NRC 2009-0027, Response to Request for Additional Information, License Amendment Request 258, Incorporate Best Estimate Large Break Loss of Coolant Accident (LOCA) Analyses Using ASTRUM
| ML090771303 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 03/04/2009 |
| From: | Meyer L Florida Power & Light Energy Point Beach |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NRC 2009-0027 | |
| Download: ML090771303 (47) | |
Text
FPL Energy Point Beach, LLC, 6590 Nuclear Road, Two Rivers, WI 54241 FPL Energy.,
Point Beach Nuclear Plant March 4,2009 NRC 2009-0027 10 CFR 50.90 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 Point Beach Nuclear Plant, Units 1 and 2 Dockets 50-266 and 50-301 Renewed License Nos. DPR-24 and DPR-27 Response to Request for Additional Information License Amendment Request 258, Incorporate Best Estimate Larqe Break Loss of Coolant Accident (LOCA) Analvses Usinn ASTRUM
References:
(1)
FPL Energy Point Beach LLC, Letter to NRC dated November 25, 2008, License Amendment Request 258, lncorporate Best Estimate Large Break Loss of Coolant Accident (LOCA) Analyses Using ASTRUM (ML083330160)
(2)
NRC Letter to FPL Energy Point Beach LLC, dated February 3,2009, Request for Additional Information Regarding ASTRUM Implementation for Large Break LOCA Analysis (ML090210403)
FPL Energy Point Beach, LLC submitted Point Beach Nuclear Plant (PBNP) Units 1 and 2, proposed License Amendment Request 258 for Commission review and approval pursuant to 10 CFR 50.90 (Reference I). The amendment requests use of NRC-approved WCAP-16009-P-A, Realistic Large Break LOCA Evaluation Methodology Using Automated Statistical Treatment of Uncertainty Method (ASTRUM) and revises Technical Specification (TS) 5.6.4.b to reference WCAP-16009-P-A. The request also proposes to implement Technical Specification Task Force (TSTF) Traveler-363A in order to eliminate the revision numbers and dates from the list of topical reports identified in TS 5.6.4.b.
The NRC staff requested additional information (RAI) in order to continue its review of License Amendment Request 258 (Reference 2). contains the FPL Energy Point Beach response to the RAI. Enclosure 2 contains corrected Figures 15 and 30 for Enclosure1 of Reference 1.
FPL Energy Point Beach has determined that this response does not alter the conclusions contained in the no significant hazards consideration nor the environmental consideration
Document Control Page 2 associated with the proposed amendment and Technical Specification changes. There are no new commitments or changes to previous commitments as a result of this submittal.
If you have any questions or require additional information, please contact Mr. Harv Hanneman at 9201755-731 7.
I declare under penalty of perjury that the foregoing is true and correct.
Executed on March 4,2009.
Very truly yours, FPL Energy Point Beach, LLC Weyer ice President Enclosures (2) cc:
Administrator, Region Ill, USNRC Project Manager, Point Beach Nuclear Plant, USNRC Resident Inspector, Point Beach Nuclear Plant, USNRC PSCW
ENCLOSURE I FPL ENERGY POINT BEACH, LLC POINT BEACH NUCLEAR PLANT, UNITS 1 AND 2 LICENSE AMENDMENT REQUEST 258 INCORPORATE BEST ESTIMATE LBLOCA ANALYSES USING ASTRUM RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION The following information is provided by FPL Energy Point Beach, LLC in response to the NRC staff's request for additional information dated February 3, 2009.
Question #l(A):
Compared to the current licensing basis, large-break loss-of-coolant accident (LOCA) results (obtained Rom a 2007 revision of the Point Beach Updated Final Safety Analysis Report), the limiting unit's best-estimate 95th percentile peak cladding temperature (PCT) is reduced by approximately 150°F. This result prompts two conclusions on the part of the staK (I) That the power uprate case is not bounding of the current licensed thermal power case, as shown by a lower PCT, or (2) that the change in statistical sampling has redefined uncertainties in such a manner that the changes in safety margin resulting from the power uprate are masked by the method implementation. Provide information to quantify:
A)
The PCT/MLO trend associated with the power uprate: Compare the results of several nominal (i.e., cases whose PCTs approach the 50th percentile) Point Beach WCOBRA/TRAC runs assuming the implementation of an Extended Power Uprate to cases assuming the current licensed thermal power level holding other parametric assumptions the same.
