RU105514U1 - NUCLEAR POWER PLANT - Google Patents

Abstract

A nuclear power plant containing a reactor with a lead coolant or its alloys, with an active zone, steam generators, pumps located under the free level of the coolant, a protective gas system, a device for introducing a gas or steam-gas mixture into the coolant path in the vicinity of a steam generator, equipped with a pressure chamber connected to a pressure head line of pumps, in one of the walls of the pressure chamber holes are made connecting the cavity of the pressure chamber with a drain chamber having a free level of the coolant, communicated with the supply line of the gas mixture and with the volume of the gas system above the free level of the coolant, characterized in that under the drain chamber is coaxial with It has a conical baffle with its apex upward, the diameter of the base of which exceeds the diameter of the drain chamber, the gap between the wall of which and the surface of the baffle forms a channel for withdrawing the two-component mixture from the drain chamber.

Description

The proposed technical solution relates to nuclear energy, to installations with fast neutron reactors cooled by lead or lead-bismuth coolant.

Known nuclear power plant containing a reactor with liquid metal lead coolant or its alloys, placed below the free level of the active zone, steam generators, pumps and a protective gas system, a device for introducing a gas or gas mixture into the coolant path in the area of entry into the pumps, the active zone and in steam generators, in which the gas mixture input device is equipped with a pressure chamber connected to the pressure line of the pumps, openings are made in one of the walls of the pressure chamber connecting the cavity of the pressure chamber with a drain chamber in communication with the supply line of the gas mixture and having a free coolant level, and with the volume of the gas system above the free coolant level (RF patent No. 78002, G21C 9/016 published November 10, 2008 - prototype).

A disadvantage of the known technical solution is that in a two-component stream formed by falling coolant jets, the liquid metal coolant — a gas or vapor-gas mixture — agglomerates gas bubbles, enlarges them, floats larger bubbles to the free surface of the coolant, separates the bubbles on this surface and enters the gas volume above the free surface of the coolant. Thereby, the quantity of reactants of the gas mixture in contact with the coolant and the reaction surface of their interaction are sharply reduced, which leads to a decrease in the efficiency of the device for introducing the gas mixture into the coolant path.

These shortcomings are addressed by the proposed solution. The problem of increasing the efficiency of the device for introducing a gas mixture into the heat carrier path is solved.

EFFECT: elimination or reduction of the probability of agglomeration of gas mixture bubbles in a stream of lead and lead-bismuth coolants at the outlet of the device for introducing the gas mixture into the coolant path by dispersing hydrogen-containing and oxygen-containing gas mixtures at the exit site, increasing the surface and contact time of gas reagents and liquid metal coolant.

This technical result is achieved in that in a nuclear power plant containing a reactor with lead coolant or its alloys, with an active zone, steam generators, pumps, a protective gas system, a device for introducing a gas or vapor-gas mixture into the coolant path in the vicinity of the steam generator, located below the free level of the coolant equipped with a pressure chamber connected to the pressure line of the pumps, holes are made in one of the walls of the pressure chamber connecting the cavity of the pressure chamber with a drain chamber A swarm with a free coolant level connected with the gas mixture supply line and with the volume of the gas system above the free coolant level, coaxially with it under the drain chamber, has a conical bump installed with its top up, the diameter of the base of which exceeds the diameter of the drain chamber, the gap between the wall of which and the surface bump, forms a channel for withdrawing a two-component mixture from the drain chamber.

Due to the installation of a conical chipper in the lower part of the drain chamber in a two-component coolant-gas flow, the speed acquires a radial component directed outward from the chamber axis (into the volume of the main coolant flow). The presence of a radial velocity component contributes to a decrease in the concentration of bubbles in the local volume of the flow, to a decrease in the probability of encountering gas bubbles in the flow, and to a decrease in the probability of their agglomeration, ascent and separation of gas on the free surface. This increases the content of gas mixtures in the liquid metal coolant flow, the reaction surface of gas mixtures with liquid metal, and dramatically increases the efficiency of the device for introducing the gas mixture into the heat carrier path.

Figure 1 presents a diagram of a nuclear power plant that implements the proposed technical solution; figure 2 is a structural diagram of a unit for inputting gas mixtures into sections of the circuit. In a nuclear reactor 1 with a lead or lead-bismuth coolant, with a coolant located below free level 2, an active zone 3, steam generators 4, circulation means, for example, pumps 5, a protective gas system including gas purification filters 6, a condensate cooler 7 with a line 8 condensate drain. In the gas volume of the reactor, water vapor condensers 9 are placed, connected by a condensate drain line 10 to a dirty water tank. The nuclear power plant is equipped with a gas mixture input device 11 in the vicinity of the steam generator 4. The gas mixture input device 11 is equipped with a pressure chamber 12 connected to the pressure line 13 of the pumps. The drain chamber 14 is in communication with the gas mixture supply line 15 and has its free coolant level 16, onto which the coolant jets 17 pour from the pressure chamber 12. The cavity of the drain chamber 14 is in communication with the gas system volume above the free coolant level 2, line 18 with controlled valves and the volume of the gas cavity 19. Line 15 is connected to a gas cylinder 20 with a reducing mixture, with a cylinder 21 with hydrogen and a cylinder 22 with argon.

