ML13154A399
| ML13154A399 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 06/05/2013 |
| From: | Thadani A Plant Licensing Branch 1 |
| To: | Korsnick M Constellation Energy Nuclear Group |
| Thadani M | |
| References | |
| TAC MF1131, TAC MF1132, EA-12-051 | |
| Download: ML13154A399 (14) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555*0001 June 5, 2013 Ms. Mary G. Korsnick Chief Nuclear Officer Chief-Operations Officer Constellation Energy Nuclear Group, LLC 100 Constellation Way, Suite 200C Baltimore, MD 21202
SUBJECT:
NINE MILE POINT NUCLEAR STATION, UNITS 1 AND 2 - REQUEST FOR ADDITIONAL INFORMATION RE: OVERALL INTEGRATED PLAN FOR RELIABLE SPENT FUEL POOL INSTRUMENTATION (ORDER EA-12-051)
(TAC NOS. MF1131 AND MF1132)
Dear Ms. Korsnick:
By letter dated February 28, 2013 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML13066A172), Constellation Energy Nuclear Group, LLC submitted an Overall Integrated Plan in response to the March 12,2012, U.S. Nuclear Regulatory Commission (NRC, Commission) Order modifying licenses with regard to requirements for Reliable Spent Fuel Pool Instrumentation (Order Number EA-12-051; ADAMS Accession No. ML12054A679) for the Nine Mile Point Nuclear Station, Units 1 and 2. The NRC staff endorsed Nuclear Energy Institute (NEI) 12-02, "Industry Guidance for Compliance with U.S.
Nuclear Regulatory Commission (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 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 licensee's submittal and identified additional information that is needed to complete the NRC staff's technical review. Please provide a response to the enclosed Request for Additional Information (RAI) by July 5, 2013. If any part of this information is not available by the July 5, 2013, response date for this RAI, please provide the date this information will be submitted.
M. Korsnick If you have any questions regarding this RAI, please contact me at (301) 415-1476, or email Mohan.Thadani@nrc.gov.
Sincerely, Mohan C. Thadani, Senior Project Manager Plant Licensing Branch 1-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-220 and 50-410 cc: Mr. Christopher Costanzo Vice President Nine Mile Point Nine Mile Point Nuclear Station, LLC P.O. Box 63 Lycoming, NY 13093 Additional Distribution via Listserv
REQU EST FOR ADDITIONAL INFORMATION OVERALL INTEGRATED PLAN IN RESPONSE TO ORDER EA-12-051 "RELIABLE SPENT FUEL POOL INSTRUMENTATION" CONSTELLATION ENERGY NUCLEAR GROUP. LLC NINE MILE POINT NUCLEAR STATION. UNITS 1 AND 2 DOCKET NOS. 50-220 AND 50-410
1.0 INTRODUCTION
By letter dated February 28, 2013 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML13066A172), Constellation Energy Nuclear Group, LLC submitted an Overall Integrated Plan (OIP) in response to the March 12, 2012, U.S. Nuclear Regulatory Commission (NRC, Commission) Order modifying licenses with regard to requirements for Reliable Spent Fuel Pool (SFP) Instrumentation (Order Number EA-12-051; ADAMS Accession No. ML12054A679) for the Nine Mile Point Nuclear Station, Units 1 and 2. The NRC staff endorsed Nuclear Energy Institute (NEI) 12-02, "Industry Guidance for Compliance with U.S.
Nuclear Regulatory Commission (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 2012-03, "Compliance with Order EA-12-051, Reliable Spent Fuel Pool Instrumentation," Revision 0, dated August 29,2012 (ADAMS Accession No. ML12221A339).
2.0 LEVELS OF REQUIRED MONITORING The OIP for Unit 1 states, in part, that
- 1. Level adequate to support operation of the normal SFP cooling system - Indicated water level on either the primary or backup instrument channel of greater than elevation 338' - 10.5" (based on loss of inlet flow to the SFP Surge Tanks as water level lowers below the skimmer weirs which results in a loss of reliable suction to SFP Cooling Pumps) plus the accuracy of the SFP water level instrument channel, which will be determined during the engineering and design phase (NMPI UFSAR Section X.H, ...). Normal operating level is maintained at elevation 339' 0"(+/-1").
