ML11242A044
| ML11242A044 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 08/19/2011 |
| From: | Belcher S Constellation Energy Group, EDF Group, Nine Mile Point |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| TAC ME1476 | |
| Download: ML11242A044 (70) | |
Text
, J' \ F Sam Belcher P.O. Box 63 Vice President-Nine Mile Point Lycoming, New York 13093 315.349.5200 315.349.1321 Fax CENGOM a joint venture of Constellation Energy-~ ~ D NINE MILE POINT NUCLEAR STATION August 19, 2011 U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 ATTENTION: Document Control Desk
SUBJECT:
Nine Mile Point Nuclear Station Unit No. 2; Docket No. 50-4 10 Response to Request for Additional Information Regarding Nine Mile Point Nuclear Station, Unit No. 2 - Re: The License Amendment Request for Extended Power Uprate Operation (TAC No. ME1476) - Anticipated Transient Without Scram Simulator Tests and Net Positive Suction Head for Emergency Core Cooling Systems
REFERENCES:
(a) Letter from K. J. Polson (NMPNS) to Document Control Desk (NRC), dated May 27, 2009, License Amendment Request (LAR) Pursuant to 10 CFR 50.90:
Extended Power Uprate (b) E-mail from R. Guzman (NRC) to J. J. Dosa (NMPNS), dated July 22, 2011, Follow-up Information Request Re: EPU ATWS Simulator Testing Plots and Data Tables (c) E-mail from R. Guzman (NRC) to J. J. Dosa (NMPNS), dated July 27, 2011, NMP2 EPU-SBO Scenario Clarification (d) E-mail from R. Guzman (NRC) to J. J. Dosa (NMPNS), dated August 4, 2011, Updated Information Request Re: NMP2 EPU - ATWS Simulator Testing Plots and SBO Scenario Clarification.
Nine Mile Point Nuclear Station, LLC (NMPNS) hereby transmits revised and supplemental information in support of a previously submitted request for amendment to Nine Mile Point Unit 2 (NMP2) Renewed Operating License (OL) NPF-69. The request, dated May 27, 2009 (Reference a), proposed an amendment to increase the power level authorized by OL Section 2.C.(1), Maximum Power Level, from 3467 megawatts-thermal (MWt) to 3988 MWt.
!r Document Control Desk August 19, 2011 Page 2 By e-mails dated July 22, July 27, and August 4, 2011 (References b through d), the NRC staff requested supplemental information regarding the Anticipated Transient without Scram (ATWS) Simulator Tests and Net Positive Suction Head (NPSH) Requirements for Emergency Core Cooling Systems (ECCS).
The Attachment to this letter provides the responses to the requests for additional information.
There are no regulatory commitments in this submittal.
Should you have any questions regarding the information in this submittal, please contact John J. Dosa, Director Licensing, at (315) 349-5219.
Very truly yours, STATE OF NEW YORK TO WIT:
COUNTY OF OSWEGO I, Sam Belcher, being duly sworn, state that I am Vice President-Nine Mile Point, and that I am duly authorized to execute and file these responses on behalf of Nine Mile Point Nuclear Station, LLC. To the best of my knowledge and belief, the statements contained in this document are true and correct. To the extent that these statements are not based on my personal knowledge, they are based upon information provided by other Nine Mile Point employees and/or consultants. Such information has been reviewed in accordance with company practice and I believe it to be reliable.
Subscribed and sworn before me, a Notary Public in and for the State of New York and County of a_'_VC_ _ ,this [C dayof )l z ,2011.
WITNESS my Hand and Notarial Seal: /-, Dc%4s /
Notary Public My Commission Expires:
q//9-A1o/ao3 OMW Date V IIlkamllhft1* W SB/DEV
Attachment:
Response to Request for Additional Information Regarding License Amendment Request for Extended Power Uprate Operation cc: NRC Regional Administrator, Region I NRC Resident Inspector NRC Project Manager A. L. Peterson, NYSERDA
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Nine Mile Point Nuclear Station, LLC August 19, 2011
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION By letter dated May 27, 2009, as supplemented on August 28, 2009, December 23, 2009, February 19, 2010, April 16, 2010, May 7, 2010, June 3, 2010, June 30, 2010, July 9, 2010, July 30, 2010, October 8, 2010, October 28, 2010, November 5, 2010, December 10, 2010, December 13, 2010, January 19, 2011, January 31, 2011, February 4, 2011, March 23, 2011, May 9, 2011, June 13, 2011, July 15, 2011, and August 5, 2011, Nine Mile Point Nuclear Station, LLC (NMPNS) submitted for Nuclear Regulatory Commission (NRC) review and approval, a proposed license amendment requesting an increase in the maximum steady-state power level from 3467 megawatts thermal (MWt) to 3988 MWt for Nine Mile Point Unit 2 (NMP2).
By e-mails dated July 22, July 27, and August 4, 2011, the NRC staff requested additional information regarding the Anticipated Transient Without Scram (ATWS) Simulator Tests and Net Positive Suction Head (NPSH) Requirements for Emergency Core Cooling Systems (ECCS). This attachment provides the responses to the requests for additional information (RAI).
