ML11195A025

to Topical Report, D.C. Cook Unit 2 Post-LOCA Long Term Cooling Boron Precipitation Reanalysis Licensing Report Text.

ML11195A025
Person / Time
Site:	Cook
Issue date:	06/30/2011
From:	Utley D Westinghouse
To:	Office of Nuclear Reactor Regulation
References
Download: ML11195A025 (22)

Text

WESTINGHOUSE NON-PROPRIETARY CLASS 3 D. C. Cook Unit 2 Post-LOCA Long Term Cooling Boron Precipitation Reanalysis Licensing Report Text D. W. Utley, Electronically Approved*

LOCA Integrated Services II Revision 0 June 2011 Approved: D. M. Crytzer, Electronically Approved*

Manager, LOCA Integrated Services II

• Electronically approved records are authenticated in the electronic document management system.

Westinghouse Electric Company LLC P.O. Box 355 Pittsburgh, PA 15230-0355

© 2011 Westinghouse Electric Company LLC All Rights Reserved

WESTINGHOUSE NON-PROPRIETARY CLASS 3 ii TABLE OF CONTENTS ACRONYM S/ABBREVIATIONS .............................................................................................................. i 1.0 POST-LOCA BORIC ACID PRECIPITATION CONTROL ....................................................... 1....

1.1 INTRODUCTION

....................................................................................................... 1 1.2 KEY INPUT ASSUMPTIONS ....................................................................................... 1 1.3 ACCEPTANCE CRITERIA ........................................................................................... 2

1.4 DESCRIPTION

OF ANALYSIS/METHODOLOGY .................................................... 2 1.5 RESULTS ............................................................................................................................ 4

1.6 CONCLUSION

S/RECOMM ENDATIONS ................................................................... 4

1.7 REFERENCES

................................................................................................................... 4 APPENDIX A .......................................................................................................................................... 11

WESTINGHOUSE NON-PROPRIETARY CLASS 3 iii ACRONYMS/ABBREVIATIONS AEP American Electric Power AEPNGG American Electric Power Nuclear Generation Group BAPC Boric Acid Precipitation Control BELOCA Best-Estimate Loss-of-Coolant Accident CFR Code of Federal Regulations DIT Design Information Transmittal ECCS Emergency Core Cooling System HHSI High Head Safety Injection HLSO Hot Leg Switchover LAR License Amendment Request LOCA Loss-of-Coolant Accident PCWG Performance Capabilities Working Group (a Westinghouse functional group that supplies design operating conditions for nuclear power plants)

PWROG Pressurized Water Reactor Owner's Group RCS Reactor Coolant System RSAC Reload Safety Analysis Checklist RWST Refueling Water Storage Tank SEE Systems & Equipment Engineering (a Westinghouse functional group that supplies ECCS flow data)

SI Safety Injection SKBOR Computer code used by Westinghouse to calculate core and sump boron concentration WCAP Westinghouse Technical Report Number Designator (stood for Westinghouse Commercial Atomic Power)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 I 1.0 POST-LOCA BORIC ACID PRECIPITATION CONTROL

1.1 INTRODUCTION

Post-LOCA boron precipitation calculations were performed in support of the D. C. Cook BELOCA Licensing Amendment Request for Unit 2. The reanalysis satisfies the requirements of 10 CFR 50.46 Paragraph (b), Item (4):

(4) Coolable Geometry. Calculated changes in core geometry shall be such that the core remains amenable to cooling.

The methodology used to demonstrate D. C. Cook's compliance with the requirements of 10 CFR 50.46 Paragraph (b) is documented in WCAP-8339 (Reference 1) for the recirculation phase up to the time of hot leg recirculation.

1.2 KEY INPUT ASSUMPTIONS The major inputs to the boron precipitation reanalysis include core power, boron, and water volume/mass assumptions for significant contributors to the containment sump. The major input parameters used in the boric acid precipitation reanalysis are given in Table 1-1.

The boric acid precipitation model is based on the following assumptions and meets NRC guidance as presented in Reference 2 and is consistent with the interim methodology reported in Reference 3.