- 2. Level adequate to provide substantial radiation shielding for a person standing on the SFP operating deck - Indicated water level on either the primary or backup instrument channel of greater than elevation 320' - 11.5" plus the accuracy of the SFP water level instrument channel, which will be determined during the engineering and design phase.
This elevation is approximately 5' above the top of the fuel racks and Enclosure
-2 ensures a minimum level of water shielding above the top of the fuel racks. Calculations performed determined that with 5' of water above the top of the racks, the largest calculated dose rate near the edge of the SFP would be well below 100 mRem/hr. Calculations to determine dose rates near the edge of the SFP with 5' of water above the top of the fuel racks were performed using SAS2H/ORIGEN-S or ORIGEN-ARP for source term calculations and MCNP5 code was used to calculate gamma (primary and capture) and neutron dose rates at the locations of interest.
MCNP5 is a general-purpose Monte-Carlo NParticle code that can be used for neutron, photon, electron, or coupled neutron/photon/electron transport. This monitoring level ensures there is adequate water level to provide substantial radiation shielding for personnel to respond to Beyond-Design-Basis External Events and to initiate SFP makeup strategies consistent with guidelines provided in NEI 12-02, Revision I ...
- 3. Level where fuel remains covered - Indicated level on either the primary or backup instrument channel of greater than elevation 315' 11.5", which is the elevation of the top of the Spent Fuel Racks plus the accuracy of the SFP level instrument channel, will [be] determined during the engineering and design phase. This monitoring level assures that there is adequate water level above the stored fuel seated in the rack.
The OIP for Unit 2 states, in part, that
- 1. Level adequate to support operation of the normal SFP cooling system - Indicated water level on either the primary or backup instrument channel of greater than elevation 352' - 7.5" (based on loss of inlet flow to the SFP Surge Tanks as water level lowers below the skimmer weirs which results in a loss of reliable suction to SFP Cooling Pumps) plus the accuracy of the SFP level instrument channel, which will be determined during the engineering and design phase (NMP2 USAR Section 9.1, ... ).
Normal operating level is maintained at elevation 352'-10" (+1- 1").
- 2. Level adequate to provide substantial radiation shielding for a person standing on the SFP operating deck - Indicated water level on either the primary or backup instrument channel of greater than elevation 334' - 11.9" plus the- accuracy of the SFP water level instrument channel, which will be determined during the engineering and design phase. This elevation is approximately 5' above the top of the fuel racks and ensures a minimum level of water shielding above the top of the fuel racks.
Calculations performed determined that with 5' of water above the top of the racks, the largest calculated dose rate near the edge of the SFP would be well below 100 mRem/hr. Calculations to determine dose rates near the edge of the SFP with 5' of water above the -top of the fuel racks were performed using SAS2H/ORIGEN-S or ORIGEN-ARP for source term calculations and MCNP5 code was used to calculate gamma (primary and capture) and neutron dose rates at the locations of interest..
MCNP5 is a general-purpose Monte-Carlo NParticle code that can be
-3 used for neutron, photon, electron, or coupled neutron/photon/electron transport. This monitoring level ensures there is adequate water level to provide substantial radiation shielding for personnel to respond to Beyond-Design-Basis External Events and to initiate SFP makeup strategies consistent with guidelines provided in NEI 12-02, Revision 1...
- 3. Level where fuel remains covered - Indicated water level on either the primary or backup instrument channel of greater than elevation 329'-1 1.9", which is the elevation of the top of the Spent Fuel Racks plus the accuracy of the SFP water level instrument channel, will be determined during the engineering and design phase. This monitoring level assures that there is adequate water level above the stored fuel seated in the rack.
