RU2682331C1 - Device for passive disposal of excess thermal energy from internal volume of object protective shell (options) - Google Patents

Abstract

FIELD: power engineering.SUBSTANCE: invention relates to a device for passive extraction of excess thermal energy from industrial facilities, nuclear power plants and thermal power plants without the use of external energy sources and equipment. In an annular two-phase thermo siphon filled with working fluid, the evaporative heat exchanger is located in the pool-cooler at the facility, the condenser heat exchanger is in the cooling channel, and the heat exchangers are connected by steam and condensate steam lines. In an embodiment of the use of an air cooling channel, the steam pipe is made of a honeycomb of several internal pipes of small diameter, Upper end of the cellular steam pipe in the condenser heat exchanger is equipped with a hydrosiphon with liquid slinger, the upper and lower ends of the condensate pipe are installed at the bottom level of both heat exchangers. In the use case of the cooling pond in which the condenser heat exchanger is immersed, both ends of the steam/water mixture steam line are installed at the bottom of both heat exchangers, the lower end of the condensate line is located at the bottom of the condenser heat exchanger, and upper end thereof is in the upper part of the evaporative heat exchanger. When using the device at low-temperature objects, for example, in fuel tanks of fuel assembly, as a working fluid in an annular two-phase thermosyphon, a mixture of water with low-boiling perfluororganic compounds can be used.EFFECT: technical result is an increase in productivity and the possibility of universal application at various industrial facilities, CHP and NPP.1 cl, 2 dwg

Description

The invention relates to the field of electric power and can be used at thermal and nuclear power plants for the passive removal of excess thermal energy from the internal volume of an object when the electric power to the transfer pumps is completely disconnected.

Known devices for a similar purpose, for example, according to the author's certificate of the USSR No. 1563295, IPC F01K13 / 02, authors A.P. Lapshina, V.P. Tatarinova et al. “The system of heat removal from the energy circuit” [1].

This heat removal system contains an air-cooled heat exchanger connected to a heat source through steam lines, the condensate outlet of which is connected to a heat source, the heat exchanger being installed at a height at which the hydrostatic pressure difference is greater than hydraulic losses, and the heat exchanger is enclosed in a housing equipped with a traction pipe and gates with piston actuators controlled by pressure in the circuit. In addition, the gates are installed at the entrance to the housing and at the exit of it into the traction pipe.

The disadvantages of this system are its limited performance in transferring thermal energy from the source to the traction pipe and low mechanical reliability due to the presence of moving units and parts: piston drive, gate valve, etc. As the working fluid circulating in the heat exchanger, only water can be used.

It is also known [2] “A device for removing excess thermal energy from the internal volume of the protective shell of a nuclear power plant by M.R. Mustafina, V.D. Bumagina and others according to the patent of the Russian Federation No. 2504031, IPC 621C 15/00.

This device, with a complete power outage, passively removes excess thermal energy to the atmosphere from the internal volume of the containment and from the cooled water in the holding pool of the fuel of the generating assemblies (FA). To this end, the device comprises three heat exchangers interconnected by a system of low-boiling coolant, which are mounted one above the other, the lower heat exchanger located in the water tank inside the middle part of the protective shell, the middle heat exchanger located the same inside the upper part of the protective shell, and the upper heat exchanger mounted on the outer surface of the wall of the dome of the containment blown by air. The system of low-boiling coolant is equipped with valves with a bellows actuator mounted on the inlet section of the third heat exchanger.

Bellows-actuated valves consist of a guiding cup located in a sleeve-like body and in a corrugated rings ring, in which a rod with a piston is placed at one end, a seat seat plate at the other end, a perforated rod guide, while between the piston and the bottom of the sleeve-like body mounted adjustable telescopic spring. In this device, the water tank is a holding pool for spent fuel nuclear fuel.

The disadvantages of this device are low reliability due to the presence of moving mechanical units, a complex valve device with a bellows actuator, the need for different calibration of the valves for opening by pressure for the phased inclusion of heat exchangers. In addition, the use of only low-boiling coolants, including freons, organofluorine compounds, etc., is not effective due to their low heat capacity and low heat of vaporization compared to water.

Also, low-boiling coolants cannot be universal working fluids for other NPP and TPP facilities operating at high temperatures.

The closest analogue (prototype) [3] is the "Pool for aging spent nuclear fuel" authors II. Sviridenko, O.Yu. Moskalenko according to the patent of Ukraine No. 83014. IPC G21C 15/18.

In this device, the spent fuel spent in the fuel assembly reactor with a system for removing residual heat energy from them through an annular two-phase thermosiphon, which has a lower heat exchanger consisting of evaporators and a collection collector, a condenser (air heat exchanger) placed in the air channel and two pipelines, is placed in the holding pool connecting heat exchangers: supply steam pipe and return condensation pipe.

The working fluid in this device is a mixture of alcohol with water and the vacuum is maintained within 0.05 * 10 ⁵ Pa, which allows you to control the temperature level of about 50 degrees Celsius.

