framatome anp - swr-1000: nrc-visit - preparation of the ...results of the mass flow balances...

SWR-1000: NRC-Visit

Preparation of the External Vessel Cooling Test

SWR 1000 - Exterior Vessel Cooling

Inlet of the water inthe gap betweenRPV and insulation

Decoupling of Flow Conditions and Heat Transfer

Water / Air-Experiments Scale 1 : 10Investigation of the global flow conditions anddetermination of requirements for the design of asegment

Water / Air-Experiments with a SectionDesigning of in- and outlets in order to reach asimilar flow behaviour as in the global model

Water / Steam-Experiments with a SectionMeasuring the Critical Heat Flux in a 1:1section model installed in the BENSON test rig- a flexible water / steam test loop

Global Model

Setup of the RPV:

• Air injection through aporous structure atthe bottom

• Eight chambers withadjustable air supply

Setup of the insulation:

• Transparent materialincluding CRD andpump housings

• Impedance probes formeasuring theadequate gas height

• Fiber optic probe formeasuring the void

Phenomenology

• Circulation can be observedThe water / gas mixture will move upwards and willbe separated at the swell level. The water will flowback

• Counter current flow can be observed at the bottomThe water/air mixture flows upwards around theRPV, single-phase water flows downwards aroundthe insulation. A portion penetrates in the water/airmixture

• Flow is approximately rotational symmetric

• Bubbles in the water/air test grow approximatelysimilar to those of boiling tests

• Rotational symmetric slug bands will be formed. Inthe case of flow without insulation, they are strongerthan in the case with insulation

• b

Phenomenology - Global Model in Operation

Phenomenology - Counter Current Flow

Phenomenology - Flow around the CRD Housings

Phenomenology - Movement of Bubbles

Fiber Optic Probe

Local Void Fraction Determination

0

0.2

0.4

0.6

0.8

1

0 1 2 3 4 5 6 7 8 9 10 11 12 13

Distance [mm]

Vo

id F

ract

ion

[-]

1,5

2

2,5

3

3,5

4

V o

l t g

e [ V

]

1,5

2

2,5

3

3,5

4

V o

l t a

g e

[ V

]

1,5

2

2,5

3

3,5

4

V o

l t a

g e

[ V

]

Time [s] →

Local Void Fractions at different Inclinations

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0 2 4 6 8 10 12 14 16

Distance from RPV [mm]

Lo

cal V

oid

Fra

ctio

n [

-]

Inclination 7°Inclination 21°

Dimension and Positions of the Probes

Average Gas Height measured with Fiber Optic Probe and Impedance Probe

0

1

2

3

4

5

0 50 100 150 200 250

Gas Mass Flow [kg/h]

Gas H

eig

ht [m

m]

Fiber Optical Probe= dh0

0.2

0.4

0.6

0.8

1

0 1 2 3 4 5 6 7 8 9 10 11 12 13

Distance [mm]

Vo

id F

ract

ion

[-]

∫

Impedance Probe

Gas Height Distribution

0,0 3,6 7,2 10,8 14,4 18,0 21,6 25,20,0

3,6

7,2

10,8

14,4

18,0

21,6

25,2

9 -10

10-11

[mm]Height

0 - 1

1 - 2

2 - 3

5 - 6

3 - 4

4 - 5

6 - 7

7 - 8

8 - 9

Decay HeatAdequate Gas Height at a Mass Flux of Y

Axi

s [c

m]

X Axis [cm]

Adequate Gas height between CRD Housing No. 128 and No. 129 (5 -6 mm)

0,0 3,6 7,2 10,8 14,4 18,0 21,6 25,20,0

3,6

7,2

10,8

14,4

18,0

21,6

25,2

9 -10

10-11

[mm]Height

0 - 1

1 - 2

2 - 3

5 - 6

3 - 4

4 - 5

6 - 7

7 - 8

8 - 9

Decay HeatAdequate Gas Height at a Mass Flux of Y

Axi

s [c

m]

X Axis [cm]

Adequate Gas height between CRD Housing No. 131 and No. 132 (6 -7 mm)

Positions of the LDA Measurements

Velocity Distribution as the Function of the Height

-0.15

-0.05

0.05

0.15

0.25

0.35

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

Dimensionless Distance [-]

No.132 and Position M

No.131 and No.132

No.130 and No.131

No.129 and No.130

No.128 and No.129

Local Velocities

-0.15

-0.05

0.05

0.15

0.25

0.35

0 0.2 0.4 0.6 0.8 1


Approximation curve between CRD Housing No. 128 and No. 129

Corrected measurement curve based on a Gaussian probability

Estimated local velocity distribution

Water Mass Flow Balance

-0.12

-0.1

-0.08

-0.06

-0.04

-0.02

0

0.02

0 0.1 0.2 0.3 0.4 0.5 0.6


-0.05

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95


( ) ( ) ( )( )

