ML13149A092
| ML13149A092 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 06/07/2013 |
| From: | Balwant Singal Plant Licensing Branch IV |
| To: | Koehl D South Texas |
| Singal B | |
| References | |
| TAC MF0827, TAC MF0828 | |
| Download: ML13149A092 (11) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 June 7,2013 Mr. Dennis L. Koehl President and CEO/CNO STP Nuclear Operating Company South Texas Project P.O. Box 289 VVadsworth, TX 77483
SUBJECT:
SOUTH TEXAS PROJECT, UNITS 1 AND 2 - REQUEST FOR ADDITIONAL INFORMATION RE: OVERALL INTEGRATED PLAN IN RESPONSE TO ORDER EA-12-051, "RELIABLE SPENT FUEL POOL INSTRUMENTATION" (TAC NOS. MF0827 AND MF0828)
Dear Mr. Koehl:
By letter dated February 28, 2013 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML13070A006), STP Nuclear Operating Company (STPNOC, the licensee), 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 South Texas Project (STP), 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 SFP 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 SFP Instrumentation," Revision 0, dated August 29,2012 (ADAMS Accession No. ML12221A339).
The NRC staff has determined that additional information, as requested in the enclosure, is needed to complete its review. The draft request for additional information (RAI) was sent to Mr. Jamie Paul of STPNOC on May 28, 2013, via e-mail, with a request to respond within 30 days from the date of the e-mail. Ms. Robyn Savage of STPNOC confirmed on May 30, 2013 that an RAI clarification call is not needed and agreed to provide the response by June 28, 2013. If any part of the information is not available by June 28, 2013, please provide the date by which this information will be provided.
D. Koehl -2 If you have any questions regarding this request, please contact me at 301-415-3016 or via e-mail at Balwant.Singal@nrc.gov.
Sincerely,
~w~~~i~ect Plant Licensing Branch IV Manager Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-498 and 50-499
Enclosure:
As stated cc w/encl: Distribution via Listserv
REQUEST FOR ADDITIONAL INFORMATION OVERALL INTEGRATED PLAN IN RESPONSE TO ORDER EA-12-051. "RELIABLE SPENT FUEL POOL INSTRUMENTATION" STP NUCLEAR OPERATING COMPANY SOUTH TEXAS PRO~IECT. UNITS 1 AND 2 DOCKET NOS. 50-498 AND 50-499 1.0 Introduction By letter dated February 28,2013 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML13070A006), STP Nuclear Operating Company (STPNOC, the licensee), 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 South Texas Project (STP), 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 SFP Instrumentation," Revision 1, dated August 2012 (ADAMS Accession No. ML12240A307), with exceptions as documented in Interim Staff Guidance (lSG) 2012-03, "Compliance with Order EA-12-051, Reliable SFP Instrumentation," Revision 0, dated August 29,2012 (ADAMS Accession No. ML12221A339).
The NRC staff has reviewed the licensee's letter dated February 28, 2013, and determined that the following request for additional information (RAI) is needed to complete its technical review.
Please provide the response to the following RAls.
2.0 Levels of Required Monitoring The OIP states, in part, that LEVEL 1: Level adequate to support operation of the normal fuel pool cooling system Plant EI. 64 ft. 2 in or 24 ft. 4 in. water level above the top of the SFP fuel storage rack.
LEVEL 2: Level adequate to provide substantial radiation shielding for a person standing on the SFP operating deck.
Plant EI 49 ft. 10 in. or 10ft. water level above the top of the SFP fuel storage rack.
Enclosure
- 2 LEVEL 3: Level where the fuel remains covered.
Plant EI 40 ft. 4 in. or 6 in. water level above the top of the SFP fuel storage rack.
'" The installation of the SFPLI [spentfuel pool level instrumentation] sensor will be such that it will measure as close as possible to the top of the SFP fuel rack.
Indicated level on either the Primary or Backup Instrument Channel of greater than%ft. above the top of SFP fuel storage racks based upon the design accuracy of the instrument channel per NEI 12-02 [Rev.1], for both the Primary and Backup Instrument Channels, satisfies the NEI 12-02 [Rev.2] requirement of+/-1 ft.
from the top of the fuel rack. This monitoring level ensures there is adequate water level above the stored fuel seated in the SFP fuel storage rack.
RAI-1
Please provide the following:
a) For Level 1, please 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). Please indicate on this sketch the datum values representing Level 1, Level 2, and Level 3 as well as the top of the fuel.
Please 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.
3.0 Instrumentation and Design Features 3.1 Instruments and Arrangement The OIP states, in part, that Both the Primary and Backup Instrument Channels will utilize permanently installed instruments ....
The Primary Instrument Channel level sensing components will be located in the northeast corner of the Spent Fuel Pool, as shown in Attachment 1....
The Backup Instrument Channel level sensing components will be located in the northwest corner of the Spent Fuel Pool, as shown in Attachment 1....
The current Plan is to mount the supporting electronic instruments outside of the spent fuel pool area, to provide a more benign radiation and environmental
-3 conditions, and also provide for reasonable and accessible locations for operators.
SFP Primary and Backup Channel Level Instruments are currently planned to be located in Radwaste Control Room of the MEAB [Mechanical Electrical Auxiliary Building]; however, STPNOC is still evaluating other possible locations (Le. relay room).