The NRC request is repeated (in italics), followed by the NMPNS response.
1 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION RAI from NRC E-mail dated July 22. 2011. as updated in NRC E-mail dated August 4. 2011 ATWS Simulator Exercises As we discussed, while the dataprovided by NMPNS in February2011 supports the NRC staff's review of the proposed EPU with respect to thermal and hydraulic design, the staff has determined that clarifying information is necessary to support its completion of the draft safety evaluation (SE) for [Advisory Committee on Reactor Safeguards] ACRS' review. Specifically, for the [Main Steam Isolation Valve]
MSIV closure and turbine trip EPU ATWS events, the staff notes that the licensee has provided the appropriatedatafor both ATWS events via CD copy datedFebruary2011; however, the staff requests the following information to conclude its review on thermal and hydraulicdesign.
- 1) Provide the sequence of both events with the transient response(s) corresponding to ATWS emergency operatingprocedure actions (e.g., turbine trips, recirculationpump trips, turbine bypass valves open, power increases, water level reduction, standby liquid control system injection, to steady state/oscillationunder control, etc.)
- 2) For clarity of the data tables for both the MSIV closure and turbine trip ATWS EPU events, provide the full name/nomenclature with description or definition of each column field (e.g.,
rrpdome, nmapmfx_z, fwslal 01, etc.).
- 3) In addition to the [Reactor Pressure Vessel] RPV Pressure vs. Time plots in both events, please include an overlay plot of Power versus Time (i.e., show power oscillations/response correspondingto the RPVpressure response).
NMPNS Response to 1) above Note: The Simulator model used for this evaluation is not an engineering simulation and the model is not the final EPU simulator upgrade. The results have been compared to the EPU design ATWS results and the response is reasonable. These figures should be used on a qualitative basis to judge operator response only.
Simulator Scenario 1 - Maximum Extended Load Line Limit Analysis (MELLLA) Isolated Anticipated Transient Without Scram (ATWS) with Main Steam Isolation Valve (MSIV) Closure Scenario Description The plant is operating at Extended Power Uprate (EPU) conditions on a limiting control rod pattern for MELLLA. A spurious MSIV isolation occurs and the reactor fails to scram with no control rod motion.
In addition, the Alternate Rod Insertion (ARI) function of the Redundant Reactivity Control System (RRCS) fails to effect control rod motion. All other features of RRCS function as designed. The crew performs actions per:
- N2-EOP-RPV, RPV Control
- N2-EOP-PC, Primary Containment Control
- N2-EOP-C5, Failure to Scram For the purpose of the ATWS transient with MSIV closure, operator action was not taken to insert control rods.
2 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Initial Conditions Reactor power at 100% of rated, 3988 MWth Core flow at 99% of rated (107.4 Mlbm/hr)
Suppression Pool Temperature 90'F Suppression Pool Level 199.5 feet Service Water Supply temperature 84'F All equipment OPERABLE Significant Event Sequence - Time (T) in Seconds T=0 All MSIVs close. Closure time is four seconds T = 3.6 High reactor pressure initiates RRCS. Reactor Recirculation pumps transfer to slow speed T = 5.1 Peak neutron flux of 225%
T = 8.6 Peak Reactor Pressure Vessel (RPV) pressure of 1350 psig T = 28.6 Automatic action - Reactor Recirculation pumps trip to OFF, feedwater runback terminates feedwater injection T = 60.6 Suppression Pool temperature reaches Boron Injection Initiation Temperature (BIIT) of 110HF T = 113 Automatic action - Boron injection initiated T = 116 Operator action - injection sources other than Reactor Core Isolation Cooling (RCIC),
Control Rod Drive (CRD) and boron are terminated and prevented T = 151 Operator action - pressure band of 800 - 1000 psig established using Safety Relief Valves (SRVs)
T = 199 Operator action - commence RPV level recovery following feedwater runback. Directed level band is from Minimum Steam Cooling Water Level (MSCWL) to Top of Active Fuel (TAF)
Reactor Water Level TAF MSCWL Actual -14" -39" Fuel Zone Indicated -55" -70" T = 251 Average Power Range Monitor (APRM) neutron flux is downscale, less than 4%
T = 273 Operator action - First loop of Residual Heat Removal (RHR) is in Suppression Pool cooling at rated flow of 7450 gpm T = 275 Operator action - RPV water level restored and maintained within directed band T = 339 Suppression Pool temperature reaches maximum value of 134.9°F T = 404 Operator action - second loop of RHR is in Suppression Pool cooling at rated flow of 7450 gpm T = 406 Reactor is in hot shutdown as indicated by neutron flux <0.1% on APRMs Figures 1 through 27 depict the plant response for a number of parameters.
3 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Simulator Scenario 2 - MELLLA ATWS with Turbine Trip Scenario Description The plant is operating at EPU conditions on a limiting control rod pattern for MELLLA. A spurious turbine trip occurs and the reactor fails to scram with no control rod motion. In addition, the Alternate Rod Insertion (ARI) function of the Redundant Reactivity Control System (RRCS) fails to effect control rod motion. All other features of RRCS function as designed. The crew performs actions per:
- N2-EOP-RPV, RPV Control
- N2-EOP-PC, Primary Containment Control
" N2-EOP-C5, Failure to Scram For the purpose of the ATWS transient turbine trip with bypass, operator action was not taken to insert control rods.