FPLE Point Beach Response Additional runs are made for cases whose PCTs approach the 50th percentile range for the Point Beach Nuclear Plant (PBNP) limiting PCTIMLO case, which is Unit 1 (as described in Reference 1). The runs are performed using the Automated Statistical Treatment of Uncertainty Method (ASTRUM), as described in WCAP-16009-P-A (Reference 2). The runs conducted in response to this question assume current PBNP analyzed thermal power level, holding other parametric assumptions the same. The current licensed power level of PBNP Units 1 and 2 is 1540 MWt; the current analyzed power level for the Large Break LOCA analysis of record is 1650 MWt The cases run here are at 1650 MWt Table 1.I compares the PCT results for the Question #lA runs and the corresponding EPU runs. The PCT results presented show the similar effect of power on PCT in all cases.
Figures 1.I through 1.I5 present the results. Figures 1.1 through 1.3 are plots of the nine (9) runs conducted in response Question #1A at 1650 MWt whose PCTs approach the 50th percentile range for Unit 1 in Reference 1. The limiting Peak Cladding Temperature (PCT) run conducted in response to this question is identified as the solid line in these figures. The total vessel water mass (Figure 1.2) is steadily increasing over the final part of the run. The vessel collapsed liquid level in the lower plenum (Figure 1.3) is stable andlor increasing over the final part of all the runs.
The reference point for the lower plenum liquid level is the bottom of the vessel.
Page 1 of 42
Figures 1.4 though 1.I 1 illustrate the key major response parameters for the limiting transient run at the current analyzed power level. Figure 1.4 presents the HOTSPOT PCT for the 1650 MWt limiting run, which has a maximum PCT of 1225 OF. This is well below the 10 CFR 50.46 criterion of 2200 OF. By comparison, this run corresponds to the second limiting PCT case in the 50th percentile range identified for the EPU conditions, which has a maximum PCT of 1306 OF.
Figure 1.5 is a plot of the pressurizer pressure. Figure 1.6 is a plot of the vessel side break flow while Figure 1.7 is a plot of the pump side break flow. Figure 1.8 presents the void fraction in the reactor coolant pumps. Figure 1.9 is the plot of the accumulator injection flow rate. Figure 1.I 0 is a plot of the High Head Safety lnjection flow rate while Figure 1.I 1 is a plot of the Low Head Safety lnjection flow rate.
Figures 1.I2 through 1.15 compare the results of the limiting case for the 50th percentile range for current analyzed power and EPU conditions. Figure 1.I2 compares the HOTSPOT PCTs results.
Figure 1.I3 is a plot of the total vessel fluid mass comparison. Figure 1.I4 provides the pressurizer pressure comparison. Finally, Figure 1.I5 is the plot of the accumulator injection flow comparison.
The PBNP Unit 1 results of the runs conducted for the current analyzed power level of 1650 MWt demonstrate that the PBNP Unit 1 ASTRUM analysis at EPU conditions (181 1 MWt) bounds the current analyzed power level. The only change in the nine (9) runs conducted in response to this question is the adjustment of the power level from EPU to the current licensed power level. It is concluded that the ASTRUM statistical method used for the EPU project provides valid results that are conservative and applicable for the current power conditions as well. Furthermore, since Unit 1 is the limiting PCTIMLO case, this conclusion is also applicable to Unit 2.
Table I.I Point Beach Unit I PCT Comparison
References:
Ranking for 1650 MWt cases 1
2 3
4 5
6 7
8 9
- 1.
