NL-13-058, Response to Request for Additional Information Re Containment Integrity Analysis
| ML13239A477 | |
| Person / Time | |
|---|---|
| Site: | Indian Point  |
| Issue date: | 08/21/2013 |
| From: | Ventosa J Entergy Nuclear Northeast |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| Shared Package | |
| ML13239A476 | List: |
| References | |
| NL-13-058, TAC MF0590, TAC MF0591 | |
| Download: ML13239A477 (34) | |
Text
Enterav Nuclear Northeast Indian Point Energy Center
'Entergy 450 Broadway, GSB P.O. Box 249 Buchanan, NY 10511-0249 Tel 914 254 6700 John A Ventosa Site Vice President Administration NL-13-058 August 21, 2013 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk 11555 Rockville Pike Rockville, MD 20852
SUBJECT:
Response to Request for Additional Information Regarding Containment Integrity Analysis (TAC NOS. MF0590 and MF0591)
Indian Point Unit Numbers 2 & 3 Docket Nos. 50-247 and 50-286 License Nos. DPR-26 and DPR-64
REFERENCES:
- 1. NRC Letter to Entergy, Request for Additional Information Regarding Containment Integrity Analysis (TAC NOS. MF0590 and MF0591),
dated June 28, 2013.
- 2. Entergy Letter NL-13-002 to NRC, Proposed Technical Specification Bases Changes to Credit Four Fan Cooler Units in Containmant Integrity Analysis, Indian Point Unit 2, dated January 28, 2013.
- 3. Entergy Letter NL-13-003 to NRC, Proposed Technical Specification Changes Regarding RWST Temperature and Containment Pressure in Containment Integrity Analysis, Indian Point Unit 3, dated January 28, 2013.
Dear Sir or Madam:
Entergy Nuclear Operations, Inc., (Entergy) is hereby providing the attached response to the NRC request for additional information, Reference 1, associated with the proposed changes to the Indian Point 2 & 3 Technical Specifications in References 2 and 3. On July 8, 2013, Entergy requested, and the NRC agreed, that due to the large amount of information requested, 60 days instead of 30 days would be acceptable for providing the responses. The responses to the request for additional information for Indian Point 2 are in Attachment 1, and the responses to the request for additional information for Indian Point 3 are in Attachment 2. A copy of the Nuclear Safety
NL-13-058 Docket Nos. 50-247 and 50-286 Page 2 of 2 Advisory Letter, "Westinghouse LOCA Mass and Energy Release Calculation Issues," NSAL-11-5, dated July 25, 2011 is provided as Attachment 3.
A copy of this response and the associated attachment is being submitted to the designated New York State official in accordance with 10 CFR 50.91.
There are no new commitments being made in this submittal. If you have any questions or require additional information, please contact Mr. Robert Walpole, Manager, Licensing at (914) 254-6710.
I declare under penalty of perjury that the foregoing is true and correct. Executed on August 21 2013.
Sincerely, JAV/ai Attachments: 1. Response to Request for Additional Information Regarding Crediting Four Fan Coolers in Containment Integrity Analysis -
Indian Point 2.
- 2. Response to Request for Additional Information Regarding Refueling Water Storage Tank Temperature and Containment Pressure in Containment Integrity Analysis - Indian Point 3.
- 3. Nuclear Safety Advisory Letter NSAL-1 1-5, 'Westinghouse LOCA Mass and Energy Release Calculation Issues",
07/25/2011.
cc: Mr. Douglas Pickett, Senior Project Manager, NRC NRR DORL Mr. William Dean, Regional Administrator, NRC Region 1 NRC Resident Inspectors Mr. Francis J. Murray, Jr., President and CEO, NYSERDA Ms. Bridget Frymire, New York State Dept. of Public Service
ATTACHMENT 1 TO NL-13-058 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION CREDITING FOUR FAN COOLERS IN CONTAINMENT INTEGRITY ANALYSIS - INDIAN POINT 2 ENTERGY NUCLEAR OPERATIONS, INC.
INDIAN POINT NUCLEAR GENERATING UNIT 2 DOCKET NOS. 50-247
Attachment 1 NL-13-058 Docket No. 50-247 Page 1 of 16 Response To Request For Additional Information - Indian Point 2 By letter dated January 28, 2013, Entergy Nuclear Operations, Inc., (Entergy), submitted a License Amendment request for Indian Point Nuclear Generating Unit Number 2 (IP2) Technical Specification Bases change regarding containment integrity analysis. The proposed change would credit four instead of three fan cooler units in the containment integrity analysis. By letter of June 28, 2013 the Nuclear Regulatory Commission requested additional information on that request. The requests and the responses are addressed below.
SCVB-RAI-1 Please list all the initial conditions used in the current most limiting large break LOCA analysis and the proposed analysis for the containment peak pressure and temperature response. In case any of the initial condition values are different in the proposed analysis from the current analysis of record, justify if the initial condition value in the proposed analysis is less conservative.
Response to SCVB-RAI-1 Tables 1, 2 and 3 show a comparison of initial conditions between the current most limiting licensing basis large break LOCA analysis done for Stretch Power Uprate (SPU) and the proposed analysis to correct the issues reported in NSAL-11-5 including some other changes. These 'other changes' are explained below.
They are due to Generic Safety Issue (GSI)-191 related changes, error corrections and a Component Cooling Water (CCW) pump performance margin enhancement (future). These 'other changes' have no impact on the proposed containment peak pressure of 45.82 psig, and result in a slightly lower pressure response subsequent to the peak, as shown in Figure 1.
" Steam generator secondary pressure has increased from 778 psia to 802 psia as a result of the steam generator bundle pressure issue discussed in NSAL-11-S. This change is conservative for the containment integrity analysis.
- Steam generator secondary mass has increased from 104300.1 Ibm to 105045.6 Ibm as a result of the steam generator bundle pressure issue discussed in NSAL-11-5. This change is conservative for the containment integrity analysis.
