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CSNI1027 IVO/LOOP-SEAL.

IVO-Loop Seal Facility (Air/Water), Two-phase behaviour of a PWR cold leg loop seal during LOCA accidents

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1. NAME OF EXPERIMENT:  IVO/LOOP-SEAL AIR/WATER.
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2. COMPUTERS
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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).
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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.
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6. PHENOMENA TESTED

Study two-phase of a PWR cold leg loop seal during loss-of-cooland accidents.
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9. STATUS
Package ID Status date Status
CSNI1027/01 01-JAN-1988 Report Only
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10. REFERENCES
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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11. TEST DESIGNATION:  Loop seal air/water.
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12. PROGRAMMING LANGUAGE(S) USED
No specified programming language
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15. ESTABLISHMENT:  
Imatran Voima Oy
Power Plant Division
Helsinki, Finland
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16. MATERIAL AVAILABLE
CSNI1027/01
Documentation in electronic format
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17. CATEGORIES
  • Y. Integral Experiments Data, Databases, Benchmarks

Keywords: air, loop, loss-of-coolant accident, pwr reactors, water.