ML18088A115
| ML18088A115 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 09/24/1976 |
| From: | Robert E. Uhrig Florida Power & Light Co |
| To: | Parr O Office of Nuclear Reactor Regulation |
| References | |
| Download: ML18088A115 (25) | |
Text
NIEC FOAM 105 12 20)
U.S, NUCLEAR BLOULATOBYCOMM
'3N NBC'DISTRIDUTloN FDB PART 50 DOCKET MATERIAL DOCKET NUMOEP Qo-3")
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ENCLOSURE REVISE ECCS, ANALYSIS FOR ST LUCIE II,.....
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FLORIDAPOWER & LIGHTCOMPANY September 24, 1976 L-76-340 Office of Nuclear Reactor Regulation Attn:
Olan D. Parr, Chief Light Water Reactors Branch 1-3 Division of Project Management U. S. Nuclear Regulatory Commission Washington, D. C.
20555
Dear Mr. Parr:
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Re:
St. Lucie Unit No.
2 ECCS Reanalysis Ddcket No. 50-389 Modifications to the Combustion Engineering STRXKIN-II Code to correct certain errors in the code and to preclude a
return to nucleate boiling have been completed and submitted to the Commission in the form of Supplement No.
4 to CENPD-135.
A reanalysis of the ECCS for St. Lucie Unit No.
2 has been performed in accordance with the revised code and is herewith submitted for your evaluation.
The Preliminary Safety Analysis Report for St. Lucie Unit No.
2 will be updated at a later date to reflect the results of this reanalysis.
Yours very truly, Robert E. Uhrig Vice President REU/LLL/hlc Attachment cc:
.Norman C. Moseley, Region II Jack R.
- Newman, Esq.
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Rt sod ECCS Anal sis for St. Lucio - Unit II INTRODUCTION Due to recent STPJKIN-II modifications
, which include the prevention of a return to nucleate boiling, a large break spectnm reanalysis has been performed for St. Lucie - Unit II.
This revision supercedes the ECCS evalua-tion >>Rich appears in Reference 2.
Il.
SP.R WRY A four-break spectnnn analysis has been performed at a peak linear heat generation rate (PLH&} of 11.6 kw/ft.
The worst break was identified as the 1.0 DEG/PD"'xth a peak clad temperature of 2120 F.
The results of this analysis demonstrate that the ECCS for St. Lucie-Unit II meets the iXRC Acceptance Criteria published in the Federal Register on January 4, 1974.
Conformance is summarized as follows:
Criterion (1) - Peak Clad Temperature.
"The calculated, maxhmun fuck clem nt cladcL'ng termerature shall not exceed 2200 F".
The analysis yielded a peak clad temperature of 2120 F
for the 1.0 DEG/PD break.
Criterion (2) - Naxirui n Claddin<< Oxidation.
"The calculated total oxida-tion of the cladding shall nowhere exceed 17-< of the total cladding thickness before oxidation".
The analysis yielded a local p,.ak clad oxidation percen-tage of 15.SS-'o for the 1.0 DEG/PD.
Criterion (3) - Yaximum dro en Generation.
'The calculated total amount of hydrogen generated from the chemical reaction of the cladding with water or steam shall not exceed 1-'o of the hypothetical amount that would be generated if all of the metal in the cladding cylinders surrounding the plenum volume, >>ere to react".
r
'.0 DEG/PD = 1.0 Bauble-Ended Guillotine at the Pump Dischar<<o
The analysis yielded 'a peak core-wide c ad. oxidation perccntaj~e of <0 902.o for the 1 ~ 0 DEG/PD.
The statements in Reference 2 demonstrating compliance >>~th Criterion 4 (eool-able, geometry) and Criterion 5 (long term cooling) are unchanged.
III. LARGE BREAK SPECTRUM AXQYSIS bithod of Calculation The only difference between the method used in Reference 2 and. that used in the current calculation is the STRIKIN-II version which was used.
The description of the current version of STRIKIN-II, which now prevents return to nucleate boiling, is given in Reference l.
As speci ied in Reference 3, the reflood heat transfer coefficients used in the R ference 2 analysis were obtained by applying a 0.8 multiplier to the KECFF-based coefficients.
