CSNI1027 IVO/LOOP-SEAL.
IVO-Loop Seal Facility (Air/Water), Two-phase behaviour of a PWR cold leg loop seal during LOCA accidents
NAME OF EXPERIMENT, COMPUTER, DESCRIPTION OF TEST FACILITY, DESCRIPTION OF TESTS, PHENOMENA TESTED, STATUS, REFERENCES, TEST DESIGNATION, LANGUAGE, ESTABLISHMENT, MATERIAL, CATEGORIES
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| Program name | Package id | Status | Status date |
|---|---|---|---|
| IVO/LOOP-SEAL | CSNI1027/01 | Report | 01-JAN-1988 |
Machines used:
| Package ID | Orig. computer | Test computer |
|---|---|---|
| CSNI1027/01 | Many Computers |
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3. DESCRIPTION OF TEST FACILITY
The experimental facility is a full-scale model of one entire cold leg. The steam flow is modelled with atmospheric air flow delivered by the high-capacity fan (3 m3/s with a head of 30 kPa). The maximum available superficial air velocity is 9 m/s in the cold leg with a diameter of 850 mm. The opening simulates a break in the long horizontal section between the RCP and the reactor pressure vessel (RPV). The RCP mock-up has been designed to give a similar flow behaviour: the overflow edge and the single-phase pressure drop are equal to those of the real RCP. The break location can be varied to simulate a botton, side or top break. The speed-controlled air fan has a buffer tank (10 m3) and throttling for the control of oscillations. Make-up water can be injected into the loop seal section with a maximum flow rate of 30 kg/s.
The measuring system records the pressures p1 and p2, and the air and make-up water flow rates. The differential pressure measurements in the horizontal section of the loop seal give average void fractions (or level values of the stratified flow).
The experimental facility is a full-scale model of one entire cold leg. The steam flow is modelled with atmospheric air flow delivered by the high-capacity fan (3 m3/s with a head of 30 kPa). The maximum available superficial air velocity is 9 m/s in the cold leg with a diameter of 850 mm. The opening simulates a break in the long horizontal section between the RCP and the reactor pressure vessel (RPV). The RCP mock-up has been designed to give a similar flow behaviour: the overflow edge and the single-phase pressure drop are equal to those of the real RCP. The break location can be varied to simulate a botton, side or top break. The speed-controlled air fan has a buffer tank (10 m3) and throttling for the control of oscillations. Make-up water can be injected into the loop seal section with a maximum flow rate of 30 kg/s.
The measuring system records the pressures p1 and p2, and the air and make-up water flow rates. The differential pressure measurements in the horizontal section of the loop seal give average void fractions (or level values of the stratified flow).
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4. DESCRIPTION OF TESTS
Three separate air/water test series were performed to determine the onset of slugging in the horizontal pipe, the residual water mass and the total two-phase drop in the loop seal. The results of flow regime transition experiments have been compared with smaller-scale experiments and with theoretical predictions to evaluate scaling criteria. The strong hysteresis of transitions found between the stratified and slug flow regimes depends on the loope seal geometry and U-tube oscillations.
Three separate air/water test series were performed to determine the onset of slugging in the horizontal pipe, the residual water mass and the total two-phase drop in the loop seal. The results of flow regime transition experiments have been compared with smaller-scale experiments and with theoretical predictions to evaluate scaling criteria. The strong hysteresis of transitions found between the stratified and slug flow regimes depends on the loope seal geometry and U-tube oscillations.
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CSNI1027/01, included references:
- Harri Tuomisto and Pirjo Kajanto:Two-Phase Flow in a Full-Scale Loop Seal Facility, Nuclear Engineering and
Design 107 (1988) 295-305
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Keywords: air, loop, loss-of-coolant accident, pwr reactors, water.