( ) ( ) ( )( ) bvvxxM

bvvxxM

velocitiespositivewithareathein

positionsofNumber

iLiiiiiioutW

velocitiesnegativewithareathein

positionsofNumber

iLiiiiiiinW

−⋅+−⋅−=

=−

−+−−=

∑

∑

−

=+++

−

=+++

1

1111;

!1

1111;

2111

)1(21

11

ρεε

ρεε

&

&

Gas Mass Flow Balance

0

0.1

0.2

0.3

0.4

0.5

0.6

0.0000 0.0050 0.0100 0.0150 0.0200 0.0250

Air Mass Flow [kg/s]

Vo

id F

ract

ion

[-]

between CRD Housing No. 128 and No. 129


0.35

0.28

0.0049 0.0094

2h

hG=ε

Results of the Mass Flow Balances

Kammerung zur Lufteindüsung

Pos. 131-132 Pos. 128-129

Border of air injection chambers

Pos. 131-132 Pos. 128-129

Position 128-129 Position 131-132

Water Mass Flow, Inlet [kg/s] 1,19 1,36

Water Mass Flow, Outlet [kg/s] 1,40 1,59

Ratio Water Mass Flow Out/In 1,18 1,17

Air Mass Flow, Injected [kg/s] 0,0043 0,0085

Air Mass Flow, Acc. Fig. 13[kg/s] 0,0049 0,0094

Ratio Out/In 1,14 1,11

Decoupling of Flow Conditions and Heat Transfer

Water / Air-Experiments Scale 1 : 10Investigation of the global flow conditions anddetermination of requirements for the design of asegment

Water / Air-Experiments with a SectionDesigning of in- and outlets in order to reach asimilar flow behaviour as in the global 1 : 1 model

Water / Steam-Experiments with a SectionMeasuring the Critical Heat Flux in a 1:1Section Model installed in the BVS - a flexibleWater / Steam-Test Loop

Scaling Procedure and Intention

Steam generation

Air injection

Procedure:

•Void measurements in the model

•Approximation of drift flux correlation parameters

•Calculation of the void fraction based on the new correlation

•Calculation of the air mass flow with similar void fraction

Inlet of the waterin the gapbetween RPV andinsulation

Void Fraction Measurement Method

1,1Φl 1,2Φl 2,1Φl 2,2Φl

( ) ( )( ) ( ) )( 2,11,12,12,21,11,2

2,12,21,11,2

ΦΦΦΦΦΦ

ΦΦΦΦ

−+−−−−−−

=llllll

llllε

Measured Void Fraction and Developed Correlation

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

0 0.002 0.004 0.006 0.008 0.01 0.012 0.014

Mass Flow [kg/s]

Void

Fra

ctio

n [-]

Experiment

Drift-FluxC0 = 3,03654

0,25

2l

glgi ñ

)ñ(ñ*g*ó*0,77575u

−=

1

..hom

0

*

*

−

+=mx

uC gigρε

ε

1

.

25,0

2

)(***77575,0*

03654,3

−

−

+=m

g

l

glg ρ

ρρσρ

ε

Mass Flows for the Tests with the Global Model

125,0

2

/

(***77575,0*

03654,3

−

−

+=AM

g

g

l

gig

&ρ

ρρσρ

ε

SWR 1000, Original

• Properties of Water/Steam (P =2-5 bar)

• Mass flux (P =2-5 bar, Q =4,5;9;13,5 MW)

SWR 1000, Model

• Properties of Water/Air (P=1 bar)

• Void (ε =0,16;0,24;0,28)

Void εAir Mass Flow

Q P 2 [bar] 3 [bar] 4 [bar] 5 [bar]4.5 [MW] 0.2224 0.1956 0.1777 0.1598

9 [MW] 0.2655 0.2454 0.2309 0.2152

13,5 [MW] 0.2839 0.2682 0.2564 0.2433

Void ε M [kg/s]

0.16 0.0100.24 0.0290.28 0.061

Kammerung zur Lufteindüsung

Comparison of Void Trends - Model (Air 1 bar) and „Original“ (Steam 3 bar)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5

Steam Mass Flow [kg/s]

vertical flow path



0

0.1

0.2

0.3

0.4

0.5

0.6

0.000 0.005 0.010 0.015 0.020 0.025 0.030

Air Mass Flow [kg/s]

Vo

id F

ract

ion

[-]

