Case superheating channel boiling water-to-water nuclear reactor

 

Usage: in nuclear engineering. Case superheating channel boiling water-to-water nuclear reactor designed in the form of power tubes, which are installed in the shell. Between the pipe and the ring formed by the annular gap, which contains a heat insulating porous layer made of a material with low absorption cross section for neutrons and is sealed on the ends. Effect: reduce the flow of thermal energy from the steam inside the power tubes to the water surrounding the hull from the outside, due to the increase in thermal resistance, i.e., improving the insulating properties of the hull superheating channel. 7 C.p. f-crystals, 1 Il.

The invention relates to nuclear engineering, and more specifically to the buildings superheating channels boiling water-to-water nuclear reactor.

The closest to the essential features of the invention is the body superheating channel boiling water-to-water nuclear reactor, made in the form of power tubes (G. N. Ushakov. Technological channels and fuel elements of nuclear reactors. M: Energoizdat, 1981, S. 109, Fig.2.16).

A disadvantage of the known case europeregio coolant, surrounding the outer wall of the power tubes, when the steam temperature exceeds the saturation temperature of water outside the pipe. The presence of the vapor phase in the ambient water will cause deterioration of the neutron-physical environment near the canal, and the boiling of water on the outer surface of the power tubes, which will take place in intermittent water and steam volumes moderator will lead to neutron-physical instability, violation of the terms of maintaining the neutron balance and to the deterioration of nuclear reactor regulation in General.

The present invention is to create superheating channel, the use of which will eliminate the possibility of boiling water (moderator) and, as consequence, increase of neutron-physical stability of boiling water-to-water nuclear reactor.

The technical result of the present invention is to reduce the flow of thermal energy from the steam inside the power tubes to the water surrounding the hull from the outside, due to the increase in thermal resistance, i.e., improving the insulating properties of the hull superheating channel.

This technical result is achieved by the fact that in the case of paroa pipe installed in the shell, between the pipe and the sides formed by the annular gap, which contains a heat insulating porous layer made of a material with low absorption cross section for neutrons and is sealed on the ends.

In addition, as a material of the heat insulating layer used zirconium oxide or aluminum oxide containing not more than 0.3% of impurity oxide of hafnium.

In addition, the insulating layer is made in the form of a coating deposited on the outer surface of the power tube or on the inner surface of the shell by plasma spraying.

In addition, the porosity of the heat insulating layer is 12-18% of the volume of the layer.

In addition, the ends of the shell are connected with the power pipe welds made TIG welding.

The invention is illustrated in the drawing, which shows a longitudinal section of the housing superheating channel.

Case superheating channel is made in the form of a power tube 1, which is installed in the shell 2 so that between them is formed the annular gap 3, in which is placed a heat insulating porous layer 4 of a material with a low absorption cross section of neutrons, which is due to its porous structure reduces heat flow from the coolant, but the physical characteristics of a nuclear reactor. The annular gap 3 on the ends sealed, for example, by means of a weld obtained electron-beam welding of the ends of the shell 2 with the power pipe 1. The sealing shell and power tubes eliminates the ingress of water into the annular gap 3 and the porous layer 4, which leads to preservation of the integrity of the insulating layer 4 and the shell 2, as otherwise in the presence of water in the annular gap 3 porous layer 4 can crack and crumble, and if water on the hot surface of the power tubes 1 may be boiling and evaporation of water, which will result in a limited volume to a sharp increase in pressure and bulging and rupture of the shell 2. Performing a weld electron beam welding will further reduce heat flow from the fluid inside the power tube 1, the surface of the water due to the formation of the annular gap 3 vacuum because technology electron beam welding provides for its implementation under vacuum. Heat insulating layer 4 may be deposited on the outer surface of the power tube 1 or the inner surface of the shell 2 by means of plasma spraying with a given porosity within 12-18% of the volume of the layer. As a researcher is 0.3% of impurity oxide of hafnium. Shell 2 made of a material identical or similar to power metal pipe 1.

When working superheating channel the coolant is water vapor (steam-water mixture) is fed into the cavity of the housing, i.e. in the cavity power pipe 1. The steam passes by the fuel elements, selects allocated in warm and hot. The output from the power tubes 1 steam has a higher temperature than when it entered it. The outside of the shell 2 flowing water with a temperature below the saturation temperature. The differences of temperature of steam flowing inside the power tube 1, and the waters surrounding the outer wall of the shell 2, is the flow of heat from the steam to the water. The total thermal resistance of the package is composed of the power tube 1, the porous insulating layer 4 and the shell 2, allows to significantly reduce the flow of heat, which completely eliminates the possibility of boiling water (vapor phase), and thus preserves the neutron-physical stability of boiling water-to-water nuclear reactor and ensures the regulation of the reactor as a whole.

Claims

1. Case superheating channel boiling water-to-water nuclear reacted pipe and shell formed annular gap, which contains a heat insulating porous layer made of a material with low absorption cross section for neutrons and is sealed on the ends.

2. The case under item 1, characterized in that the material of the heat insulating layer used zirconium oxide or aluminum oxide containing not more than 0.3 % of impurity oxide of hafnium.

3. The case under item 1 or 2, characterized in that the insulating layer is made in the form of a coating deposited on the outer surface of the power tubes.

4. The case under item 1 or 2, characterized in that the insulating layer is made in the form of a coating deposited on the inner surface of the shell.

5. Building on PP.1, or 2 and 3 or 2 and 4, characterized in that the porosity of the heat insulating layer is 12-18% of the volume of the layer.

6. The case under item 3 or 4, characterized in that the coating is performed by plasma spraying.

7. Building on PP.1, or 2, or 2 and 3 or 2 and 4 or 3 and 5 or 4 and 5 or 3, 5 and 6, or 4, 5 and 6, characterized in that the ends of the shell are connected with the power pipe welded seam.

8. The case under item 7, characterized in that the welded seam is made of electron-beam welding.

 

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