD-ISG-2012-03 and NEI 12-02 as discussed below.
The MPS3 SFP Primary and Back-up instrument channels will use Guided Wave Radar (GWR) based level measurement technology. GWR level measurement instruments work based on the Time Domain Reflectometry (TDR) principal. The device transmits low-intensity electromagnetic pulses along a rigid or flexible conductor where pulses move at the speed of light. When the pulses reach the surface of the medium to be measured, a portion of the signal is reflected back to the electronics. The instrument measures the time from when the pulse is transmitted to when it is received; half of the measured time will be equivalent to the distance from the reference point~of the device to the surface of the measured process. The time value will be representative of the measured level and converted for use in displaying level information.
Attributes of a GWR/TDR system include:
" A sensor probe that is submerged in the process medium.
" Device performance that is not affected by dust, foam, agitated surfaces, boiling surfaces, changes in pressure, changes in temperature, changes in dielectric constant, or changes in density.
" The requirement to locate sensitive electronic equipment outside of the SFP area.
- Low power consumption.
- No mechanical moving parts which simplifies the installation and reduces maintenance.
" The ability to detect level with accuracy that meets the requirements of NEI 12-02.
The primary and back-up channels will use a fixed instrument providing continuous level measurement over the entire range. The measured range will be from approximately elevation 50'-4" to elevation 25'-4" - for a total indicated range of approximately 25'-0" (300 inches). SFP level is verified daily in accordance with existing procedures.
Page 3 of 12
Serial No. 12-165B Order EA-12-051 Docket No. 50-423 Primary instrument channel level sensing components will be located on the east wall of the SFP. Back-up instrument channel level sensing components will be located in the west wall of the SFP.
V. Reliability Reliability of the primary and back-up instrument channels will be assured by conformance with the guidelines of NRC ISG JLD-ISG-2012-03 and NEI 12-02, as discussed in Section IX, Qualification. Reliable level indication will be functional at all times consistent with Section XIII, Testing.
VI. Instrument Channel Design Criteria Instrument channel design criteria will be consistent with the guidelines of NRC ISG JLD-ISG-2012-03, Revision 0 and NEI 12-02, Revision 1.
Design criteria for both the primary and back-up channels will be consistent with the design criteria and basis associated with the SFP as described in the MPS3 UFSAR Section 9.1.3.1.
Design requirements will be used as input to drive the detailed design, final equipment and vendor selection and final implementation.
VII. Arrangement The primary and back-up channel level sensor probes will be installed on opposite sides of the SFP to maintain adequate channel separation. In the conceptual design, the SFP probes bolt to a triangular mounting plate for installation at the corner of the SFP or a rectangular plate for mounting at the side of the SFP. The mounting options will allow the probe to be installed within a few inches of the SFP liner, minimizing the chances of interference with other structures, and occupying limited space on the SFP deck. Existing barriers and physical separation will be used to provide a level of protection for the sensor and interconnecting cable located along the SFP wall or on the refueling floor. These physical barriers will protect the instrument sensors and cables from potential missiles generated by an event. The final sensor mounting design and cable routing will maintain a low profile to ensure that there is no interference with the existing fuel handling equipment. Specific details will be developed during the detailed design phase.
Page 4 of 12
Serial No. 12-165B Order EA-12-051 Docket No. 50-423 Vendor electronics will be located in a mild environment of the Auxiliary Building providing adequate protection from temperature, humidity, and radiation. Level indicators also will be located in the Auxiliary Building. This display location is designed to withstand tornado effects and is not within a very high radiation or locked high radiation area. Due to cable length considerations, locating the display in this area is still under consideration. Specific details will be developed during the detailed design phase.
The cables associated with a channel's sensor, power supply and indicator will be independently routed in separate raceways from cables associated with the other channel.
VIII. Mounting Both the primary and backup systems will be installed as Seismic Category I to meet NRC ISG JLD-ISG-2012-03 and NEI 12-02 guidance requirements.
IX. Qualification General The sensors and cables for both channels will be reliable at temperature, humidity, and radiation levels consistent with the spent fuel pool water at saturation conditions over an extended period of time. Post event temperature at sensors and for cables located above the SFP is assumed to be 212 0 F. Post event humidity in the SFP floor area near and above the SFP is assumed to be 100% with condensing steam. The sensors and cables located in the vicinity of the SFP will be qualified to withstand peak and total integrated dose radiation levels for their installed location based on post event SFP water level equal to Level 3 for an extended period of time.
Sensor cable terminations will not be subject to pool overflow. The mounting and cable connecting the sensors will be qualified to the SFP environment described above. Conduit design in the SFP area will be installed to Seismic Class 1 criteria. Both existing and new barriers will be used to provide a level of protection for the exposed cable located on or near the refueling floor from missiles that may be generated by an event. The existing and new raceways used to route the sensor cable to the indicating transmitters (electronics) enclosures will be installed to Seismic Class 1 criteria.