" The increase in the number of fan coolers from 3 to 4 was necessary to gain margin to offset the NSAL-11-5 issues.
" The ECCS flow during recirculation alignment has increased from 1864 gpm to 2191 gpm as a result of refining the RHR System hydraulic analysis to be consistent with plant operations at the start of cold leg recirculation.
- The total hot leg recirculation flow has changed from 822 gpm to 1096 gpm, as a result of an error correction to not include the spilling line assumption.
- The RHR heat exchanger UA has changed as a result of providing heat exchanger UAs based on the ECCS flow during the various recirculation periods outlined in Table 3.
A
Attachment 1 NL-13-058 Docket No. 50-247 Page 2 of 16
" The RHR heat exchanger shell side flow has changed from 1326 gpm to 1243 gpm due to correction of a previously mis-reported value and as a result of GSI-191 calculations.
- The CCW heat exchanger UA has increased from 2.40 BTU/Hr-°F to 2.41 BTU/Hr-°F as a result of refining the round-off for this value.
" The CCW heat exchanger shell side flow has decreased from 4936 gpm to 4592 gpm as a result of the CCW pump performance margin enhancement (future).
- The CCW heat exchanger tube side flow has decreased from 5000 gpm to 4800 gpm for conservatism in the Service Water pump performance.
- The miscellaneous heat load has decreased from 19.675x10 6 Btu/hr to 18.9x10 6 Btu/hr as a result of reduction in the Spent Fuel Pool Heat load.
SCVB-RAI-2 Please list all the assumptions used in the current most limiting large break LOCA analysis and the proposed analysis for the containment peak pressure and temperature response. In case any of the assumptions are different in the proposed analysis from the current analysis of record, justify if the assumption in the proposed analysis is less conservative.
Response to SCVB-RAI-2 All assumptions used in the reanalysis for NSAL-11-5 are the typical assumptions made in performing the LOCA M&E calculation per the WCAP-10325-P-A methodology and the use of the containment code COCO from WCAP-8327. Assumptions with regard to ECCS recirculation and the timing of ECCS recirculation spray provided by the residual heat removal (RHR) pumps have been refined due to GSI-191 considerations. The analysis values for the containment initial conditions and heat sinks have not changed since the SPU analysis. The performance of the containment spray and fan coolers are identical to that used in the SPU analysis. The major assumption change is allowing credit for 4 Fan Cooler Units in the containment analysis. As explained in the License Amendment Request, 4 Fan Cooler Units are available for the worst single failure of the emergency diesel generator.
SCVB-RAI-3 Please list the computer codes used for the calculation of the proposed mass and energy (M&E) release during the various phases of LOCA (blowdown, refill, reflood and post-reflood) and justify their use if they differ from those used in the current licensing basis analysis.
Response to SCVB-RAI-3 The Westinghouse analysis methodology for long-term LOCA M&E releases is documented in WCAP-10325-P-A. A series of codes are used to calculate the LOCA M&E releases.
" SATIMP is an input processor developed to automate SATAN calculations.
" SATAN78 is used to calculate the releases during the blowdown phase of the transient.
Attachment 1 NL-13-058 Docket No. 50-247 Page 3 of 16
" REFLOOD10325 is used to calculate the releases for the refill, reflood and a portion of the post-reflood phase of the transient (WREFLOOD for the reflood phase and FROTH for the post-reflood phase are part of the REFLOOD10325 code).
" EPITOME is used for the long-term post-reflood phase and decay heat boil-off calculations.
These computer codes are the same as used in the current licensing basis analysis (SPU) and the NSAL-11-5 analysis, with the only change in the version number for the EPITOME code because of the code error correction to address NSAL-11-5 issues. Thus there have been no changes or new software tools for the NSAL-11-5 analysis.
SCVB-RAI-4 Please list the computer codes used for the proposed containment pressure and temperature response and justify their use if they differ from those used in the current licensing basis analysis.
Response to SCVB-RAI-4 The Westinghouse analysis methodology for the containment response uses the COCO code and is described in WCAP-8327. This is the same computer code as used in the current licensing basis (SPU) and the NSAL-11-5 analysis.
SCVB-RAI-5 Please describe the impact of the changes in M&E input to the following containment analyses:
a) Containment gas temperature response under LOCA and MSLB accident for Equipment Environment Qualification (EQ) b) Containment wall temperature response under LOCA and MSLB accident Response to SCVB-RAI-5 a) A comparison of the LOCA containment atmosphere temperature for the current licensing basis analysis and the NSAL-11-5 analysis is shown in Figure 2. The peak licensing basis containment atmosphere temperature is 266.81°F and the NSAL-11-5 peak temperature is 266.46°F. Subsequent to the peak, the NSAL-11-5 temperature is lower than the analysis of record. This is due to credit for the 4th available fan cooler that provides improved heat removal from the containment and reduces the effect of any increased heat addition from the NSAL-11-5 issues. Thus there is no impact on LOCA EQ.
The MSLB accident was not impacted by NSAL-11-5, and so there are no changes in M&E releases, containment response or EQ.
b) Figure 3shows a comparison of the design basis LOCA containment wall temperature for the current licensing basis analysis and the NSAL-11-5 analysis. As seen from the Figure, there is no change in the peak temperature. Figures 4 and 5 are performed with different initial conditions than the design basis analysis to address temperature limits on the un-insulated and insulated steel liner as discussed in Chapter 5 of the FSAR. These are a limit of 247°F for the uninsulated portions of the steel liner and a temperature rise of less than 80°F on the insulated portions. In Figure 4 the re-analysis of the liner temperature to correct for
Attachment 1 NL-13-058 Docket No. 50-247 Page 4 of 16 NSAL-11-5 errors, shows that the uninsulated temperature of the steel shell remains below 247°F. In Figure5, the rise of the insulated liner temperature is about 20'F, much less than the limit of 80°F. Thus, there is no impact on the LOCA containment wall temperature response.
