RS-13-178, Response to Request for Additional Information, Overall Integrated Plan in Response to Commission Order Modifying License Requirements for Reliable Spent Fuel Pool Instrumentation (Order No. EA-12-051)
| ML13200A343 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 07/19/2013 |
| From: | David Helker Exelon Generation Co |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| EA-12-051, RS-13-178 | |
| Download: ML13200A343 (14) | |
Text
RS-13-178 Order No. EA-12-051 July 19, 2013 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Peach Bottom Atomic Power Station, Units 2 and 3 Renewed Facility Operating License Nos. DPR-44 and DPR-56 NRC Docket Nos. 50-277 and 50-278
Subject:
Response to Request for Additional Information - Overall Integrated Plan in Response to Commission Order Modifying License Requirements for Reliable Spent Fuel Pool Instrumentation (Order No. EA-12-051)
References:
- 1. Exelon Generation Company, LLC letter to USNRC, Overall Integrated Plan in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Requirements for Reliable Spent Fuel Pool Instrumentation (Order Number EA-12-051), dated February 28,2013 (RS-13-034)
- 2. NRC Order Number EA-12-051, Issuance of Order to Modify 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 24, 2013 In Reference 1, Exelon Generation Company, LLC (EGC) provided the Peach Bottom Atomic Power Station, Units 2 and 3, Overall Integrated Plan in Response to the March 12, 2012 Commission Order Modifying Licenses with Regard to Requirements for Reliable Spent Fuel Pool Instrumentation, pursuant to NRC Order No. EA-12-051 (Reference 2).
The purpose of this letter is to provide the response to the NRC request for additional information (Reference 3) regarding the Peach Bottom Atomic Power Station, Units 2 and 3 Overall Integrated Plan in Response to the Commission Order Modifying Licenses with Regard to Requirements for Reliable Spent Fuel Pool Instrumentation (Order No. EA-12-051).
The Peach Bottom Atomic Power Station, Units 2 and 3 Spent Fuel Pool Instrumentation design is proceeding on the schedule identified in the Overall Integrated Plan provided in Reference 1.
The enclosed responses to the NRC request for additional information are intended not to provide preliminary or conceptual information. The requested information, when fully developed, will be provided upon detailed design completion based on the milestone schedule dates provided in each response.
U.S. Nuclear Regulatory Commission Response to Request for Additional Information (Order EA-12-051)
July 19, 2013 Page 2 This letter contains no new regulatory commitments. If you have any questions regarding this response, 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 19th day of July 201 Respectfully submitted, David P. Helker Manager Licensing & Regulatory Affairs Exelon Generation Company, LLC
Enclosure:
- 1. Peach Bottom Atomic Power Station, Units 2 and 3 - Response to Request for Additional Information - Overall Integrated Plan in Response to Commission Order Modifying License Requirements for Reliable Spent Fuel Pool Instrumentation (Order No. EA-12-051) cc: Director, Office of Nuclear Reactor Regulation NRC Regional Administrator - Region I NRC Senior Resident Inspector - Peach Bottom Atomic Power Station, Units 2 and 3 NRC Project Manager, NRR - Peach Bottom Atomic Power Station, Units 2 and 3 Mr. Robert J. Fretz, Jr, NRRIJLD/PMB, NRC Mr. Robert L. Dennig, NRRIDSS/SCVB, NRC Mr. Blake Pumell, NRC Project Manager, NRR Director, Bureau of Radiation Protection Pennsylvania Department of Environmental Resources S.1. Gray, State of Maryland R. R. Janati, Chief, Division of Nuclear Safety, Pennsylvania Department of Environmental Protection, Bureau of Radiation Protection
Enclosure 1 Peach Bottom Atomic Power Station, Units 2 and 3 Response to Request for Additional Information Overall Integrated Plan in Response to Commission Order Modifying License Requirements for Reliable Spent Fuel Pool Instrumentation (Order No. EA-12-051)
(11 pages)
Response to Request for Additional Information (Order EA-12-051) 1 of 11
1.0 INTRODUCTION
By dated February 2013 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML13059A390), Exelon Generation Company, LLC (the licensee) submitted an Overall Integrated Plan (OIP), for Peach Bottom Atomic Power Station (PBAPS),
Units 2 and in response to the March 12,201 U.S. Nuclear Regulatory Commission (NRC)
Order modifying licenses with regard to requirements for reliable spent fuel pool {SFP}
Instrumentation (Order Number EA-12-051; ADAMS Accession No. ML12054A679). The NRC staff endorsed Nuclear Energy Institute (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 (ADAMS Accession No. ML12240A307), with exceptions, as documented in Interim Staff Guidance (ISG) 2012-03 "Compliance with Order EA-12-051, Reliable Spent Fuel Pool Instrumentation," Revision 0, dated August 29, 2012 (ADAMS Accession No. ML12221A339).
