ML19345B725
| ML19345B725 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 11/25/1980 |
| From: | Lundvall A BALTIMORE GAS & ELECTRIC CO. |
| To: | Clark R Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8012020425 | |
| Download: ML19345B725 (16) | |
Text
.
B ALTIMORE G AS AND ELECTRIC COMPANY P. O. H O X 1475 B A LTIMO R c. M A R YL A N D 21203 AnvHun c. Lua ovaLL,JR.
e Neverter 25, 1980 u.n.
Of f Ice of Nuclear Peactor Regulation U. S. Nuclear Fogulatory Commission Ruhington, D. C.'20555 AMENTION:
Mr. R. A. Clark, Chief Operating Peactors Branch #3.
N m
Division of Licensing
!fr.li c:p r
S LEJ ECT: Cal vert Clif f s Nuclear Pcwer Plan t 2;.N Unit No. 1, Docket No. 50-317
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(,f,
Amendment to Operating License LPE-53 ly;;;
g, Supplement 2 to Fi(th Cycle License Application
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PEFERENCE 1:
A. E. Lundvall to R. A. Clark letter dated m
9/22/80, Fifth Cycle License Application
)
GentIemen:
Reference 1 presented the results and conclusions of the ECCS enalysis for Calvert Cli f f s Unit 1, Cycle 5.
Although the original conclusions reporied in Section 8.0 have been verif ied, ccepletion of the indepen-dent verification has determined that the specific results for peak clad terporature and clad oxidation require a ninor revision.
Although the clad tempereture < nd clad oxidation values recain well belcw 10CFF50.46 limi ts, a veri fied calculation utilizing CE's NRC approved evaluation nodel indicaind the reported peak clad *emperature should increase from 0
1942 F to 1937eF.
This increase exceeds the 200F tolerance above which it is considered necessary to revise the ECCS portion of the reload report.
Except for the small incrase in clad iemperat ure and oxidation, the original conclusions pertaining to Unit 1, Cycle 5 remain unchanged.
A revised Section 8.0 is attached to this letter.
Very truly yours, BALTIMOPE RAS ANC ELECJRIC COMPANY
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l'l,,/ ur A. E. Lon/ - llI, Jr.
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Attachment:
40 copies 8012020 42F
Of fice of fluclear Pcactor Regulation AttenTicn f'r. P. A. Clark November 25, 1980 Pace two Copies To:
J. A. Biddison, Esquire (w/out Encl.)
G. F. Trowbridge, Esqui re (w/ cut Encl. )
f/r. E. L. Ccnner, Jr., f1PC f/r. P. W. Kruse, CE i
ATTACHMENT 8.0 Introduction and Summary An ECCS performance analysis was performed for Calvert Cliffs Unit 'I Cycle 5 to demonstrate compliance with 10 CFR 50.46 which presents the NRC Acceptance U)
Criteria for Emergency Core Cooling Systems for Light-Water-Cooled reactors The analysis justifies an allowable peak linear heat generation rate (PLHGR) of 15.5 kw/ft. This PLHGR represents an increase over the Cycle 4 limit of 14.2 kw/ft and is equal to the existing limit for Unit-II. The method of analysis and detailed results which support this value are presented herein.
8.1 Method of Analysis The analysis for Unit II Cycle 2 operation (6), approved by the NRC, was used as the reference cycle analysis for the Unit I Cycle 5 evaluation.
The Unit II analysis was selected as the reference since the core in Unit I Cycle 5 is comprised only of high density stable fuel as in Unit II Cycle 2 and the PLHGR for Unit II is 15.5 kw/ft'. The one residual low density fuel assembly contained in Unit I Cycle 457) was removed.
The method of analysis used the NRC approved C-E evaluation model(2)
The model was used to.re-evaluate the limiting large break LOCA performance.
The blowdown and refill-reflood hydraulic calculations employed in Unit II Cycle 2 were performed generically for both Units I & II and apply to the Unit I_ fifth fuel cycle. Therefore, only the STRIKIN-II(3) calculations were necessary to account for the different fuel pin conditions.
~
Burnup dependent. calculations were performed using the FATES (4) and STRIKIN-II(3) codes to determine the limiting condition for the ECCS performance analysis.
The PARCH (9) code was not utilized in the Cycle 5 evaluation.
The late reflood heat transfer benefit from the use-of the PARCH generated steam cooling heat transfer coefficients would have reduced the peak clad temperature reported herein.
8.2 Resultt Table 1 presents the analysis results reported for the 1.0 DES /PD* break.
The 1.0 DES /PD break is the limiting break for Unit I Cycle 5.
The reference cycle analysis for Unit II Cycle 2 defines this as the limiting break size for high density fuel when clad rupture occurs during the refill period as predicted in this evaluation for Unit I.