The MSLB accident was not impacted by NSAL-11-5, and so there are no changes in M&E releases, containment response or containment wall temperature response.
SCVB-RAI-6 Please describe the impact of the changes in M&E input to the following containment analyses:
a) Sump water temperature response under LOCA and MSLB accident b) Net positive suction head (NPSH) analysis for containment spray and safety injection pumps during the recirculation phase. The uncertainty in the required NPSH provided by the pump manufacturer should be accounted as per guidance in Enclosure 1 of SECY-11-0014.
Response to SCVB-RAI-6 a) A comparison of the LOCA containment sump water temperature for the current licensing basis analysis and the NSAL-11-5 analysis is shown in Figure 6 for the double ended pump suction break with minimum ECCS flows. Subsequent to the peak, the sump temperature is slightly lower in the proposed analysis. This was evaluated for impact on GSI- 191. The slightly lower sump temperature following the peak will be beneficial for chemical generation as less chemicals are formed at lower temperatures. Also, the slightly lower sump temperature following the peak will have no impact on chemical precipitation, as the GSI-191 minimum sump temperature conservatively bounds the results of the re-analysis for NSAL-11-5.
The MSLB accident was not impacted by NSAL-11-5, and so there are no changes in M&E releases. Sump water temperature is not credited in the MSLB analyses and is therefore not impacted.
b) During the recirculation phase of a LOCA, the Recirculation/RHR pumps provide containment spray and cold leg recirculation flow (the Containment Spray Pumps are not used after the RWST empties and the High Head Safety Injection Pumps would be used in piggy back mode with the Recirculation/RHR pumps for a SBLOCA and in Hot Leg recirculation mode). The sump NPSH calculations for the recirculation pumps (located inside containment) and the RHR pumps (located outside containment) assumed a sump temperature of 264.4°F and the maximum sump temperature post ECCS cold leg recirculation was 256.68°F, which occurred for the NSAL-11-5 reanalysis. Thus, there is margin available in the NPSH temperature assumption between 256.68°F and 264.4°F. The NPSH calculations for the NSAL-11-5 analysis were performed in the same way as for the SPU and did not credit containment accident pressure above saturation pressure. The Containment Accident Pressure credit issue and associated uncertainties in the required NPSH are generic issues and under consideration by the PWR Owner's Group in which Entergy is a participant. The NPSH calculation for GSI-191 was not affected, as the change in water level resulting from the re-analysis was evaluated to be very small, and would be bounded by the water level assumed in the GSI-191 NPSH analysis.
The MSLB accident was not impacted by NSAL-11-5, and so there are no changes in M&E releases. The MSLB transient is over by the time the recirculation phase begins, and therefore NPSH is not impacted.
Attachment 1 NL-13-058 Docket No. 50-247 Page 5 of 16 SCVB-RAI-7 NUREG-0800, Standard Review Plan (SRP) 6.2.1.5 describes the minimum containment pressure analysis for emergency core cooling system (ECCS) performance capability. Regulatory Guide (RG) 1.157, Section 3.12.1 provides guidance for calculating the containment pressure response used for evaluating cooling effectiveness during the post-blowdown phase of a LOCA. The RG states that the containment pressure should be calculated by including the effects of containment heat sinks and operation of all pressure-reducing equipment assumed to be available. Using the above guidance, please describe the impact of the changes in M&E input on the minimum containment pressure analyses for ECCS performance.
Response to SCVB-RAI-7 RAI-7 is related to the minimum back pressure calculation used in LOCA peak cladding temperature (PCT) analyses. The WCAP-10325-P-A codes, including EPITOME, are not used in performing either Appendix K large break analyses or the Best Estimate large break analyses and the issues identified in NSAL-11-5 have no effect on the LOCA PCT calculation or methods used to calculate the minimum containment backpressure for the ECCS calculation.
SCVB-RAI-8 Please describe the error in the EPITOME computer code that is used to determine the M&E release rate during the long-term steam generator depressurization phase of the LOCA transient. How much was the energy release (in percentage) underestimated due to error in the EPITOME code?
Response to SCVB-RAI-8 The error in the EPITOME code was that some of the long term LOCA mass and energy releases were not being written to the file used by the containment codes to calculate the containment post-LOCA containment pressure and temperature response. The error is such that a portion of the LOCA M&E is not added to the M&E during a very small time period. At the time of peak pressure the missing energy for IP2 was an increase of about 3.1% and at 3600 seconds the energy release had been under-estimated by about 2.1%.
SCVB-RAI-9 Please provide a copy of Nuclear Safety Advisory Letter, "Westinghouse LOCA Mass and Energy Release Calculation Issues," NSAL-11-5, dated July 25, 2011.
Response to SCVB-RAI-9 is a copy of Nuclear Safety Advisory Letter, "Westinghouse LOCA Mass and Energy Release Calculation Issues," NSAL-11-5, dated July 25, 2011.