Initial Conditions Reactor power at 100% of rated, 3988 MWth Core flow at 99% of rated (107.4 Mlbm/hr)
Suppression Pool Temperature 90'F Suppression Pool Level 199.5 feet Service Water Supply temperature 84'F All equipment OPERABLE Significant Event Sequence - Time (T) in Seconds T=0 Main turbine trips.
T = 0.5 All five turbine bypass valves are full open T=1 High reactor pressure initiates RRCS. Reactor Recirculation pumps transfer to slow speed T =2 Peak neutron flux of 185%
T = 2.8 Peak Reactor Pressure Vessel (RPV) pressure of 1187 psig T =26 Automatic action - Reactor Recirculation pumps trip to OFF, feedwater runback terminates feedwater injection T = 104 Operator action - RPV water level stabilized following feedwater runback in a band of 50 to 80 inches on wide range level indication.
T = 110.6 Automatic action - Boron injection initiated T = 153.6 Suppression Pool temperature reaches Boron Injection Initiation Temperature (BIIT) of 11 0IF T = 191 Operator action - pressure band of 800 - 1000 psig established using Safety Relief Valves (SRVs)
T = 216 Operator action - injection sources other than Reactor Core Isolation Cooling (RCIC),
Control Rod Drive (CRD) and boron are terminated and prevented T = 256 Operation action - RPV level is in desired band from Minimum Steam Cooling Water Level (MSCWL) to Top of Active Fuel (TAF) 4 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Reactor Water Level TAF MSCWL Actual -14" -39" Fuel Zone Indicated -55" -70" T = 269 Suppression Pool temperature reaches maximum value of 120.7°F T =338 Operator action - First loop of Residual Heat Removal (RHR) is in Suppression Pool cooling at rated flow of 7450 gpm T = 373 Average Power Range Monitor (APRM) neutron flux is downscale, less than 4%
T = 425 Operator action - second loop of RHR is in Suppression Pool cooling at rated flow of 7450 gpm T = 465 Reactor is in hot shutdown as indicated by neutron flux <0.1% on APRMs Figures 28 through 54 depict the plant response for a number of parameters.
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ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 1 Transient Test EPU Isolated ATWS MELLLA RPV Dome Pressure (rrpdome) 14001400I Automatic action - RPV pressure control above 1000 psig on SRVs in relief mode.
1200 1000
- 1. 800
&. Operator action - manual pressure control using SRVs. Pressure band 800 - 1000 psig.
> 600 400 200 0 100 200 300 400 500 600 700 800 900 1000 Seconds 6 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 2 Transient Test EPU Isolated ATWS MELLLA Neutron Flux (nmapmfx-z) 250 200
- x 150 a.
100 50 0
0 100 200 300 400 500 600 700 800 900 1000 Seconds 7 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 3 Transient Test EPU Isolated ATWS MELLLA Narrow Range RPV Level (fwslal0l) 200 180 160
-*140
- - Narrow Range bottom of scale - 145 inches.
120
-1
~5100
> 80 z 60 40 20 0 100 200 300 400 500 600 700 800 900 1000 Seconds 8 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 4 Transient Test EPU Isolated ATWS MELLLA Wide Range RPV Level (rrlwml1420) 200 150 0
-6100 C 50 Minimum usable Wide Range level indication is 25 inches.
0
-50 .......
0 100 200 300 400 500 600 700 800 900 1000 Seconds 9 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 5 Transient Test EPU Isolated ATWS MELLLA Feedwater Flow (fwfwtot-z) 20 18
-]
16 14 Operator action - recover RPV water level following feedwater runback.
2 12 10 L.10A8 4-2 Automatic Action -
feed water runback 0 100 200 300 400 500 600 700 800 900 1000 Seconds 10 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 6 Transient Test EPU Isolated ATWS MELLLA Main Steam Flow (msfmslt-z) 20 18 16 Transient initiation - Full MSIV Closure.
16
"*14
- 12 0
EI1
- 8 6
4 2-0-
0 100 200 300 400 500 600 700 800 900 1000 Seconds 11 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 7 Transient Test EPU Isolated ATWS MELLLA Total Core Flow (rrffcrz) 120 100 Automatic Action - Reactor Recirculation pumps trip from high to low speed at T= 3.6 seconds.
Automatic Action - Reactor Recirculation pumps trip from low speed to off at T= 28.6 seconds if neutron flux is above 4%.
80 -i I-
=* 60 o0
.2 0
o 40 - III 0.
20 0
-20 I 2 3 4 6 0 0 I 0 100 200 300 400 500 600 700 800 900 1000 Seconds 12 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 8 Transient Test EPU Isolated ATWS MELLLA Final Feedwater Temperature (fwtrxt) 500 450 400 U-0) 0 350 2'
I-,
300 0.