RAI-1
Please provide the following for both units:
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. 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.
c) Detailed information regarding the analysis used to determine Level 2 including assumptions for amount and location of source material, assumptions regarding future changes to amount of source material and locations that are valid for the stated 100 mrem/hr dose rate appropriately marked on the floor plan. Include a discussion regarding dose rates for stored spent fuel versus that of other material that may be stored in the pool.
3.0 INSTRUMENTATION DESIGN FEATURES 3.1 Arrangement The OIP for Unit 1 states, in part, that SFP water level sensors wi" be installed in the northeast corner and near the northwest corner of the SFP at elevation 340 feet. Transmitters will be located in the Reactor Building at elevation 318 feet immediately below the SFP operating floor. This elevation is expected to have a lower temperature and will not have a 100% steam condensing environment. The radiation dose at the transmitter
-4 location will also be less as the concrete SFP walls will provide significant radiation shielding. The SFP walls will also provide protection from event generated missiles. These locations provide reasonable protection against missiles and will not interfere with SFP activities. The SFP is seismically qualified for a Design Basis Earthquake. Credited equipment and cables will be protected from event generated missiles by use of new or existing barriers.
The sensors will be located such that they cannot interfere with movement of the fuel handling machine and will not interfere with fuel cask transfers to the onsite Independent Spent Fuel Storage Installation.
Cabling for power supplies and indications for each channel will be routed in separate conduits from cabling for the other channels.
The OIP for Unit 2 states, in part, that SFP water level sensors will be installed in the northeast corner and in the northwest corner of the SFP at elevation 353'-10". Transmitters will be located in the Reactor Building at elevation 328'-10" immediately below the SFP operating floor. This elevation is expected to have a lower temperature and will not have a 100% steam condensing environment. The radiation dose at the transmitter location will also be less as the concrete SFP walls will provide significant radiation shielding. The SFP walls will also provide protection from event generated missiles. These locations provide reasonable protection against missiles and will not interfere with SFP activities. The SFP is seismically qualified for a Design Basis Earthquake. Credited equipment and cables will be protected from event generated missiles by use of new or existing barriers.
The sensors will be located such that they cannot interfere with movement of the fuel handling machine and will not interfere with fuel cask transfers to the onsite Independent Spent Fuel Storage Installation.
Cabling for power supplies and indications for each channel will be routed in separate conduits from cabling for the other channels. Separation will be maintained between the primary and backup channel cables and enclosures.
RAI-2
Please provide, for both units, a clearly labeled sketch or marked-up plant drawing of the plan view of the SFP area, depicting the SFP inside dimensions, the planned locations/placement of the primary and back-up SFP level sensor, and the proposed routing of the cables that will extend from the sensors toward the location of the read-out/display device.
- 5 3.2 Mounting The alP for Unit 1 states, in part, that Mounting will be Seismic Class 1. Installed equipment will be seismically qualified to maintain the current seismic class of the SFP which is Seismic Class 1 (NMP1 UFSAR section X.H.2.0 and X.J.2.1 . .. An evaluation of other hardware stored in the SFP will be conducted to ensure it will not create an adverse interaction with the fixed SFP instrument locations.
The alP for Unit 2 states, in part, that Mounting will be Seismic Class 1. Installed equipment will be seismically qualified to maintain the current seismic class of the SFP which is Seismic Class 1 (NMP2 USAR section 9.1 ... ). An evaluation of other hardware stored in the SFP will be conducted to ensure it will not create an adverse interaction with the fixed SFP instrument locations.
Please provide the following for both units:
a) The design criteria that will be used to estimate the total loading on the mounting device(s), including static weight loads and dynamic loads. Describe the methodology that will be used to estimate the total loading, inclusive of design basis maximum seismic loads and the hydrodynamic loads that could result from pool sloshing or other effects that could accompany such seismic forces.
b) A description of the manner in which the level sensor (and stilling well, if appropriate) will be attached to the refueling floor and/or other support structures for each planned point of attachment of the probe assembly. Indicate in a schematic the portions of the level sensor that will serve as points of attachment for mechanical/mounting or electrical connections.
c) A description of the manner by which the mechanical connections will attach the level instrument to permanent SFP structures so as to support the level sensor assembly.
d) Address how other hardware stored in the SFP will not create adverse interaction with the fixed instrument location(s).