FPL Energy Point Beach Letter to NRC dated November 25,2009, License Amendment Request 258, Incorporate Best Estimate Large Break Loss of Coolant Accident (LOCA)
Analyses Using ASTRUM (ML083330160)
Page 2 of 42 Max PCT (OF)
( I 650 MWt) 1225 1224 1216 1208 1206 1182 1167 1166 1159 Max PCT CF)
(1811 MWt) 1306 1302 1301 1286 1283 1292 1287 1300 1307
- 2.
WCAP-16009-P-A, "Realistic Large-Break LOCA Evaluation Methodology Using the Automated Statistical Treatment of Uncertainty Method (ASTRUM)," January 2005.
Page 3 of 42
P C T 1
0 0 PEAK C L A D D I N G TEMP.
h LL V
2?
3
-CI E E e
400- -
200 I
I I
1 I
I I
I l
I I
I I
1 l
I l
l l
l 0
50 100 150 200 250 Time (s) 1
~
4 m
Figure 1.1 Point Beach Unit 1 WC/T Peak Cladding Temperature for the 9 Cases at 1650 MWt Page 4 of 42
V F Y A S S 0
0 0 V E S S E L WATER MASS E
e -
UJ UJ 5i 0
100 m
300 400 500 Time (s)
Figure 1.2 Point Beach Unit I Total Vessel Fluid Mass for the 9 Cases at 1650 MWt Page 5 of 42
LQ-LEVEL 1
0 0 COLLAPSED L l Q. LEVEL Figure 1.3 Point Beach Unit 1 Lower Plenum Liquid Level for the 9 Cases at 1650 MWt Page 6 of 42
I i
L I
I l
h l
l J
i L
l I
~
b T
Q 1 W a
a
!lm l i i (%lXD
Figure 1.5 Point Beach Unit 1 Pressurizer Pressure for the Limiting PCT Case at 1650 MWt Page 8 of 42
Figure 1.6 Point Beach Unit I Vessel Side Break Flow for the Limiting PCT Case at 1650 MWt Page 9 of 42 500 50000 40000 30000 E
n V
a
+
z 20000 E
Time (s) 14am23ao V)
V) 0
=E 10000--
-10000 1
1 1
1 I
1 1
8 I
f 1
1 I
I I
I I
I I
I 0
100 m
300 400
Figure 1.7 Point Beach Unit 1 Pump Side Break Flow for the Limiting PCT Case at 1650 MWt Page 10 of 42
I n t a c t Loop B r o k e n Loop Figure 1.8 Point Beach Unit 1 Void Fraction in Pumps for the Limiting PCT Case at 1650 MWt Page 11 of 42
Figure 1.9 Point Beach Unit 1 Accumulator Injection Flow for the Limiting PCT Case at 1650 MWt Page 12 of 42
0 50 100 150 200 Time (s) l4mawo Figure 1.10 Point Beach Unit I High Head Safety Injection Flow for the Limiting PCT Case at 1650 MWt Page 13 of 42
Figure 1.11 Point Beach Unit I Low Head Safety Injection Flow for the Limiting PCT Case at 1650 MWt Page 14 of 42
- - - - - C u r r e n t P o r e r C o n d i t i o n s EPU C o n d ~ t ~ o n s Figure 1.12 Point Beach Unit 1 HOTSPOT PCT Comparison Page 15 of 42
C u r r e n t P o w e r C o n d i t i o n s EPU C o n d i t i o n 8 Figure 1.13 Point Beach Unit I Total Vessel Fluid Mass Comparison Page 16 of 42
C u r r e n t P o y e r C o n d i t i o n s EPU C o n d t t i o n s Figure 1.14 Point Beach Unit I Pressurizer Pressure Comparison Page 17 of 42
C u r r e n t P o w e r C o n d i t i o n s EPU C o n d i t i o n s Figure 1.15 Point Beach Unit 1 Accumulator Mass Flow Comparison Page 18 of 42 250 25w MOO-1500--
E e
V Q) e 3 looo--
B E
cn cn s 500-0-
-500 3me (s)
V l
l I
I I
I I
I I
B I
I t
I I
I l
I I
I 0
50 100 150 m
Question #I (B):
Compared to the current licensing basis, large-break loss-of-coolant accident (LOCA) results (obtained from a 2007 revision of the Point Beach Updated Final Safety Analysis Report), the limiting unit's best-estimate 95th percentile peak cladding temperature (PC73 is reduced by approximately 150°F. This result prompts two conclusions on the part of the stat? (1) That the power uprate case is not bounding of the current licensed thermal power case, as shown by a lower PCT, or (2) that the change in statistical sampling has redefined uncertainties in such a manner that the changes in safety margin resulting from the power uprate are masked by the method implementation. Provide information to quantify:
B)
The PCT/MLO trend associated with changing from CQD to ASTRUM: Compare generic results for PCT and MLO for plants that have implemented a CQD/ASTRUM change without significant accompanying changes in plant parameters. Include central indicators and bounding values, FPLE Point Beach Response Table 1.2 below compares generic results for Peak Cladding Temperature (PCT) and Maximum Local Oxidation (MLO) for both the 1996 methodology and the 2004 ASTRUM evaluation model.
