ML103270051
| ML103270051 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 11/15/2010 |
| From: | Repko R Duke Energy Carolinas |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| TAC ME4051, TAC ME4052 | |
| Download: ML103270051 (16) | |
Text
REGIS T. REPKO Duke Vice President OVEnergy McGuire Nuclear Station Duke Energy MGO1 VP / 12700 Hagers Ferry Rd.
Huntersville, NC 28078 980-875-4111 980-875-4809 fax regis.repko@duke-energy.corn November 15, 2010 U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Attention: Document Control Desk
Subject:
Duke Energy Carolinas, LLC (Duke Energy)
McGuire Nuclear Station, Units 1 and 2 Docket Numbers 50-369 and 50-370 Response to Request for Additional Information Related to License Amendment Request for Emergency Core Cooling System (ECCS) Water Management Initiative (TAC NOs. ME4051 and ME4052)
Reference:
Letter from Duke Energy to NRC, dated May 28, 2010 Letter from NRC to Duke Energy, dated October 12, 2010 On May 28, 2010, Duke Energy submitted a license amendment request (LAR) for the Renewed Facility Operating Licenses (FOL) and Technical Specifications (TS) for McGuire Nuclear Station Units 1 and 2 to allow the manual operation of the Containment Spray System (CSS) in lieu of automatic actuation, and revise the minimum volume and low level setpoint on the Refueling Water Storage Tank (ML101600256).
On October 12, 2010, the NRC transmitted a Request for Additional Information (RAI). Duke Energy's response to these RAI questions is contained as Attachment 1 to this letter.
Replacement Technical Specification page 3.6.6-2 is enclosed in Attachment 2 to this letter.
This page was changed by Amendments 259/239, approved by the NRC Safety Evaluation of August 24, 2010 (ML100690007). The replacement page does not contain any changes in addition to those requested by our May 28, 2010 submittal.
The Regulatory Commitments contained in Attachment 3 to the May 28, 2010 submittal are supplemented by the additional Regulatory Commitment contained as Attachment 3 to this letter.
The responses provided by this letter do not result in any impact to the original No Significant Hazards Consideration or the Environmental Consideration contained in the May 28, 2010 submittal.
Pursuant to 10 CFR 50.91, a copy of this letter is being sent to the designated official of the State of North Carolina.
www. duke-energy.com
U.S. Nuclear Regulatory Commission November 15, 2010 Page 2 If you have any questions or require additional information, please contact K. L. Ashe at (704) 875-4535.
Very truly yours, R. T. Repko Attachments
U.S. Nuclear Regulatory Commission November 15, 2010 Page 3 Regis T. Repko affirms that he is the person who subscribed his name to the foregoing statement, and that all the matters and facts set forth herein are true and correct to the best of his knowledge.
Regis Tv Repko, Vice President, McGuire Nuclear Station Subscribed and sworn to me:
Date n)AA Notary Public C,
My commission expires: Jate*
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I K*
SEAL
U.S. Nuclear Regulatory Commission November 15, 2010 Page 4 xc (with attachments):
L. A. Reyes Regional Administrator, Region II U.S. Nuclear Regulatory Commission Marquis One Tower 245 Peachtree Center Ave., NE Suite 1200 Atlanta, Georgia 30303-1257 J. B. Brady NRC Senior Resident Inspector McGuire Nuclear Station J. H. Thompson (addressee only)
NRC Senior Project Manager (McGuire)
U.S. Nuclear Regulatory Commission Mail Stop 0-8 G9A Washington, DC 20555-0001 W. L. Cox III, Section Chief North Carolina Department of Environment and Natural Resources Division of Environmental Health Radiation Protection Section 1645 Mail Service Center Raleigh, NC 27699-1645 f
U.S. Nuclear Regulatory Commission November 15, 2010 Attachment 1 Response to NRC Request for Additional Information
U.S. Nuclear Regulatory Commission November 15, 2010 REQUEST FOR ADDITIONAL INFORMATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION REGARDING LICENSE AMENDMENT REQUEST RELATED TO EMERGENCY CORE COOLING SYSTEM (ECCS) WATER MANAGEMENT INITIATIVE McGUIRE NUCLEAR STATION, UNITS 1 AND 2
- 1. Provide documentation (including any calculations addressing tank geometry) for establishing the required range of the instrumentation loop used by the operators to achieve this technical specification (TS) surveillance requirement (SR). Provide a calculation of the instrumentation loop uncertainty analysis, including required calibration tolerances associated with the loop readout device, especially in the vicinity of the level corresponding to 383,146 gallons.