Attachment 1 NL-13-058 Docket No. 50-247 Page 6 of 16 TABLE - I SYSTEM PARAMETERS FOR INDIAN POINT UNIT 2 COMPARISON OF THE STRETCH POWER UPRATE AND THE ANALYSIS PERFORMED TO ADDRESS THE ISSUES IN WESTINGHOUSE NSAL- 11-5 Parameters Value SPU NSAL-11-5 RCS Pressure (psia) (with 60 psi uncertainty) 2310 NC*
Core Thermal Power (MWt) (without uncertainties) 3216 NC Reactor Coolant System Total Flowrate (lbm/sec) 34,250 NC Vessel Outlet Temperature (TF) (with uncertainty) 613.3 NC Core Inlet Temperature (TF) (with uncertainty) 545.7 NC Vessel Average Temperature (TF) 579.5 NC Initial Steam Generator Steam Pressure (psia) 788 802 Steam Generator Tube Plugging (%) 0 NC Initial Steam Generator Secondary Side Mass (Ibm) 104300.1 105045.6 Assumed Maximum Containment Backpressure (psia) 61.7 NC Accumulator Water Volume (ft3 ) per accumulator (including line volume) 770 NC N 2 Cover Gas Pressure (psia) 700 NC Temperature (TF) 130 NC Safety Injection Delay, total (sec) (from beginning of event)
(Minimum ECCS case) 49.1 NC
- - NC - no change
Attachment 1 NL-1 3-058 Docket No. 50-247 Page 7 of 16 TABLE - 2 (Sheet I of 3)
LOCA CONTAINMENT RESPONSE ANALYSIS PARAMETERS FOR INDIAN POINT UNIT 2 SPU NSAL-1 1-5 Service water temperature (°F) 95 NC RWST water temperature ( 0 F) 110 NC Initial containment temperature (0 F) 130 NC Initial containment pressure (psia) 16.7 NC Initial relative humidity (%) 20 NC Net free volume (ft3) 2.61x 106 NC Reactor Containment Air Recirculation Fan Coolers Total 5 NC Analysis maximum 4 NC Analysis minimum 3 4 Containment Hi-i setpoint (psig) 10.0 NC Delay time (sec)
With Offsite Power 60.0 NC Without Offsite Power NA NA Containment Spray Pumps Total 2 NC Analysis minimum I NC Flowrate (gpm)
Injection phase (per pump) 2180 NC Recirculation phase (total) 0 0 Containment Hi-3 setpoint (psig) 30. NC Delay time (sec)
With Offsite Power (delay after High High setpoint) NA NA Without Offsite Power (total time from t-0) 60.0 NC ECCS Recirculation Switchover, sec Minimum Safeguards 1500. NC Containment Spray Termination on LO-LO RWST Level, (sec)
Minimum Safeguards 2354. NC
Attachment 1 NL-13-058 Docket No. 50-247 Page 8 of 16 TABLE - 2 (Sheet 2 of 3)
LOCA CONTAINMENT RESPONSE ANALYSIS PARAMETERS FOR INDIAN POINT UNIT 2 SPU NSAL-I 1-5 Emergency Core Cooling System (ECCS) Flows (GPM)
Minimum ECCS Injection alignment 2871.2 NC Recirculation alignment 1864.0 2191 Residual Heat Removal System RHR Heat Exchangers Modeled in analysis 1 NC Recirculation switchover time, sec Minimum Safeguard 1500. NC UA, 106 .868 to .625 BTU/hr-°F depending 0.767 upon the RHR flow rate Flows - Tube Side and Shell Side - gpm Tube side Minimum Safeguard 1864. 2191 Shell side Minimum Safeguard 1326. 1243.
Attachment 1 NL-13-058 Docket No. 50-247 Page 9 of 16 TABLE - 2 (Sheet 3 of 3)
LOCA CONTAINMENT RESPONSE ANALYSIS PARAMETERS FOR INDIAN POINT UNIT 2 Component Cooling Water Heat Exchangers Modeled in analysis 2 NC UA, 106 (sum of UA for two CCW Hx) 2.40 2.41 BTU/hr-°F Flows - Shell Side and Tube Side - gpm Shellside 4936. 4592.
Tubeside 5000. 4800.
Additional heat loads, (BTU/hr) 19.675x 06 18.9x 106
Attachment 1 NL-13-058 Docket No. 50-247 Page 10 of 16 TABLE - 3 INDIAN POINT UNIT 2 SAFETY INJECTION FLOW MINIMUM SAFEGUARDS USED IN THE LOCA M&E CALCULATION RCS Pressure Total Flow (psia) I (gpm)
INJECTION MODE (REFLOOD PHASE)
SPU NSAL-I 1-5 14.7 3250.0 NC 34.7 3097.8 NC 54.7 2932.7 NC 61.7 2871.2 NC 74.7 2753.6 NC 94.7 2558.3 NC 114.7 2330.3 NC 214.7. 872.1 NC INJECTION MODE (POST-REFLOOD PHASE) 61.7 1 2871.2 NC COLD LEG RECIRCULATION MODE 1500 to 2354 NC 61.7 1864 2191 COLD LEG RECIRCULATION MODE WITH RECIRC SPRAY 2654 to 17,100sec l 2354 to 12,200 sec 61.7 1864 1870 COLD LEG RECIRCULATION POST RECIRC SPRAY TERMINATION 17,100 to 23,400 sec / 12,240 to 23,400 sec 61.7 1864 2191 HOT LEG RECIRCULATION MODE (23,400 seconds to end of transient) 61.7 1 822 1 1096
Attachment 1 NL-13-058 Docket No. 50-247 Page 11 of 16 INDIAN POINT UNIT 2 DEPS LOCA WITH MINIMUM ECCS FLOWS STRETCH POWER UPRATE (SPU) AOR VS NSAL- 11-5 AND GSI-191 SPU ANALYSIS
.NSAL-11-5 and GSI-191 Analysis 50-40-CLI UJ L0 20 .
/-
0 1 2 5 4 5 to 10 10 10 10 10 Time (s)
Figure 1
Attachment 1 NL-13-058 Docket No. 50-247 Page 12 of 16 INDIAN POINT UNIT 2 DEPS LOCA WITH MINIMUM ECCS FLOWS STRETCH POWER UPRATE (SPU) AOR VS NSAL-1 1-5 AND GSI-191 SPF ANALYSIS
. N.
NSA L- 1 1-5 a nd GSI- 19 A aI y s is U-I (CD LLJ iji i,i-I,--
i-li M
i'K LLJ n
LLJ 01 2 3 4 5 10 10 10 10 10 10 Time (s)
Figure 2
Attachment 1 NL-13-058 Docket No. 50-247 Page 13 of 16 INDIAN POINT UNIT 2 DEPS LOCA WITH MINIMUM ECCS FLOWS STRETCH POWER UPRATE (SPU) AOR VS NSAL-11-5 AND GSI-191 SPU ANALYSIS NSAL-11-5 and GSI-191 Analysis 300 LL I
LJ270........................