• The boric acid concentration of the core boil-off makeup, drawn from the containment sump water during recirculation, is a calculated weighted average boron concentration. The calculation of the mixed mean boron concentration assumes maximum boron concentration for all sources, minimum mass for dilution sources, and maximum mass for boration sources.

• The sump mixed mean boron concentration is calculated as a function of the pre-trip RCS conditions.

" The liquid mixing volume used in this calculation includes 50 percent of the lower plenum as supported in Reference 4.

• The core mixing volume used in the calculations considered the potential negative effects of loop pressure drop.

" The boric acid concentration limit is the experimentally determined boric acid solubility limit as reported in Reference 5 and summarized in Table 1-2 and Figure 1-1.

" NRC requirements pertaining to the decay heat generation rate for boric acid accumulation (1971 ANS Standard for an infinite operating time with 20 percent uncertainty) were considered when performing the boric acid precipitation calculations. The assumed core

WESTINGHOUSE NON-PROPRIETARY CLASS 3 2 power addresses instrument uncertainty as identified by Section 1.A of 10 CFR 50, Appendix K.

• ECCS recirculation flows are shown to dilute the core and replace core boil-off, thus keeping the core quenched.

The boric acid precipitation reanalysis input assumptions have been developed based on plant specific data provided by AEPNGG A core power of, 3,482 MWt was assumed. Inputs for the appropriate minimum ECCS recirculation flows were provided by SEE. Maximum containment spray pump flow rates were used since these maximize the RWST drain down rates. Data on the minimum calculated ice melt rate was used since this minimizes the calculated sump dilution at the tim e of HLSO... ....... ..... .. . . .

1.3 ACCEPTANCE CRITERIA The acceptance criteria for the long-term cooling analysis are demonstrated by calculating a BAPC plan time with methods, plant design assumptions, and operating parameters that are consistent with the interim methodology reported in Reference 3. The goal of this reanalysis is to demonstrate the continued acceptability of the latest HLSO completion time of 7.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> after a LOCA given in ES-1.4 (Reference 6).

The BAPC reanalysis includes review of two hot leg recirculation flow checks. The first hot leg recirculation flow check determines the acceptability of hot leg recirculation flow from one SI pump (all lines injecting) to provide dilution flow for a cold leg break. The final hot leg recirculation flow check determines if boric acid precipitation is precluded during the 15 minute switchover of the discharge of the HHSI from the cold legs to the hot legs. The results of these flow checks are summarized in Section 1.5.

1.4 DESCRIPTION

OF ANALYSIS/METHODOLOGY The methodology for calculating the maximum time to complete HLSO in order to preclude the potential for boric acid precipitation is established under the current NRC "interim" methodology (discussed in more detail below), which is based on the Reference 7 NRC stipulations. This interim methodology addresses features including the use of Appendix K decay heat, a core mixing volume which accounts for voiding, credit for some lower plenum mixing, and a calculation that accounts for system effects. The core voiding calculation intended for use in the reanalysis is based on Appendix K decay heat and atmospheric pressure (14.7 psia).

The agreement on an interim methodology for boric acid precipitation analyses is documented in Reference 3. The continued use of this interim approach was also discussed in a meeting between the PWROG and the NRC on November 18, 2010 (Meeting Summary is in Reference 8). Current operation is justified on the basis documented in References 9 through 11.

This analysis uses the "standard" interim methodology with the following modifications.

1) Standard analyses assume, all ice melts and mixes with the RWST at the beginning of the transient. This was deemed non-conservative since the ice is at a lower boron concentration

WESTINGHOUSE NON-PROPRIETARY CLASS 3 3 than the RWST. Due to the long duration of ice melt into the containment sump, and the overflow of sump fluid into the inactive reactor cavity region, a decay heat weighted average of the sump boric acid concentration was used. The calculation assumed RWST boric acid concentration until the time of initiating sump recirculation. After initiating recirculation, the sump boric acid concentration was a function of the initial RCS boron, contributions from accumulators and RWST boron, and the contribution from ice melt. For purposes of computing the vessel boric acid concentration, this time varying boric acid concentration of the containment sump fluid was weighted by decay heat, since boric acid concentrates faster earlier in the transient due to greater amounts of decay heat.