The disadvantages of the prototype are as follows:

- low productivity due to the low heat of vaporization of the alcohol mixture;

- the need to maintain a predetermined vacuum in the thermosiphon;

- narrow purpose: used only for air cooling;

- is not a universal device, the design and working fluid of which can be used to remove thermal energy from various industrial units, nuclear power plants, and thermal power plants.

The task of the invention is to remedy these disadvantages and create a device for passive removal of thermal energy from different types of sources having high performance and a wide range of temperatures.

The technical result of the invention according to the first embodiment is as follows. Increased device performance due to the fact that:

- the steam pipeline between the heat exchangers is made of honeycomb consisting of several pipes of small diameter, through which steam bubbles in a shell mode move portions of the working fluid;

- an air siphon is placed in the air heat exchanger at the end of the honeycomb pipe to condense the vapors in the liquid and overflow it to the bottom of the heat exchanger;

- the return condensation pipe between the heat exchangers is made with a finned surface and is equipped with a check valve, which allows creating efficient film evaporation of the liquid on the pipe walls and the forced heating mode of the working fluid with the check valve closing.

The technical result of the invention according to the second embodiment is as follows:

- simplified design and increased reliability of the device when used for passive removal of excess energy into a reservoir: it does not have moving elements and does not contain adjustable nodes;

- the choice of possible working fluids (working fluids) for different conditions of application of the device at industrial facilities, TPPs and nuclear power plants has been expanded.

The technical result of the first embodiment in air cooling is achieved due to the fact that in the annular two-phase thermosiphon filled with a working fluid containing an evaporative heat exchanger located in the cooler pool at the facility, a condenser heat exchanger in the cooling channel, and the heat exchangers are connected by steam and condensation pipelines, and steam the pipeline is made of honeycomb from several internal pipes of small diameter, heat exchangers are represented by body structures, the upper end of the cell th steam condensing heat exchanger in the pipeline gidrosifonom equipped with overflow liquid and the upper and lower ends of the condensing pipe installed at the bottom of both heat exchangers.

The technical result according to the first embodiment is also achieved due to the fact that the condensation pipe is equipped with cooling fins and a check valve.

The technical option according to the second option for water cooling is achieved due to the fact that the evaporative heat exchanger of the annular two-phase thermosyphon filled with the working fluid is located in the cooler pool at the facility, and the condenser heat exchanger is in the cooling pond, and the heat exchangers are connected by steam and condensation pipelines, and in the use case cooling pond, in which the condenser heat exchanger is immersed, both ends of the steam pipe are installed at the bottom of both heat exchangers mennikov, the lower end of the condensation pipe is located at the bottom of the condenser heat exchanger, and its upper end is located in the upper part of the evaporative heat exchanger.

In FIG. 1 shows a variant of the proposed “Device for removing excess thermal energy from the internal volume of the protective shell of the object (Option 1)” with the placement of an external heat exchanger in the traction ventilation pipe (air), and in FIG. 2 presents the option "Devices ..." with the placement of an external heat exchanger in a cooling pond.

The device according to the first embodiment (Fig. 1) contains a pool 1 of a product cooler at NPP or TPP facilities, in which a sealed evaporative heat exchanger 2 is connected, connected by a honeycomb pipe 3, inside which pipes of a smaller diameter are placed, with an external hermetic condenser heat exchanger 4 containing a hydrosiphon 5 with cooling fins 6, and the heat exchangers are connected by a return condensation drain pipe 7. The heat exchangers are filled with a working fluid 8 with an evaporation temperature and heat of vaporization in relation to the requirements of the facility on which the proposed device is used. This can be water at nuclear power plant reactors, such as VVER and RBMK with an evaporation temperature of 100 degrees Celsius at normal atmospheric pressure, freons, organofluorine compounds, etc. for low-temperature facilities, including for exposure pools of spent fuel assemblies of 9 reactors for temperature ranges of 30 ... 70 degrees Celsius. According to the first option (Fig. 1), the excess heat energy is passively removed from the object to the atmosphere through the traction ventilation cooling channel 10, and to improve heat transfer, all heat exchangers are equipped with cooling fins 11. To increase the capacity of the heat energy removal device, the condensation pipe is also equipped with a check valve 12, rotating under its own weight on a hinge (not shown in the drawing) and cooling fins 13.

According to the second option (Fig. 2) “Devices ...” passive removal of excess thermal energy is carried out into the reservoir by means of an external hermetic condensing heat exchanger 4 connected to a hermetic evaporative heat exchanger 2 of the pool 1 of the cooler at the facility by the discharge pipe 14 of the steam-water mixture and the condensation drain pipe 15.