3.3 Qualification The alP for Units 1 and 2 states, in part, that Components of the instrument channels will be qualified for shock and vibration using one or more of the following methods:
-6
- Components will be supplied by manufacturers using commercial quality programs (such as IS09001, Quality management systems - Requirements) .
. . with shock and vibration requirements included in the purchase specification at levels commensurate with portable handheld device or transportation applications;
- Components will 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 will be inherently resistant to shock and vibration loadings, such as cables.
The following measures will be used to verify that the design and installation is adequate for seismic effects on instrument channel components used after a potential seismic event for installed components (with the exception of battery chargers and replaceable batteries). Applicable, components of the instrument channels will be rated by the manufacturer (or otherwise tested) for seismic effects at levels commensurate with those of postulated design basis event conditions in-the location of the instrument channel component using one or more of the following methods:
- A 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 will be demonstrated based on the guidance in Sections 7,8,9, and 10 of IEEE Standard 344-2004, IEEE Recommended Practice for Seismic Qualification of Class 1E Equipment for Nuclear Power Generating Stations . .. or a substantially similar industrial standard;
- Proposed devices will be demonstrated to be 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 will be installed (g levels and frequency ranges); or
- The capability to withstand seismic motion consistent with that of existing design basis loads at the installed locations will be demonstrated.
RAI-4
Please provide the following for both units:
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-Oesign-Basis (BOB) ambient temperature, humidity, shock, vibration, and radiation conditions.
b) A description of the testing and/or analyses that will be conducted to provide
-7 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) Please provide a description of the specific method or combination of methods that will be used to confirm the reliability of the permanently installed equipment during and following seismic conditions to maintain its required accuracy.
3.4 Independence The OIP for Units 1 and 2 states, in part, that The primary instrument channel will be redundant to and independent of the backup instrument channel, including power supplies.
RAI-6
Please provide the following for both units:
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 precluded.
b} Further information on how each level measurement system, consisting of level sensor electronics, cabling, and readout devices will be designed and installed to address independence through the application and selection of independent power sources, the use of physical and spatial separation, independence of signals sent to the location(s) of the readout devices, and the independence of the displays.
3.5 Power Supplies The OIP for Unit 1 states, in part, that The primary and backup channels will be powered from dedicated batteries and local battery chargers. The battery chargers for both channels will normally be powered from non-safety related 120V AC [alternating current] power. Minimum battery life of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> will be provided. The battery systems will include provision for battery replacement should the battery charger be unavailable following the event. Spare batteries will be readily available.
During a loss of normal power, the battery chargers will be connectable to another 120V AC power source. This will be from portable generators stored onsite, consistent with the reasonable protection requirements associated with
-8 NEI 12-06 ... or from generators deployed from off-site by the mitigating strategies resulting from Order EA-12-049, at approximately 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after the event.
The alP for Unit 2 states, in part, that The primary and backup channels will be powered from dedicated batteries and local battery chargers. The battery chargers for both channels will normally be powered from non-safety related 120V AC power. Minimum battery life of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> will be provided.
During a loss of normal power, the battery chargers will be connectable to another 120V AC power source. This will be from portable generators stored onsite, consistent with the reasonable protection requirements associated with NEI 12-06 ... or from generators deployed from off-site by the mitigating strategies resulting from Order EA-127049, at approximately 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after the event. The battery systems will include provision for battery replacement should the battery charger be unavailable following the event. Spare batteries will be readily available.
RAI-7
If the level measurement channels are to be powered through a battery system (either directly or through an Uninterruptible Power Supply (UPS>>, please provide, for both units, 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 FLEX Program plans.
3.6 Accuracy The alP for Units 1 and 2 states, in part, that The accuracy will be consistent with the guidelines of NRC JLD-ISG-2012-03 and NEI 12-02. Instrument channels will be designed such that they will maintain their design accuracy following a power interruption or change in power source without recalibration.