Figure 2 shows in more detail a device for introducing a gas or vapor-gas mixture into the coolant stream. It includes a pressure chamber 12 connected to a pressure line 13 of the pumps. Openings 24 are made in the bottom 23 of the pressure chamber 12, connecting the cavity of the pressure chamber 12 with the drain chamber 14. From the holes 24, jets of liquid metal 17 flow. In the drain chamber 14 there is a free level of coolant. The gas volume of the drain chamber 14 is communicated by the supply line of the gas mixture 15 with the volumes of the gas system above the free level of the coolant.

In the lower part of the drain chamber 14, coaxially with it, a conic chipper 25 is installed with its top pointing upward, the diameter of the base of which exceeds the diameter of the drain chamber 14, the gap 26 between the wall of which and the surface of the chipper forms a channel for removing the two-component mixture from the drain chamber. The chipper 25 is welded to the drain chamber 14. The operation of the nuclear power plant in the technological mode of cleaning from coolant oxides and surfaces of the reactor loop is carried out in the following ways:

The basis for the cleaning is either an unacceptable content of a controlled oxygen impurity in the coolant and in the circuit, or routine cleaning (according to the established cleaning periods), or cleaning after decompression of the circuit due to an accident or during the repair period.

In the cylinder 20, a reducing gas mixture is prepared by supplying gas from the cylinders 21 and 22. If necessary, the protective gas in the gas cavity 19 of the reactor 1 is replaced with a reducing argon-hydrogen mixture. Pumps are put into operation, which supply the liquid metal coolant to the pressure chamber 12 of the device 11. The gas mixture is supplied through line 15 to the drain chamber 14 of the device 11. The coolant from the pressure chamber 12 through the openings 24 in its wall enters the drain chamber in the form of falling jets 14. The surface of the jets of liquid metal is in contact with the reducing gas mixture. The jets of liquid metal falling to the free level 16 of the coolant in the device 11 capture and disperse the reducing gas phase, the small bubbles of which are transported by the flow of the liquid metal coolant to the surface of the steam generator and other parts of the circuit, cleaning them from deposits of coolant oxides. Purification is carried out by reducing oxides to form a clean coolant and water vapor. The bubbles of the latter agglomerate, float and separate on the free surface 2 of the coolant in the reactor circuit. Steam due to the diffusion of convective currents in the volume of the gas cavity 19 enters the condenser coolers 9 and enters the "dirty water" tank through line 10. A cleaning mode is possible in which a reducing gas mixture through a line 18 with controlled valves enters from the volume of the gas cavity 19 into the drain chamber 14 of the device 11 due to ejection of jets of liquid metal flowing out to the free level 16 of the coolant in the device 11. As the content decreases (" operation ") of hydrogen in the composition of the circulating reducing gas mixture, it is supplied to the gas system, while maintaining the concentration of hydrogen in the mixture at about 30% by volume.

After the completion of the cleaning process, controlled by reducing the rate of hydrogen loss in the gas mixture, stopping the accumulation of water condensate in the condensers 9 and according to the readings of the oxygen content sensors in the liquid metal coolant, the supply of the reducing gas mixture to the volume of the gas cavity 19 is stopped.

Thus, the coolant is cleaned of oxygen impurities due to the contact of the falling jets with the developed surface with the reducing gas mixture, and the surfaces (steam generator, etc.) are cleaned by delivering small bubbles of the gas mixture to the coolant flow to them.

Application of the proposed technical solution will allow:

- increase the efficiency of cleaning heat exchange (steam generator, core) and isothermal surfaces of the reactor loop with lead or lead-bismuth coolant from deposits of coolant impurities-oxides, eliminate the formation of deposits of significant thickness, "breakdown" of deposits and clogging of the channels of the active zone.

- increase the efficiency of the controlled content of oxygen impurities in the coolant of the reactor loop, if necessary, the deformation of protective oxide coatings on the inner surfaces of the loop by introducing into the volume of the drain chamber of the device oxidizing gas mixtures;

- accelerate the regime of cleaning the coolant and the circuit from the oxides of the coolant;

- eliminate the possibility of failure of the cleaning devices with nozzle nozzles, due to clogging of the gas outlet holes in the nozzles with impurities contained in the coolant.

Claims (1)

A nuclear power plant containing a reactor with lead coolant or its alloys, with an active zone, steam generators, pumps, a protective gas system, a device for introducing a gas or gas mixture into the coolant path in the area of the steam generator, equipped with a pressure chamber connected to a pressure head pump lines, holes are made in one of the walls of the pressure chamber connecting the cavity of the pressure chamber with a drain chamber having a free coolant level, connected with the supply line of the gas mixture and with the volume of the gas system above the free level of the coolant, characterized in that a conical baffle is installed coaxially with the apex upward under the drain chamber, the diameter of the base of which exceeds the diameter of the drain chamber, the gap between the wall of which and the surface of the baffle forms an exhaust channel two-component mixture from the drain chamber.