"Device ..." according to the first embodiment works as follows. When the cooler in the pool 1 and, accordingly, in the sealed evaporative heat exchanger 2 reaches the temperature set for passive heat removal, for example, 57.2 degrees Celsius for the mixture of perfluorohexane CF3 (CF2) 4CF3 working fluid with water, perfluorohexane begins to evaporate and its vapor enters the pipes small diameter of the honeycomb pipe 3. Bubbles of liquid vapor 8, rising up, carry along and push, like pistons, portions of still unevaporated water with a higher heat capacity. The optimal diameter of the small diameter pipes that make up the honeycomb pipe 3 for water vapor is from 5 to 16 mm. [four]. (See Scheklein S.E., Starikov E.V. Nikitin A.D. Steam-liquid engine. Utility Model Patent of the Russian Federation No. 160724. IPC F03G 7/06). The vapor of the working mixture, passing through the liquid layer in the hydrosiphon 5, condenses, the accumulated liquid overflows over the edge of the hydrosiphon to the cooling fins 6 and, falling to the bottom of the condensing heat exchanger 4, returns to the evaporative heat exchanger 2 along the walls of the drain pipe 7.

Heat is removed to the atmosphere by the air flow V of the traction ventilation cooling channel 10, washing the housing and fins 11 of the external condensing heat exchanger 4.

In the operating mode, the non-return valve, ajar under its own weight, is not used, since the liquid column in the pipe 7, equal to the height of the heat exchanger 2, counteracts the vapor pressure of the liquid, and the effect of the airlift in the large diameter pipe is insignificant, therefore, the liquid vapor in the operating mode will only move along honeycomb pipe 3. In addition, the ribs 13 of the pipeline 7 contribute to its additional cooling, creating film evaporation on the walls [5]. (See Tananayko Yu.M., Vorontsov EG Methods of calculation and research of film processes). Valve 12 can be used when operating in critical operating conditions of the device when explosive evaporation of liquid occurs. In this case, the valve rotates and closes the inlet to the pipe 7.

The device according to the second embodiment works as follows (Fig. 2).

When the cooler reaches the pool 1 and, accordingly, in the sealed evaporative heat exchanger 2, the temperature set for heat removal is accumulated, liquid vapor accumulates in the upper part of the heat exchanger 2, which creates excess pressure and pushes the working fluid 8 through the steam return pipe 14 to the external water-tight condenser heat exchanger 4, located in a cooling pond.

Since the condenser heat exchanger 4 is sealed and completely filled with the working fluid 8, the latter is forced to rise through the discharge condensate pipe 15 in the presence of excessive pressure, overflowing again into the sealed heat exchanger 2.

Heat is removed to the reservoir by cooling water of the heat exchanger body 4 directly and through its ribs 11.

For example, in pool 1 of a fuel assembly cooler, it is necessary to maintain a temperature of about 43 degrees Celsius. To do this, we use a working fluid 8 from a mixed composition of water in equal proportions with perfluorohexane and perfluoropentane, having a boiling point of 57.2 and 29.3 degrees Celsius, respectively, and an average of 43.2 degrees. Thus, the evaporating vapors of these perfluororganic compounds force water with a higher heat capacity to move along the circuit between the heat exchangers, which increases the efficiency of heat transfer.

Thus, the present invention, using the appropriate working fluid with a given temperature and heat of vaporization, has high productivity and can find universal application in various industrial facilities, nuclear power plants and thermal power plants.

INFORMATION SOURCES

1. Lapshin A.P., Tatarinov V.P. and others. The system of heat removal from the energy circuit. USSR copyright certificate No. 1563295. IPC F01K13 / 02 (analogue).

2. Mustafin M.R., Bumagin V.D. etc. A device for removing excess thermal energy from the internal volume of the protective shell of a nuclear power plant. RF patent No. 2504031. IPC G21C 15/00 (analog).

3. Sviridenko I.I., Moskalenko O.Yu. Pool for spent nuclear fuel. Patent of Ukraine No. 8314. IPC G21C 15/18 (prototype).

4. Scheklein S.E., Starikov E.V., Nikitin A.D. Steam-liquid engine. RF patent for utility model No. 160724. IPC F03G 7/06.

5. Tananayko Yu.M., Vorontsov E.G. Methods of calculation and research of film processes. Kiev, 1975.

6. Kolykhan L.I., Naganov A.V. et al. Passive safety system of a nuclear power plant. USSR copyright certificate No. 1829697. IPC G21CC 9/00 (analog).

7. UK patent No. 1225997. IPC G21C 15/18, 1971 (analog).

8. The patent of Germany No. 3129289. IPC G21C 15/18? 1982 (analog).

Claims (1)

A device for passively removing excess thermal energy from the internal volume of the object’s containment containing an annular two-phase thermosiphon filled with working fluid, the evaporative heat exchanger of which is located in the cooler pool at the object, and the condenser heat exchanger in the cooling channel, the heat exchangers being connected by steam and condensate steam pipelines, characterized in that the steam pipeline is made cellular from several internal pipes of small diameter, the upper end of the cellular steam pipe the water in the condenser heat exchanger is equipped with a hydrosiphon with a liquid overflow, the upper and lower ends of the condensate pipe are installed at the bottom of both heat exchangers, and the condensate pipe is equipped with cooling fins and a check valve, and water or mixed water is used as a working fluid in the ring two-phase thermosiphon for low-temperature objects composition of water with low boiling organo perfluorine compounds.

Images