Duke Energy Response:
One (1) non-safety related narrow range (NR) instrument loop is provided for each of McGuire's two Refueling Water Storage Tanks (RWST). This narrow range instrument loop is normally relied upon to verify the Technical Specification minimum contained volume surveillance. The RWST volume per inch level is derived as follows:
Tank volume per inch =rr/4 (D) 2 (7.48 gals/ft3 )(1 ft/1 2 inches), where D is equal to the inside diameter of the RWST, or 39.964 ft. This diameter is based on the dimensions of the lower tank band which is the area of interest and conservative based on the bottom tank ring, which has the greatest wall thickness (least volume per unit level). Therefore,
-rr/4 (39.964 ft) 2 (7.48 gals/ft3 )(1 ft/12 inches) = 781.9 gallons/inch. Approximately 15, 638 gallons are unavailable due to being below the tank outlet nozzle.
This RWST volume per level correlation was utilized in the containment analyses to determine the 383,146 gallon Technical Specification minimum contained volume. This volume corresponds to a 490 inch "actual tank level," or a 470 inch "indicated level".
The indicated RWST level ranges are 0-500 inch and 450-500 inches (i.e., a 50 inch range) for the wide range and narrow range level instrumentation, respectively.
The loop readout devices for the narrow range level instrumentation include an Operational Aid Computer (OAC) display and an analog indicator located on the main control board. The proposed Technical Specification minimum volume corresponds to an indicated level of 470 inches which is near the middle of the 450 to 500 inch span.
The OAC display is the more accurate, and it includes a capability to trend the tank level over time. Therefore, it will be used preferentially to monitor tank level changes in the vicinity of 470 inches.
The calculation of the total loop uncertainty for the RWST narrow range (NR) level instrumentation reflects the planned replacement of the existing Rosemount Model 1151 transmitter with a more accurate Rosemount Model 3051S (Ultra) "smart" transmitter.
Along with the transmitter replacement, the span of the upper narrow range level instrumentation is being reduced from a current span of 125 inches to 50 inches.
Electronic alarm modules will be used to actuate main control board annunciators for RWST makeup and high level. The following parameters are taken into consideration Page 1 of 8
U.S. Nuclear Regulatory Commission November 15, 2010 for the instrument loop uncertainty analysis, where applicable:
- Device accuracy,
- Drift,
- Temperature effects,
- Calibration effects (including device setting tolerance and measurement & test equipment),
- Power supply effects,
- Repeatability,
- Resolution/readability, and
- Variations in the process physical properties The required "loop" calibrationtolerances, using the Rosemount Model 3051S (Ultra)
'smart" transmitter, are outlined below. The calibration tolerances cover the span of the narrow range instrumentation from 450 to 500 inches.
0 The NR alarm device setting tolerances shall be 5 +/-0.50% span.
- The NR main control board indication device setting tolerances shall be < +/-2.0%
span.
- The NR OAC device setting tolerances shall be < +/-0.3% span.
The total loop uncertainties (TLU) associated with the periodic Technical Specification minimum RWST volume surveillance are summarized in the table below:
'Analog Indicator OAC
(+)TLU (inches) I 1.96 0.50
- 2. Provide the indicated acceptance value used by the operators to determine that there is at least 383,146 gallons in the RWST. Demonstrate that this value allows for the total instrument loop uncertainty described in [question] 1 above.