LC F--
LU-U,)
150 0 1 2 345 10 10 10 10 10 10 Time (s)
Figure 3
Attachment 1 NL-13-058 Docket No. 50-247 Page 14 of 16 INDIAN POINT UNIT 2 NSAL-11-5 REANALYSIS FSAR CHAPTER 5.1 LINER TEMPERATURE LIMITS DEPS BREAK, MINSI 4 RCFCs WALL I SURFACE TEMP (DEG-F)
WALL TEMPERATURE LIMIT OF 247 DEG-F 260
-- 240" CD..
uJ 220 rii CF-LUj V) 140-.. . . . ..
<100 12 - . .
01 2 3 1. 5 5 10 10 10 10 10 10 10 TIME (SECONDS)
Figure 4
Attachment 1 NL-1 3-058 Docket No. 50-247 Page 15 of 16 INDIAN POINT UNIT 2 NSAL-1 !-5 REANALYSIS FSAR CHAPTER 5.1 LINER TEMPERATURE LIMITS DEPS BREAK, MINS, 4 RCFCs WALL 13 WALL 14 WALL --15 WALL 16 170 12 CD1 . . . .. . . . . . .. .
F- I /:/
9" 120 ... . . - #'10 "
U)
U-j B............................
110 0 1 2 3 4 5 6 10 10 10 10 10 10 10 TIME (SECONDS)
Figure 5
Attachment 1 NL-1 3-058 Docket No. 50-247 Page 16 of 16 INDIAN POINT UNIT 2 DEPS LOCA WITH MINIMUM ECCS FLOWS STRETCH POWER UPRATE (SPU) AOR VS NSAL-11-5 AND GSI-191 SPU ANALYSIS NSAL-11-5 and GSI-191 Analysis Sump Water Temperature used in the NPSH calculation ECCS cold leg recirculation time 300 I 270 . . . . . . . . . . . . . . . .. . . . . . . . . . .. . . . . . . . . . . . . . . . .
Li. .
110111 10 fi1 l!0 0 1 11 1l 0O Time (s)
Figure 6
ATTACHMENT 2 TO NL-13-058 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING REFUELING WATER STORAGE TANK TEMPERATURE AND CONTAINMENT PRESSURE IN CONTAINMENT INTEGRITY ANALYSIS - INDIAN POINT 3 ENTERGY NUCLEAR OPERATIONS, INC.
INDIAN POINT NUCLEAR GENERATING UNIT 3 DOCKET NO. 50-286
Attachment 2 NL-1 3-058 Docket No. 50-286 Page 1 of 14 Response To Request For Additional Information - Indian Point 3 By letter dated January 28, 2013, Entergy Nuclear Operations, Inc., (Entergy), submitted a License Amendment Request for Indian Point Nuclear Generating Unit Number 3 (IP3) Technical Specification change regarding containment integrity analysis. The proposed change would limit Refueling Water Storage Tank temperature to <105°F and limit containment pressure to <1.5 psig under certain conditions. By letter of June 28, 2013 the Nuclear Regulatory Commission requested additional information on that request. The requests and the responses are addressed below.
SCVB-RAI-1 Please list all the assumptions used in the current most limiting large break loss-of-coolant accident (LOCA) analysis and the proposed analysis for the containment peak pressure and temperature response. In case any of the assumptions is different in the proposed analysis from the current analysis of record, justify ifthe assumption in the proposed analysis is less conservative.
Response to SCVB-RAI-1 All assumptions used in the reanalysis for NSAL-11-5 are the typical assumptions made in performing the LOCA M&E calculation per the WCAP-10325-P-A methodology and the use of the containment code COCO from WCAP-8327. Assumptions with regard to ECCS recirculation and the timing of ECCS recirculation spray provided by the residual heat removal (RHR) pumps have been refined due to GSI-191 considerations. The analysis values for the containment heat sinks have not changed since the SPU analysis. The performance of the containment spray and fan coolers are identical to that used in the SPU analysis.
Tables 1, 2 and 3 show a comparison of initial conditions between the current most limiting licensing basis large break LOCA analysis done for Stretch Power Uprate (SPU) and the proposed analysis to correct the issues reported in NSAL-11-5 including some other changes. These 'other changes' are explained below. They are due to Generic Safety Issue (GSI)-191 related changes, error corrections and a Component Cooling Water (CCW) pump performance margin enhancement (future). These 'other changes' have no impact on the proposed peak containment pressure of 42.38 psig, and result in a slightly lower pressure response subsequent to the peak, as shown in Figure 1.
- Steam generator secondary pressure has increased from 787 psia to 804 psia as a result of the steam generator bundle pressure issue discussed in NSAL-11-5. This change is conservative for the containment integrity analysis.
" The RWST temperature has been reduced from 110°F to 105°F. This reduction was necessary to gain margin needed to offset the NSAL-11-5 issues. It should be noted that typical RWST temperatures seldom go higher than 95°F.
" The containment initial pressure assumption in the containment analysis has been reduced from 17.2 psia to 16.2 psia. This reduction was necessary to gain margin to offset the NSAL-11-5 issues. It should be noted that a high accuracy containment pressure indicator has been locally installed to assure that the accident analysis initial condition is met.
Attachment 2 NL-13-058 Docket No. 50-286 Page 2 of 14
" The recirculation spray flow rate provided by the RHR pumps was reduced from 970 gpm to 960 gpm to be consistent with the offsite dose calculation.
- The ECCS flow during recirculation alignment has decreased from 2080 gpm to 1110 gpm. The flow of 2080 gpm applies only to the SPU analysis and is the sum of 1110 gpm SI and 970 gpm spray recirculation flow.
" The total hot leg recirculation flow has changed from 717 gpm to 984.7 gpm, as a result of an error correction to not include the spilling line assumption.
