“integral pwr design natural circulation flow stability ... · 6 blind calculation for both tests...

“Integral PWR Design Natural Circulation Flow Stability and Thermal hydraulic

Coupling of Containment and Primary System during Accidents ”

SURENDRA KUMAR YADAV

RS&A Directorate, NPCIL, INDIA

3rd Workshop of IAEA-ICSP On 27 – 30 March 2012, Dejeon, Republic of Korea

1

CONTENT OBJECTIVE OF NPCIL PARTICIPATION

OSU MASLWR TEST FACILITY

THERMAL HYDRAULICS CODE USED IN ANALYSIS

ASSUMPTIONS USED IN THE ANALYSIS

NODALIZATION FOR MASLWR TEST FACILITY

EXPERIMENTAL PROCEDURE FOR SP-2 AND SP-3

INITIAL AND BOUNDARY CONDITION OF SP-2 & SP3

BLIND CALCULATION RESULTS OF SP-2


CONCLUSION

FUTURE WORK 2

3

• Improve understanding of natural circulation and other thermal

hydraulic phenomena expected to occur in integral type PWRs

• Evaluate system code capabilities to predict natural circulation

phenomena for integral type PWR, their practicality and efficiency,

by simulating an integrated experiment

• Suggest necessary code improvements or new experiments to

reduce uncertainties

Objectives of NPCIL Participation

• The experience gained during participation would be fruitful

in identifying strength and weaknesses of in house

developed computer code- “ATMIKA”.

4

OSU MASLWR Test Facility Exterior Pool, CPV

High Pressure Containment, HPC

Heat Transfer Plate

Riser

Helical Coil SG

Pressuriser

Core

5

• Integral pressurized light water reactor relying on natural circulation during both steady-state and transient operation

• Full pressure (11.4 MPa) and full temperature (590 K)

• 1:3 length, 1:254 volume, and 1:1 time scale

• Test Facility Includes:

– Reactor pressure vessel, RPV

– Helical coil steam generator, SG Coil

– Containment vessel, HPC

– Cooling pool Vessel, CPV

– Automatic depressurization system, ASD

– Data acquisition system for RPV, SG Coil, HPC and CPV

OSU MASLWR Test Facility

6

Blind calculation for both tests are performed using Thermal Hydraulic system code RELAP-5/MOD-3.2.

The RELAP5/MOD-3.2 code has been developed for best-estimate transient simulation of light water reactor coolant systems during postulated accidents.

The code includes many generic component models from which general systems can be simulated. The component models include pumps, valves, pipes, heat releasing or absorbing structures, reactor point kinetics, electric heaters, jet pumps, turbines, separators, accumulators, and control system components

The RELAP5 hydrodynamic model is a one-dimensional, two-fluid model for flow of a two-phase steam-water mixture that can contain non-condensable components in the steam phase and/or a soluble component in the water phase.

Thermal Hydraulics Code Used In Analysis

7

Assumptions used in the Analysis

• All SG Coil tubes lumped together.

• 56 cylindrical core rods are lumped together and modeled as representative single rod.

• Heat loss from HPC and CPV not considered.

• HPC is modeled as single tower instead of two towers as in double blind calculations.

• All ADS valves (PCS-106a, PCS-106b, PCS-108a and PCS-108b) are modeled as trip valves.

• For maintaining initial and boundary conditions time dependent volumes are used at SG inlet and outlet.

• Atmospheric temperature is considered as 25 0C.

8

Nodalisation Diagram for Blind

Predictions

9

Salient Features of Modeling/Nodalisation • To the extent possible, entire test facility has been simulated

as per the actual configuration.

• Size of the control volumes are selected such that it should give the proper representation of instruments.

• Logics for ADS Valve, pressuriser heater operation are as per procedure of Test.

• Heat Structures includes:- Core Heaters Pressuriser Heaters SG Coil Heat Transfer from Hot leg to Cold leg of RPV RPV Heat Loss Heat transfer Plate between HPC and CPV Heat structure for HPC

10

Experimental Procedure for SP-2 Objective : Conduct a loss of feed water transient with subsequent ADS Valve actuation and long term cooling to determine the progression of a loss of feed water transient in the OSU-MASLWR) test facility. Main Steps of Experiment

Establish Steady state condition with Core power level at 299+2 kW

Trip the Main Feed Water Pump

When PZR pressure reaches 1300 psig (8.963 MPa gage), Core Heater power starts on decay power mode.