The 50th percentile PCT value is also shown. The comparison is done for plants that have implemented a change in Best Estimate Large Break LOCA (BELOCA) without significant changes in plant parameters.
Table 1.2 Comparisons of Sample Results for CQD and ASTRUM The results in Table 1.2 explicitly present the differences in methodologies (response surfaces for CQD, Reference 1 and non-parametric for ASTRUM, Reference 2) and the statistical sampling used by the ASTRUM methodology. Also, please refer to Section 12 of the ASTRUM Topical (Reference 2) for an example of PWR application of the 2004 methodology.
References:
- 1.
WCAP-12945-P-A, Volume 1, Revision 2, and Volumes 2 through 5, Revision 1, "Code Qualification Document for Best Estimate LOCA Analysis," March 1998.
Page 19 of 42
- 2.
WCAP-16009-P-A, "Realistic Large-Break LOCA Evaluation Methodology Using the Automated Statistical Treatment of Uncertainty Method (ASTRUM)," January 2005.
Question #2:
Page 2 of Enclosure 1 to the license amendment request mentions "rackup items". Please define this term, list the items, and provide a disposition relative to the ASTRUM analysis.
FPLE Point Beach Response "Rackup itemsn are plant-specific Peak Cladding Temperature (PCT) assessments against the Large Break LOCA Analysis-of-Record (AOR). These assessments are reported as required by 10 CFR 50.46, and are also tracked as "rackup items" against the AOR so the aggregate PCT (inclusive of all evaluations) is known. These assessments (rackup items) typically result from either changes in plant operation or error corrections to the Analysis-of-Record.
The rackup items currently identified on the PBNP Units 1 and 2 Large Break LOCA Rackup items list is provided below. Note that the current LBLOCA rackup items are for the current LBLOCA AOR at Point Beach, which is based on the 1999 Evaluation Model (EM) as applied to Upper Plenum Injection plants (Reference 1). This EM is based on the previous Best Estimate methodology, the Code Qualification Document (CQD, Reference 2). The Best-Estimate analysis performed for the PBNP Units 1 and 2 EPU program utilizes the 2004 Best Estimate EM, ASTRUM (Reference 3) and once approved by the NRC, will supersede the current AOR. As a result, none of the following rackup items listed below will be applicable to the PBNP Units I and 2 ASTRUM analyses documented in Reference 4.
ECCS Model Assessments PCT Racku~
Items:
MONTECF Decay Heat Uncertainty Error: Please refer to Reference 5 for a detailed description of this error. Note that this error is only applicable to the 1999 EM (Reference 1) and therefore does not apply to the ASTRUM analysis for PBNP Units 1 and 2.
Revised Blowdown Heatup Uncertaintv Distribution: Please refer to Reference 6 for a detailed description of this error. Note that the Point Beach Units 1 and 2 ASTRUM analysis uses revised blowdown heatup heat transfer multipliers. Therefore, no PCT assessment is necessary for the new ASTRUM analysis for PBNP Units 1 and 2.