This approach has been retained in the current analysis.
- Recently, WC approved.
a method developed by C-E (4) to apply the FLECHE-based correlation to 16xl6(
fuel such as that used in St. Lucie 2.
Use-of te reflood heat transfer coefficients obtained with the new method would substartially lower clad temperatures, or, alternately,
>>ould allow a PLHGR increase Emer enc Core Coolin S stem Assum tions The ECCS assiriptiors are the same as those stated in Reference 2
except for a change in the flow delivered by the Low Pressure Safet>
Injection (LPSI) punps to the vessel.
At the time 'the analysis reported in Reference 2 was performed, the ECCS design included a common header for the t>>o LPSl pmys.
lilith the common header, either LPSI pump could deliver.
flow to all four Reactor Coolant System cold legs.
Subsequently, the header design >>as modif ed.
In the revised desi',
.each LPSI pump delivers flow to its own header,
>>hich in turn provides flow to t>>o cold legs.
Since the worst single failure is the failure of one LPSI pump to start, the revised header design results in a LPSI flow to the vessel equal to 50~ of that delivered b>
one paul; the other 50-:. spills through the cold leg rupture.
C.
Core S stem and Containment Parameters The parameters are the same as those given in Reference 2 with the exception of the parameters which are 'related to the PLHGR.
These paraneters, which now reflect a PLHGR of 11.6 kw/ft, are shown in Table III-l.
D.
h~as
. The analysis reported in Reference 2 identified the worst break to be' guillotine rupture.
In this analysis, a three-break guillotine
.spectrum was, therefore, performed.
In addition, a representative slot break from Reference 2 was also analyzed.
The calculations have been performed. for breaks at the puJnp discharge over a range of break sizes varying from 605 to 100: of the double-ended cold leg pipe area.
E.
Results The blowdo.~a hydraulics have not changed. from those presented in Reference 2.
The.eflood results are unchanged from Referenc 2
except for slight changes in the downcomer water level and the reflood at transfer coefficient.
The time-dependent downcomer water level and hot spot reflood heat transfer coefficient are shown in Figures III-1 and III-8 respectively.
These figures. are listed along with all other figures in Table III-2.
The times of interest for each of the breaks are the same as those reported in Reference 2 except for the hot rod ':
nyture times.
Tne new rupture tihes are included in Table III-3, which contains a summary of the peak clad temperatures and oxidati'on percentag s
for the break sp ct~m. Figure III-12 shows pe~ cl'ad temperature plotted versus break si e a-.d type, indicating that the worst break is the 1.0
'EG/PD ruptu.e.
F.
Co uter Code Version Identification The following code versions were used in this analysis:
STRIKIN-II: 'ersion 76234~
COMPERC-II:
Version 75097 G.
Lar e Break Anal sis Hot and Suction Le Breaks Note that the large break analysis spectrum of breaks does not include the hot leg or the pump suction leg breaks.
As docu-mented in the -St. Lucie Unit 2 PSAR (Appendix 6C, Section 3.0, Rev.
42 of 11/10/76). by reference to docketed submittals, it has been established that analysis of these breaks is not required since they have been shown to result in peak clad temperatures far below those of the limiting breaks.
The cal-culated effects of the modifications to the STRIKIN-II Code "Includes modificatiohs of Reference 1
and the safety injection system piping change, as demonstrated in the present reanalysis.,
would not alter this conclusion, i.e., the hot and suction leg breaks would not become limiting breaks.
IV SMALL BREAK SPECTRUM ANALYSIS The small break spectrum presented in CENPD-137 was reviewed to determine if the recent changes made to STRIKIN-II (CENPD-135, Supplement
- 4) would. influence the results shown therein.
The con-clusion reached was that the STRIKIN-II changes would have no impact on those results and that the'peak clad temperatures for all small breaks will remain as reported in CENPD-137.
Those results demon-strate that the small breaks remain much less limiting than large breaks.
In addition, the design changes to the safety injection system piping described in III.B. above, do not affect the small break
- analysis, and the analysis presented in CENPD-137 remains appli-cable to St. Lucie Unit 2.