" The RHR heat exchanger UA has changed as a result of providing heat exchanger UAs based on the ECCS flow during the various recirculation periods outlined in Table 3.
" The RHR heat exchanger shell side flow has changed slightly from 1096 gpm to 1099.2 gpm.
" The CCW heat exchanger UA has increased from 1.44 BTU/Hr-°F to 2.98 BTU/Hr-°F as a result of accounting for two CCW heat exchangers in operation post-LOCA and a small change related to GSI-191.
- The CCW heat exchanger shell side flow has decreased from 7420 gpm to 3980 gpm. The analysis of record used two times 3710 gpm for two CCW heat exchangers in operation. The actual CCW flow should have been 3710 gpm. The change from 3710 gpm to 3980 gpm is a result of CCW pump performance margin enhancement (future) and updating the conservative CCW analysis performed in 1989.
- The CCW heat exchanger tube side flow has decreased from 7221 gpm to 5500 gpm for conservatism in the Service Water pump performance.
SCVB-RAI-2 Please list the computer codes used for the calculation of the proposed Mass and Energy (M&E) release during the various phases of LOCA (blowdown, refill, reflood and post-reflood) and justify their use if they differ from those used in the current licensing basis analysis.
Response to SCVB-RAI-2 The Westinghouse analysis methodology for long-term LOCA M&E releases is documented in WCAP-10325-P-A. A series of codes are used to calculate the LOCA M&E releases.
" SATIMP is an input processor developed to automate SATAN calculations.
- SATAN78 is used to calculate the releases during the blowdown phase of the transient.
- REFLOOD10325 is used to calculate the releases for the refill, reflood and a portion of the post-reflood phase of the transient (WREFLOOD for the reflood phase and FROTH for the post-reflood phase are part of the REFLOOD10325 code).
" EPITOME is used for long-term post-reflood phase and decay heat boil-off calculations.
These computer codes are the same as used in the current licensing basis analysis (SPU) and the NSAL-11-5 analysis, with the only change in the version number for the EPITOME code because of the code
Attachment 2 NL-13-058 Docket No. 50-286 Page 3 of 14 error correction to address NSAL-11-5 issues. Thus there have been no changes or new software tools for the NSAL-11-5 analysis.
SCVB-RAI-3 Please describe the containment analysis methodology including the computer codes used for the proposed containment analysis and justify the use of the methodology and the computer codes if different from what is used in the current licensing basis analysis.
Response to SCVB-RAI-3 The Westinghouse analysis methodology for the containment response uses the COCO code as described in WCAP-8327. This is the same computer code as used in the current licensing basis (SPU) and the NSAL-11-5 analysis.
SCVB-RAI-4 Please describe the impact of the changes in M&E input to the following containment analyses:
(c) Containment gas temperature response under LOCA and MSLB accident for Equipment Environment Qualification (EQ)
(d) Containment wall temperature response under LOCA and MSLB accident Response to SCVB-RAI-4 (c) A comparison of the LOCA containment atmosphere temperature for the current licensing basis analysis and the NSAL-11-5 analysis is shown in Figure2. The peak licensing basis containment atmosphere temperature is 260.4°F and the NSAL-11-5 peak temperature is 262.95°F. As a result of the penalty associated with the EPITOME error correction, the peak temperature for the NSAL-11-5 analysis has increased slightly compared to the current licensing basis analysis. This was evaluated for LOCA EQ. and all equipment in the containment remains qualified.
The MSLB accident was not impacted by NSAL-11-5, and so there are no changes in M&E releases, containment response or EQ. The MSLB analyses credit a conservatively high RWST temperature for safety injection and containment sprays, which bounds the proposed RWST temperature limit of 105°F.
The MSLB analysis also utilizes a conservative initial containment pressure of 2.5 psig which bounds the proposed initial containment pressure of 1.5 psig.
(d) Figure 3 shows a comparison of the design basis LOCA containment wall 2 temperature (part of the steel shell) for the current licensing basis analysis and the NSAL-11-5 analysis. As seen from the Figure, there is a slight increase (3.3°F) in the peak wall temperature around the time that peak pressure and temperature were calculated. The FSAR Chapter 5 liner temperature analysis, which is performed with different initial conditions than the design basis analysis, used wall 2 to determine the limiting temperature of the steel shell. This limit is 247°F for the uninsulated portions of the steel liner. The SPU liner temperature result was 234.8°F, which was 12.2°F below the 247°F limit. Based on the available margin, the liner temperature was not analyzed for NSAL-11-5, as it was concluded that the liner temperature limit would continue to be met with a 3.3°F increase in the wall temperature.
Attachment 2 NL-13-058 Docket No. 50-286 Page 4 of 14 The MSLB accident was not impacted by NSAL-11-5, and so there are no changes in M&E releases, containment response or containment wall temperature response. The MSLB analyses credit a conservatively high RWST temperature for safety injection and containment sprays, which bounds the proposed RWST temperature limit of 105°F. The MSLB analysis also utilizes a conservative initial containment pressure of 2.5 psig which bounds the proposed initial containment pressure of 1.5 psig.
SCVB-RAI-5 Please describe the impact of the changes in M&E input to the following containment analyses:
a) Sump water temperature response under LOCA and MSLB accident b) Net positive suction head (NPSH) analysis for containment spray and safety injection pumps during the recirculation phase. The uncertainty in the required NPSH provided by the pump manufacturer should be accounted as per guidance in Enclosure 1 of SECY 0014.
Response to SCVB-RAI-5 a) A comparison of the LOCA containment sump water temperature for the current licensing basis analysis and the NSAL-11-5 analysis is shown in Figure 4 for the double ended pump suction break with minimum ECCS flows. Subsequent to the peak, the sump temperature is slightly lower in the proposed analysis. This was evaluated for impact on GSI- 191. The slightly lower sump temperature following the peak will be beneficial for chemical generation as less chemicals are formed at lower temperatures.