Inconsistent Vessel Vertical Level Modelinq: Please refer to Reference 7 for a detailed description of this error. Note that this error is only applicable to the 1999 EM (Reference 1) and therefore does not apply to the ASTRUM analysis for PBNP Units 1 and 2.
Revised Downcomer G ~ D Inputs: Please refer to Reference 7 for a detailed description of this error. Note that this error is only applicable to the 1999 EM (Reference 1) and therefore does not apply to the ASTRUM analysis for PBNP Units I and 2.
HOTSPOT Fuel Relocation Error: Please refer to Reference 8 for a detailed description of this error. Note that the PBNP Units 1 and 2 ASTRUM analysis uses the updated version of the HOTSPOT code which has fixed the fuel relocation error.
Page 20 of 42
Plant Modification Evaluations PCT Rackup Item:
1.4% Uprate Evaluation: The ASTRUM analysis for PBNP Units 1 and 2 as documented in Reference 4 accounts for EPU conditions and has incorporated the subject 1.4% uprate.
This rackup item does not apply to the ASTRUM analysis for PBNP Units 1 and 2.
References:
I. WCAP-14449-P-A, Revision 1, "Application of Best Estimate Large Break LOCA Methodology to Westinghouse PWRs with Upper Plenum Injection," October 1999.
- 2.
WCAP-12945-P-A, Volume 1, Revision 2, and Volumes 2 through 5, Revision 1, "Code Qualification Document for Best Estimate LOCA Analysis," March 1998.
- 3.
WCAP-16009-P-A, "Realistic Large-Break LOCA Evaluation Methodology Using the Automated Statistical Treatment of Uncertainty Method (ASTRUM)," January 2005.
- 4.
FPL Energy Point Beach, LLC Letter to NRC dated November 25,2008, License Amendment Request 258, Incorporate Best Estimate Large Break Loss of Coolant Accident (LOCA) Analyses Using ASTRUM (ML083330160)
- 5.
Nuclear Management Company, LLC Letter to NRC dated April 25,2001, ECCS Evaluation Model Changes, 10 CFR 50.46, Point Beach Nuclear Plant, Units 1 and 2 (ML011280068)
- 6.
Nuclear Management Company, LLC Letter to NRC dated April 25,2005, Point Beach Nuclear Plant, Units 1 and 2, ECCS Evaluation Model Changes, 10 CFR 50.46 (ML051230202)
- 7.
Nuclear Management Company, LLC Letter to NRC dated June 27,2007, Point Beach Nuclear Plant, Units 1 and 2, ECCS Evaluation Model Changes (ML071800510)
- 8.
FPL Energy Point Beach Letter to NRC dated June 16, 2008, Point Beach Nuclear Plant, Units 1 and 2, ECCS Evaluation Model Changes (ML081690700)
Question #3:
Figures 13 and 15 bear different titles but appear to show the same information. Please explain.
FPLE Point Beach Response Figure 15 of Reference 1 below is incorrect and was submitted in error. The correct Figure 15, titled "Unit 1 WCOBRAiTRAC Peak Clad Temperature for all 5 Rod Groups for the Limiting PCT Case" is provided in Enclosure 2.
In addition, Figure 30 of Reference 1 below was submitted in error. The correct Figure 30 titled "Unit 2 Downcomer Collapsed Liquid Level for the Limiting PCT Case," is provided in Enclosure 2.
Page 21 of 42
Reference:
- 1.
FPL Energy Point Beach Letter to NRC dated November 25,2008, License Amendment Request 258, Incorporate Best Estimate Large Break Loss of Coolant Accident (LOCA)
Analyses Using ASTRUM (ML083330160)
Question #4:
Figure 13 presents the average channel collapsed liquid level from the limiting PCT case. Four hundred twenty to 500 seconds following the break, the oscillations in collapsed liquid level become quite severe. Please evaluate the result and explain the phenomenon. Also provide graphs from other cases in the 420-500 second time range to show whether these oscillations are anomalous for the limiting case.
