ML120170213

Incorporation of Westinghouse Model for Upper Plenum Injection in 1981 Evaluation Model Wreflood Code

ML120170213
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Site:	Point Beach
Issue date:	02/22/1983
From:	Westinghouse, Div of CBS Corp
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ML120170214	List: ML120170213 ML20071B448
References
NUDOCS 8302280312
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Text

INCORPORATION OF THE WESTINGHOUSE MODEL FOR UPPER PLENUM INJECTION IN THE 1981 EVALUATION MODEL WREFLOOD CODE

1.

INTRODUCTION.

2.

SUMMARY

OF MODEL.

3.

SUMMARY

OF RESULTS.

3.1 Base case and non-UPI.

3.2 Coverage sensitivities.

4.

CONCLUSIONS.

5.

REFERENCES.

6.

LIST OF TABLES AND FIGURES.

)

6.1 Base case and non-UPI.

6.2 Coverage sensitivities.

7.

FIGURES AND TABLES.

A 8302280312 830222 PDR ADOCK 05000266 P

PDR

LINCORPORATION OF THE "VIETIIGHOUSE 1-IODEL FOR UPPER PLE11UNI IN.JECTION' IN! THE 1 981 EVALUATION MODEL WTREFLOOD CODE

1.

INTRODUCTION.

The original design of 11estinghouse two-loop plants included both high head ECC injection into the hot legs and high or low head injection into the cold legs, so that no singl.e failure could defeat the ECC injection. Later, the hot leg injection was deleted and lines were re-routed to direct low head injection flow into the upper plenum, due to the possibility that steam generated in the core might, entrain ECC water injected into the hot leg.

The Westinghouse ECCS evaluation model for two-loop plants equipped with UPI originally assumed that water injected into the upper plenum did not interact with steam and entrained water rising from the core; the UPI water was therefore modeled as if delivered through a cold leg injection location. A more elaborate model for upper plenum injection has been described in the letter NS-TI1A-2172 (Reference 1), which forms the basis for the results reported here.

. 2.

SUMARY OF MODEL.

The model and associated FORTRAN coding for upper plenum injection

• escribed in the letter NS-TMA-2172 account for the following physical phenomena:

Metal-water heat transfer in the upper plenum, Core heat transfer and steam generation, Steam condensation, Entrainment (horizontal and vertical).

The metal heat release to UPI water from the upper plenum metal structures is calculated using a lumped thermal capacitance model for the metal structures.

The core heat transfer model assumes that the core is divided into two distinct regions, one region covered uniformly by UPI water and the other having no contact with UPI water. In the region covered by UPI water, the heat transfer is calculated based on decay heat removal above the top quench front, and decay heat plus stored energy removal in the unquenched portion of the core. The standard VIREFL.OOD heat transfer calculations are performed for the region of the core not covered by UPI water.

The steam generation rate from bottom reflood is calculated by adding the core heat release in the non-UPI region to the, carryover from bottom reflood.

If any subcooling remains in the UPI water after core heat is added, it is used to condense steam.generated from the water entering through the bottom of the core. Water falling into the core consists of steam condensed, plus any water entrained by this steam. The amount of condensation is limited to the total bottom steam flow in the UPI covered region, i.e., the UPI water is assumed not to interact with bottom steam in the region of the core not covered by UPI water.

The amount of water entrained vertically by the steam generated from the UPI water is calculated using a correlation based on the injection flow and steam generation rate; horizontal entrainment is assumed to be a constant 1.67 percent of the injected flow. The total steam generation due to upper plenum injection consists of steam generation due to UPI water-core interaction plus vertical and horizontal entrainment.

The UPI water which is not lost due to steam generation or entrainment is assumed to fall directly to the lower plenum.

A more detailed discussion of the UPI model utilized in this analysis is presented in Reference 1. -

'3. '

SUMMARY

OF RESULTS.

The Westinghoue upper plenum injection (UPI) model and FORTRAN coding described in letter NS-THA-2172 (Reference 1) was ncorporated in the 1981 Model version of the WREFLOOD code

• (References 2 and 3).

This UPI model is intrinsically based on the mass and energy core model described in the same letter. The results reported here are also based on the 1981 Model Version COCO, SATAN and LOCTA codes (References 2, 4, 5 and 6).