E 250 I-C-4)
"* 200 0
u- 150 50 100 0
50 0 10O0 200 300 400 500 600 700 800 900 1000 Seconds 13 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 9 Transient Test EPU Isolated ATWS MELLLA Main Condenser Vacuum (mxvacb) 29 28.5
" 28
" 27.5 E -, 27 U) 26.5 0
C 0 26 "i 25.5 25 24.5 .....
0 100 200 300 400 500 600 700 800 900 1000 Seconds 14 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 10 Transient Test EPU Isolated ATWS MELLLA Turbine Bypass Valve Position (tcvbpvav) 1 0.9
,0.8 0
0.7
-0.6
'ii0 0.5 0.
0.
0.
I=10.2 0.1 0
0 100 200 300 400 500 600 700 800 900 1000 Seconds 15 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 11 Transient Test EPU Isolated ATWS MELLLA Turbine Control Valve Position (msvtmcv) 1 0.9 00.8 0
o IL 0.7 0.6 o0.2 oO.
0.
-0.
0 0.2 0.1 0-0 100 200 300 400 500 600 700 800 900 1000 Seconds 16 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 12 Transient Test EPU Isolated ATWS MELLLA Fuel Zone RPV Level (ZAR2R6 1OZ) 60 40 20
~0
-20
- 13
--JD>
-40 No0-60 -6 *!- -5 to -70 inches indicated water level = 14 to -39 inches actual z 1 A/l" water level. -39 inches is minimum steam cooling water level.
= -80
-100 120 Operator Action - recover RPV water level to a band of -55 to -70 inches. Minimum
-140 water level caused by automatic feedwater runback.
-160 0 100 200 300 400 500 600 700 800 900 1000 Seconds 17 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 13 Transient Test EPU Isolated ATWS MELLLA Drywell Pressure (PCPDWCMS) 15.7 15.6
'R15.5
=15.4 I.
15.3 15.2 1 5 .....
15.1 15.0 0 100 200 300 400 500 600 700 800 900 1000 Seconds 18 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 14 Transient Test EPU Isolated ATWS MELLLA Suppression Chamber Pressure (PCPCHMB) 16 15.8 20
"!15.6 2 15.4 0.
E15.2
.0 15 0
14.6 14.4 0 100 200 300 400 500 600 700 800 900 1000 Seconds 19 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 15 Transient Test EPU Isolated ATWS MELLLA Drywell Temperature (PCTDRYWL) 130 128 126 0124 122 120 E
iT 118 116 114 112 110 108 12300000 1 010O0 200 300 400 500 600 700 800 900 1000 Seconds 20 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 16 Transient Test EPU Isolated ATWS MELLLA (Suppression Chamber Air Temperature (PCTSPAIR) 104 U.102 0) 100 E
90 (0 094 C.,
88......
90 88 0 100 200 300 400 500 600 700 800 900 1000 Seconds 21 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 17 Transient Test EPU Isolated ATWS MELLLA Suppression Pool Temperature (PCTSP) 160 140
.120 100 0
0.
E 80 0
0
.2 60 CL
.- 40 20 0
0 100 200 300 400 500 600 700 800 900 1000 Seconds 22 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 18 Transient Test EPU Isolated ATWS MELLLA Boron Injection Flow Rate (SLFTOTALSYSTEM) 14 12 S10 E_ Nominal boron injection rate is 86 gpm with two Standby Liquid Control (SLC) pumps.
o 8 U-E 6
-I 4
0) 0 100 200 300 400 500 600 700 800 900 1000 Seconds 23 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 19 Transient Test EPU Isolated ATWS MELLLA RPV Boron Concentration (RRCBORON) 1.80E+03 1.60E+03 1.40E+03 1.20E+03 CL
.0 1.OOE+03 CA W8.OOE+02 0A 26.OOE+02 2.00E+02 O.OOE+O0 0 100 200 .300 400 500 600 700 800 900 1000 Seconds 24 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 20 Transient Test EPU Isolated ATWS MELLLA Core Reactivity (CRXREAC) 2000 0
-2000 S-4000 4)
-6000 0
-8000
-10000
-12000
-14000 .
0 100 200 300 400 500 600 700 800 900 1000 Seconds 25 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 21 Transient Test EPU Isolated ATWS MELLLA HCTL Limit (SPDSA1 18) 152 150 A S148 E
2146 144 I--
Z 142 C,
140 "Z Heat Capacity Temperature Limit (HCTL) is a function of RPV pressure and Suppression Pool level.
138 136 T......
0 100 200 300 400 500 600 700 800 900 1000 Seconds 26 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 22 Transient Test EPU Isolated ATWS MELLLA HCTL Margin (SPDSA1 19) 60 50 Im40
- )4o
.J I--
o 30 I--
L-200 0 100 200 300 400 500 600 700 800 900 1000 Seconds 27 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 23 Transient Test EPU Isolated ATWS MELLLA RHR "A" Pump Flow (RHFPMP1A) 1200 1000 E 800 0
U.
M. 600 E E= Nominal RHR flow for Suppression Pool cooling is 7450 gpm.
O.< Assumed operator action time is 1080 seconds.