FPLE Point Beach Response The core fully quenches -230 seconds and the collapsed liquid level plot in question shows levels well above that required for the core to remain covered by a two-phase mixture with all fuel rods quenched as boiling continues. The cause of the oscillations is an imbalance in the vessel hydrostatics. Before the time period in question, downcomer liquid levels as well as reactor coolant system loop pressure drop cause oscillations in the core liquid levels. However, as the decay heat decreases, core steam flow also decreases which allows increased draining of liquid inventory into the core from the upper plenum (see Figure 4.1). As the liquid enters the core, there is a tendency for crossflow within core channels which redistributes the increased core inventory.
The increased core liquid inventory and redistribution of the inventory between core channels can further affect the hydrostatic balance in the vessel which leads to the oscillations.
The process is illustrated in Figure 4.2 through Figure 4.8. Figures 4.2 through 4.5 show the vertical continuous liquid mass flow rate (FLM) source at the top of each respective core channel and the direct effect the draining of liquid into the core has on the core collapsed liquid levels.
Further, Figures 4.6 through 4.8 show how the crossflow horizontal gap continuous liquid mass flow rate (WLM) in and out of the average channel behaves as the liquid inventory enters the core channels from above.
Investigation into whether the magnitude of oscillations for the limiting case is anomalous was performed by plotting the collapsed liquid level in the average channel for top 10 PCT cases (see Figures 4.9 through 4.18). As expected, the magnitude of the oscillations is case dependent, showing that the severity of the oscillations is dependent on the specific vessellcore conditions and how they affect the hydrostatic balance as core boiling continues. Therefore, collapsed liquid level oscillations are neither restricted to nor anomalous for the limiting case.
Page 22 of 42
M T H 0 0 0 0 5 12 0
0 A V G UP O u t e r G l o b a l LQ-LEVEL 1 6 0
0 UP I n n e r G l o b a l C L L 440 460 Time After Break (s)
Figure 4.1 lnner and Outer Global Upper Plenum Collapsed Liquid Levels at Extended Power Uprate Conditions Page 23 of 42
M a s s F l o w R a t e
( I b r n q )
FLM 1
C o l l a p s e d L i u i d L e v e l
( f b )
0 L P [ b ]
- - - - - - - - - LQ-LE(\\/EL 2
o L P CH 400 420 440 460 480 Time After Break (s)
Figure 4.2 Collapsed Liquid Level and Continuous Liquid Flow at Top of Low Power Core Channel at Extended Power Uprate Conditions Page 24 of 42
M a s s F l o w R a t e (Ib;$')
F L Y 1
0 G T CH C o l l a p s e d L i u i d L e v e l
( f b )
L Q - L E I E L 4
o GT CH 420 440 460 480 500 Time After Break (s)
Figure 4.3 Collapsed Liquid Level and Continuous Liquid Flow at Top of Guide Tube Core Channel at Extended Power Uprate Conditions Page 25 of 42
M a s s F l o w R a t e
( I b 5 9 )
F L Y
- 1.