Duke Energy Response:
The preferred indication for use by the operators to determine that there is at least 383,146 gallons in the RWST is the Operational Aid Computer (OAC) display; however, the analog indication can also be utilized. The proposed minimum volume of 383,146 gallons corresponds to an indicated level of 470 inches. The periodic Technical Specification surveillance for RWST minimum volume will include an allowance above the 470 inch minimum indicated level which envelopes the magnitude of the level instrument loop uncertainty associated with the read-out end device (OAC or analog indicator). An indicated level of 471 inches on the OAC display will demonstrate that the RWST contains no less than the minimum required volume, while an indicated value of 472 inches on the analog indicator will demonstrate that the RWST contains no. less than, the minimum volume.
- 3. Provide a description of the periodic calibration surveillance method associated with the maintenance of the instrument loop that is used to provide operators with the information needed to satisfy this TS SR for the RWST. Provide the basis for the 7-day surveillance interval.
Page 2 of 8
U.S. Nuclear Regulatory Commission November 15, 2010 Duke Energy Response:
The "loop" calibration is performed by inputting differential pressure values at the level transmitter, and verifying the output at each end-device (analog indicator, computer, bistable, etc.).
The 7-day surveillance frequency for the required RWST Technical Specification minimum volume is based on the current frequency specified by the Standardized Technical Specification (NUREG-1431) Surveillance Requirement Bases. Similar to the current design, the modified RWST narrow range level loop will have computer and annunciator alarms to provide early warning of low RWST level, prior to tank level falling below the Technical Specification minimum surveillance level. The tank make-up and low level alarm setpoints are specified above the proposed Technical Specification minimum level of 470 inches by an allowance that envelopes the alarm loop uncertainty magnitude.
- 4. Discuss the alternate instrumentation available and steps taken when this instrument fails (or is otherwise unavailable) and justify these steps.
Duke Energy Response:
As discussed in McGuire's May 28, 2010 LAR, the narrow range RWST instrument loops are used to verify the pre-accident initial conditions of the RWST volume in accordance with TS SR 3.5.4.2. This surveillance ensures the minimum volume of borated water is available by the ECCS and Containment Spray for accident mitigation.
When the Narrow Range RWST level instrument is unavailable for any reason, alternate instrumentation is available for use. This alternate instrumentation consists of three, wide-range, safety-related level instruments, FWP-5000, -5010, and -5020. The indicated RWST level ranges are 0-500 inch and 450-500 inches for the wide range and narrow range level instrumentation, respectively. The total loop uncertainties for both the narrow-range and wide-range instruments have been calculated following the guidance in ISA RP 67.04.02, "Methodologies for the Determination of Setpoints for Nuclear Safety-Related Instrumentation", and Duke Energy Engineering Directives Manual EDM-102, "Instrument Setpoint/Uncertainty Calculations". To account for the additional TLU when using the wide-range level instruments, an additional allowance above the Technical Specification limit is specified in the surveillance procedures.
Surveillance is performed using procedures PT/1(2)/A/4600/003C, which are being revised to take this specified allowance into account:
The ability to use the wide range indication as a back-up for the narrow range loop has been validated by calculation.
- 5. In Section 3.2.3 of the LAR, the licensee states that: The delayed actuation of containment spray proposed by this amendment request can cause sump temperature to exceed current design temperature of 190 0 F. At the time of switchover, sump temperature is approximately 197 0 F and remains above 190°F for about 9 minutes. Provide detailed discussion concerning how the increased sump Page 3 of 8
U.S. Nuclear Regulatory Commission November 15, 2010 temperature factors into the equipment qualification (EQ) revised environmental profiles and any affects on EQ qualified equipment.
Duke Energy Response:
In terms of the McGuire ECCS Water Management Project, the increased sump liquid temperature was included in the environmental temperature profile used to evaluate EQ equipment located inside the Reactor Building (Containment and Annulus locations).
The evaluation of EQ equipment is documented in a site calculation. The following information specifically addressing the sump temperature is taken from the calculation:
As shown in Figure B-4A and Figure B-4B, there are some periods of elevated temperature in the response profile calculated in Reference 6 [the Long-Term Containment Response - Manual Containment Spray Initiation] versus the current design basis profile. By including the sump temperature profile due to the ECCS Water Management modifications into the overall "EQ Equip Evaluation Curve" provided in Figure B-6A, there is additional thermal content added to the evaluation curve which provides a bounding temperature profile.