400 200 0
0 100 200 300 400 500 600 700 800 900 1000 Seconds 28 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 24 Transient Test EPU Isolated ATWS MELLLA RHR "B" Pump Flow (RHFPMP1B) 1200 1000 0
. 800
-- Nominal RHR flow for Suppression Pool cooling is 7450 gpm.
Assumed operator action time is 1080 seconds.
0 U-0.
E 600
, 400 200 0
0 100 200 300 400 500 600 700 800 900 1000 Seconds 29 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 25 Transient Test EPU Isolated ATWS MELLLA RHR "C" Pump Flow (RHFPMP1C) 100 90 Short duration flow is due to operator action taken to terminate and prevent sources that inject inside the core shroud. Pump on minimum flow, no RPV injection.
80 70 E
.2 j=60 M 50 E
a-o40
,30 20 10 0
0 100 200 300 400 500 600 700 800 900 1000 Seconds 30 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 26 Transient Test EPU Isolated ATWS MELLLA Total SRV Flow (MSFSRVWTRSC) 6000 5000 E
=4000 500)
.23000
-a 0
1000 0
0 100 200 300 400 500 600 700 800 900 1000 Seconds 31 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 27 Transient Test EPU Isolated ATWS MELLLA Suppression Pool Level (SPDSA1 17) 200.8 200.6 0
. 200.4
.6..
- j200.2 I...
200 0
M199.8 199.6 0 100 200 300 400 500 600 700 800 900 1000 Seconds 32 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 28 Transient Test EPU Turbine Trip ATWS MELLLA RPV Dome Pressure (rrpdome) 1400 Automatic action - RPV pressure control above 1000 psig on SRVs in relief mode.
1200 1000 0._
0.
800 Operator action - manual pressure control using SRVs and Electrohydraulic Control/turbine bypass valves. Pressure band 800 - 1000 psig.
0.
600 400 200 0 100 200 300 400 500 600 700 800 900 1000 Seconds 33 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 29 Transient Test EPU Turbine Trip ATWS MELLLA Neutron Flux (nmapmfx-z) 200 180 160 140 1**20u U-2100 80 60 40 v 20 0
0 100 200 300 400 500 600 700 800 900 1000 Seconds 34 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 30 Transient Test EPU Turbine Trip ATWS MELLLA Narrow Range RPV Level (fwslal0l) 200 180 160 0- 140
- Narrow Range bottom of scale - 145 inches.
m 120
,-I 100
> 80 z 60 40 20 0
0 100 200 300 400 500 600 700 800 900 1000 Seconds 35 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 31 Transient Test EPU Turbine Trip ATWS MELLLA Wide Range RPV Level (rrlwrnl420) 200 150 0
"* 100 0
Miiu sbeWide Range level indication is 25 inches.
-5 0 0 100 200 300 400 500 600 700 800 900 1000 Seconds 36 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 32 Transient Test EPU Turbine Trip ATWS MELLLA Feedwater Flow (fwfwtot-z) 20 18 16-
-- 14 o12 u.
%10
_8 iB Automatic Action - feedwater runback.
Operator action - prevent injection from sources other than systems required to 0shutdown
-- 6 the reactor until below top of active fuel.
0 , ,
0 100 200 300 400 500 600 700 800 900 1000 Seconds 37 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 33 Transient Test EPU Turbine Trip ATWS MELLLA Main Steam Flow (msfmslt-z) 20 18 16 Transient initiation - Turbine Trip with Bypass.
16 "14-
.2 312-U-
E l0 Co 8-4-
0 6
4 ht JAAAdAA ,,AAA 2
0 i i 0 100 200 300 400 500 600 700 800 900 1000 Seconds 38 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 34 Transient Test EPU Turbine Trip ATWS MELLLA Total Core Flow (rrffcrz) 120 100 Automatic Action - Reactor Recirculation pumps tip from high to low speed at T = 1 second.
Automatic Action - Reactor Recirculation pumps trip from low speed to off at T = 26 seconds if neutron flux is above 4%.
" 80
.0 o60 60 M=
0 20 40 20 0
0 100 200 300 400 500 600 700 800 900 1000 Seconds 39 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 35 Transient Test EPU Turbine Trip ATWS MELLLA Final Feedwater Temperature (fwtrxt) 500 450 400 U*
0) 350 300 E 250 150 u.
0.
100 50 0100 200 300 400 500 600 700 800 900 1000 Seconds 40 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 36 Transient Test EPU Turbine Trip ATWS MELLLA Main Condenser Vacuum (mxvacb) 29 28.5 28 E 27.5 cn 27 0
M 26.5 E
26 25.5 25 24.5 0 100 200 300 400 500 600 700 800 900 1000 Seconds 41 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 37 Transient Test EPU Turbine Trip ATWS MELLLA Turbine Bypass Valve Position (tcvbpvav) 1.2 1
0 0-0.
cn 0
50.6 0.4 m__
0 0.2 0 10O0 200 300 400 500 600 700 800 900 1000 Seconds 42 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 38 Transient Test EPU Turbine Trip ATWS MELLLA Turbine Control Valve Position (msvtmcv) 1 0.9
"-0.8 0
.2 o0.
o0.
a.