2) The "standard" interim methodology assumes that all of the liquid begins in the sump and is uniformly mixed. This was-deemed--to-be inappropriate given that D. C. Cook Unit 2 contains ice condensers which melt at a variable rate throughout the duration of the transient. In addition, the inactive sump regions needed to be taken into account. Therefore, a more accurate decay heat weighted sump average boron concentration calculation that accounted for overflow into the inactive sump regions during the ice melt transient was performed to model more realistic dilution of the sump. This final decay heat weighted sump average boron concentration was then used as the Sump Average Boron Concentration used in the SKBOR run to determine the acceptability of the maximum HLSO time.

3) Standard analyses do not consider the impact of core mixing volume decreases on the boric acid concentration during switchover procedures. The current hot leg switchover time and plant operating procedures result in ECCS flows that temporarily drop below the injected flow necessary to replace core boil-off (plus entrainment) during the HLSO process. The calculation of boric acid precipitation addressed not exceeding the boric acid solubility limit during this reduction.

4) Standard analyses typically look at the sump mixed mean boron concentration to determine if the ice was considered to be a dilution or boration source (based on whether it was higher or lower than the mixed mean). Since a time varying sump concentration and volume are computed, preliminary calculations were performed to determine acceptable boron and mass assumptions of the ice bed. Using minimum ice mass yielded a decay heat weighted sump average boron concentration greater than that of the ice mass boron concentration. This identified the ice mass as a dilution source, validating the minimum mass assumption for use in the analysis.

5) Standard analyses do not account for draindown effects. Standard analyses assume the sump is full of all constituents at the start of transient. Only an early draindown case was considered as a late draindown case was considered to be non-conservative. The early draindown case injects greater amounts of boron into the core region when decay heat is the most severe. In addition, the early draindown of the RWST generates a higher sump boron concentration at the time of sump recirculation as the ice mass has had less time to dilute the sump.

6) The methods used to calculate the "effective" sump volume in this analysis are not historically consistent with Post-LOCA methodology as ice condenser plants present a

WESTINGHOUSE NON-PROPRIETARY CLASS 3 4 unique situation. For analytical purposes, the sump cain be viewed-as having- two-mechanisms of filling. One mechanism is by way of overflowing, where the sump is allowed to fill to its capacity and then proceed to spill into a non-communicable area. The other mechanism is by overfilling, where the sump is allowed to fill beyond its physical capacity. The latter method is used for this analysis. The sump is allowed to fill beyond its physical capacity, as if it were infinite in volume. This modeling of the sump is conservative with respect to the "overflowing" model of the sump. The infinite volume of the sump minimizes the impact of sump dilution sources that dilute the sump for extended periods of time, such as the ice beds. Therefore, a maximum "effective" sump mass was calculated for use in generating a sump average boron concentration as described in item 2 above, and maximum sump volumes were used.

Note: The current HLSO methodology is currently under study as part of a PWROG program (Reference 12) in response to the NRC concerns outlined in Reference 7, as well as complex effects associated with GSI-191/Generic Letter 2004-02 (e.g., various chemical and debris related mixing effects; Reference 13).

1.5 RESULTS Post-LOCA BAPC calculations have been successfully completed for the D. C. Cook Unit 2 BELOCA LAR support. The points in time cited in the following discussion refer to time after the initiation of a LOCA event.

The BAPC analysis demonstrates the continued acceptability of the current maximum HLSO completion time of 7.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />. Completing the switchover to hot leg recirculation by 7.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> will ensure the maximum core region boric acid concentration does not meet or exceed the solubility limit of boric acid at atmospheric conditions.