0 AVG CH C o l l a p s e d L i u i d L e v e l
( f b )
- - - - - LQ-LE%EL 3
o A V G CH 400 420 440 460 480 500 Time After Break (s)
Figure 4.4 Collapsed Liquid Level and Continuous Liquid Flow at Top of Average Core Channel at Extended Power Uprate Conditions Page 26 of 42
M a s s F l o w R a t e
( I b z q )
F L Y 1
0 HA CH C o l l a p s e d L i u i d L e v e l (f;)
L Q - L E I E L 5
o HA CH Figure 4.5 Collapsed Liquid Level and Continuous Liquid Flow at Top of Hot Core Assembly Channel at Extended Power Uprate Conditions Page 27 of 42
WLM M a s s F l o w R a t e ( I b m / s )
WLM 13 1 2 FLY M a s s F l o w R a t e $;bm/s)
- - - - - - - - - F L Y 1
F L Y 2 3 1
0 LP t o A V G 420 440 460 480 Time After Break (s)
Figure 4.6 Continuous Liquid Flow at Top of Low Power Channel and Crossflow at the Top of Low Power Channel to Average Channel at Extended Power Uprate Conditions Page 28 of 42
WLM M a s s F l o w R a t e ( I b m / a )
WLM 15 1 2 0 AVG t o GT F L Y M a s s F l o w R a t e $kbm/s)
F L Y 1
0 AVG CH Figure 4.7 Continuous Liquid Flow at Top of Average Channel and Crossflow at the Top of Average Channel to Guide Tube Channel at Extended Power Uprate Conditions Page 29 of 42
WLM Y a s s F l o w R a t e (Ibm/s)
WLM 1 6 1 2 0 A V G t o HA FLM Y a s s F l o w R a t e \\;bm/s)
FLU 1
0 A V G CH Figure 4.8 Continuous Liquid Flow at Top of Average Channel and Crossflow at the Top of Average Channel to Hot Assembly Channel at Extended Power Uprate Conditions Page 30 of 42
LQ-LEVEL 3
0 0 non-GT CH 440 460 Time After Break (s)
Figure 4.9 Limiting PCT Case Average Channel Collapsed Liquid Level at Extended Power Uprate Conditions Page 31 of 42
L Q - L E V E L 3
0 0 non-GT C H 440 460 Time After Break (s)
Figure 4.10 2nd Limiting PCT Case Average Channel Collapsed Liquid Level at Extended Power Uprate Conditions Page 32 of 42
LQ-LEVEL 3
0 0 non-GT CH 440 460 480 Time After Break (s)
Figure 4.1 1 3rd Limiting PCT Case Average Channel Collapsed Liquid Level at Extended Power Uprate Conditions Page 33 of 42
LO-LEVEL 3
0 0 non-GT CH 400 420 440 460 480 500 Time After Break (s)
Figure 4.12 4th Limiting PCT Case Average Channel Collapsed Liquid Level at Extended Power Uprate Conditions Page 34 of 42
L Q - L E V E L 3
0 0 non-GT CH 440 460 Time After Break (s)
Figure 4.13 5th Limiting PCT Case Average Channel Collapsed Liquid Level at Extended Power Uprate Conditions Page 35 of 42
LQ-LEVEL 3
0 0 non-GT CH 440 460 Time After Break (s)
Figure 4.14 6th Limiting PCT Case Average Channel Collapsed Liquid Level at Extended Power Uprate Conditions Page 36 of 42
LQ-LEVEL 3
0 0 non-GT CH 440 460 Time After Break (s)
Figure 4.15 7th Limiting PCT Case Average Channel Collapsed Liquid Level at Extended Power Uprate Conditions Page 37 of 42
L Q - L E V E L 3
0 0 non-GT CH Figure 4.1 6 4-.........................."...............................
8th Limiting PCT Case Average Channel Collapsed Liquid Level at Extended Power Uprate Conditions 2-0 Page 38 of 42 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
I I
I I
400 420 440 460 480 500 Time After Break (s)
LQ-LEVEL 3
0 0 non-GT C H 440 460 480 Time After Break (s)
Figure 4.17 9th Limiting PCT Case Average Channel Collapsed Liquid Level at Extended Power Uprate Conditions Page 39 of 42
LQ-LEVEL 3
0 0 non-GT CH 440 460 Time After Break (s)
Figure 4.18 10th Limiting PCT Case Average Channel Collapsed Liquid Level at Extended Power Uprate Conditions Page 40 of 42
Question #5:
Provide reference linear heat rates assumed in the analyses: average, peak, hot rod average, hot assembly average, and hot assembly peak.