60.
0.1 "o0.4 a .3 0
00.2 0.1 0 10O0 200 300 400 500 600 700 800 900 1000 Seconds 43 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 39 Transient Test EPU Turbine Trip ATWS MELLLA Fuel Zone RPV Level (ZAR2R6 10_Z) 60 40 20 0
20 0 -20 0 -55 to -70 inches indicated water level = -14 to -39 inches actual water level.
N -39 inches is minimum steam cooling water level.
- -40 U-
-60
-80
-1000..
0 100 200 300 400 500 600 700 800 900 1000 Seconds 44 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 40 Transient Test EPU Turbine Trip ATWS MELLLA Drywell Pressure (PCPDWCMS) 15.6 15.5
" 15.4 0115.3 15.2 15.1 15.2 0 100 200 300 400 500 600 700 800 900 1000 Seconds 45 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 41 Transient Test EPU Turbine Trip ATWS MELLLA Suppression Chamber Pressure (PCPCHMB) 15.4 15.3 15.2 015.1 0
I-0.
- 15 E
014.9 "i
CL 14.8 U) 14.7 14.6 14.5 1230000..
010O0 200 300 400 500 600 700 800 900 1000 Seconds 46 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 42 Transient Test EPU Turbine Trip ATWS MELLLA Drywell Temperature (PCTDRYWL) 130 128 126 124 w 122 S120 E
118 116 114 112 110 108 .
0 100 200 300 400 500 600 700 800 900 1000 Seconds 47 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 43 Transient Test EPU Turbine Trip ATWS MELLLA Suppression Chamber Air Temperature (PCTSPAIR) 97 966 UL 295 a-E 93 (D
92
.* 91 C.)
C90 89 88 1230000..
0 10O0 200 300 400 500 600 700 800 900 1000 Seconds 48 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 44 Transient Test EPU Turbine Trip ATWS MELLLA Suppression Pool Temperature (PCTSP) 140 120 n2 100 -
C1..
E 80 I--
0 06
- o. 40-
- a. 20 0 20-0 100 200 300 400 500 600 700 800 900 1000 Seconds 49 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 45 Transient Test EPU Turbine Trip ATWS MELLLA Boron Injection Flow Rate (SLFTOTALSYSTEM) 14 12 Nominal boron injection rate is 86 gpm with two Standby Liquid Control (SLC) pumps.
010 E
- 2
ý: 8 0
U-E 6
-J 4
2 0 100 200 300 400 500 600 700 800 900 1000 Seconds 50 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 46 Transient Test EPU Turbine Trip ATWS MELLLA RPV Boron Concentration (RRCBORON) 2.50E+03 2.00E+03 CL 0
1.50E+03 0
0 1.00E+03 0
> 5.00E+02 O.OOE+O00....
0 10O0 200 300 400 500 600 700 800 900 1000 Seconds 51 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 47 Transient Test EPU Turbine Trip ATWS MELLLA Core Reactivity (CRXREAC) 5000 0
4--... . .
C.)
t-5000 4) 0-10000
-15000
-20000 .......
0 100 200 300 400 500 600 700 800 900 1000 Seconds 52 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR V EXTENDED POWER UPRATE OPERATION Figure 48 Transient Test EPU Turbine Trip ATWS MELLLA HCTL Limit (SPDSA1 18) 145 144 I,,.
0) 143 E
0 i 142 Heat Capacity Temperature Limit (HCTL) is a function of RPV presure and E Suppression Pool level.
0 140
- a. 139 0
138 137 136 0 100 200 300 400 500 600 700 800 900 1000 Seconds 53 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 49 Transient Test EPU Turbine Trip ATWS MELLLA HCTL Margin SPDSA1 19 60 50 0)40
-J I-g30 20 10 0
0 100 200 300 400 500 600 700 800 900 1000 Seconds 54 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 50 Transient Test EPU Turbine Trip ATWS MELLLA RHR "A" Pump Flow (RHFPMP1A) 1200 1000 E 800
-Nominal / Assumed RHR flowaction operator for Suppression time is 1080Pool cooling is 7450 gpm.
seconds.
0 u.
- o. 600 E
n,
- 400 200 0
0 100 200 300 400 500 600 700 800 900 1000 Seconds 55 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 51 Transient Test EPU Turbine Trip ATWS MELLLA RHR "B" Pump Flow (RHFPMP1B) 1200 1000 U)
E 800
- "- Nominal RHR flow for Suppression Pool cooling is 7450 gpm.
.2 Assumed operator action time is 1080 seconds.
- o. 600 E
en
- 400 200 0
0 100 200 300 400 500 600 700 800 900 1000 Seconds 56 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 52 Transient Test EPU Turbine Trip ATWS MELLLA RIR "C" Pump Flow (RHFPMP1C) 0.9 0.8 ch0.7 E
ze
- 0.6
.0 U.
IL.