The NRC staff has reviewed the February 28, 2013, response by the licensee and determined that the following Request for Additional Information (RAI) is needed to complete its technical review. The sections that follow are numbered to coincide with the arrangement presented in NEI 12-02.
2.0 LEVELS OF REQUIRED MONITORING The 01 P states, in part, that key SFP levels will be identified as follows:
Level 1 - level adequate to support operation of the normal fuel pool cooling system: For both units, this level on the primary and backup [spent fuel pool instrumentation (SFPI)] channels is greater than 22 feet 9 inches (elevation 232 feet 9 inches) plus instrument accuracy above top of the spent fuel storage racks. This level is based on the design accuracy of the SFPI channel, and a resolution of 1 foot or better for both the primary and backup instrument channels. The daily SFP level is monitored and recorded under an operator's
[surveillance test (ST)] procedure. The PBAPS SFPs have weirs that maintain the normal level between 232 feet 9 inches and 233 feet 0 inches, with 232 feet 10 inches the normal level per the ST.
Level 2 - level adequate to provide substantial radiation shielding for a person standing on the spent fuel pool operating deck: For both units, this level on the primary and backup SFPI channels is greater than 10 feet 0 inches (elevation 220 feet 0 inches) plus instrument accuracy above the top of the spent fuel storage racks. This is based on specification of this level as adequate in NRC JLD-ISG-2012-03 and NEI 12-02, the design accuracy of the SFPI channel, and the relatively low sensitivity of dose rates to water depth changes at this level. This level ensures there is adequate water to provide substantial radiation shielding from direct gamma radiation from stored spent fuel.
Level 3 - level at which fuel remains covered: For both units, this level on the primary and backup SFPI channels is greater than 0 feet 0 inches (elevation 210 feet 0 inches) plus instrument accuracy above the top of the spent fuel storage racks. This is based upon the design accuracy of the SFPI channel, and a
Response to Request for Additional Information (Order EA-12-051)
Page 2 of 11 resolution better than 1 foot for both the primary and backup SFPI channels. This monitoring level assures there is water covering the spent fuel stored in the racks.
RAI-1
Please provide the following:
a) For level 1, specify how the identified location represents the HIGHER of the two points described in the NEI 12-02 guidance for this level.
b) A clearly labeled sketch depicting the elevation view of the proposed typical mounting arrangement for the portions of instrument channel consisting of permanent measurement channel equipment (e.g., fixed level sensors and/or stilling wells, and mounting brackets). Indicate on this sketch the datum values representing Level 1, Level 2, and Level 3, as well as the top of the fuel racks. Indicate on this sketch the portion of the level sensor measurement range that is sensitive to measurement of the fuel pool level, with respect to the Level 1, Level 2, and Level 3 datum points.
Response
a) The Spent Fuel Pools at Peach Bottom Units 2 and 3 have skimmers and scuppers. The top of the weir is normally set at elevation 232'- 8.5" to maintain a Spent Fuel Pool water level of 232'-10" when the Fuel Pool Cooling system is in service. The water in the fuel pool flows over the weir and into the skimmer surge tanks from which the Fuel Pool Cooling Pumps draw suction. Fuel Pool Skimmer Surge Tank Level switches LS-2(3)696 will trip the Fuel Pool Cooling Pumps if the Skimmer Surge Tank level falls to elevation 213'-0". Therefore the 232'-10" elevation based on the elevation of the fuel pool weir is the higher of the two points noted in NEI 12-02, Section 2.3.1.
b) Please reference the following sketch. Level probe mounting details in the Spent Fuel Pool area will be provided in accordance with the response to RAI-3.
Response to Request for Additional Information (Order EA*12*051)
Page 3 of 11 Ii[
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(JOOl (1-'/SJJlh) X 40' ' ASUlltcSfl CAL JR JNI'S & 3) 3.0 INSTRUMENTATION DESIGN FEATURES 3.2 Arrangement The 01 P states, in part, that:
The SFPI design will install fixed primary and backup SFP level sensors, considering the northeast and southeast corners of the Unit 2 and Unit 3 SFPs.