The 1981 evaluation model modified in this manner for upper plenum injection was used to analyze the effects of UPI on the 0.4 DECLG LOCA blowdown transient for Point Beach Unit 1.

Only the 0.4 CD break results are considered since this case has historically been limiting for two-loop plants and since the discharge coefficient should not greatly influence the comparison of upper plenum injection results with standard results.

3.1 Base case and non-UPI.

The results of this analysis for the base case (upper plenum coverage of 301) are shown in Tables 1-3 and Figures 1-12. A

'comparison of these results with those of the 1981 ECCS model (unmodified for upper plenum injection) for the same conditions (shown in Tables 1-3 and Figures 1-12),. shows that the UPI version predicts a considerable benefit in flooding rate. Despite a 1.63 second penalty in the UPI case BOC time due.to the assumption in i

the model of not adding top-injected water to the lower plenum during refill, the 1981 Model version with the UPI modeled predicts a 151 F benefit in PCT in comparison with results of the non-UPI case.

3.2 Coverage sensitivities.

The NS-TIA-2172 model was also run for core coverages of 50S, 70' and 100% to determine the sensitivity of the model to core coverage.

These results, shown in Tables 4-5 and Figures 13-19, predict an increase in PCT with increasing core coverage.

Both the 50% and 70% core coverage cases still show a benefit in calculated PCT in comparison with the non-UPI case (146F and 60F benefits, respectively), while the 100% coverage case shows a 130F penalty.

1L

4.

CONCLUSIONS e

S-T'MA-2172 model for upper plenum injection provides a benefit in calculated flooding rate and PCT when analyzing a minimum safeguards condition with 30% core coverage. In modeling UPI an important beneficial effect is the calculation of steam condensation, while a flooding rate penalty is the result of calculated steam generation. Steam generation is predominant during the early part of the transient; as the core cools, the UPI water subcooling is available to condense steam and steam condensation becomes more influential during the latter part of the transient. Increasing the core coverage accentuates the effect of steam generation and hence produces lower average flooding rates. NS-THA-2172 concluded on the basis of test results that 30% coverage is an upper bound for core coverage.

0II

5. REFERENCES

1. Anderson, T. 1., "Modifications to the ii ECCS evaluation model (February 1978 version) for two-loop upper plenum injection plants", NS-TMA-2172, December 6, 1979.

2. "Westinghouse ECCS Evaluation Model, 1981 Version",

XCAP-9220-P-A (Proprietary version), and NCAP-9221-P-A (Non-proprietary version), Revision 1, 1982.

3.

Kelly, R.D., et al., "Calculational Model for Core Reflooding after a Loss-of-Coolant Accident (WREFLOO Code)". WCAP-8170 (Proprietary Version), WCAP-8171 (Non-Proprietary Version), June 1974.

L.

Bordelon, F.M., and Murphy E.T., "Containment Presure Analysis Code (COCO)", WCAP-8327 (Proprietary Version), WCAP-8326 (Non-Proprietary Version), June 1974.

Bordelon, F.M., et al., "SATAN-VI Program: Comprehensive Space-Time Dependent Analysis of Loss-of-Coolant". WCAP-8302 (Proprietary Version),

WCAP-8306 (Non-Proprietray Version), June 1974.

6.

Bordelon, F.M., et al., "LOCTA-IV Analysis", WCAP-8301 (Proprietary Version), June 1974.

Program: Loss-of-Coolant Transient Version),.WCAP-8305 (Non-Proprietary w

I

6. LIST OF TABLES AND FIGURES 6.1 BASE CASE (30i coverage) AND NON-UPI TABLES

1. Time sequence of events, UPI and non-UPI.

2. Cladding parameters, UPI and non-UPI.

3.

Calculation assumptions.

FIGURES

1. Core pressure

2. Core pressure drop

3. Core flow, top and bottom

4. Break flow rate

5. Accumulator flow (during blowdown)

6. Fluid temperature.

a. UPI

b. non-UPI

7. Fluid quality.

a. UPI

b. non-UPI

8. Mass velocity.

a. UPI

b. non-UPI

9. Core and downcomer water levels.

a. UPI

b. non-UPI

10. Flooding rate.

a. UPI

b. non-UPI

11. Peak clad temperature.

a. UPI

b. non-UPI

12. Heat transfer coefficient.

a. UPI

b. non-UPI

'I I

5.

