RU2361163C2 - Heat exchanger - Google Patents

Abstract

FIELD: heating.

SUBSTANCE: invention relates to nuclear power engineering, namely, to heat exchangers incorporated with passive heat removal systems intended for nuclear power plants. The proposed heat exchanger comprises the chamber, hear exchange pipe bundle arranged in the duct receiving cooling medium fed from below, and hear carrier drain circuit. Vapour feed branch pipe is connected to the said chamber, the branch pipe outlet being arranged above the heat exchange pipes ends. Note here that outlets of the said pipes are immersed in condensate.

EFFECT: simple design, higher reliability, lower weight and cost, and reduced metal input.

2 dwg

Description

The invention relates to nuclear energy, and more particularly to heat exchangers for passive heat removal systems for nuclear power plants.

In the event of accidents with loss of power supply of the power unit, passive heat removal of the residual heat of a nuclear reactor is required, for example, by using an air-cooled heat exchanger.

Known heat exchanger containing a bundle of slightly inclined pipes located in the channel into which the cooling medium enters from below and connected to the upper and lower coolant chambers / England patent No. 1173717, MKI F4S /.

Closest to the proposed invention is a heat exchanger containing a bunch of slightly inclined pipes located in the channel into which the cooling medium enters from below and connected to the upper and lower coolant chambers, the last of which is equipped with a drain to remove the coolant from the lower chamber (Russian patent No. 2179289, IPC F28B 1/06, registered on December 22, 1995) - adopted as a prototype.

When using such a heat exchanger in a system of passive heat removal of a nuclear power plant, the passive principle is achieved by the natural circulation of a heat carrier cooled by atmospheric air, due to the high-altitude location of the heat exchanger relative to the steam generator from which the steam comes.

A disadvantage of the known heat exchangers is their large mass due to the presence of two heavy thick-walled chambers designed to withstand the pressure of the steam coming from the steam generator.

The need for a high-altitude arrangement of heat exchangers in the NPP building requires the strengthening of the NPP building. A particularly high force exerted on the building by the heat exchanger occurs during seismic events. Securing a heavy heat exchanger increases the cost of the building.

In addition to the cost of building a nuclear power plant, the presence of two chambers determines:

the high cost of manufacturing the heat exchanger itself and double the number of spare parts (gaskets, fasteners for removable covers, sealing chambers of the heat exchanger);

increased transportation costs;

the high cost of servicing the heat exchanger during operation (inspection of two chambers with their mandatory decompression).

The invention is aimed at solving the problem of reducing the cost of the heat exchanger, reducing the cost of its maintenance during operation, reducing the cost of the building of nuclear power plants.

The technical result is a simplification of the design and, as a consequence, an increase in reliability, a decrease in mass and, therefore, metal consumption and cost reduction.

The technical result in the implementation of the invention is achieved by the fact that in the heat exchanger containing the chamber, a bundle of heat exchanger tubes located in the channel into which the cooling medium, drainage to remove the coolant flows from below, a pipe for supplying steam is connected to the camera, and the output part of the pipe for supplying steam located above the outlet ends of the heat exchanger tubes, while the outlet ends of the heat exchanger tubes are flooded with condensate.

The chamber includes a housing to which a bundle of heat exchange tubes, a drainage and a pipe for supplying steam are connected. In addition, the camera has a removable cover sealing the camera.

With such a device, the heat exchanger decreases its mass and, therefore, metal consumption by eliminating one of the chambers, including a removable cover with sealing and fastening elements.

The cost of manufacturing a heat exchanger and spare parts for it, including the elements of sealing and fastening removable covers in its kit, is reduced.

The cost of transporting the heat exchanger is reduced.

Reduces the cost of installing the heat exchanger on site.

The maintenance costs of the heat exchanger during operation are reduced: inspection of the condition of the chambers.

With a decrease in the mass of heat exchangers, the cost of building a building decreases.

The invention is illustrated by drawings.

Figure 1 shows a front view of a heat exchanger with a bundle of heat transfer tubes.

Figure 2 shows a fragment of a heat exchanger chamber.

The heat exchanger includes a bundle of heat transfer tubes 1, a channel 2 for directing a cooling medium, such as air, to the bundle of heat transfer tubes 1, chamber 3.

The chamber 3 includes a housing 4, a steam inlet 5, the outlet 6 of which is located above the outlet ends 7 of the tubes of the heat exchange bundle 1, a drain 8 for removing the heat transfer medium, a removable cover 9. The sealing and fastening elements of the removable cover are not shown.

The heat exchanger operates as follows.

Water vapor enters the chamber 3 through the steam supply pipe 5, the outlet part of which (upper end) 6 is located above the upper row of the output ends of the tubes 7 of the heat exchange bundle 1. The output ends of the heat exchange tubes are below the condensate level, which is ensured by the height of the drain pipe 8 to remove the coolant . Steam is sent to the inlet ends of the heat exchanger tubes 1 and then, passing through the heat exchanger tubes 1, it condenses, and the condensate is drained into the chamber 3 through the outlet ends 7 of the tubes of the heat exchanger bundle 1 flooded with condensate, thus draining.

Cooling medium, such as atmospheric air, enters the heat exchanger from below, passes through channel 2, formed by the frame of the heat exchanger, sheathed from the inside with sheets and partitions (not shown) that direct air to the finned sections of the heat exchanger tubes.

Natural circulation of the heat carrier from the steam generator to the heat exchanger and from the heat exchanger to the steam generator is carried out due to a column of condensate located in the lower sections of the heat exchanger tubes between the chamber and the lower rows of the heat exchanger heat exchanger tubes.

Thus, the proposed heat exchanger in comparison with the prototype has the advantage, namely: at the same power with the prototype, the proposed heat exchanger is lighter. During its manufacture and maintenance during operation, costs are less. The cost of building a nuclear power plant.

It is most advisable to use the proposed invention in the safety systems of nuclear power plants, and primarily in the system of passive heat removal from the reactor when the nuclear power plant is de-energized.

Claims (1)

A heat exchanger comprising a chamber, a bundle of heat exchanger tubes located in a channel into which a cooling medium enters from below, drainage for removing heat carrier, characterized in that a pipe for supplying steam is connected to the chamber, the outlet part of the pipe for supplying steam being located above the output ends of the heat exchange pipes while the output ends of the heat exchanger tubes are flooded with condensate.

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