The sensors on each unit will be separated by a distance in excess of 30 feet.
The SFPI design will verify the eastern sides of the SFPs meet arrangement criteria and facilitate associated conduit runs, or will design to a more appropriate arrangement. The sensors will be mounted, to the extent practical, near the pool walls and below the pool curb to minimize their exposure to damaging debris and not interfere with SFP activities. SFPI channel electronics and power supplies will be located in seismic and missile protected areas either below the Reactor
lCUiUC;Ol for Additional Information (Order EA~ 1 )
The areas environmental for each
RAI-2
1-11"'::1"' provide a clearly labeled sketch or marked* up plant drawing of the plan view of the SFP area, depicting the SFP inside dimensions, the planned locations/placement of the primary and back~up SFP level and the proposed routing of the cables that will extend from the sensors toward the location of the read~outldisplay device.
Response
The current plan for the design of the SFPI system based on the Exelon Nuclear program schedule for Peach Bottom is to start the design phase for Unit 3 in November of 2013 with design completion and 100% acceptance of the design in June of 2014. The requested information will provided in the August 2014, 6~month Integrated Plan Update. The Unit 2 design phase is to start in June 2014 and completion is scheduled for December 2014. The Unit 2 information will be included as part of the February 2015, 6~month Integrated Plan Update.
3.3 Mounting The 01 P states, in part, that:
Design of the mounting of the sensors in the SFP shall be consistent with the seismic Class I criteria. Installed equipment will be verified to be seismically adequate for the seismic motions associated with the maximum seismic ground motion considered in the design of the plant area in which it is installed.
RAI-3
Please provide the following:
a) The design criteria that will be used to estimate the total loading on the mounting device(s), including static weight loads and dynamiC loads. Describe the methodology that will be used to estimate the total loading, inclusive of design-basis maximum seismic loads and the hydrodynamic loads that could result from pool sloshing or other effects that could accompany such seismic forces.
b) A description of the manner in which the level sensor (and stilling well, if appropriate) will be attached to the refueling floor and/or other support structures for each planned point of attachment of the probe assembly. Indicate in a schematic the portions of the level sensor that will serve as points of attachment for mechanical/mounting or electrical connections.
Response to Request for Additional Information (Order EA-12-051) 5 of 11 c) A of the manner by which the mechanical connections will attach the level instrument to permanent SFP structures so as to support the level sensor assembly.
Response
The current plan for the design of the SFPI system based on the Exelon Nuclear program schedule for Peach Bottom is to start the design phase for Unit 3 in November of 2013 with design completion and 100% acceptance of the design in June of 2014. The requested information will be provided in the August 2014, 6-month Integrated Plan Update. The Unit 2 design phase is to start in June 2014 and completion is scheduled for December 2014. The Unit 2 information will be included as part of the February 2015, 6-month Integrated Plan Update.
3.4 Qualification The OIP states, in part, that:
Components of the SFPI channels will be rated by the manufacturer (or otherwise tested) for shock and vibration during and following any applicable event, using one or more of the following methods:
- components use known operating principles, are supplied by using commercial quality programs (such as IS09001) with shock and vibration requirements included in the purchase specification and instrument design.
The components will be designed and tested for operation in environments where significant shock and vibrations are common,
- components have substantial history of operational reliability in environments with significant shock and vibration loadings, such as transportation applications, or
- components are inherently resistant to shock and vibration loadings, such as cables.
SFPI components (except for battery chargers and replaceable batteries) will be rated by the manufacturer (or otherwise tested) for seismic effects at levels commensurate with postulated design basis event conditions in the area, using one or more of the following methods: ...
RAI-4
Please provide the following:
a) A description of the specific method or combination of methods you intend to apply to demonstrate the reliability of the permanently installed equipment under Beyond-Design-Basis (BDB) ambient temperature, humidity, shock, vibration, and radiation conditions.
b) A description of the testing and/or analyses that will be conducted to provide assurance that the equipment will perform reliably under the worst-case credible design-basis
Response to Request for Additional Information (Order EA-12-051)
Page 6 of 11 loading at the location where the equipment will be mounted. Include a discussion of this seismic reliability demonstration as it applies to (i) the level sensor mounted in the SFP area, and (ii) 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.