Open ADS Valve-PCS-106A after18 s of initiation of Decay power

Continue ADS Valve PCS-106A operation as per logic

Open all other valve when DP between RPV and HPC is < 5 psig

Terminate Experiment when PPRZ < 75 psig or 5 Hours of elapsed

11

Experimental Procedure for SP-3 Objective : To conduct the experiment at various operating power levels in the OSU-MASLWR test facility.

Main Steps of Experiment

Establish Steady state condition with Core Power Level at 40 kW

Step up the Core Heater power to 80 kW and achieve steady state with saturated conditions at the SG outlet

Step up the Core Heater power to 120 kW and achieve steady state with saturated conditions at the SG outlet

Continue increase Stepwise core Heater power to 320 kW and achieve steady state

Terminate Experiment After Achieving Steady State with Core Power Level at 320kW.

12

Initial Condition of SP-2 Instrument Initial Condition in

Experiment of SP-2 Pressurizer Pressure MPa(a) 8.719 Pressurizer Level (m)– LDP-301 0.3607 Feed water Temperature (oC) – TF-501 21.39 Steam Outlet Temperature (oC)–TF-611 to 634 196.56 to 216.07 Steam Outlet Temperature (oC) – FVM-602T 205.38 Steam Pressure (MPa(a)) – PT-602 1.428 Steam Pressure (MPa(a)) – FVM-602P 1.411 HPC Pressure (MPa(a)) – PT-801 0.1255 HPC Water Level (m) – LDP-801 2.8204 HPC Temperature (oC)– TF-811 to TF-861 26.44 to 27.36 CPV Water Level (m)– LDP-901 635.03 Core Outlet Temperature (oC) – TF-106 251.52 Core Inlet Temperature (oC)–TF-121 to TF-124 214.82 to 215.11 Riser Outlet Temperature (OC) – TF-111 245.91 Primary SG Outlet Temp (oC) – TF-131 to 134 211.89 to 216.02 Pressurizer Steam Temperature (oC) – TF-301 302.69

Steady State Achieved

8.716 0.3584 21.36

204.01 204.01 1.427 1.427 0.128 2.827 27.0

635.09 257.85 222.57 256.61 221.66 301.16

13

Instrument Initial Condition in Experiment of SP-3

Steady State Achieved

Pressurizer Pressure (MPa(a)) – PT-301 8.718 8.718 Pressurizer Level (m) – LDP-301 0.3574 0.3583 Feed water Temperature (oC) – TF-501 31.49 31.65 Steam Outlet Temperature (oC) –TF-611 to TF634

242.62 to 261.09 260.45

Steam Outlet Temperature (oC) – FVM-602T

205.44 260.45

Steam Pressure (MPa(a)) – PT-602 1.464 1.465 Steam Pressure (MPa(a)) – FVM-602P 1.446 1.465 Core Outlet Temperature (oC) – TF-106 262.76 261.08 Core Inlet Temperature (oC) –TF-121 250.11 to 250.69 251.55 Riser Outlet Temperature (oC) – TF-111 261.13 260.85 Primary SG Outlet Temperature (oC) – TF-131 TO TF-134

251.07 to 254.52 251.32

Pressurizer Steam Temperature (oC) – TF-301

303.11 301.16

Initial Condition of SP-3

14

Core Heater power for steady state is 297.55 kW and for transient as observed in Experiment

Steam Pressure : 1.428 MPa (a)

Feedwater temperature : 21.21oC

Pressurizer pressure : 8.718 MPa(a)

Pressuriser Heater OFF on PPRZ >1300 Psig

SG coil Feed water flow rate : 0.11162 kg/s during steady state (assumed) to achieve steam superheat of around 15OF.

First Opening of ADS Valve-106A at 48 s after Feed Pump Trip and thereafter ADS valve open/closes as per test logics.

Operation of Valve PCS-106B, 108A, 108B and SV-800 are simulated as per the test procedure.

Boundary Condition of SP-2

15

Core Heater power for steady state is 40.0 kW and for transient as observed in Experiment

Steam Pressure : 1.465 MPa (a)

Feed water temperature : 21.3oC to 31.5oC

Pressurizer pressure : 8.718 MPa(a)

SG coil Feed water flow rate is used as given in BC Table

SG coil Outlet Temperature is used as given in BC Table

ADS Valve PCS-106A&B, 108A, 108B and SV-800 are Closed throughout the transient.