6.2 COVERAGE SENSITIVITIES TABLES Time sequence of events, 50M 70% and 1007 core coverage.

Cladding parameters, 50% 70% and 100' coverage.

FIGURES

13. Fluid temperature.

a. 50% b. 70% c. 100%

14.

Fluid quality.

a. 50% b. 70% c. 100%

15. I-ass velocity.

a. 50% b. 70% c. 100%

16. Core and downconer water levels.

a. 50% b. 70% c. 100%

17.-Flooding rate.

a. 50% b. 70% c. 100%

8. Peak cladding temperature.

a. 50% b. 70% c. 100%

19. Heat transfer coefficient.

a. 50% b. 70% c. 100%

TABLE 1 TI; Z SEQUENCZ OF EVEVTS --

DECLG CD = 0.4 0.0 Rx trip signal S. I. signal Acc. injection End of bypass End of blowdown Pump injection Bottom of core recovery (BOC)

0. 4ZO

0. V1 2.0. 3

.5. 31

+0. 2-509 Acc. empty (D. 42.0 3.57 zo. 3 23-3 81

33. 63

55. 7 Start 0.0 55.7?

TABLE 2 CLADDING PARAMETERS Peak clad temp, F PCT location, ft Local Zr/H20 reaction (max), %.

Location of max reaction, Total Zr/H20 reaction, %

Hot rod burst time, see Hot rod burst location, ft ft U.

-I0-1177

7. 2.5

1. 5/

7. ZS 1138 3.503 7.5 55.'

6..0 6.0

TABLE 3 CALCULATION ASSUMPTIONS NSSS power, 1t, 102' of Peak linear power, kw/ft, 102, of Peaking factor Acc. water volume, per tank, cubic feet Acc. pressure, psia Number of SI trains operating Steam generator tube plugging Z. 2.1 f/co

/4 /(70

-Il

TABLE 4 TIME SEQUENCE OF EVENTS -

DECLG CD = 0.4 Rx trip signal S. I. signal Acc. injection End of bypass End of blowdown Pump injection Bottom of core recovery (BOC)

Ace. empty 0.0 see,

().

$10)

g. 57 20.33 2 3.33 40.26 590. 211 0.0 0.4q ZO z3. 33

Z5. it

40. 2.6

55. 71 o*Co Zo 33 2-3' 2-S. PI

• 5-1 --

TABLE 5 CLADDING PARAMETERS Peak clad temp, F PCT location, ft Local Zr/H20 reaction (max), %

Location of max reaction, ft Total Zr/H20 reaction, S Hot rod burst time, sec Hot rod burst location, ft So% C~vt~~C 10o 7.

So 17.2S

/11 6'.0 41.,Zo 6.00 I

A

/. 85' 1.'13 6.00 6.00

/00 7o Zo 6:.

I. ZS

7. 25

3. 66 4 7.2 0 6.00 I

I

FIGURE 1 0

Core pressure I

a I

4 U.

U' U.

2 tiet SEC 2500.0 wo 1500.0 4*

1000.0 500.00 0.0 9

40 I

I 6

'11

I I

NJE1 3

U' ytMf 61CC)

. as.ooo Mo

r.

0.0

-o.c0 MA.N00 o!

FIGURE 3.

Core flow, top and bottom soe.0 08

.3

e.

.elIq at g

tnt esit

S.00t.0t S.00t*04 W.

2e.,o&o I.00( 0 0.0 I is I

1 4

1 lt SISECI

ICcftor 1c rm.o IFS0.0 "O 1500.0 a II.

750.00 soo.0o 0.0U 4I T

q o TIHE ISECI a

I.

F, g

Ii

FIGURE 6A Fluid temperature, UPI FLUt0 ff",

Atgua T.00 it t150.0 I 00.0 I1000.0 on 1I750.00 500.00 0.00 0.0 g

8 a

88 a

TIEt ESusD

FIGURE 6B Fluid temperature, non-UPI FLul1( TP(IAIuRE BURST.

6.00 o

)

P[AK.

1.50 ii.

C3 C O 0

8 0

C TIME8 4 TIME 4SECI

?000.'

S..

a..

C I50.09 1250.D I4 9z A.

d.

La I

S.a 1000.0 150.CD 500.(0 250. 0 0.0 Ct o

C3 a

ci

FIGURE 7A Fluid quality PI i1, PAs.

?

QUAL TY F F ul0SUR T*.00

.i ra -t t !!