,-,0.5 E
0.4 S0.3 0.2 0.1 0
0 100 200 300 400 500 600 700 800 900 1000 Seconds 57 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 53 Transient Test EPU Turbine Trip ATWS MELLLA Total SRV Flow (MSFSRVWTRSC) 5000 4500
-64000 E 3500 I II 3000 B
- 0) a 32000 0
U-
'1500 0
1000-500 0 I 0 100 200 300 400 500 600 700 800 900 1000 Seconds 58 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 54 Transient Test EPU Turbine Trip ATWS MELLLA Suppression Pool Level (SPDSA1 17) 200.4 200.3
.2 200.2 200.1 u 200 199.9 199.8 6199.7 CL 0.
199.6 199.5 199.42000000890 0 10O0 200 300 400 500 600 700 800 900 1000 Seconds 59 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION NMPNS Response to 2) above Table 1 provides the full name/nomenclature to describe/define each column field.
Table 1 Excel Spreadsheet Nomenclature References Column Reference Description/definition rrpdome Reactor Pressure Vessel (RPV) Dome Pressure (psig) nmapmfx z Neutron Flux (%)
fwslal 01 Narrow Range RPV Level (inches) rrlwmr1420 Wide Range RPV Level (inches) fwfwtot z Feedwater Flow (Mlbm/hr) msfmslt z Main Steam Flow (Mlbm/hr) rrffcr z Recirculation Flow (Mlbm/hr) fwtrxt Final Feedwater Temperature ('F) mxvacb Main Condenser Vacuum (inches Hg) tcvbpvav Turbine Bypass Valve Position msvtmcv Turbine Control Valve Position ZAR2R610 Z Fuel Zone RPV Level (inches)
PCPDWCMS Drywell Pressure (psia)
PCPCHMB Suppression Chamber Pressure (psia)
PCTDRYWL Drywell Temperature (fF)
PCTSPAIR Suppression Chamber Air Temperature ('F)
PCTSP Suppression Pool Temperature ('F)
SLFTOTALSYSTEM Boron Injection Flowrate (lbm/sec)
RRCBORON RPV Boron Concentration (ppm)
CRXREAC Core Reactivity ($)
SPDSA1 18 Heat Capacity Temperature Limit (HCTL) ('F)
SPDSA1 19 HCTL Margin ('F)
RHFPMP1A Residual Heat Removal (RHR) "A" Pump Flow (lbm/sec)
RHFPMP1B RHR "B" Pump Flow (lbm/sec)
RHFPMP1C RHR "C" Pump Flow (lbm/sec)
MSFSRVWTRSC Total Safety Relief Valve (SRV) flow (Ibm/sec)
SPDSA1 17 Suppression Pool Level (feet)
NMPNS Response to 3) above Figures 55 and 56 provide overlay plots that show RPV pressure and reactor power versus time for both of the ATWS Simulator exercises.
60 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 55 Transient Test EPU Isolated ATWS MELLLA
.- RPV Dome Pressure [psig] (rrpdome) - Neutron Flux [%] (nmapmfxz) 1400 250 Automatic action - RPV pressure control above 1000 psig on SRVs in relief mode 1200 1000 150 800 Operator action - manual pressure control using SRVs. Pressure band 800 - 1000 psig 600 100 400 50 200 0 0 0 100 200 300 400 500 600 700 800 900 1000 Seconds 61 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 56 Transient Test EPU Turbine Trip ATWS MELLLA RPV Dome Pressure [psig] (rrpdome) - Neutron Flux [%] (nmapmfxz) 1400 250 Automatic action - RPV pressure control above 1000 psig on SRVs in relief mode 1200 1000 "200 150 800 Operator action - manual pressure control using SRVs and Electrohydraulic Control/turbine bypass valves. Pressure band 800 - 1000 psig 600 100 400 50 200 0 0 0 100 200 300 400 500 600 700 800 900 1000 Seconds 62 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION RAI from NRC E-mail dated July 27, 2011 ECCS NPSH Station Blackout (SBO) Scenario The technical staff requests additional clarification in NMPNS' RAI response dated May 9, 2011, regarding the operation of the pumps during [a] SBO, particularlyafter the coping period. The RAI response stated that the SBO scenario was not included in the licensee's evaluation as the [Reactor Core Isolation Cooling] RCIC pump is relied upon during the copingperiod. Nothing was said in the response about operation of other pumps past the SBO copingperiod.
NMPNS Response Following the 4-hour SBO coping period, there are a number of different scenarios that could be analyzed due to the various offsite or on-site electrical power sources that could be returned to service. To address NPSH margins during the recovery period of a SBO event, NMPNS made the following assumptions to maximize suppression pool temperature:
- Only one Emergency Diesel Generator or Offsite AC power supply to one emergency bus is restored after 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />. Thus, a single loop of Residual Heat Removal (RHR) suppression pool cooling is assumed to become available after 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.
- This recovery evaluation conservatively assumes reduced containment spray mode flow rate through the RHR heat exchanger, which reduces the assumed heat removal as compared to the suppression pool cooling spray mode that would be used for the majority of the restoration time frame. Note: this flow rate is lower than that assumed for the Design Basis Accident - Loss of Coolant Accident (DBA-LOCA) or Alternate Shutdown Cooling (ASDC) scenarios. The RHR pump NPSH calculations conservatively assume maximum LPCI mode run-out flow conditions.