FPLE Point Beach Response The PBNP Unit 1 ASTRUM analysis supports a core average power of 181 1 MWt including uncertainties, and the core average linear power is 7.0 kWIft. The core average channel fuel assemblies in WCOBRAlTRAC in the ASTRUM analysis are modeled at an average power of 8.4 kWlft. The Core Operating Limits Report (COLR) maximum total peaking factor (Fa) value is 2.6, and the COLR maximum enthalpy rise peaking factor (FAH) value is 1.68. The hot rod average linear heat rate and the hot assembly average linear heat rate supported by the ASTRUM analysis are 11.8 kW/ft and 11.3 kWm maximum, respectively. In the limiting PCT case, the hot assembly peak linear heat rate is 15.5 kWlft, and the hot rod peak linear heat rate is 16.1 kWIft.
In the NRCapproved ASTRUM methodology, the nominal total peaking factor (Fq) is sampled over the range from a minimum of the maximum baseload value to a maximum of the COLR limit of 2.6, minus uncertainties, for each individual case (see WCAP-16009-P-A, Table 1-1 0). The 16.1 kWlft value is the W C O B M R A C hot rod peak kWlft value for the case(s) that proved limiting in PCT and was generated according to the sampling methodology.
The PBNP Unit 2 ASTRUM analysis yields the same results as Unit 1.
The peak and average linear heat rates are sampled for every run, according to the referenced methodology (Reference 1 ).
Reference:
- 1.
WCAP-16009-P-A, "Realistic Large-Break LOCA Evaluation Methodology Using the Automated Statistical Treatment of Uncertainty Method (ASTRUM)," January 2005.
Question #6:
The assumed amount of steam generator tube plugging has changed in an apparently non-conservative direction. Please explain.
FPLE Point Beach Response The 25% steam generator tube plugging (SGTP) level used for the current Large Break LOCA analysis of record has been revised for the ASTRUM analysis. Due to the current plant operations, chemistry conditions, and forecast predictions at the PBNP Units 1 and 2, the maximum SGTP level is anticipated to be 10% (Reference 1). The limit of 10% is bounding with respect to the current plugging levels for Units 1 and 2 (References 2 and 3). Table 1.3 below identifies the total number of steam generator tubes plugged to date for Units 1 and 2.
Page 41 of 42
Table 1.3 Point Beach Units 1 and 2 Steam Generator Tubes Plugged
References:
- 1.
FPL Energy Point Beach Letter to NRC dated November 25,2008, License Amendment Request 258, Incorporate Best Estimate Large Break Loss of Coolant Accident (LOCA)
Analyses Using ASTRUM (ML083330160)
Steam Generator "B"
- of tubes plugged 6 = (0.19%)
4 = (0.11%)
Unit 1 (3,214 total tubes)
Unit 2 (3,499 total tubes)
- 2.
FPL Energy Point Beach Letter to NRC dated October 25, 2007, Spring 2007 Unit 1 (U1 R30) Steam Generator Tube lnspection Report (ML072990108)
Steam Generator "A"
- of tubes plugged 4 = (0.12%)
0 = (O)%
- 3.
FPL Energy Point Beach Letter to NRC dated September 16, 2008, Spring 2008 Unit 2 (U2R29) Steam Generator Tube lnspection Report (ML082590073)
Page 42 of 42
ENCLOSURE 2 FPL ENERGY POINT BEACH, LLC POINT BEACH NUCLEAR PLANT, UNITS 1 AND 2 LICENSE AMENDMENT REQUEST 258 INCORPORATE BEST ESTIMATE LBLOCA ANALYSES USING ASTRUM RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION The following pages provide the corrected Figures 15 and 30.
2 pages follow
1 0
O
. ? o t R c J 2
0 G ~
o t
A s s e r n 2 y 3
0 0 g u i d e T u b e s 4
0 0 S C - O P - F 5 U 5
0 O L o w P c w e r Figure 15 - Unit 1 ~ C D B M R A C Peak Clad Temperature for all 5 Rod Groups for the Limiting PCT Case Page 32 of 52
Figure 30 - Unit 2 Downcomer Collapsed Liquid Level for the Limiting PCT Case Page 47 of 52