(Note to Reviewer: Attached Figures B-4A and Figure B-4B are the logarithmic and linear scale plots, respectively, of the same data).
Based on the review and evaluations documented within the calculation, there were no adverse impacts on equipment due to the revised profiles, and all EQ equipment located within the Containment and Annulus locations for McGuire Nuclear Station remain qualified for the environmental profiles proposed for the McGuire ECCS Water Management Project.
- 6. The existing plant design has containment spray (CS) pump (400HP) loaded on the emergency diesel generator (EDG) at step 4 of the sequencer. The proposed change will manually start this large motor on the EDG when it is almost fully loaded. Provide detailed discussion of calculation results which demonstrate the EDGs ability to start a CS system pump after EDG sequencing is completed while maintaining adequate voltage and frequency for all other 1 E loads. Also provide discussion about how the EDG is tested for this evolution to support operability.
Duke Energy Response:
As currently designed, the Containment Spray pump motor is automatically started in Load Group 4. The worse case frequency dip and overshoot occur in Load Group 1; the worse case voltage dip is in Load Group 1 and the worse case voltage overshoot is in Load Group 6. Following implementation of the proposed license amendment request, the Containment Spray Pump motor start logic will be blocked until the Emergency Diesel Generator (EDG) Load Sequencer is reset. An Electrical Transient Analysis Program (ETAP) EDG dynamic analysis has shown that, following implementation of the change, the worse case frequency dip and overshoot remain in Load Group 1; the worse case voltage dip will remain in Load Group 1 and the worse case voltage overshoot will remain in Load Group 6. As shown by the voltage and frequency traces developed in the ETAP EDG dynamic analysis, the start of the containment spray pump motor at the Page 4 of 8
U.S. Nuclear Regulatory Commission November 15, 2010 end of the loading sequence will not have any impact on EDG operation. The frequency dip and overshoot remains within +/- 2% of nominal frequency. The voltage dip and overshoot remains within +/- 10% of nominal voltage. Therefore, the Regulatory Guide 1.9 Revision 3 restoration time to steady state is not challenged.
EDG Testing of the Containment Spray Pump engineering change is twofold:
- 1) Diesel Generator Load Sequencer Logic Testing
- 2) Diesel Generator Loading Acceptance Testing Following implementation of the proposed amendment request, the EDG Load Sequencer logic associated with containment spray will be checked via a Temporary.
Test Procedure. This test will ensure the containment spray pump motor load shed logic operates correctly, the containment spray pump motor start logic is blocked during EDG Load Sequencer actuation and the containment spray pump motor start logic not blocked following EDG Load Sequencer reset. Following this test and the completion of the routine EDG Load Sequencer Surveillance Testing, the EDG Load Sequencer will be declared Operable.
Each EDG will be tested via the Engineered Safety Features Actuation Periodic Test (ESF) Procedure to ensure the EDG is capable of starting the containment spray pump motor after the other ESF loads have been started. The Containment Spray Pump will be manually started and voltage and frequency response recorded. Following .
confirmation that voltage and frequency transient response meets the requirements of Regulatory Guide 1.9, Revision 3, the EDG will be declared operable.
The EDG load sequencer logic and load acceptance testing will be completed prior to the first entry into Mode 4 operations following the implementing refueling outage.
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APPENDIX B FIGURE B-4A LONG TERM EQ CONTAINMENT TEMPERATURE RESPONSE SUMP WATER TEMPERATURE (Logarithmic Time Scale) 250 -,MCC-1552.U8-OO-0403, Rev. 0 Calculatecd Long Trnl'rm Ieperaiurc
-C(urrent 1)8 (I'SAR)'Ternperature 200 Ci 0
- .150 0 ~
_1- ___
S100 50 -
1.Ei00 I.E-t01 I.E+/-02 I.Et03 .E-,O4 I.E-O5 I.Ei06 I.E+07 TIME (SECONDS)
MCC-1381.05-00-0330, Rev. 0 Environmental Qualification (EQI Equipment Evaluation For Containment APPENDIX B By.-
Profile Revisions Due To ECCS Water Manaaement Initiatives Page B7 Checked: jt-
APPENDIX B FIGURE B-4B LONG TERM EQ CONTAINMENT TEMPERATURE RESPONSE SUMP WATER TEMPERATURE (Linear Time Scale) 2 50 . . . . . .. . .. . . . . . . . ..