The results of the evaluation confirm that 15.5 kw/ft is an acceptable value for the PLHGR in Cycle 5 The peak clad temperature and maximum local and core wide clad oxidation values as shown in Table i are below 10 CFR 50.46 acceptance limits.
Table 2 Presents a list of the significant parameters displayed graphically for the limiting 1.0 DES /PD break.
8.3 Evaluation of Results 9
The reason for the lower peak clad temperature (PCT) for Unit I Cycle 5 (Table 1) as compared to the Reference Cycle, Unit II Cycle 2, despite a higher initial stored, energy for Cycle 5 (Table 3) was due to the more favorable overall fuel performance, a lower heat sink temperature and improved heat transfer conditions, e.g., a lower fuel rod gas pressure and a lower hot bundle linear heat rate (Table 3), hence a lower hot bundle average power.
n Since Unit I Cycle 5 had a lower hot bundle average power than in the Reference Cycle, the transient enthalpy during the later portions of the blowdown period was lower.
Therefore, the residual fuel stored energy and clad temperature at the start of the refill period were also lower.
- DCS/PD = Double-Ended Slot at Pump Discharge
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The fuel and clad ~ heat up during the refill period therefore proceeded at a slower rate resulting both in lower clad temperatures and lower clad oxidation-than in the Reference Cycle.
The hot rod gas pressure (Table 3) which was initially lower than in the Reference Cycle, together with the lower refill period fuel and clad temperatures resulted in clad rupture occuring 3.4 seconds later than in the Reference Cycle. As a consequence of this delay in clad rupture, the more favorable refill period heat removal from the fuel and clad was prolonged.
During the reflood period, after reflood rates have fallen below 1.0 inches per second, the lower average hot bundle power enhanced the ro4-to-rod radiation cooling of the hot rod by providing a lower heat sink temperature. The net result was a slightly lowerpCT(by 4 F) and a lower peak local clad oxidation (by 0.5 ) as shown in Table 1.
8.4-Conclusion As discussed above, conformance to the fiCS criteria is summarized by the analysis results presented in Table 1.
The results of the analysis identified the peak clad temperature as 1987'F as opposed to the acceptance limit of 2200 F.
The peak local clad oxidation was 9.7% versus the acceptance limit of 17% and the peak core wide clad oxidation was less than.51 % versus the acceptance limit of 1.0%.
Hence, Unit I Cycle 5 operation-at a peak. linear heat generation rate of 15.5 kw/ft and at a power level of 2754 Mwt (102% of 2700 ljw ) will result in acceptable ECCS performance.
t 8.5 Computer Code Version Identification The following version of Combustion Engineering ECCS Evaluation Model computer code was used in this analysis:
STRIKIN-II:
Version tio. 77036
8.6 References-1.
Acceptance Criteria for Emergency Core Cooling Systems for Light Water Cooled Nuclear Power Reactors, Federal Ragister, Vol. 39, No. 3 -
Friday, January 4, 1974.
2.
CENPD-132, " Calculative Methods. for the CE Large Break.LOCA Evaluation Model", August 1974 (Proprietary).
CENPD-132, Supplement.1, " Updated Calculative Methods for the CE Large Break LOCA Evaluation Model", December 1974 (Proprietary).
CENPD-132, Supplement 2, " Calculational Methods for the CE Large Break LOCA Evaluation Model", July 1975 (Proprietary).
3.
CENPD-135, "STRIKIN-II, A Cylindrical Geometry Fuel Rod Heat Transfer Program", April 1974 (Proprietary).
CENPD-135, Supplement 2, "STRIKIN-II, A Cylindrical Geometry Fuel Rod Heat Transfer Program (Modification)", February 1975 (Proprietary).
CENPD-135, Supplement 4, "STRIKIN-II, A Cylindrical Geometry Fuel Rod Heat Transfer Program", August 1976 (Proprietary).
CENPD-135, Supplement 5, "STRIKIN-II, A Cylindrical Geometry Fuel Rod Heat Transfer Program", April 1977 (Proprietary).
4.
CENPD-139, "CE Fuel Evaluation Model", July 1974 (Proprietary).
5.
CENPD-137, " Calculative Methods for ' the CE Small Break LOCA Evaluation Model", Combustion Engineering Proprietary Report, August 1974 (Proprietary).
CENPD-137, Supplement 1, " Calculative Methods for the CE Small Break Evaluation Model", January 1977 (Proprietary).
6.
To be supplied by BG&E '(Calvert Cliffs II Cycle II ECCS Analysis).
7.
To be supplied by BG&E (Calvert Cliffs I Cycle IV ECCS Analysis).
8.
To be supplied by BG&E (Calvert Cliffs II Cycle I ECCS Analysis).
9.
CENPD-138, " PARCH - A FORTRAft-IV Digital Program to Evaluate Pool Boiling, Axial Rod and Coolant Heatup", August 1974 (Proprietary).
CENPD-138, Supplement 2-P January 1977 (Proprietary).