Boundary Condition of SP-3

16

0.0 4000.0 8000.0 12000.0 16000.0

0.0

10.0

20.0

30.0

40.0

HEA

TER

PO

WER

(kW

)

LEGENDEXPERIMENTAL POWERDECAY POWER SIMULATED

Fig.-2 HEATER POWER AFTER 30 SECOND OF FEED PUMP STOPPED

RELAP-5/MOD-3.2 : SIMULATION OF MASLWR TEST FACILITYTEST : SP-2

-2000.0 -1000.0 0.0 1000.0 2000.0 3000.0 4000.0 5000.0 6000.0TIME (Sec.)

0.0

100.0

200.0

300.0

400.0

HEA

TER

PO

WER

(KW

)

LEGENDEXPERIMENTAL DATAUSED IN MODELING

Fig.- 3 HEATER POWER IN TEST SP-3


-2000.0 -1000.0 0.0 1000.0 2000.0 3000.0 4000.0 5000.0 6000.0TIME (Sec.)

0.000

0.040

0.080

0.120

FEED

FLO

W (K

g/Se

c.)

LEGENDEXPERIMENTAL DATAUSED IN MODELING

Fig.- 4 SG COIL FEED FLOW DURING THE EXPERIMENT OF SP-3


Graphical representation of Heater Power in Experiment and Used in Analysis

17


Event Sequence of Events Time (s)

Experiment Calculation Start of simulation – steady state 0.0 0.0

Stop MFP & Close HPC vent valve SV-800 0.0 0.0

PZR pressure reaches 9.064 MPa(a) (1300 psig) Enter decay power mode

28.0 28.0

PZR pressure reaches 9.409 MPa(a) (1350 psig) De-energize PZR heaters & Open ADS vent valve (PCS-106A)

48.0 48.0

Record opening and closing times for PCS-106A Record opening and closing times for SV-800 Never opened Never opened Start long-term cooling when DP between RPV and HPCbecomes less than 5 psi (0.034 MPa) Open and remain open of PCS-106A and PCS-106B Open and remain open of PCS-108A and PCS-108B

4024 4114 s PCS-106B 4116 s PCS-108A 4117 s PCS-108B

4780 All PCS valve open simultaneously

End of test when - PZR pressure ≤ 0.617 MPa(a) (75 psig) - 5 hours have elapsed

Not Specified 14360

Sequence of Event of SP-2

18

FIG. 3.1.1 SECONDARY SIDE (SG COIL) FEED WATER FLOW

-4000 0 4000 8000 12000 16000TIME (Sec.)

-0.040

0.000

0.040

0.080

0.120

FL

OW

(K

g/S

.)RELAP-5/MOD-3.2 : SIMULATION OF MASLWR TEST FACILITY

TEST : SP-2

FIG. 3.1.2 RPV PRESSURE PT-301(Pa)

0 200 400 600 800 1000TIME (Sec.)

2.0E+006

4.0E+006

6.0E+006

8.0E+006

1.0E+007

PRES

SUR

E (P

a)


FIG. SG COIL OUTLET PRESSURE PT-602

-4000 0 4000 8000 12000 16000TIME (Sec.)

1.40E+006

1.41E+006

1.42E+006

1.43E+006

PRE

SSU

RE

(Pa

)

RELAP5 : SIMULATION OF MASLWR TEST FACILITYTEST : SP-2

FIG. 3.1.5A RPV TEMPERATURE AT VARIOUS LOCATIONS

0 100 200 300 400TIME (Sec.)

480.0

500.0

520.0

540.0

560.0

580.0

TEM

PER

ATU

RE

(K)

LEGENDCORE OUTLETCORE INLETDOWNCOMER OUTLETCHIMNEY OUTLETPRZ TOP


19


-4000 0 4000 8000 12000 16000TIME (Sec.)

0.0E+000

2.0E+006

4.0E+006

6.0E+006

8.0E+006

1.0E+007

PRES

SUR

E (P

a)RELAP-5/MOD-3.2 : SIMULATION OF MASLWR TEST FACILITY

TEST : SP-2

Fig. 3.1.6 PRESSURE IN HPC, PT-801 (Pa).