These piping changes affect only the LPSI pump delivery and have no effect upon the HPSI pump delivery.
While the large break analysis is controlled by the LPSI delivery flow, the small break analysis is controlled by the HPSI delivery flow.
REFERP'CES d
1.
CBFD-135, Supplement 4,
"STRIKIN-II, A Cylindrical Geometry Fuel Rod Heat Transfer Progxam, (August, 1976 Modification)", August, 1976.
(Proprietary).
2..
Preliminary Safety Analysis Report for St. Lucie - Unit II, Appendix 6C, Section 6.0 "ECCS FAC Analysis", as amended per Revision 42, November 10, 1975.
3.
Supplement to the Status Report by the Directorate of Licensing in the Matter of Combustion Engineering, Inc.,
ECCS Evaluation Model Conformance to 10 CFR 50, App ndix K, November 13, 1974.
H 4.
Letter from Karl Kniel PilRC) to A. E. Scheror (C-E) dated August 2, 1976.
5.
~~'PD-213, "Application of FLEQE Reflood Heat Transfer Coefficients to C-E's 16xl6 Fuel Bundles", J.
H. Holderness,
- January,
.1976.
~.
Table III-1 St. Lucie - Unit II Coro Parameters guuant it Peak Linear Heat Generation Rate (PLHGR)
Gap Conductance at.
PLHGR Fuel Centerline Temperature at PLHGR Fu 1 Averag Temperature at PUEGR Value ll.6 lac/ft 1199 Btu/hr-ft - F 2 0 2987 F
1976 F
Table III-2 St. Lucie - Unit II Large Break Spectrum Plots Break Size, T
e, and. Location Plot Figure Number All Breaks 0.8 x Double-Ended Slot Break in Pump Discharge Leg (0.8 X DES/PD) 1.0 x Double-Ended Guillotine Break in Pm@ Discharge Leg (1.0 X D=-G/rD)
Water Level in Down-comer during Reflood Peak Clad Temperature Peak Clad Temperature Local Clad Oxidation Hot Spot Gap Conductance III-1 III-2 III-5 III-4 III-S Clad, Fuel Centerline, Fuel
- Average, and Coolant Temper-ature for the Hottest. Node III-6 Hot Spot Heat Transfer, Coefficient III-7 Hot Spot Heat Transfer Coefficient During Re flood III-8 Hot Rod Internal Gas Pressure III-9 0.8 X Double-End d Guillotine Break in Pump Discharge Leg (0.8 X DEG/PD) 0.6 X Double-Ended Guillotine Break in Pump Discharge Leg (0.6 Y DEG/PD)
All Breaks Peak Clad Temperature Peak Clad Temperature Peak Clad Temperature vs. Break Area III-10 III-11 III-12
~ ~
4
. Table III-3 St. Lucie - Unit II Peak Clad Temperatures and Oxidation Percentages for the Break Spectrum Break Hot Rod Rupture Time (Sec)
Peak Clad Temperature
( F)
Clad Oxidation Local Core-Nide 11.6 kw/ft 0.8 DES/PD 1.0 DEG/PD O.S DEG/PD 0.6 DEG/PD 83.20 76.79 81.05 97.01 2111 2120 2114
~
2089 15.50 15.85 15.65 13.00
- 0. 894
+ 0.902 c 0.897
- 0. S39
FtsusE III-1 ST, LUCIE I I e
1.0 x DOUBLE END.D CUILLOTI!~!E BR:%l< IN PU,"1P DISCHARGE LEG IlATER'EVEL I "<
DOHI'iCOf"lER DURIi'~G REFLOOD 18 >>000 15 000 12.>>000
~~~
9 000 I
}
6>>000 3 >>000 0>>000 CD
'D CD
'D CD CO CD CD CD CD CD nJ CD CD CD AJ CD CD TXYiE l'IFTER CONTACTS SEC
ST.