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Table'1 Calvert Cliffs Unit I' Cycle 55 ymiting Break: Size (1.0 DES /PD)'
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Blowdown! Peak Peak Clad-Time of Peak Time of Clad
' Peak Local Total Core-Wide Clad Temperature
- Temperature Clad Temperature Rupture Clad 0xidation Clad 0xidation
- Analysis dni.t I, Cycle.5:
1725'F 1987 F 250. sec 32.8 sec 9.7%
~
<c.51%
Reference Cycle.'
(Unit II, Cycle 2) 1725*F'
-1991 F 248.'sec 29.4 sec 10.24%
<.51%
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=
m r
r
9 e
b Table 2 Calvert Cliffs I ' Cycle 5 Analysis Plots
. Figure.
Variables Designation Peak ~ Clad Temperature lA Hot Spot Gap. Conductance-1B Peak Local Clad 0xidation -
1C Clad Temperature, Centerline Fuel Temperature, Average Fuel. Temperature and Coolant Temperature for Hottest Node 1D i
Hot Spot Heat Transfer Coefficient' 1E Hot Rod Internal Gas Pressure 1 F.
=
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i Table 3 Significant Parameters Unit I Values Unit II Values Quanti ty Cycle 5 Cycle 2 j Reactor Power Level (102% of Nominal) 2754 2754 Mwt Average Linear Heat Rate.(102% of Nominal) 6.45 6.52-kw/ft
-Peak Linear Heat Generation Rate:(PLHGR)
Hot Assembly, Hot' Channel 15.5 15.5 kw/,ft
' Peak Linear Heat Generation Rate (PLHGR)
Hot Assembly, Average Channel 13.43 13.57 kw/ft Gap Conductance at PLHGR.
1704*
1731*
BTU /hr-ft 7
Fuel-Centerline Temperature at PLHGR 3626*
3604*
F 1
Fuel Average Temperature at PLHGR 2242*
2219*
F i Hot Rod Gas Pressure 1144*
1198*
psia (HotRodBurnup-758*
1522*
MWD /MTU t
- For high density fuel, when gap conductance is minimum 4
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4 1
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FIGURE lA CALVERT~ CLIFFS UNIT I: CYCLE V 1,0.x DOUBLE ENDED SLOT ~ BREAK IN PU.MP DISCHARGE LEG-PEAK CLAD TEMPERATURE 2200-i HIGH DENSITY-FUEL AT 15.5 KW/FT I
'2000 I
s.
-1800' u_
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1600 J
7 les jf D
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1000 i
.600 s
600 0
100 200 300 400
- 500 S00
'T;IME,:SECONOS 3
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FIGURE 1B CALVERT CLIFFS UNIT I CYCLE V 1.0 x DOUBLE ENDED SLOT BREAK IN PUMP DISCHARGE LEG HOT SPOT GAP CONDUCTANCE
-1600 i
i HIGH DEilSITY FUEL AT 15.5 KW/FT I
1400 1200 u_
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a 3
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- TIME, SECONOS
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FIGURE IC-CALVERT CLIFFS UillT I CYCLE V-1,~0 x DOUBLE ENDED SLOT BREAK Ifi PUMP. DISCHARGE LEG PEAK LOCAL CLAD OXIDATION 16-l HIGH DEllSITY FUEL AT 15.5 KW/FT i
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SECONCS Y
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FIGURE ID CALVERT CLIFF' UNIT I CYCLE V o
LO x DOUBLE ENDED SLOT BREAK IN PUMP DISCHARGE LEG CLAD TEMPERATURE, CENTERLINE FUEL TEMPERATURE, AVERAGE-3500 HIGH DENSITY FUEL AT 15.5 K\\uFT 3000j 2600 e-g
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FUEL CENTERLINE g
h AVERAGE FU EL g
2000 l; g
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1000 l-i y COOLANT 1
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0 100 200 300 400 500 600 TIME.
SECONDS
FIGURE 1E CALVERT CLIFFS-~ UNIT I CYCLELV-1.0-x DOUBLE ENDED SLOTLBREAK IN PUMP. DISCHARGE LEG
'l60; HOT-SPOT HEAT' TRANSFER COEFFICIENT I
r i
140
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- l; 5.
G 80 :
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-300 400 500 600 i
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SECONDS L
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FIGURE 1F
-CALVERT CLIFFS UNIT I CYCLE V 1.0 x-DOUBLE EilDED SLOT BREAK'Ifl PUMP DISCilARGE LEG HOT R0D. INTERNAL GAS PRESSURE 1400 i
i i
i i
HIGH DENSITY FUEL AT 15.5 KW/FT 1200 P
=1144,0 PSIA f i ; ig 1000 RUPTURE AT 32,8 SEC 5
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E 800 -
u75 0?
wE 600 400 200 t
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O 20 40 EO 80 100 12r TIME, SEC0ilDS
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