Boric acid concentrations in the core were shown to remain below the atmospheric solubility limit of boric acid for the 15 minute SI flow interruption during the BILSO procedure. SI flow in hot leg recirculation mode was also shown to provide sufficient dilution flow to address cold leg breaks as shown in Figure 1-2.

1.6 CONCLUSION

S/RECOMMENDATIONS The Post-LOCA long term cooling reanalysis maintains that the HLSO completion time of 7.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> (ES-1.4, Reference 6) after the initiation of a LOCA is acceptable.

1.7 REFERENCES

1. WCAP-8339 (Non-Proprietary), "Westinghouse Emergency Core Cooling System Evaluation Model - Summary," June 1974.

2. NRC Letter from D. S. Collins to J. A. Gresham, "Clarification of NRC Letter Dated August 1, 2005, Suspension of NRC Approval for Use of Westinghouse Topical Report

WESTINGHOUSE NON-PROPRIETARY CLASS 3 5 CENPD-254-P, 'Post-LOCA Long-Terni Cbolifig Model,' Due to Discovery of Non-Conservative Modeling Assumptions During Calculations Audit (TAC NO. MB1365),"

11-23-2005. (ML052930272). .. - -. ..- .

3. NRC Letter from S. E. Peters to S. L. Rosenberg, "Summary of August 23, 2006 Meeting with the Pressurized Water Reactor Owners Group (PWROG) to Discuss the Status of Program to Establish Consistent Criteria for Post Loss-of-Coolant (LOCA) Calculations,"

10-3-2006. (ML062690017).

4. Beaver Valley EPU SER Report, "Safety Evaluation Related to Extended Power Uprate at Beaver Valley Power Station, Unit Nos. I and 2," 7-19-2006. (ML061720376).

5. P. Cohen, Water Coolant Technology of Power Reactors, Chapter 6, "Chemical Shim Control and pH Effect," ANS-USEC Monograph, 1980 (Originally published in 1969).

6. 12-OHP-4023-ES-1.4, Rev. 2, "Transfer to Hot Leg Recirculation," 8-29-2005.

7. NRC letter from D. S. Collins to G. C. Bischoff, "Suspension of NRC Approval for Use of Westinghouse Topical Report CENPD-254-P, 'Post LOCA Long Term Cooling Model,'

Due to Discovery of Non-Conservative Modeling Assumptions During Calculation Audit (TAC No. MB1365)," 11-23-2005. (ML053220569).

8. NRC Public Meeting Summary from J. G. Rowley to M. S. Ash, " 11/18/20 10 Summary of Open Meeting with the Pressurized Water Reactor Owners Group (PWROG)

Regarding the PWROG Boric Acid Precipitation Program," 2-3-2011. (ML110140477).

9. WCAP-16590-NP, "WCAP-Technical Basis for Response to NRC Request for Justification of Current Operation for Post-LOCA Boric Acid Precipitation Issues," June 2006.

10. LTR-LIS-06-415, "Closeout of PWR Owners Group Program - PA-ASC-0290," 7 2006.

11. OG-06-200, "Suspension of NRC Approval for Use of Westinghouse Topical Report CENPD-254-P, Post LOCA Long Term Cooling Model, Due to Discovery of Non-Conservative Modeling Assumptions During Calculation Audit, PA-ASC-0290," 6 2006. (ML061720175).

12. PWR Owners Group Project PA-ASC-0264, Rev. 3, "Post-LOCA Boric Acid Precipitation Analysis Methodology," October 2010.

WESTINGHOUSE NON-PROPRIETARY CLASS 3 6

13. NRC Generic Letter 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized Water Reactors," 9/13/04.

(ML042360586).