- MCC- 1552.08-00-0403, Rev. 0 Calculated Long Term "remperaturc CurTent DB (FSAR) l~empnraure 0
1 L t 1 Z)200 200 ------- - -----------------
-J L I i I .O tO0
... . ..... ........... .................. 5 I ..06 . . . .. . ..
... .. .. ... .. .. . ,,E-_ 0.0,E . .... _
TIME (SECONDS)
MCC-1 381 .05-00-0330, Rev. 0 Environmegntal Qualification (EQ) Eguipment Evaluation For Containment APPENDIX B By:
Profile Revisions Due To ECCS Water Management Iniftiatives Page B8 Checked:
APPENDIX B FIGURE B-6A LONG TERM EQ REACTOR BUILDING TEMPERATURE RESPONSE EQ EVALUATION CURVE (Logarithmic Time Scale) 250
- ILower Coat (ECCS WM)
Lower Cont (Calculated Long lTrn)
Lower Cont (Current DB) (PEP)
-Upper Coit (ECCS WM)
. Upper Cont (Calculated LongTerin)
- Upper Coat (Current 1313)(PEP) 74 - Annulus (ECCS WM)
Surp Temp (ECCS WM) 200 41 Swnp Tcmp (Calculated Long Term)
Sump Temp (Current DB) (FSAR) iiQ Eq!jjp Evaluation Curve
~ 50 z.
1 z~
50 +
I.E+00 I.E+01 L.E+02 I .E+03 L.E-04 ILE fo5 I.Et06 I.E+07 TIME (SECONDS)
MCC-1381.05-00-0330, Rev. 0 Environmental Qualification (EQ) EpuiDment Evaluation For Containment APPENDIX B By: (4me Profile Revisions Due To ECCS Water Management Initiatives Page B1 1 Checked: AtS I
U.S. Nuclear Regulatory Commission November 15, 2010 Attachment 2 Replacement Technical Specification Page
Containment Spray System 3.6.6 SURVEILLANCE FREQUENCY SR 3.6.6.2 Verify each containment spray pump's developed head at In accordance with the flow test point is greater than or equal to the required the Inservice developed head. Testing Program SR 3.6.6.31 Verify each automatic containment spray valve in the flow 18 months path that is not locked, sealed, or otherwise secured in position, actuates to the correct position on an actual or simulated actuation signal.
SR 3.6.6.4 Verify each containment spray pump starts automatically 18 months on an actual or simulated actuation signal.
SR 3.6.6.5 Verify that each spray pump is de-energized and 18 months prevented from starting upon receipt of a terminate signal and is allowed to start upon receipt of a start permissive from the Containment Pressure Control System (CPCS).
SR 3.6.6.6 Verify that each spray pump discharge valve closes or is 18 months prevented from opening upon receipt of a terminate signal and is allowed to open upon receipt of a start permissive from the Containment Pressure Control System (CPCS).
SR 3.6.6.7 Verify each spray nozzle is unobstructed. Following activities which could result in nozzle blocka~ge McGuire Units 1 and 2 3.6.6-2 Amendment Nos. 259, 239
U.S. Nuclear Regulatory Commission November 15, 2010 Attachment -
NRC Commitments The following identifies those actions committed to by Duke Energy in this document. Any other statements made in this licensing submittal are provided for informational purposes only and are not considered to be regulatory commitments. Please direct any questions you may have in this matter to K. L. Ashe at (704) 875-4535:
- 1. The EDG load sequencer logic and load acceptance testing will be completed prior to the first entryinto Mode 4 operations following the implementing refueling outage.
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