Also, the slightly lower sump temperature following the peak will have no impact on chemical precipitation, as the GSI-191 minimum sump temperature conservatively bounds the results of the re-analysis for NSAL-11-5.
The MSLB accident was not impacted by NSAL-11-5, and so there are no changes in M&E releases.
Sump water temperature is not credited in the MSLB analyses and is therefore not impacted.
b) During the recirculation phase of a LOCA, the Recirculation/RHR pumps provide containment spray and cold leg recirculation flow (the separate Containment Spray Pumps are not used after the RWST empties and the High Head Safety Injection Pumps would be used in piggy back mode with the Recirculation/RHR pumps for a SBLOCA and in hot leg recirculation mode). The sump NPSH calculations for the recirculation pumps (located inside containment) and the RHR pumps (located outside containment) assumed a sump temperature of 242.8°F, and the maximum sump temperature post ECCS cold leg recirculation was 241.5°F, which occurred for the NSAL-11-5 reanalysis. Thus, there is margin available in the NPSH temperature assumption between 242.8°F and 241.5°F. The NPSH calculations for the NSAL-11-5 analysis were performed in the same way as for the SPU and did not credit containment accident pressure above saturation pressure. The Containment Accident Pressure credit issue and associated uncertainties in the required NPSH are generic issues and under consideration by the PWR Owner's Group in which Entergy is a participant.
The NPSH calculation for GSI-191 was not affected, as the change in water level resulting from the re-analysis was determined to be very small, and was bounded by the water level assumed in the GSI-191 NPSH analysis.
Attachment 2 NL-13-058 Docket No. 50-286 Page 5 of 14 The MSLB accident was not impacted by NSAL-11-5, and so there are no changes in M&E releases. The MSLB transient is over by the time the recirculation phase would begin, and is therefore not impacted.
SCVB-RAI-6 NUREG-0800, Standard Review Plan (SRP) 6.2.1.5 describes the minimum containment pressure analysis for emergency core cooling system (ECCS) performance capability. Regulatory Guide (RG) 1.157, Section 3.12.1 provides guidance for calculating the containment pressure response used for evaluating cooling effectiveness during the post-blowdown phase of a LOCA. The RG states that the containment pressure should be calculated by including the effects of containment heat sinks and operation of all pressure-reducing equipment assumed to be available. Using the above guidance, please describe the impact of the changes in M&E input on the minimum containment pressure analyses for ECCS performance.
Response to SCVB-RAI-6 RAI-6 is related to the minimum back pressure calculation used in LOCA peak cladding temperature (PCT) analyses. The WCAP-10325-P-A codes, including EPITOME, are not used in performing either Appendix K large break analyses or the Best Estimate large break analyses and the issues identified in NSAL-11-5 have no effect on the LOCA PCT calculation or methods used to calculate the minimum containment backpressure for the ECCS calculation.
SCVB-RAI-7 Please describe the error in the EPITOME computer code that is used to determine the M&E release rate during the long-term phase of the LOCA transient. How much was the energy release (in percentage) underestimated due to errors in the EPITOME computer code?
Response to SCVB-RAI-7 The error in the EPITOME code was that some of the long term LOCA mass and energy releases were not being written to the file used by the containment codes to calculate the containment post-LOCA containment pressure and temperature response. The error is such that a portion of the LOCA M&E is not added to the M&E during a very small time period. At the time of peak pressure the missing energy for IP2 was an increase of about 2.88% and at 3600 seconds the energy release had been under-estimated by about 1.92%.
Attachment 2 NL-1 3-058 Docket No. 50-286 Page 6 of 14 TABLE - 1 SYSTEM PARAMETERS FOR INDIAN POINT UNIT 3 COMPARISON OF THE STRETCH POWER UPRATE AND THE ANALYSIS PERFORMED TO ADDRESS THE ISSUES IN WESTINGHOUSE NSAL-11-5 Parameters Value SPU NSAL-11-5 RCS Pressure (psia) (with 60 psi uncertainty) 2299. NC*
Core Thermal Power (MWt) (without uncertainties) 3216 NC Reactor Coolant System Total Flowrate (Ibm/sec) 37,444,4 NC Vessel Outlet Temperature (OF) (with uncertainty) 610.5 NC Core Inlet Temperature (OF) (with uncertainty) 548.5 NC Vessel Average Temperature (OF) 572.0 NC Initial Steam Generator Steam Pressure (psia) 787 804 Steam Generator Tube Plugging (%) 0 NC Initial Steam Generator Secondary Side Mass (Ibm) 100,668.7 NC Assumed Maximum Containment Backpressure (psia) 61.7 NC Accumulator Water Volume (ft3) per accumulator (including line volume)