Accuracy will consider SFP conditions, e.g., saturated water and steam environment. Additionally, instrument accuracy will be sufficient to allow trained personnel to determine when the actual water level exceeds the specified lower level of each indicating range (levels 1, 2 and 3) without conflicting or ambiguous indication. The accuracy will consider the resolution requirements of Figure 1 of NEI 12-02. Actual accuracy for the indication under all required conditions will be determined during the engineering and design phase.
-9
RAI-8
Please provide the following for both units:
a) An estimate of the expected instrument channel accuracy performance (e.g. in %
of span) under both a) normal SFP level conditions (approximately Level 1 or higher) and, b) at the BOB conditions (i.e., radiation, temperature, humidity, post seismic and post-shock conditions) that would be present if the SFP level were at the Level 2 and Level 3 datum points.
b) A description of the methodology that will be used for determining the maximum allowed deviation from the instrument channel design accuracy that will be employed under normal operating conditions as an acceptance criterion for a calibration procedure to flag to operators and to technicians that the channel requires adjustment to within the normal condition design accuracy.
3.7 Testing The OIP for Units 1 and 2 states, in part, that Testing will be consistent with the guidelines of NRC ~ILD-ISG-2012-03 and NEI 12-02. Instrument channel design will provide for routine testing and calibration that can be performed in-situ consistent with Order EA-12-051 and the guidance in NEI 12-02. Details will be determined during the engineering and design phase. Additional testing and calibration information is provided in Section XV of this plan.
RAI- 9 Please provide the following for both units:
a) A description of the capability and provisions the proposed level sensing equipment will have to enable periodic testing and calibration, including how this capability enables the equipment to be tested in-situ.
b) A description of how such testing and calibration will enable the conduct of regular channel checks of each independent channel against the other, and against any other permanently-installed SFP level instrumentation.
c) A description of how functional checks will be performed, and the frequency at which they will be conducted. Describe how calibration tests will be performed, and the frequency at which they will be conducted. Provide a discussion as to how these surveillances will be incorporated into the plant surveillance program.
d) A description of what 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.
- 10 4.0 PROGRAM FEATURES 4.1 Procedures The OIP for Units 1 and 2 states, in part, that Procedures will be developed using guidelines and vendor instructions to address the maintenance, operation, and abnormal response issues associated with the new SFP instrumentation.
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 . ..
RAI-10
Please provide, for both units, a description of the standards, guidelines and/or criteria that will be utilized to develop procedures for inspection, maintenance, repair, operation, abnormal response, and administrative controls associated with the SFP level instrumentation, as well as storage and installation of portable instruments.
4.2 Testing and Calibration The OIP for Units 1 and 2 states, in part, that Processes will be established and maintained for scheduling and implementing necessary testing and calibration of the primary and backup SFP water level instrument channels to maintain the instrument channels at the design accuracy.
Testing and calibration of the instrumentation will be consistent with vendor recommendations and any other documented basis. Calibration will be specific to the mounted instrument and the monitor. Out of service time as identified in NEI 12-02 will be incorporated consistent with the programmatic process used for compliance with NRC Order EA-12-049, Issuance of Order to Modify Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events ... Functionality testing will be performed at the frequency delineated in NEI 12-02. Additional testing information is provided in Section XI of this plan.
Instrument channel out of service times as identified in NEI 12-02 will be implemented and controlled consistent with the programmatic process used for compliance with NRC Order EA-12-051.
- 11
RAI-11
Please provide the following for both units:
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 what compensatory actions are planned in the event that one of the instrument channels cannot be restored to functional status within 90 days.
ML13154A399 (*) see Merna ML13142A490 **via email OFFICE LPL1-1/PM LPL 1-1/LA** NRRlSBPB/BC(*) LPL1-1/BC (A) LPL1-1/PM NAME MThadani KGaldstein GCasta RBeali IDPickett MThadani ABaxter/far far DATE 06/05/13 06/04/13 05/24/13 06/05/13 06105113