-4000.0 0.0 4000.0 8000.0 12000.0 16000.0-2000 2000 6000 10000 14000

Time( sec)

0.0E+000

4.0E+005

8.0E+005

1.2E+006

1.6E+006

2.0E+006

200000.0

600000.0

1000000.0

1400000.0

1800000.0

PRES

SUR

E (P

a)


FIG. 3.1.5B RPV TEMPERATURE AT VARIOUS LOCATIONS

-4000 0 4000 8000 12000 16000TIME (Sec.)

400.0

440.0

480.0

520.0

560.0

600.0

TEM

PER

ATU

RE

(K)



Fig. 3.1.8 TEMPERATURE IN HPC AT DIFFERENT ELEVATIONS.

-4000.0 0.0 4000.0 8000.0 12000.0 16000.0-2000 2000 6000 10000 14000

Time( sec)

250.0

350.0

450.0

550.0

300.0

400.0

500.0

TEM

PER

ATU

RE

( K )

LEGENDTF-811TF-821TF-831TF-841TF-851TF-861


20

FIG. 3.1.16 PRIMARY MASS FLOW RATE

-4000 0 4000 8000 12000 16000TIME (Sec.)

-2.0

0.0

2.0

4.0

6.0

MA

SS F

LO

W R

AT

E (K

g/S)

LEGENDFLOW IN CHIMNEYFLOW IN DOWNCOMER


Fig. 3.1.10 PRIMARY MASS INVENTORY (Kg)

-4000.0 0.0 4000.0 8000.0 12000.0 16000.0-2000 2000 6000 10000 14000

Time( sec)

120.0

160.0

200.0

100

140

180

RPV

MA

SS IN

VEN

TOR

Y (K

G)


Fig. 3.1.14 VOID FRACTION IN RPV AT DIFFERENT LOCATIONS

-4000.0 0.0 4000.0 8000.0 12000.0 16000.0-2000 2000 6000 10000 14000

Time( sec)

0.0

0.4

0.8

1.2

0.2

0.6

1.0

VOID

FR

AC

TIO

N LEGENDCORE-OUTUPPER-PLENUMSG INLETSG-OUTLET


FIG. 3.1.15 DIFFERENTIAL PRESSURE ACROSS VARIOUS LOCATIONS OF RPV

-4000 0 4000 8000 12000 16000TIME (Sec.)

0.0

10000.0

20000.0

30000.0

DIF

F. P

RES

SUR

E (P

a)

LEGENDDP-COREDP-CHIMNEYDP-SG-DOWNCOMER


21

Fig. 53.1.11 FLOW THROUGH ADS VALVES, PCS-106A

0.0 1000.0 2000.0 3000.0 4000.0 5000.0500.0 1500.0 2500.0 3500.0 4500.0

Time( sec)

0.00

0.10

0.20

0.30

0.40

0.05

0.15

0.25

0.35

MA

SS F

LOW

RA

TE (

Kg/

S )


Fig. 3.1.18 FLOW THROUGH ADS VALVES, PCS-106A, 106B, PCS-108A AND PCS-108B

-4000.0 0.0 4000.0 8000.0 12000.0 16000.0-2000.0 2000.0 6000.0 10000.0 14000.0

Time( sec)

-0.10

0.00

0.10

0.20

0.30

0.40

-0.05

0.05

0.15

0.25

0.35

MA

SS F

LOW

RA

TE (

Kg/

S )

LEGEND106-A106-B108-A108-B


Fig. 53.1.25 FLOW THROUGH RELIEF VALVE, SV-800 (kg/s)

-4000.0 0.0 4000.0 8000.0 12000.0 16000.0-2000.0 2000.0 6000.0 10000.0 14000.0

Time( sec)

-0.40

-0.20

0.00

0.20

0.40

-0.30

-0.10

0.10

0.30

MA

SS F

LOW

RA

TE (

Kg/

S )


Fig.3.1.24 CUMULATIVE FLOW THROUGH ADS VALVES, PCS-106A & B, PCS-108A AND PCS-108B

-4000.0 0.0 4000.0 8000.0 12000.0 16000.0-2000 2000 6000 10000 14000

Time( sec)

-40.0

0.0

40.0

80.0

-20.0

20.0

60.0

CU

MM

ULA

TIVE

DIS

CH

AR

GE

( Kg) LEGEND

106-A106-B108-A108-B


22

Fig. 3.1.8 TEMPERATURE IN HPC AT DIFFERENT ELEVATIONS.

