APPLICATION OF GAS-LIFT IN NUCLEAR REACTORS AND ITS EXPERIMENTAL VALIDATION

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1 APPLICATION OF GAS-LIFT IN NUCLEAR REACTORS AND ITS EXPERIMENTAL VALIDATION Jiří POLANSKÝ Chief scientist Pavel ŽITEK Construction of experimental device expert Václav VALENTA Senior expert Nuclear power engineering

2 CONTENT ZÁPADOČESKÁ APPLICATION OF UNIVERZITA GAS-LIFT V IN PLZNI NUCLEAR REACTORS AND ITS Department introduction Introduction to the GAS LIFT theory Modeling of the phenomena The experimental device description Measuring description Used measuring methods Results Conclusions

STRUCTURE OF THE DEPARTMENT Department of

Fluid-mechanics and thermo-mechanics - MTT -

3 STRUCTURE OF THE DEPARTMENT Department of Power System Engineering has two section - Fluid-mechanics and thermo-mechanics - MTT - Heat, nuclear and alternative devices - TJAZ Ing. Jiří POLANSKÝ, Ph.D. Head of department Prof. Ing. Jiří LINHART, CSc. Representative of the HOD Prof. Ing. Radim MAREŠ, CSc. Head of MTT section Ing. Pavel ŽITEK Head of TJAZ section

4 ACTIVITIES OF THE DEPARTMENT Most activities of the department are focused to increasing efficiency and reliability of energy machinery and devices. The department is focused to environmental protection as well. Heat exchangers for IV. Generation Nuclear Reactors (primary/secondary circle) MSR salt cleaning gas separator Heat exchange intensification with Gas-lift method Turbomachines channel blading, output diffuser, seals Redefiniton of the accident with coolant loss Big LOCA type Determination of the methodic of the seismic hazard of selected location Blades and tubes vibration Burned fuel containers

5 KKE LABORATORY

6 GAS LIFT INTRODUCTION There is possible to use a very well known gas-lift for the intensification of natural flow in nuclear reactors. The information about pumping of the water from mines using the gas come from Chemnitz from the middle of the eighteenth century. It is now used intensively in two forms during crude-oil mining: continual delivery of the gas into the flow periodical injection of the gas, which is more effective for mining It is only possible to use the continual gas delivery method in nuclear reactors. It is possible to use He as a gas. In MSR the gas-lift is suitable for cleaning the fuelcooling mixture of fluoride salts from gaseous fission products and therefore removing the problems with Xenon Fission product poisoning of classic reactors.

7 MAP OF DISTRIBUTION OF THE TYPES OF A TWO-PHASE FLOW (TAITEL) Superficial velocities on the axis. Superficial velocity of fluid is velocity, where is alone in the cross sectional area of flow. This type is prefered for using Gaslift in MSR The disperse bubble flow is technically homogeneous, because the bubbles are very small. Its valid for the disperse bubble mode, that vg = vl, the gas slip ration S = vg/vl = 1.

different authors Map of distribution of the types of a two-phase

8 MAP OF DISTRIBUTION DIFFERENT AUTHORS There can be up to of-the-order differentes between boundary are various according to different authors Map of distribution of the types of a two-phase flow (Hasan and Kabir) Map of distribution of the types of a two-phase flow (Kay)

9 PARENT OF FLUID

10 HYDRAULIC LOSSES IN THE PRIMARY CIRCUIT There is a problem in determination of weight flow rates of the fluid and gas W a W g to get to the sphere of the disperse bubble flow. There were deduced the relations for natural nuclear reactor coolant flowing and reactors with flowing fuel-cooling MSR mixture. We obtain this relation for natural heat flowing in the primary circuit - on condition that the temperature changes only in the active zone and the heat exchanger - from the solution of the continuity equation and the Bernoulli s equation: W pr Ā 2 W pr g zv zc Tc 0 2 is the weight flow rate for the balanced flow of the coolant in the zone [kg/s] are total hydraulic losses in the primary circuit is the medium flow cross-section of the circuit pr A pr 2