WESTINGHOUSE NON-PROPRIETARY CLASS 3 7 WESTINGHOUSE NON-PROPRIETARY CLASS 3 7 Table 1-1 Post-LOCA Sump Boron Calculation Input Parameters Summary Parameter Value Analyzed Core Power (MWt) 3,482 RWST Boron Concentration, Maximum 2,600 (ppm)

RWST Volume, Min to LO Level (gallons) 280,00001' RWST Total Delivered Volume (gallons) 420,000[21 RWST Temperature, Minimum (°F) 70 Accumulator Boron Concentration, 2,600 Maximum (ppm)

Accumulator Water Delivered, Maximum 3,884 Accumulator Water/Gas Temperature, 60 Minimum ('F)

Ice Boron Concentration, Maximum (ppm) 2,300 Ice Mass, Minimum (lbm) 2,200,000 Notes:

1. This is the RWST volume from the tech spec minimum level to the level at the identified set points.

2. The full RWST delivered volume was conservatively chosen, and is a source of margin in the calculations if a smaller delivered volume is justified.

WESTINGHOUSE NON-PROPRIETARY CLASS 3 8 WESTINGHOUSE NON-PROPRIETARY CLASS 3 8 Table 1-2 Boric Acid Solution Solubility Limit Pressure, Solubility Temperature, *F psia g H3BO3/100 g of Solution in H20 P = Atmospheric Pressure 32 14.7 2.70 41 14.7 3.14 50 14.7 3.51 59 14.7 4.17 68 14.7 4.65 77 14.7 5.43 86 14.7 6.34 95 14.7 7.19 104 14.7 8.17 113 14.7 9.32 122 14.7 10.23 131 14.7 11.54 140 14.7 12.97 149 14.7 14.42 158 14.7 15.75 167 14.7 17.41 176 14.7 19.06 185 14.7 21.01 194 14.7 23.27 203 14.7 25.22 212 14.7 27.53 217.9 14.7 29.27 P = PSAT 226.0 19.3 31.47 242.8 26.3 36.69 260.1 35.5 42.34 277.3 47.1 48.81 289.9 57.5 54.79 304.7 71.9 62.22 318.9 88.3 70.67 339.8 = Congruent Melting of H3B03

WESTINGHOUSE NON-PROPRIETARY CLASS 3 9 WESTINGHOUSE NON-PROPRIETARY CLASS 3 9 70 60 Boric Acid Boiling Point, 50 218 'F 0.

40 30 20 10 P=Patm I P=Psat _ __o 0

0 50 100 150 200 250 300 350 Temperature ("F)

Figure 1-1 Boric Acid Solubility Limit

WESTINGHOUSE NON-PROPRIETARY CLASS 3 10 Boric Acid Concentration-(wt. )

NO HL DILUTION FLO, WITH ALL OF AVAILABLE HL DILUTION FLOW BORIC ACID SOLUBILITY LIMIT IN AOR Udsil Flow Rate (I*m/scc)

CORE BOILOFF

.HL SI FLOW I VU

-~- ~ --

-~~~~ ~ - ---- -- -- - - - - -

40-30- -r"I W

0~

20- -40 10-v 2 t I U 0 4 Time 6 8 (hr) t*S.it Ra a* Z7255r*763 Figure 1-2 Boil-off, SI, and Core Dilution Rate at a 7.5 Hour HLSO Time at 14.7 psia

WESTINGHOUSE NON-PROPRIETARY CLASS 3 I1I Appendix A The following contains information that has previously been requested by the NRC pertaining to boric acid precipitation analyses performed by Westinghouse for D. C. Cook Unit 2.

1. Information regarding the D. C. Cook Unit 2 NSSS:

a. Volume of the lower plenum, core and upper plenum below the bottom elevation of the hot leg, each identified separately. Also provide heights of these regions.

Table Ala-i: Lower Plenum, Core, and Upper Plenum Volumes Volume (ft3)

Lower Plenum [ ]a,c Core [ ]a,c Upper Plenum Below the Bottom Elevation of the Hot Leg [ ]a,c Table Ala-2: Lower Plenum, Core, and Upper Plenum Heights Height (ft) pc Lower Plenum Core 12.000 Upper Plenum Below the Bottom Elevation of the Hot Leg [ a,c

WESTINGHOUSE NON-PROPRIETARY CLASS 3 12 WESTINGHOUSE NON-PROPRIETARY CLASS 3 12

b. Loop friction and geometry pressure losses-from-the core exit through the steam generators to the inlet nozzle of the reactor vessel. Also, provide the locked rotor RCP k-factor. Please provide the mass flow rates, flow areas, k-factors, and coolant temperatures for the pressure losses provided (upper-plenum, hot legs, SGs, suction legs, RCPs, and discharge legs). Please include the reduced SG flow areas due to plugged tubes. Please also provide the loss from each of the intact cold legs through the annulus to a single broken cold leg. Please also provide the equivalent loop resistance for the broken loop and separately for the intact loop.