-4000.0 0.0 4000.0 8000.0 12000.0 16000.0-2000 2000 6000 10000 14000

Time( sec)

250.0

350.0

450.0

550.0

300.0

400.0

500.0

TEM

PER

ATU

RE

( K )



Fig. 3.1.12 TEMPERATURE IN HEAT TRANSFER PLATE AT DIFFERENT ELEVATIONS.

-4000.0 0.0 4000.0 8000.0 12000.0 16000.0-2000 2000 6000 10000 14000

Time( sec)

250.0

350.0

450.0

550.0

300.0

400.0

500.0

Tem

pera

ture

( K

)



Fig. 3.1.13 TEMPERATURE IN HEAT TRANSFER PLATE AT DIFFERENT ELEVATION.

-4000.0 0.0 4000.0 8000.0 12000.0 16000.0-2000 2000 6000 10000 14000

Time( sec)

300.0

320.0

340.0

360.0

380.0

310.0

330.0

350.0

370.0

Tem

pera

ture

( K

)

LEGENDTF-814TF-824TF-834TF-844TF-854


Fig. 3.1.9 TEMPERATURE IN CPV AT DIFFERENT ELEVATIONS.

-4000.0 0.0 4000.0 8000.0 12000.0 16000.0-2000 2000 6000 10000 14000

Time( sec)

280.0

320.0

360.0

300

340

Tem

pera

ture

( K

)

LEGENDTF-815TF-825TF-835TF-845TF-855


23

Fig. 3.1.12 TEMPERATURE IN HPC, HEAT TRANSFER PLATE AND CPV AT 6.99 EL .

-4000.0 0.0 4000.0 8000.0 12000.0 16000.0-2000 2000 6000 10000 14000

Time( sec)

250.0

270.0

290.0

310.0

330.0

350.0

260.0

280.0

300.0

320.0

340.0

Tem

pera

ture

( K

)

LEGENDTF-811TF-812TF-814TF-815



-4000.0 0.0 4000.0 8000.0 12000.0 16000.0-2000 2000 6000 10000 14000

Time( sec)

250.0

270.0

290.0

310.0

330.0

350.0

260.0

280.0

300.0

320.0

340.0

Tem

pera

ture

( K

)



Fig. 3.1.12 TEMPERATURE IN HPC, HEAT TRANSFER PLATE AND CPV AT 227 EL .

-4000.0 0.0 4000.0 8000.0 12000.0 16000.0-2000 2000 6000 10000 14000

Time( sec)

250.0

290.0

330.0

370.0

410.0

450.0

270.0

310.0

350.0

390.0

430.0

Tem

pera

ture

( K

)



Fig. 3.1.12 TEMPERATURE IN HPC, HEAT TRANSFER PLATE AND CPV AT 317 EL .

-4000.0 0.0 4000.0 8000.0 12000.0 16000.0-2000 2000 6000 10000 14000

Time( sec)

250.0

300.0

350.0

400.0

450.0

500.0

275.0

325.0

375.0

425.0

475.0

Tem

pera

ture

( K

)



24

Fig 3 1 19 HEAT LOSS FROM RPV (W)

-4000.0 0.0 4000.0 8000.0 12000.0 16000.0-2000 2000 6000 10000 14000

Time( sec)

0.0

400.0

800.0

200.0

600.0

1000.0

HEA

T LO

SS (W

)


Fig. 3.1.22 HEAT TRANSFER HOT LEG TO COLD LEG ACROSS CHIMNEY (kW)

-4000.0 0.0 4000.0 8000.0 12000.0 16000.0-2000 2000 6000 10000 14000

Time( sec)

-6.0

-2.0

2.0

6.0

-4.0

0.0

4.0

HEA

T TR

AN

SFER

(kW

)



-4000.0 0.0 4000.0 8000.0 12000.0 16000.0-2000 2000 6000 10000 14000

Time( sec)

250.0

300.0

350.0

400.0

450.0

500.0

275.0

325.0

375.0

425.0

475.0

Tem

pera

ture

( K

)


Fig. 3.1.20 CORE POWER (kW)

-4000.0 0.0 4000.0 8000.0 12000.0 16000.0-2000.0 2000.0 6000.0 10000.0 14000.0

Time( sec)

0.0

100.0

200.0

300.0

50.0

150.0

250.0

CO

RE

POW

ER (k

W)

25

FIG. 3.1.3 WATER LEVEL IN RPV, LDP-106 (m)

-4000 0 4000 8000 12000 16000TIME (Sec.)