RAI-2
Please 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 sensor, and the proposed routing of the cables that will extend from the sensors toward the location of the read-out/display device.
3.2 Mounting The OIP states, in part, that Consideration will be given to the maximum seismic ground motion that occurs at the installation location for the permanently installed equipment which is documented in the UFSAR [Updated Final Safety Analysis Report] Section 3.7.
The mountings shall be designed consistent with the highest safety or seismic classification of the SFP. The level sensors will be mounted on seismically qualified brackets.
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 and dynamic loads. Please 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. Please 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.
-4 3.3 Qualification The OIP states, in part, that Both channels will be reliable at temperature, humidity and radiation levels consistent with the SFP water at saturation conditions for no fewer than seven (7) days post-event. Level equipment installed in the SFP and areas in the Fuel Handling Building (FHB) will be designed and tested to remain functional when subjected to the following expected post-event conditions:
- 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 SFP water at LEVEL 3 as described in the ORDER
- Temperatures of 212 of and 100% relative humidity environment
- Boiling Water and/or steam environment
- Concentrated borated water environment 7.3.1 Seismic Reliability:
The reliability of the permanently installed instrument channel components will be demonstrated through an appropriate combination of design, analYSiS, operating experience and/or testing of components to meet the seismic conditions in the area of the SFP that are applicable at the time of submittal of this Plan and will meet the seismic reliability requirements of NEI 12-02 [Rev. 1] and the ISG. If changes in the seismic design basis occur, they will be processed in accordance with existing plant procedures.
The reliability of seismic design and installation will be demonstrated in accordance with the guidance in Sections 7,8,9, and 10 of [Institute of Electrical and Electronics Engineers] IEEE Standard 344-2004 (Ref. 7) or a substantially similar industrial standard. The instruments will meet the shock and vibration requirements of NEI 12-02 [Rev.1] and the ISG.
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 (BOB) 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 loading at the location where the equipment will be mounted.
Please include a discussion of this seismic reliability demonstration as it applies
- 5 to a) the level sensor mounted in the SFP area, and b) any control boxes, electronics, or read-out and re-transmitting devices that will be employed to convey the level information from the level sensor to the plant operators or emergency responders.
c) A description of the specific method or combination of methods that will be used to confirm the reliability of the permanently installed equipment during and following seismic conditions to maintain its required accuracy.
3.4 Independence The OIP states, in part, that AC [alternating current] or DC [direct current] power sources utilized for the Primary and Backup Channels will be from different buses such that no one single failure will interrupt power to both SFPLI channels.
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 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 states, in part, that For Unit 1 and Unit 2, the power supplies for the Primary and Backup Instrument Channels will be provided from different power buses to assure that the loss of one bus will not result in the loss of both channels. In addition, each instrument channel shall have a backup battery power supply for uninterrupted operation after loss of power. Power will be of sufficient capacity to maintain level indication until offsite resources become available.
RAI-6
If the level measurement channels are to be powered through a battery system (either directly or through an uninterruptible power supply (UPS), please provide the deSign criteria that will be
- 6 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 OIP states, in part, that The minimum accuracy for the channel will be maintained following a loss of power, without calibration and will consider the effect of environmental conditions on the accuracy. Minimum accuracy requirements shall meet the requirements of NEI 12-02. 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.
RAI-7
Please provide the following:
a) An estimate of the expected instrument channel accuracy performance under both a) normal SFP level conditions (approximately Level 1 or higher) and b) at BOB conditions (Le., 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 OIP states, in part, that Testing of the installed instrument channels will be consistent with the guidelines of NEI 12-02 [Rev.1] and the ISG. Specific test procedures will be implemented for functional testing of the installed instrument systems, from the sensor through the display, as defined in Section 11.0.
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.
7 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. Please 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.
3.8 Display The OIP states, in part, that The Primary and Backup Instrument Channel display(s) are located in the Radwaste Control Room, which is an accessible location following a Large Scale External Event (LSEE); however, other locations are still being considered.
The two displays will be sufficiently separated by the distance required for independent channels. The location selected for these displays will be such that damage resulting from a LSEE will not damage both displays.
SFP Primary and Backup Channel Level Instruments are currently planned to be located in Radwaste Control Room of the MEAB; however, STPNOC is still evaluating other possible locations (i.e. relay room).
In addition, the Primary and Backup Channel Instruments will drive remote indication located in the Main Control Room.
RAI-9
Please provide the following:
a) 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.
b) 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.
- 8 4.0 Program Features 4.1 Procedures The OIP states, in part, that Procedures for the maintenance and testing, and the training of the required personnel on these procedures will be completed prior to the required date for completion of these modifications per Section 3.0.
RAI-10
Please provide 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 states, in part, that Specific test procedures will be implemented for functional testing of the installed instrument systems, from the sensor through the display, as defined in Section 11.0.
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. Please 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.
D. Koehl -2 If you have any questions regarding this request, please contact me at 301-415-3016 or via e-mail at Balwant.Singal@nrc.gov.
Sincerely, IRA!
Balwant K. Singal, Senior Project Manager Plant Licensing Branch IV Division of Operating Reactor licensing Office of Nuclear Reactor Regulation Docket Nos. 50-498 and 50-499
Enclosure:
As stated cc w/encl: Distribution via Listserv DISTRIBUTION:
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