Table Alb-1: Loop Friction and Geometry Pressure Losses from the Core Exit Through the Steam Generators to the Inlet Nozzle of the Reactor Vessel k Flow Area 0% SGTP Loss 10% SGTP Loss 2 Coefficient Coefficient (dimensionless) (in (ft/gpm 2 ) (ft/gpm 2)

Upper Plenum to a,c ]a,c a, c Same Hot Leg Nozzle Hot Leg Nozzle [ ac [ ]a,c [ c Same Hot Leg N/A N/A [ a,c Same Steam Generator N/A N/A [ Same Inlet Steam Generator Tubes, Inlet to U- N/A N/A [ [ C Bend Steam Generator N/A N/A [ ]a,C [ ]a,c U-Bend Steam Generator Tubes, U-Bend N/A N/A a,c [ a,c Outlet Steam Generator N/A N/A ac Same Outlet Pump Suction Leg N/A N/A [ ]ac Same Cold Leg N/A N/A [ ]c Same Cold Leg Nozzle [ a,c [ ]a,c [ ]a,c Same

WESTINGHOUSE NON-PROPRIETARY CLASS 3 13 WESTINGHOUSE NON-PROPRIETARY CLASS 3 13 Table Alb-1: Loop Friction and Geometry Pressure Losses from the Core Exit Through the Steam Generators to the Inlet Nozzle of the Reactor Vessel k Flow Area 0% SGTP Loss 10% SGTP Loss (2 Coefficient Coefficient (dimensionless) (in) (ft/gpm 2) (ft/gpm ) 2 Intact Cold Leg to [ ]a,c ]a,c Same Broken Cold Leg Table Alb-2: Locked Rotor Reactor Coolant Pump (RCP) k-factor 10% SGTP 0% SGTP Loss Loss kArea Flow Coefficient Ls (dimensionless) Area) (ftfgpm2) Coefficient

( in2) m(ft/gpm 2

)

Locked Rotor (Forward Flow) N/A N/A [ c Same Locked Rotor (Reverse Flow) N/A N/A [ c Same Table Alb-3: Mass flow rates, flow areas, k-factors, and coolant temperatures for the pressure losses provided Mass Flow 0% SGTP 10% SGTP k-factor Coolant Rate (lbm/hr) Flow Area (in 2) Flow Area (in2) (ft/gpm 2) Temperature (fF)

Upper Plenum to [ a'C Same [ 581.9 Hot Leg Nozzle Hot Leg Nozzle ]ac a [ ac Same [ c 581.9 Hot Leg [ [ c Same [ a 581.9 Steam Generator [ [ Same [ 581.9 Inlet Steam Generator Tubes, Inlet to U- [ 'C [ ] [ ]aC [ ac 547.6 Bend

WESTINGHOUSE NON-PROPRIETARY CLASS 3 14 Table Alb-3: Mass flow rates, flow areas, k-factors, and coolant temperatures for the pressure losses provided Mass Flow 0% SGTP 10% SGTP k-factor Coolant Rate (ibm/hr) Flow Area (in 2) Flow Area (in2) (ft/gpm 2) Temperature (fF)

Steam Generator ac a ac a~C 547.6 U-Bend Steam Generator Tubes, U-Bend [ ]ac [ [ [ ]ac 547.6 Outlet Steam Generator [ C Same [ 513.0 Outlet Pump Suction [ ac Same [ 513.0 Leg Cold Leg ]C ac[ [ ]ac Same a]ac 513.3 Cold Leg Nozzle [ [ c Same [ a 513.3 Intact Cold Leg to Broken Cold Not Modeled [ a Same [ c 513.3 Leg

c. Capacity and boron concentration of the RWST.