Response
The current plan for the design of the SFPI system based on the Exelon Nuclear program schedule for Peach Bottom is to start the design phase for Unit 3 in November of 2013 with design completion and 100% acceptance of the design in June of 2014. The requested information will be provided in the August 2014, 6-month Integrated Plan Update. The Unit 2 design phase is to start in June 2014 and completion is scheduled for December 2014. The Unit 2 information will be included as part of the February 2015, 6-month Integrated Plan Update.
3.5 Independence The OIP states, in part, that:
The primary SFPI channel will be independent of the backup SFPI channel. This independence will be achieved through physical and electrical separation of each channels' components commensurate with hazard and electrical isolation needs.
RAI-5
Please provide the following:
a) A description of how the two channels of the proposed level measurement system meet this requirement so that the potential for a common cause event to adversely affect both channels is minimized to the extent practicable.
b) Further information describing the design and installation of each level measurement system, consisting of level sensor electronics, cabling, and readout devices. Please 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.
Response
The current plan for the design of the SFPI system based on the Exelon Nuclear program schedule for Peach Bottom is to start the design phase for Unit 3 in November of 2013 with design completion and 100% acceptance of the design in June of 2014. The requested
to Request for Additional Information (Order EA-1 Page 7 of 11 information will be provided in the August 2014, 6-month Integrated Plan Update. The Unit 2 design phase is to start in June 2014 and completion is scheduled for December 2014. The Unit 2 information will be included as part of the February 201 6-month Integrated Plan Update.
3.6 Power Supplies The OIP states, in part, that:
The SFPI design will identify power sources from different buses. Upon loss of normal power, individual channel installed batteries will automatically maintain continuous channel operation. The batteries will be replaceable and be sized to maintain channel operation until off-site resources can be deployed by the mitigating strategies resulting from Order EA-12-049. Each channel will have provisions for connection to another suitable power source, as designed and supplied in accordance with Order EA-12-049.
RAI-6
Please provide the following:
a) A description of the electrical alternating current 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 Uninterruptible 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 BOB event for the minimum duration needed, consistent with the plant mitigation strategies for BOB external events (Order EA-12-049).
Response
The current plan for the design of the SFPI system based on the Exelon Nuclear program schedule for Peach Bottom is to start the design phase for Unit 3 in November of 2013 with design completion and 100% acceptance of the design in June of 2014. The requested information will be provided in the August 2014, 6-month Integrated Plan Update. The Unit 2 design phase is to start in June 2014 and completion is scheduled for December 2014. The Unit 2 information will be included as part of the February 2015, 6-month Integrated Plan Update.
3.7 Accuracy The OIP states, in part, that:
The SFPI design will select components designed to maintain their accuracy following a power interruption or change in power source without recalibration.
Response to Request for Additional Information (Order EA-12-051)
Page 8 of 11 SFPI channel including display accuracy, to be determined during detailed will consider SFP conditions, as identified in the Qualification section.
SFPI channel accuracy will be sufficient to allow trained personnel to determine when the actual level reaches the specified lower level of each indicating range (Levels 1, 2 or 3) without conflicting or ambiguous indications.
RAI-7
Please provide the following:
a) An estimate of the expected instrument channel accuracy performance (e.g., in % of span) under both: (i) normal SFP level conditions (approximately Level 1 or higher); and (ii) at the BDB conditions (i.e., radiation, temperature, humidity, post-seismic and post-shock conditions) that would be present if the SFP level were at the Level 2 and Level 3 datum points.
b) A description of the methodology that will be used for determining the maximum allowed deviation from the instrument channel design accuracy that will be employed under normal operating conditions as an acceptance criterion for a calibration procedure to flag to operators and to technicians that the channel requires adjustment to within the normal condition design accuracy.
Response
The current plan for the design of the SFPI system based on the Exelon Nuclear program schedule for Peach Bottom is to start the design phase for Unit 3 in November of 2013 with design completion and 100% acceptance of the design in June of 2014. The requested information will be provided in the August 2014, 6-month Integrated Plan Update. The Unit 2 design phase is to start in June 2014 and completion is scheduled for December 2014. The Unit 2 information will be included as part of the February 2015, 6-month Integrated Plan Update.
3.8 Testing The 01 P states, in part, that:
The SFPI design will provide for routine testing and calibration consistent with the guidelines of NRC JLD-ISG-2012-03 and NEI 12-02, such as in-situ testing and calibration. Details will be determined during detailed engineering design, in accordance with established processes and procedures.