- As defined in Section 2.3.5 of Attachment 11 to the NMP2 EPU License Amendment Request dated May 27, 2009, the suppression pool temperature after 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> is 186'F. For that SBO scenario, the reactor pressure after 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> is 180 psia (165.3 psig).
- The Shutdown Cooling (SDC) interlock is at 128 psig; therefore, the suppression pool heatup would continue with one RHR loop of suppression pool cooling until SDC is initiated when reactor pressure is reduced below 128 psig. This evaluation conservatively assumes SDC initiation is achieved when reactor pressure reaches 100 psia (85 psig).
- Reactor depressurization from 180 psia (165.3 psig) to below the SDC permissive is achieved with one SRV remaining open to the suppression pool with one loop of RHR in suppression pool cooling mode.
- The 3 RHR pumps at NMP2 have individual suction strainers; therefore, a multiple RHR pump suction lineup on a common header suppression pool source is not applicable to the NMP2 RHR pump SBO recovery.
Qualitative Discussion:
With the above-described assumptions, suppression pool temperature would increase during the reactor cooldown and operations would control the cooldown to below 212'F if no containment accident pressure is assumed to exist as a result of containment spray. As analyzed, the suppression pool level is increased by greater than 2 feet at the end of the 4-hour coping period. This represents an additional 2 feet of head above that assumed for the RHR pump NPSH margins for the ASDC event. Note that the RCIC suction 63 of 67
0 ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION source is the Condensate Storage Tank (CST). During SBO recovery, no debris loading on the strainer is assumed. Thus, for SBO recovery, the margin is defined based on the ASDC event margin plus 2 feet of head, which results in a minimum NPSH margin ratio above 1.6 when the suppression pool is at 212'F.
Quantitative Assessment:
With the assumptions noted above, a simple suppression pool heatup estimate is shown in Figure 57. The suppression pool temperature increases over a two to three hour period to above 200'F, but is predicted to remain below 208'F for the duration of the recovery period. The reactor pressure is reduced below the assumed 85 psig after approximately 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> from SBO initiation (8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> after the initial 4-hour coping period). Consistent with the ASDC assumptions, the 1.6 margin ratio is maintained with suppression pool temperature below 208'F. Therefore, the 1.6 margin ratio is maintained assuming no containment accident pressure and conservatively assuming no credit for the increased suppression pool level predicted for SBO during the recovery phase with RCIC taking suction from the CST.
Figure 57
- SBO Recovery Phase 210 V77 205 200 M
a.,
E
-* 195 0
0 C
0 sw190 CL C.
185 180 0 5 10 15 20 25 30 35 Time (Hours) 64 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION RAI from NRC E-mail dated August 4. 2011 ECCS NPSH In letter dated May 9, 2011, it was stated that the [Low Pressure Coolant Injection] LPCI ([Residual Heat Removal] RHR) pumps could operate at margin ratio of less than 1. 6for approximately 839 minutes
(-14 hours)for [Design Basis Accident - Loss of Coolant Accident] DBA-LOCA and 376 minutes (-6.3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />) for [Alternate Shutdown Cooling] ASDC. It was further stated that the operational times were based on the tabular values for suppression pool temperature versus time developed to generate the graphs in NMP2 EPULAR dated May 27, 2009. However, the graphs that were included in the EPULAR only go up to 105 seconds (-28 hours). It is not clear how long a period did NMPNS evaluate the operation of the pumps. During long-term cool-down, the pumps could operate at aflow rate higher than during short-term, thus potentially reducing [Net Positive Suction Head] NPSHA4. Please provide additionalinformation to assure the staff that NMPNS has considered allfactors that could potentially affect the margin ratio during long-term cooling in arrivingat the above mentioned times.
NMPNS Response Figures 58 and 59 provide the long term suppression pool temperature versus time for the DBA-LOCA and ASDC scenarios. The evaluated time periods for the DBA-LOCA and ASDC scenarios are approximately 12 days and approximately 2.5 days, respectively. Both scenarios assume that the RHR pumps are operating at the design basis suppression pool cooling flow rate for the duration of the event.
The NPSH margin assessment conservatively applied the design basis runout flow assumption.
For the DBA-LOCA and ASDC scenarios, the NPSH margin ratios are above 1.6 for suppression pool temperatures below 202'F and 208'F, respectively. (Note: The difference in maximum temperatures is due to assuming a debris loading on the strainer for the DBA-LOCA case and assuming no debris loading on the strainer for the ASDC case.)
65 of 67
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 58 DBA LOCA Long Term Suppression Pool Temperature Response 220 200 0 180 E
c
.W 140 CL *. ~Assumes RHR in suppression pool Coc ling mode at
- a. design flow for the dur tion of the event.
120 100 _
0 2 4 6 8 10 12 Time (Days) 66 of 67
I -~
ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR EXTENDED POWER UPRATE OPERATION Figure 59 ASDC Long Term Suppression Pool Temperature Response 220 200 180 0
0 E
a..
c o 160 I-0 0
0.
140 120 100 0 0.5 1 1.5 2 2.5 3 Time (Days) 67 of 67 A