Corresponding mass flows according mass sources

(injection / evaporation) for the 100% decay heat case

Measurement of Safety Margins

M

M

M

M

M

Test Vessel

Heater

TrickleCooler

Piston Pump

ReductionValve

Heater

Feedwater CirculationPump

Pressurizer

Main Cooler

Spray Condensor

Aim of the experiments:

Measurement of the Critical Heat Fluxabove decay heat

Procedure:• Implementation of a 1:1 scaled segment

in the BVS by considering the in- andoutflow conditions evaluated from thewater / air - experiments

• Instrumentation of the RPV-wall withthermocouples in order to identify thelocation of the boiling crisis (CHF)

• Adjusting the mass flow in such a waythat the feed water mass flow is equal tothe evaporated

• Increasing the heat input stepwise until aboiling crisis-occurred or a relevant safetymargin is reached.

Conclusions and Consequences

• The natural circulation inside the gap between theinsulation and RPV is very strong - compared to thewater supply of the external circulation. Thus, it isnecessary to simulate the internal circulation in awater steam experiment.

• The flow experiments indicate almost rotational symmetricflow conditions.

The effect of flow and heating conditions is unknown, whichmight be influenced by the flow orientation from the centreposition:

• The effect of a straight-line configuration will be lower flowresistance - compared to a non-straight-line configuration -and herewith a higher mass flows in this area.

• The effect of a non-straight-line configuration will be a betterheat transfer behaviour - compared to a straight line configuration.

Conclusion: There will be no significant cross flow between thedifferent orientations if the flow conditions are almost similar forboth extreme configurations. In this case it is conservative touse the straight line configuration for a heatable test section.

Straight-Line Configuration

Non-Straight-LineConfiguration

Global and Section Model Measurements

-0.15

-0.05

0.05

0.15

0.25

0.35

0.45

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

X Dimensionless Distance [-]

Global Model

Section Model

Global Model

Section Model

Heatable Section Model - Top View

Bordersof a comparable section

Heatable Section Model - Side View

Heatable Section Model - Heating Concept

Heatable Section Model - CRD Housing connection

10

Tube20

2

External Vessel Cooling Test- Test Objective

Identification of the safety margins of the exterior cooling

concept of the RPV, taking into consideration the influence

of the control rod drive housings

Test Vessel

Heater

TrickleCooler

PistonPump

ReductionValve

Heater

Feedwater Pump

Pressurizer

Main Cooler

SprayCondenser

External Vessel Cooling Test- Manufacturing, Heating Wires (1)

0.00

100.00

200.00

300.00

400.00

500.00

600.00

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15Segment No. [-]

Hea

t F

lux

[kW

/m2]

Heat Flux Decay HeatDesign Max. Pos. Heat Flux

External Vessel Cooling Test- Manufacturing, Heating Wires (2)

External Vessel Cooling Test- Measuring Equipment, Pressure/Level

Pressure differences shall be measured at three different levels

l Each of the pressure and pressure drop sensors has to be checked against acalibrated pressure checking device or a water column

l The aim of these measurements is to measurethe water level. Therefore, an accuracyof +/- 2% can be accepted

External Vessel Cooling Test- Measuring Equipment, Mass Flow

The inlet mass flow will be measured via an orifice. This measurement will bechecked via the measurement of the time to fill a defined volume of 60 liters

l The orifice should be chosenin a way that a mass flowcould be measured from0.4 to 0.0025kg/s at 104°C

l The aim of these measurementsis to check, whether the testobject will be supplied withalmost constant flow conditions.Therefore, an accuracy of+/- 4% can be accepted

External Vessel Cooling Test- Measuring Equipment, Inlet Temperature

The inlet temperature measurement will be checkedvia measuring the boiling temperature at ambientconditions. An accuracy of +/- 2K can be accepted

External Vessel Cooling Test- Measuring Equipment, Heated Surface (1)

> The temperature measurements of the heated surface will be checked basedon plausibility

l Plausibility check is described in the Test Procedure (FANPTGT1/02/e42)

l Installation has to be done and checked according to the respectivedrawing

External Vessel Cooling Test- Measuring Equipment, Heated Surface (2)

External Vessel Cooling Test- Measuring Equipment, Power Supply

The measurement of voltage andcurrent supplying the heating wiresis part of the BENSON test riginstrumentation.l The functioning of this has been

checked during test running inAugust 2002

l Within further tests in the followingyears this standard instrumentationwill be checked regularly again

External Vessel Cooling Test Data Acquisition Software (1)

Online display

External Vessel Cooling Test- Data Acquisition Software (2)

"Quicklook"

framatome anp - swr-1000: nrc-visit - preparation of the ...results of the mass flow balances...

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