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Serial No. 12-165B Order EA-12-051 Docket No. 50-423 Instrument channel reliability will be demonstrated via combination of design, analyses, operating experience, and/or testing of channel components for the following sets of parameters:
" Conditions in the area of instrument channel components,
- Effects of shock and vibration on the instrument channel components, and
" Seismic effects on instrument channel components used during and following a potential seismic event.
Augmented quality requirements consistent with NEI 12-02, Appendix A-1 will be applied to this project.
Conditions Temperature, humidity and radiation levels consistent with conditions in the vicinity of the SFP and the area of use considering normal operational, event and post-event conditions will be addressed in the engineering and design phase. These conditions will be considered for no fewer than seven days post-event or until off-site resources can be deployed by the mitigating strategies resulting from Order EA-12-049 (Reference 5). Examples of post-event (beyond-design-basis) conditions that will be considered are:
- Radiological conditions for a normal refueling quantity of freshly discharged (100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br />) fuel with Level 3 SFP water level as described in Section III,
" Temperatures of 212 degrees F and 100% relative humidity environment,
" Boiling water and/or steam environment,
" A concentrated borated water environment, and
" The impact of FLEX mitigating strategies.
Shock and Vibration Components of the instrument channels will be qualified for shock and vibration using one or more of the following methods:
Components are supplied by manufacturers using commercial quality programs (such as IS09001, Quality managementsystems - Requirements (Reference 6)) with shock and vibration requirements included in the purchase specification at levels commensurate with portable hand-held device or transportation applications; Page 6 of 12
Serial No. 12-165B Order EA-12-051 Docket No. 50-423
" Components have a substantial history of operational reliability in environments with significant shock and vibration loading, such as portable hand-held device or transportation applications; or
" Components are inherently resistant to shock and vibration loadings, such as cables.
Seismic For seismic effects on the installed instrument channel components, the following measures will be used to verify that the design and installation are adequate. Applicable components of the instrument channels are rated by the manufacturer (or otherwise tested) for seismic effects at levels commensurate with those of postulated design basis event conditions at the location of the instrument channel component using one or more of the following methods:
- Substantial history of operational reliability in environments with significant vibration, such as for portable hand-held devices or transportation applications. Such a vibration design envelope will be inclusive of the effects of seismic motion imparted to the components proposed at the location of the proposed installation;
" Adequacy of seismic design and installation is demonstrated based on the guidance in Sections 7, 8, 9, and 10 of IEEE Standard 344-2004, IEEE Recommended Practicefor Seismic Qualificationof Class 1E Equipmentfor Nuclear Power GeneratingStations, (Reference 7) or a substantially similar industrial standard; or
" Demonstration that proposed devices are substantially similar in design to models that have been previously tested for seismic effects in excess of the plant design basis at the location where the instrument is to be installed (g-levels and frequency ranges).
These requirements will be used as design input for the detailed design, vendor selection, and final implementation.
X. Independence The primary instrument channel will be redundant to and independent of the back-up instrument channel. Both the primary and back-up instrument channels will be of the same technology, manufacturer, and model.
Independence will be achieved through physical separation of the final installed instruments.
The two (2) permanently installed instrument sensors will be separated by a distance Page 7 of 12
Serial No. 12-165B Order EA-12-051 Docket No. 50-423 comparable to the shortest length of a side of the pool, to the extent practical, based on the existing SFP geometry and construction. The cables associated with each channel will follow separate and independent routes from the instruments to each electronic's enclosure and from the enclosures to the displays. The normal AC or DC power source for each channel will be provided from independent and separate sources.
XI. Power Supplies The normal power supply for each channel will be provided by different power sources such that loss of one power source will not result in the loss of both channels. In addition to the normal plant AC and/or DC power supply to each channel, a back-up power source will also be provided to each channel in the form of a back-up battery independent of the normal AC or DC power sources.
Specific details will be developed during the detailed design phase.
XIl. Accuracy The instrument channels will maintain their design accuracy following a power interruption or change in power source without requiring recalibration. Since the instrumentation is generally commercial off the shelf supplied components, the vendor published instrument accuracies will be verified as acceptable and will be used as a basis for final configuration and calibration procedures.
Accuracy requirements will consider SFP conditions, e.g., saturated water, steam environment, and concentrated borated water. Additionally, instrument accuracy will be sufficient to allow trained personnel to determine when the actual level exceeds the specified lower level of each indicating range (levels 1, 2 and 3) without conflicting or ambiguous indication. The GWR/TDR equipment selected will have accuracy within the resolution requirements of NEI 12-02, Figure 1.