F. 19 WS.

14 c a

&a oa c

o o

a 0ut

%SEq 1111222(~

1.o000 t.500

- 1.0000 O

3 0.5oo 0.5000 0.600 0.0 I

I.2500

.0000 3 0.7500 O.

b

.50 S0.500 0.0 I

I

FIGURE BA 50.000 ass velocity, UPI "V000 uts

.0 tA(

co 50.000 C3 U-100.00 40M.00 Timt IsEC)

FIGURE 8B C2 Cp M ~. UJUSO CD a a 3 C3 C),0-C C3*

S C)0C0C00X3 o> C, 0300C) 004p-1u JIM I(C a

C; C3 0>

C3 C;

a~ al a 00c~c C> 00000cc~

C) 9 99030 C3 C

0cc U- 00 V, o M C2 C!

C3 CD oa ci Cb C!

9 9 clcO*

Vo to 00000 I".

'5010o0 a

0.0

-54000 LI a

-j S..

"'-II I

3.00 0.00 440..00

FIGURE 9A Core and downcomer water levels, UPI 8

1s14 (Stc tec.o 0

.c.'oo 1?.50 tl.000 t?.500 10.000

?.500

.W 0.0 aa a

a

FIGURE 9B_____

20.000Core and downcomer water levels, non-UPI 11.5005 15.0000 10.00 C3 E

-D c

'C31

FIGURE 10A Flooding r, l.5000 1.2500 1.000

0. m O.WN O

e-o o

aMCI s

TiNet ISECl

0

?.0000 1.1500 1.50000

• 1500 0.0000 I0.600 0.0

FIGURE 11A

?500.0 Peak clad

(,TtMP.14O RO0

? 1500.0 CD o1000.0 a fto.

W 00.0 0.0 s.

9 10 temperature, UPI BURST* 6.00 itaP

• 50i S

TIME ISED)

I.

FIGURE 11B Peak clad temperature, non-UPI (tAD AVG.1IHP.0OI ROD URSI.

6.00 it I a

9 9

a; 9

I ON[ l ((

a C3 1000.0 0

Cs O

O

$500.0 o

1000.0 500.00 0.0 C:

C2 C%

9

FIGURE 12A mlardHeat trans 600.00 500.00

%.00.00 a

z 300.00

?00. 00 60.000 50.000 a 40.000 30.000...

- 0.000

.0000 5a ao 4 1000 3.0000

?.0000 t.0000 o

o0 fer coefficient, UPI URS?.

6.00 Pi C-Api 2

t a

S 9S

f.

TIME ISECI

FIGURE 12B Heat transfer coefficient, non-UPI 600. no HEAT IRANS.COMUI(I(NI1 SURSI.

6.00 FT( I PEAK.

153 fie 500.00

.40

~0.00 z300.00 200.00 60.000' 50.000 40.000 4A 30.000 2 0.000 5.0000 6.0000 3.0000 t.0000 1.0000 4C

FIGURE 13A Fluid temperature, fLl0 TEMPEATURE I

GUNSt.

6.00 Ftt )

PEA.

.?S FTIe I

I I

I I

I I

a 3 E

3.

I TInE Istc

?000.0 M150.0 a

a

'S Lit 1250.0 1000.0 1o.00 100.00 0.0 5o 70 Lab a

I- -

,-r-

FIGURE 13B Fluid temperature, 70%

LUID T[MP[AATURE sumst*

6*00 ft )

PEAK.

?* Y FI

?000.0 2 1750.0 1500.0 1250.0 a,.1000.0 10.00

~ 50.00 250.00 0.0 It R

le TINt ISEC

'707o

3.

3 I__

-I o

I.

C I

L--

q st

M00.0 1 1750.0 tas a

$25.0 S1000.0 I,

ooIo I

FIGURE 13C Fluid temperature, 10%

FLUID TIMP EATUtE IU.O 1 PE As. 7.25 FTe 4

I 1

I.

C I

I TIM IStI 2*

st H

P177 PS.00 4!

0D I

-- I I

FIGURE 141A Ct t tf 3 W;.i!t2s t.?500 te 1.0000 a

S0. m00 S..o 9.0 GUR Tf.