N2 Cover Gas Pressure (psia) 807.2 NC Temperature (OF) 555.0 NC 130 NC Safety Injection Delay, total (sec) (from beginning of event)
(Minimum ECCS case) 27.8 NC
- NC - no change
Attachment 2 NL-13-058 Docket No. 50-286 Page 7 of 14 TABLE - 2 (Sheet 1 of 3)
LOCA CONTAINMENT RESPONSE ANALYSIS PARAMETERS FOR INDIAN POINT UNIT 3 COMPARISON OF THE STRETCH POWER UPRATE AND THE ANALYSIS PERFORMED TO ADDRESS THE ISSUES IN WESTINGHOUSE NSAL-1 1-5 SPU NSAL-11-5 Service water temperature (OF) 95 NC RWST water temperature (OF) 110 105 Initial containment temperature (OF) 130 NC Initial containment pressure (psia) 17.2 16.2 Initial relative humidity (%) 20 NC Net free volume (ft3) 2.61x 106 NC Reactor Containment Air Recirculation Fan Coolers Total 5 NC Analysis maximum 4 NC Analysis minimum 4 NC Containment Hi-1 setpoint (psig) 5.12 NC Delay time (sec)
With Offsite Power 48.21 NC Without Offsite Power NA NA Containment Spray Pumps Total 2 NC Analysis maximum 1 NC Analysis minimum 1 NC Flowrate (gpm)
Injection phase (per pump) 2237.9 NC Recirculation phase (total) 970 960 Containment Hi-3 setpoint (psig) 24.63 NC Delay time (sec)
With Offsite Power (delay after High High setpoint) NA NA Without Offsite Power (Delay from setpoint) 60.0 NC ECCS Recirculation Switchover, sec Minimum Safeguards 1623.8 NC Containment Spray Termination on LO-LO RWST Level, (sec)
Minimum Safeguards 3355 NC
Attachment 2 NL-13-058 Docket No. 50-286 Page 8 of 14 TABLE - 2 (Sheet 2 of 3)
LOCA CONTAINMENT RESPONSE ANALYSIS PARAMETERS FOR INDIAN POINT 3 SPU NSAL-11-5 Emergency Core Cooling System (ECCS) Flows (GPM)
Minimum ECCS Injection alignment 4581.4 NC Recirculation alignment 2080 1110 Residual Heat Removal System RHR Heat Exchangers Total 2 NC Modeled in analysis 1 NC Recirculation switchover time, sec Minimum Safeguard 1623.8 NC UA, 106 * .777 to .59 BTU/hr-OF depending 0.62 upon the RHR Hx tube side flow rate Flows - Tube Side and Shell Side - gpm Tube side Minimum Safeguard 2080. 1110 ECCS Hot Leg Recirculation 717 984.7 Shell side Minimum Safeguard 1096 1099.2
Attachment 2 NL-13-058 Docket No. 50-286 Page 9 of 14 TABLE - 2 (Sheet 3 of 3)
LOCA CONTAINMENT RESPONSE ANALYSIS PARAMETERS FOR INDIAN POINT 3 Component Coolinq Water Heat Exchanqers Modeled in analysis 2 NC UA, 106 * (sum of UA for two CCW Hx) 1.44 2.98 BTU/hr-OF Flows - Shell Side and Tube Side - gpm Shellside 7420 3980 Tubeside 7221 5500 (service water)
Additional heat loads, (BTU/hr) 18.85x10 6 NC
Attachment 2 NL-13-058 Docket No. 50-286 Page 10 of 14 TABLE - 3 INDIAN POINT UNIT 3 SAFETY INJECTION FLOW MINIMUM SAFEGUARDS USED IN THE LOCA M&E CALCULATION RCS Pressure Total Flow (psia) (gpm)
INJECTION MODE (REFLOOD PHASE)
SPU NSAL-11-5 14.7 5252.3 NC 34.7 4975.2 NC 54.7 4687.2 NC 64.7 4536.1 NC 74.7 4367.1 NC 94.7 4012.4 NC 104.7 3825.0 NC 114.7. 3630.0 NC INJECTION MODE (POST-REFLOOD PHASE) 61.7 1 4581.4 ] NC COLD LEG RECIRCULATION MODE 1623.8 to 3916.2 sec 1623.8 to 3535.2 sec 61.7 1 2080 1110 COLD LEG RECIRCULATION MODE WITH RECIRC SPRAY 3916.2 to 18,316.2 sec 1 3535.2 to 14,400 sec 61.7 2080] 1110 COLD LEG RECIRCULATION POST RECIRC SPRAY TERMINATION 18316.2 to 23,400 sec 14,400 to 23,400 sec 61.7 2080] 1110 HOT LEG RECIRCULATION MODE (23,400 seconds to end of transient) 61.7 F 717 984.7
Attachment 2 NL-13-058 Docket No. 50-286 Page 11 of 14 INDIAN POINT UNIT 3 DEPS BREAK WITH MINIMUM ECCS FLOWS STRETCH POWER UPRATE (SPU) AOR VS NSAL- 11-5 AND GSI191 SPU Contoipmoe t Pressure
. . NSAL-1 -5 aiid GSI191 Corlaiarment Pressure 45 40-
-. 55 j 30-Ln 25--- -
LAJ 20- . . . . . .
S 15 -- - - -
10-0 2 3 5 1 7 10 10 1o to 10 10 10 10 Time (s)
Figure 1 IP' Pat-c 9)of I
Attachment 2 NL-13-058 Docket No. 50-286 Page 12 of 14 INDIAN POINT UNIT 3 DEPS BREAK WITH MINIMUM ECCS STRETCH POWER UPRATE (SPU) AOR VS NSAL-11-5 AND GSH191 SPU Analysis NSAL-11-5 and GSI191 Anolysis
/ 260. . . . . . . . . . . . . . . . . . . . . .. ' .. " .... ..... .. ..... ... ... . .... ..... . .
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0 2 3 4 5 6 7 10 10 10 10 10 10 10 10 TIME(Seconds)
Figure 2
Attachment 2 NL-13-058 Docket No. 50-286 Page 13 of 14 INDIAN POINT UNIT 3 DEPS BREAK WITH MINIMUM ECCS STRETCH POWER UPRATE (SPU) AOR VS NSAL- 11-5 AND GSI191 Wall 2 Surface Temperature for SPU Wall 2 Surface Temperature for NSAL-11-5 and GSI-191 i,
LJ LJ a,
D F-a-
LU C,
-. J LU 0 1 2 1 4 5 7 10 10 10 10 10 10 10 10 TIME (Seconds)
Figure 3
Attachment 2 NL-13-058 Docket No. 50-286 Page 14 of 14 INDIAN POINT UNIT 3 DEPS BREAK WITH MINIMUM ECCS FLOWS STRETCH POWER UPRATE (SPU) AOR VS NSAL-11-5 AND GSI191 SPU SUMP TEMPERATURE NSAL-11-5 SUMP TEMPERATURE
-SUMPTEMPERATURE ASSUMED IN THE NPSH CALCULATION TIME OF ECCS COLD LEG RECIRCULATION 1623.8 SECONDS 280"
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10-0 1 2 3 4 7 10 10 10 10 10 10 10 10 Time (s)
Figure 4