11 MEDIUM FLOW CROSS-SECTION, MEDIUM DENSITY 1 A L L x 0 dx x. A x 1 L V x 0 x. A x. dx L V is the total circuit length is the total volume of the coolant in the circuit

12 MASS FLOW RATE c T T T max min c p P W is the thermal heating in the active zone P is the total heat output of the zone, cp is the thermal capacity of the fuel After the adjustment we obtain: g P W zv z pr cp c zv, zc are the medium heights of position of the exchanger and the active zone in the primary circuit

13 MASS FLOW RATE FOR GAS-LIFT For gas-lift it applies in the tractive cylinder of the diameter according to the rule of A K m D K gaslift W Wl Wg kg s

14 MASS FLOW RATES OF THE GAS The amount of the gas supplied by the m vents into the tractive cylinder of the gaslift Wg is determined by the following relation p 2 p 2 1 r Tg p1 p1 Wg Cd d m p 4 1 m Cd p1 p2 is the number of the vents of the d diameter, is the loss coefficient that has to be determined experimentally, is the gas pressure in front of the strangling hole, is the gas pressure behind the strangling hole к=1,66 for single atomic gases (He, Ar, Kr), к=1,4 for O2, N2, CO, air

15 EXPERIMENTAL AND NUMERICAL MODELLING

16 SIMPLIFIED SCHEME OF THE PRIMARY CIRCUIT 1. Active zone 2. Crossing to tractive cylinder 3. Gas intake (He) for the gaslift 4. tractive cylinder 5. Compensator of volume with free surface 6. Area for collected gas 7. Counterflow exchanger 8. Crossing to the cold branch tubing 9. Cold branch 10. Collecting chamber 11. Distribution vents for flowing into the active zone

17 DEMONSTRATOR OF THE TWO-PHASE FLOW

18 REDUCTION WITH CHANGEABLE INSTER Therefore it is essential to change the diameter of individual vents for air intake easily in order to control the size of the created bubbles in the tractive cylinder.

19 NATURAL CONVECTION AND GAS-LIFT MEASURING AND ANALYSES The flow rate at natural convection and using gas-lift The flow rate measuring with using electromagnetic flowmeter Bubbles size and the flow rate measuring using by PIV Impact of the natural convection to the flow rate Bubbles and fluid speed measuring and analyses Bubbles size mapping according to their distance from air intake

20 THE PRINCIPLE OF THE PIV METHOD

21 THE PRINCIPLE OF STEREO PIV

22 DATA ANALYSES FROM PIV

23 BUBBLE SIZE MEASURING

24 THE PRINCIPLE OF PIV - LIF

25 THE PRINCIPLE OF THE UVP METHOD

26 DATA MONITORING

27 DATA MONITORING

28 TWO-PHASES FLOW VISUALIZATION

29 TWO-PHASES FLOW VISUALIZATION

30 CONCLUSION Flow fields on simplified model of MSR using Gas lift was measured by PIV and also predicted by two-phase flow theory. Methodology of measurement and calculation was established. Particle image velocimetry device and two-phase flow demonstrator (TFD) was used for experimental investigation. Currently a two-phase flow demonstrator is in reconstruction. Measuring and controlling of heat exchanger and gas input device will be more accurate in future. Other scheduled updates: Measuring and data evaluation improving. Inductive flow meter coupled with PIV device. Velocity and size of bubbles as a gas-lift parameters function. Size of bubbles as a distance from gas input function. Different spectrums of bubbles measuring.

31 CONTACT ZÁPADOČESKÁ APPLICATION OF UNIVERZITA GAS-LIFT V IN PLZNI NUCLEAR REACTORS AND ITS Additional information Department website Faculty website University website Secretariat KKE Department of Power System Engineering University of West Bohemia in Pilsen Univerzitní Plzeň tel: (+420) fax: (+420) cerna@kke.zcu.cz

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