Table Ale-1: Capacity and boron concentration of the RWST Capacity Boron Concentration (gal) (ppm)

RWST, Minimum 280,000 2350 (1)

RWST, Maximum 420,000 (2) 2600 (1) Technical Specification SR 3.5.4.3 states to verify the RWST boron concentration is greater than 2400 ppm. The value of 2350 ppm accounts for 50 ppm of B-10 depletion.

(2) The 420,000 gal value conservatively bounds the RWST maximum capacity including tank uncertainties. Actual RWST volume delivered to the containment sump may be less.

WESTINGHOUSE NON-PROPRIETARY CLASS 3 15 WESTINGHOUSE NON-PROPRIETARY CLASS 3 15

d. Capacity of the condensate storage tank Table Ald-i: Capacity of the condensate storage tank Volume (ft3)

Condensate Storage Tank, Post-LOCA Analysis Not Modeled

e. Flushing flow rate at the time of switch to simultaneous injection Table Ale-i: Flushing Flow Rate Flushing Flow Rate (Ibm/see)

Flushing Flow at HLSO (3) 9 (3) Flushing flow is calculated as rhsl - thbo,1.

f. IPSI runout flow rate

WESTINGHOUSE NON-PROPRIETARY CLASS 3 16 WESTINGHOUSE NON-PROPRIETARY CLASS 3 16

g. Capacities and boron concentrations for BIT storage tanks Table Alg-1: Capacities and boron concentrations of the BIT storage tanks Capacity Boron Concentration (gal) (ppm)

Boron Injection Tank (4) 900 2,600 (4)

Since the BIT is non-functional, the BIT volume can be conservatively represented as additional ECCS piping volume, modeled at the RWST maximum concentration.

h. Flow rate into the RCS from the BIT Table Alh-1: Flow rate into the RCS from the BIT Flow Rate (gpm)

Boron Injection Tank Not Modeled (5)

(5) Since the BIT is non-functional and remains in the ECCS piping volume, flow from the BIT has the RWST as the source.

WESTINGHOUSE NON-PROPRIETARY CLASS 3 17

2. Please provide the following elevation data:

a. bottom elevation of the suction leg horizontal leg piping, cold leg diameter

b. top elevation of the cold leg at the reactor coolant pump discharge

c. top elevation of the core (also height of core)

d. bottom elevation of the downcomer Table A2-1: Elevation Data Elevation (ft) (6)

Bottom of Suction Leg Horizontal Piping [ ac Top of Cold Leg at Reactor Coolant Pump Discharge ]C P

Top of the Core (also Core Height) ]*c a (12.000)

Bottom of the Downcomer [ ]a*c "I All elevations are referenced from the bottom of the reactor vessel.

3. Please provide the limiting bottom and top skewed axial power shapes.

The limiting bottom skewed power shape is shown in Figure A3-1 with an axial offset of

-15.482%. The limiting top skewed power shape is shown in Figure A3-2 with an axial offset of 15.041%.

WESTINGHOUSE NON-PROPRIETARY CLASS 3 18 WESTINGHOUSE NON-PROPRIETARY CLASS 3 18 BOTTOM SKEWED AVGPWR 0 0 0 1.4' 1.2' rj0.8 La..

0 2 4 6 8 10 12 Elevation (ft)

Figure A3-1 Limiting Bottom Skewed Power Shape for Average Power Rod

WESTINGHOUSE NON-PROPRIETARY CLASS 3 19 WESTINGHOUSE NON-PROPRIETARY CLASS 3 19 TOP SKEWED AVGPWR 0 0 0 1.4' 1.2 1~

NI LL4 0.8 0.6 0.4 E~ '~.

U.z i . i I I i i l l l l l

• 4 0 2 4 6 8 10 12 Elevation (ft)

Figure A3-2 Limiting Top Skewed Power Shape for Average Power Rod