Specific details regarding accuracy will be obtained from the supplier during the detailed design phase.
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Serial No. 12-165B Order EA-12-051 Docket No. 50-423 X111. Testing Instrument channel design will provide for routine testing and calibration consistent with Order EA-12-051 and the guidance in NEI 12-02. Sensors will be designed to allow testing and/or calibration via in-situ methods while mounted in the pool. Removal of the sensor from the pool will not be required for calibration or testing.
Specific details regarding testing procedures and calibration requirements will be reviewed and determined with the supplier during the detailed design phase.
XIV. Display Trained personnel must be capable of monitoring the SFP water level from a location remote to that of the SFP area (e.g. control room, remote shutdown panel or other appropriate and accessible location). To that end, the selected location for the display(s) will ensure SFP level information is promptly made available to plant staff and key decision makers.
Since final indicator location will be based on the detailed design package, the distance between the sensing element and the display is currently not fully defined. However, it is expected that the display will be located at a distance within 500 feet from the sensing element in an appropriate and accessible area with the following characteristics:
- Occupied or promptly accessible to the appropriate plant staff giving appropriate consideration to various drain down scenarios,
" Outside the area surrounding the SFP floor, e.g., an appropriate distance from the radiological sources resulting from an event impacting the SFP,
" Inside a structure providing protection against adverse weather, and
" Outside any very high radiation area or locked high radiation area during normal operation.
The conceptual design locates the electronic enclosure and primary display in the Auxiliary Building. Specific details regarding the display and display location(s) will be finalized during the detailed design phase.
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Serial No. 12-165B Order EA-12-051 Docket No. 50-423 XV. Instrument Channel Program Criteria Traininq The Systematic Approach to Training (SAT) will be used to identify the population to be trained and to determine both the initial and continuing elements of the required training. Training will be completed prior to placing the instrumentation in service.
Specific details regarding training will be reviewed and determined between the plant and the supplier as part of the procurement process for the new instruments.
Procedures Procedures will be developed using guidelines and vendor instructions to address the maintenance, operation, and abnormal response issues associated with the new SFP instrumentation.
Procedures will address a strategy to ensure SFP water level addition is initiated at an appropriate time consistent with implementation of NEI 12-06, Diverse and Flexible Coping Strategies (FLEX) Implementation Guide (Reference 8).
Procedures will also address the following situations:
" If, at the time of an event or thereafter until the unit is returned to normal service, an instrument channel ceases to function, its function will be recovered within a period of time consistent with the emergency conditions that may apply at the time.
" If, at the time of an event or thereafter until the unit is returned to normal service, an instrument channel component must be replaced, commercially available components may be used that may or may not meet all of the qualifications (Section VII) to maintain the instrument channel functionality.
Testing and Calibration Processes will be established and maintained for scheduling and implementing necessary testing and calibration of the primary and back-up spent fuel pool level instrument channels to maintain the instrument channels at the design accuracy. Testing and calibration of the Page 10 of 12
Serial No. 12-165B Order EA-12-051 Docket No. 50-423 instrumentation will be consistent with vendor recommendations and any other documented basis. Calibration will be specific to the mounted instrument and the monitor.
XVI. Need for Relief and Basis Dominion Nuclear Connecticut, Inc. is not requesting relief from the requirements of Order EA-12-051 or the guidance in NRC ISG JLD-ISG-2012-03 at this time.
Consistent with the requirements of Order EA-12-051 and the guidance in NEI 12-02, the six-month reports will delineate progress made, any proposed changes in compliance methods, updates to the schedule, and if needed, requests for relief and their bases.
XVII. References
- 1) US Nuclear Regulatory Commission Order EA-12-051, "Issuance of Order to Modify Licenses with Regard to Reliable Spent Fuel Pool Instrumentation," March 12, 2012
- 2) 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, August 2012
- 3) NRC Interim Staff Guidance JLD-ISG-2012-03, "Compliance with Order EA-12-051, Reliable Spent Fuel Pool Instrumentation," Revision 0, August 29, 2012
- 4) Millstone Power Station Unit 3 Updated Final Safety Analysis Report
- 5) US Nuclear Regulatory Commission Order EA-12-049, "Issuance of Order to Modify Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events," March 12, 2012
- 6) ISO9001, "Quality management systems - Requirements," Fourth Edition
- 7) IEEE Standard 344-2004, "IEEE Recommended Practice for Seismic Qualification of Class 1E Equipment for Nuclear Power Generating Stations" Page 11 of 12
Serial No. 12-165B Order EA-12-051 Docket No. 50-423
Revision 0, August 2012 Page 12 of 12