RAI- 8 Please provide the following:
a) A description of the capability and provisions the proposed level sensing equipment will have to enable periodic testing and calibration, including how this capability enables the equipment to be tested in-situ.
Response to Request for Additional Information (Order EA-12-051)
Page 9 of 11 b) A description of how such testing and calibration will enable the conduct of regular channel checks of each independent channel against the other, and against any other permanently-installed SFP level instrumentation.
c) A description of how calibration tests and functional checks will be performed and the frequency at which they will be conducted. Discuss how these surveillances will be incorporated into the plant surveillance program.
d) A description of what preventative maintenance tasks are required to be performed during normal operation, and the planned maximum surveillance interval that is necessary to ensure that the channels are fully conditioned to accurately and reliably perform their functions when needed.
Response
The current plan for the design of the SFPI system based on the Exelon Nuclear program schedule for Peach Bottom is to start the design phase for Unit 3 in November of 2013 with design completion and 100% acceptance of the design in June of 2014. Following the issue of the design, procedure development will begin with a projected January 2015 completion date.
The information will be provided in the February 201 6-month Integrated Plan Update. The Unit 2 information will be included as part of the August 2015, 6-month Integrated Plan Update.
3.9 Display The 01 P states, in part, that:
The primary and backup instrument displays will be located at the control room, alternate shutdown panel, or other appropriate and accessible location. The specific location will be determined during detailed design.
RAI-9
Please provide the following:
a) The specific location for the primary and backup instrument channel display.
b) If the primary or backup display location is other than the main control room, then 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" to various drain-down scenarios and external events.
Response to Request for Additional Information (Order EA-12-051)
Page 10 of 11
Response
The current plan for the design of the SFPI system based on the Exelon Nuclear program schedule for Peach Bottom is to start the design phase for Unit 3 in November of 2013 with design completion and 100% acceptance of the design in June of 2014. The requested information will be provided in the August 2014, 6-month Integrated Plan Update. The Unit 2 design phase is to start in June 2014 and completion is scheduled for December 2014. The Unit 2 information will be included as part of the February 2015, 6-month Integrated Plan Update.
4.0 PROGRAM FEATURES 4.2 Procedures The alP states, in part, that:
Procedures will be developed using guidelines and vendor instructions to address the maintenance, operation and abnormal response issues associated with the SFPI primary and backup channels.
RAI-10
Please provide the following:
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.
Response
The current plan for the design of the SFPI system based on the Exelon Nuclear program schedule for Peach Bottom is to start the design phase for Unit 3 in November of 2013 with design completion and 100% acceptance of the design in June of 2014. Following the issue of the design, procedure development will begin with a projected January 2015 completion date.
The information will be provided in the February 2015, 6-month Integrated Plan Update. The Unit 2 information will be included as part of the August 2015, 6-month Integrated Plan Update.
4.3 Testing and Calibration The 01 P states, in part, that:
Response to Request for Additional Information (Order EA-12-051 )
Page 11 of 11 The testing and calibration of the SFPI will be consistent with vendor recommendations or other documented basis. Calibration will be specific to the mounted instruments and the displays. The Improved Instrument Setpoint Control Program (IISCP) will control the SFPI. The preventative maintenance process will control the recurring calibration task scope and frequency.
RAI-11
Please provide the following:
a) Further information describing the maintenance and testing program the licensee will establish and implement to ensure that regular testing and calibration is performed and verified by inspection and audit to demonstrate conformance with design and system readiness requirements. Include a description of your plans for ensuring that necessary channel checks, functional tests, periodic calibration, and maintenance will be conducted for the level measurement system and its supporting equipment.
b) A description of how the guidance in NEI 12-02, Section 4.3 regarding compensatory actions for one or both non-functioning channels will be addressed.
c) A description of the compensatory actions to be taken in the event that one of the instrument channels cannot be restored to functional status within 90 days.
Response
The current plan for the design of the SFPI system based on the Exelon Nuclear program schedule for Peach Bottom is to start the design phase for Unit 3 in November of 2013 with design completion and 100% acceptance of the design in June of 2014. Fo"owing the issue of the design, procedure development will begin with a projected January 2015 completion date.
The information will be provided in the February 2015, 6-month Integrated Plan Update. The Unit 2 information will be included as part of the August 2015, 6-month Integrated Plan Update.