LUCIE II 0,8 x DOUBI E ZADED SLOT BREAK IN PUIlP DWICHARGE LEG PEAK CLAD TENPERATURE 2000 1800 12.0 0 1000 800
'r 00 0
12.0 2.t 0 360 800
P00 ST, LUCIE II
.1.0 x. DOUBLE ENDEAUILLOTINE BREAK IN PUNP %CHAROE LEG
. PEAK CLAD TEi"1PERATURE 000 JB00 3400 J 2.00 3000 8'0 0 600 400 0
j.2.0 2.40 360 TT.HE'.I-SF CONf.)~
480 18 ST.
LUCrE lr
,1,0 x. DOUBLE ENDBOUILLOTINE BREAK IN PUNP I%CHARGE LEG LOCAL CLAD OX'SEDATION 1O OC CD 0
12.0
\\
e40 3I 0 TT.HF):
'RI=..C(li>!n3 480 800 7PO
j 800 IGURE y
sT.
wc>E tt e
j,0 x DOUHLE ENDED GUILLOTINE BPEAK IN PUHP DISCHARGE LEG HOT SPOT GAP CONDUCTANCE j 800 3400 LL.
C) l l I I
I 2.00
~ 1000 800 Soa 400 11.6 KN/FT 2.0 0 0
0 P40 380 480 y3 600
4500 ST, LUCIE II 1.0 'x DOUBLE ENDP~UILLOTINE BREAK IN PUi'IPSCHARGE LEG CLAD TEMPERATURE, CENTERLINE FUEL.TEMPERATURE, AVERAGE FUEL TEHPERATURE
'AND COOLANT TEMPERATURE FOR HOTTEST NODE tt QQQ 3500 U.;6 e/FT 3000 2.50 Q FUEL CEt<TERLIHE-:
AVERSE I-uEL CLAD:
3 000 500 COOLANT;,
0 0
12.0 P ~0, 360 TXYit=,.
SECONDS 480 600
ST, LUCIE I I 1.0 x DOUBLE Ef ED GUILLOTINE BREAK iN PU i
DISCHARGE LEG HOT SPOT HEAT TRANSFER COEFF ICIENT 80
~l C>
I't-60 l
gp 2.0 10 0
2.40 360 480 600
e
\\
F,ieuRE III.-8 ST, LUCIE II 1.0 x DOUBLE ENDED GUILLOTINE BREAK IN PUNP DISCHARGE LEG HOT SPOT HEAT TRANSFER COEFFICIENT DURING REFLOOD 30a000 25~000
~t CD I
U I
2.0 F000 3.5 ~000 IM CD I
3.0 ~000 5n000 0~000 CD CD CD CD CD X
CD CD Cd CD CDtl CO CD CD CD CD TINE AFTER CONTACT
( SEC
)
0 Fij.use I I I-9 ST, LUCIE II 1,0 x DOUBLE ENDED GUILLOTINE BREAK IN PUNP DISCHARGE LEG
'HOT ROD INTERNAL GAS PRESSURE 1200 1000 P P~ ITIAL = 1102 PS IA 800 RUPTURE (76,79 SEC) 600 000 200 0
0 20 00 60 80 100 TIilE, SECONDS
22.00 I
0,8 x DOUBLE ENDE 6UILI OTINE HREAK IN PUNP QSCHAR6E LE6 AK CLAD TH")PERATURE r
?.000
~
~
'+ ~
1800 J800
~ J.400
~s 12.0 0 1000 800 800 400 0
3.? 0 2.40 380 480 SQQQglQ 5 18 800
2.2.0 0 h
I 0,6 x DOUBLE Ei'D GUILLOTINE BREAK Ii'l PUI+DISCHARGE LEG PEAK CLAD,TENPFRATUiME 2.000 3.800
'i 400 j000 800 600 400 0
l2.0 2.4 0 360 TENET SECONDS 600
/2.0
FieuoE III-12 ST, LUCIE II PEAK CLAD TPlPERATURE vs BREAK AREA 2200,0 2000,0 C) 1800,0 1600,0 PEAK LHGR = 11,6 OlFT 0
DISCHARGE LEG SLOT g
DISCHARGE LEG.GUILLOTINES 1000,0 DISCHARGE LEG BREAKS 0,6 DE 0,8 DE-1,0 DE 1200,0 0
2,0 0,0 6,0 8,0 BREAK AREA, FT2 10,0