2.4

2.8

3.2

3.6

4.0

4.4

RP

V L

EV

EL

(m

)RELAP-5/MOD-3.2 : SIMULATION OF MASLWR TEST FACILITY

TEST : SP-2

FIG. 3.1.4 WATER LEVEL IN PRESSURISER, LDP-301 (m)

-4000 0 4000 8000 12000 16000TIME (Sec.)

0.00

0.10

0.20

0.30

0.40

0.50

RPV

LEV

EL (m

)


Fig. 3.1.7 WATER LEVEL IN HPC, LDP-801 (m)

-4000.0 0.0 4000.0 8000.0 12000.0 16000.0-2000.0 2000.0 6000.0 10000.0 14000.0

Time( sec)

2.4

2.8

3.2

3.6

4.0

2.6

3.0

3.4

3.8

LEVE

L (m

)


Fig. 3.1.23 WATER LEVEL IN CPV, LDP-901 (m).

-4000.0 0.0 4000.0 8000.0 12000.0 16000.0-2000.0 2000.0 6000.0 10000.0 14000.0

Time( sec)

4.0

5.0

6.0

7.0

8.0

4.5

5.5

6.5

7.5

LEVE

L (m

)


26

Discussion on Results of SP-2

• Initiation of loss of feed water transient results thermosyphoning break down

• Pressure and Temperature of RPV at all locations increases. While temperature of cold leg of RPV is increases relatively faster as compared to hot leg but relatively lower temperature water remains at the bottom.

• Subsequently cold leg temperature also approaches to hot leg temperature

• RPV flow reduces form 1.8 kg/s to 1.6 kg/s before conversion of heater power mode to decay mode. RPV flow further reduce to around 1.0 kg/s before opening of ADS Valve.

• No super heating of primary coolant

27


• Core remains well cooled throughout the transient • With steam discharge to containment its temperature

increases at top nodes only • CPV temperature remains in sub-cooled state throughout the

transient

28

FIG. HEAT TRANSFER FROM CORE ROD IN W

-2000 0 2000 4000 6000 8000TIME (Sec.)

0.0E+000

1.0E+005

2.0E+005

3.0E+005

4.0E+005

PO

WE

R (W

)RELAP5 : SIMULATION OF MASLWR TEST FACILITY

TEST : SP-3

FIG.3.2.2 SECONDARY SIDE FEED WATER FLOW

-2000 0 2000 4000 6000 8000TIME (Sec.)

0.000

0.040

0.080

0.120

FLO

W (K

G/S

EC.)



-2000 0 2000 4000 6000 8000TIME (Sec.)

8.0E+006

8.4E+006

8.8E+006

9.2E+006

PRES

SUR

E (P

a)


FIG. 3.2.4 RPV TEMPERATURE AT VARIOUS LOCATIONS

-2000 0 2000 4000 6000 8000TIME (Sec.)

480.0

500.0

520.0

540.0

560.0

580.0

TEM

PER

ATU

RE

(K)



29

FIG. 3.2.5 WATER LEVEL IN RPV, LDP-106 (m)

-2000 0 2000 4000 6000 8000TIME (Sec.)

4.000

4.050

4.100

4.150

4.200

4.250

RPV

LE

VE

L (

m)


FIG.3.2.6 WATER LEVEL IN PRESSURISER, LDP-301 (m)

-2000 0 2000 4000 6000 8000TIME (Sec.)

0.200

0.250

0.300

0.350

0.400

0.450

RPV

LEV

EL (m

)


FIG. 3.2.7 PRIMARY MASS FLOW RATE

-2000 0 2000 4000 6000 8000TIME (Sec.)

0.8

1.0

1.2

1.4

1.6

1.8

2.0

MA

SS F

LOW

RA

TE (K

g/S)

LEGENDFLOW IN CHIMNEYFLOW IN DOWNCOMER


FIG. 3.2.11 DIFFERENTIAL PRESSURE ACROSS VARIOUS LOCATIONS OF RPV

-2000 0 2000 4000 6000 8000TIME (Sec.)