6.00 W tA.72 7*

FIGURE 14B Fluid quality, 70%

fTEt (Stti 1.4000 "a 0.500 1.000 30 o 0.500 0.0

1.4000 Fluid quality,10' OUALITY-Of FLU URT.*

t.2500 us7 ad

a. -a a

ust(St

FIGURE 15A 5o.ooo lIass velocity, 50%

MASS V(LOCITY BURST.

6.00 FTI I P(AK.

F.25 iTIOP

0.

-10000

-150.00

.400

@4 04 W; J I

s o oa

• *oo-a

• a T

e*

Tint ISECI

50.000 0.0

-50.000 30

-100.00 E

-150.00 400.00 FIGURE 15B Mass velocity, 707 MASS VEiOcIry I

SI, i--?-

jsUTn 6

I I I lI!III 1

I I itili L

~

i~

.1 -

I

• i

• I i I -

. i i i i W ow po a

n FTU 0

I 11a e1@

Tnf IStC N

PEA.15 FT4**

I I I 11111 LLLL I 1111N1.

~

2 I~S225~

I 4 /

I 0

I I I J

0.0 too

-1'0.00 a0

-M.00 0

0 0

00000 II Iue IS S

a

FIGURE 16A Core/downcomer water levels, 50%

L I

5o07o TINE (StC

?0.000 11.500 1S.000 10.000 S.0000 0.o I

i

~Ip...

U

.* 0 I

I Coe~~

E

FIGURE 16B Core/downcomer water levels, 70%

I U.

C tIME ISECI 2o.000 17.500 12.500 I?.00 F.00 2.50w 9.0S C!

40 i

I V

FIGURE 16C ae ees ocl Core/dowflcomer watrlvl,10 I

R 1c 20.000 V1.500 115.000 I?.500

.0 tIN! itEC f07

/007o 19 a

moor_--

?.00m I.7500 1.3000 I.2500 "1.00wo p.rso 0.0 e4sc eU 0

• FIGURE 17A Flooding rate, 50%

a

-- 0070 a

U I

TIME ISEC) a

?.0000 1.7500 1.5000 ma*

1.000

.- 0.1500 0.

TINE IStCi

z FIGURE 17C Flooding rate, 1000 I

I I

I

?.0000 1.2500 I.1500 0.000

.o I

I I

I 5

I I

I I

too O I

C TMEt ISECI V

C!

0 8

I 7z I--,"

FIGURE 18A Peak cladding temperature, 50%

CLAD AVC.TIMP.Hot ROD -IVW 00 FTI 3

a Plan.

?ts FTq*

• 200.0 tal a a

0 a

e 1000.0 4*

100.00 0.0 3 I TINt ISM 2500.0 507o

FIGURE 18B Peak cladding temperature, 70%

CLAD AVE.T(MOVpIT 000 eUST.

g.00 Fit I MA<* iaS t' rMoo.o

? 5000.0 ta M.

a C

0 15M00 o a 1000.0 0.0 I

I I

I I

I.

7007o a

I SS tpett(CI I

I I

I o

it t

I L-us

FIGURE 18C Peak cladding temperature, 100%

CLAD AVL.

INP***0 WOD URS..00 I

PtA U

I I

I I

I TIME ISCI

. ??5 F"I'e loo O, S

0

?5200.0*

Ca O

40 9..

o 03 I

1E st 77 V//////

I IV I

FIGURE 19A leat trans. coeff., 50",

MCAT TRAlo.C[FFIC[0T BUtST.

6.00 f I

PIAN*

1*FOFTI*I I

II I

600.00 500.00 4 400.00 a

z 300.00 W0.000 53 0.000 a 0.000

?0.000 3 2.0000 2.0000 1.0000 e.00

.m I

3.

U O

o 3 I TINE ISECI I I I

ILf_

3 U a

I

FIGURE 19B Heat trans. coeff.,, 701; EAT t f"ANS.COFILItNit URT-00 FT( I PEAS. 7.25 FYE**

TIE ISECI 600.00 500.00 Ia 300.00 "0000

~t M.00 60.000 50.000 4 0.000

'a 20.000 M

20.000 5.0000 4.w 3.0000 t.0000 1.0000 a

U I

5 S

1319 1

Ilid 00 O*9 I

g I oJ aoi 7:T I

I

£mIIJoIUu v.

%O

~

~

06 MOMo 3

sei~~i 3

S I

P 4b om*g O

OM*i o.4 OWNO rrw oo.~ I 00,00 PrM I.)lj U*L

.1 A