0.0

4000.0

8000.0

12000.0

16000.0

20000.0

DIF

F. P

RES

SUR

E (P

a)

LEGENDDP-COREDP-CHIMNEYDP-SG-DOWNCOMER


30

FIG. 3.2.12 STEAM OUTLET FLOW FVM-602-M (Kg/s)

-2000 0 2000 4000 6000 8000TIME (Sec.)

0.00

0.10

0.20

0.30

STEA

M F

LOW

RA

TE (K

g/S)


FIG.3.2.13 SG COIL OUTLET TEMPERATURES, FVM-602-T (K)

-2000 0 2000 4000 6000 8000TIME (Sec.)

460.0

480.0

500.0

520.0

540.0

560.0

TEM

PER

ATU

RE

(K)


FIG.3.2.14 SG COIL INLET PRESSURE PT-511 TO PT-531 (Pa)

-2000 0 2000 4000 6000 8000TIME (Sec.)

1.40E+006

1.44E+006

1.48E+006

1.52E+006

1.56E+006

1.60E+006

PRES

SUR

E (P

a)


FIG.3.2.10 PRIMARY MASS INVENTORY (RPV)

-2000 0 2000 4000 6000 8000TIME (Sec.)

0.0

40.0

80.0

120.0

160.0

200.0

INV

EN

TO

RY

(K

g)


31

Fig. 3.2.8 VOID FRACTION IN RPV AT DIFFERENT LOCATIONS

-2000.0 0.0 2000.0 4000.0 6000.0 8000.0-1000 1000 3000 5000 7000

Time( sec)

0.0

0.4

0.8

0.2

0.6

1.0

VOID

FR

AC

TIO

N

LEGENDCORE-OUTUPPER-PLENUMSG INLETSG-OUTLET


FIG.3.2.15 HEAT TRANSFER FROM HOT LEG TO COLD LEG ACROSS CHIMNEY IN W

-2000 0 2000 4000 6000 8000TIME (Sec.)

-5000.0

-4000.0

-3000.0

-2000.0

-1000.0

0.0

1000.0

HE

AT

TR

AN

SFE

R (W

)RELAP-5/MOD-3.2 : SIMULATION OF MASLWR TEST FACILITY

TEST : SP-3

FIG. 3.2.16 HEAT TRANSFER FROM RPV TO SG COIL IN kW

-2000 0 2000 4000 6000 8000TIME (Sec.)

-400.0

-300.0

-200.0

-100.0

0.0

HE

AT

TR

AN

SFE

R (k

W)


FIG. 3.2.9 HEAT LOSS FROM RPV TO AMBIENT IN W

-2000 0 2000 4000 6000 8000TIME (Sec.)

600.0

640.0

680.0

720.0

760.0

HE

AT

TR

AN

SFE

R (W

)


32

Discussion on Results of SP-3 • As Heater power in primary side increases, RPV pressure

increase to around 9.1MPa due to less effective heat transfer to secondary side

• Natural circulation flow follows the heater power, flow increases from 0.85 kg/s to 1.82 kg/s during the transient

• During pressure rise of RPV, hot leg temperature increases more compared to cold leg temperature, whereas vice verca when pressure reduction.

• RPV level first increase to around 4.3 m then reduces to around 4.03 m before settling to around 4.08 m (lower than steady state level).

• No voiding in RPV • Core remains well cooled throughout the transient

33

Future Work • Modeling of three banks of SG Coils

• Modeling HPC shell heater

• Incorporation of check valve or other modeling mechanism to restrict SG steam back flow

• Any other feature identified

S. K. Yadav NPCIL, MUMBAI, INDIA 91-9869317249 (Mobile) 91-22-25995091 (Office)

34

35

S. No.

Valve-106A Operation in Experiment Valve-106A Operation in Code Prediction

Open (s) Close (s) Open (s) Close (s) 1. 48.00 131.00 48 156 2. 165.00 175.00 173 188 3. 222.00 231.00 217 229 4. 287.00 295.00 271 281 5. 359.00 367.00 341 351 6. 434.00 443.00 423 433 7. 512.00 520.00 512 522 8. 591.00 599.00 605 614 9. 670.00 678.00 701 710 10. 750.00 758.00 798 807

43. 3617.00 3632.00 4305 4317 44. 3715.00 3731.00 4424 4426 45. 3814.00 3832.00 4543 4555 46. 3917.00 3938.00 4657 4670 47. 4024.00 Remains Open 4780 Remains Open

“integral pwr design natural circulation flow stability ... · 6 blind calculation for both tests...

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