RU2487298C1 - Jet apparatus for steam generator pgv-1000 - Google Patents

Abstract

FIELD: power engineering.

SUBSTANCE: jet apparatus comprises a casing made as cylindrical, installed vertically in a drop channel of a steam generator and connected with a lower part to a guide deflector, a cylindrical nozzle sunk for the half of its length into the upper part of the casing to create a circular gap between the cylindrical nozzle and the casing for supply of steam generator feedwater into the casing from the area under a perforated sheet, narrowing channels arranged inside walls of the cylindrical nozzle and connected via supply tubes with a distributing header with the possibility of feedwater supply from narrowing channels into the casing at the angle of 75 degrees to the vertical line, at the same time the upper cut of the cylindrical nozzle is connected with the perforated sheet, which lets through the steam generator feedwater from the area above the perforated sheet into the upper part of the cylindrical nozzle and further into the casing.

EFFECT: increased multiplicity of feedwater circulation at a hot side of a steam generator resulting in increased steam productivity with preservation of its geometric dimensions.

2 cl, 3 dwg

Description

The invention relates to nuclear energy, in particular for use in PGV-1000 steam generators, serially used at nuclear power plants with a WWER-1000 reactor.

In the case of a traditional steam generator, the separation and vaporization processes are based on the natural circulation process. During the operation of the steam generator, the feed water enters one longitudinal distributing collector and is fed to the rows of transverse sprinklers installed under a hole sheet above the tubular packages on the side of the hot collector. This cold feed water from the distributor manifold is heated to saturation, partially condensing the steam in the steam-water mixture under the hole sheet formed as a result of heat exchange of the main water of the steam generator with tubular packets, is mixed with the main water of the steam generator (having a saturation temperature), and is already mixed in this way, it is lowered in between the tubular packages (into the lowering channels), due to natural circulation, after which it again participates in heat exchange with the tubular packages. At rated power, part of the steam, breaking into the lowering channels, blocks the lowering of cold water and the frequency of circulation decreases.

The main known disadvantages of such steam generators:

- due to the non-uniformity of heat generation on the hot and cold sides of the steam generator, there is an unevenness of the steam load (steam consumption over the cross section of the steam generator) and the water level above the hole sheet, and, as a result, the risk of moisture being thrown (released) into the steam lines;

- at rated power, steam usually breaks into the lowering channels and through the edge of the hole sheet, which dramatically reduces the multiplicity of circulation on the hot side of the steam generator;

- the formation of stagnant zones with a high concentration of dissolved salts and corrosion products and the precipitation of sludge.

Thus, in the nominal mode of operation of the steam generator there are quite significant performance losses, due mainly to an inefficient circulation scheme and a decrease in the circulation ratio.

To minimize the consequences of the above disadvantages, inkjet devices can be used.

The prior art inkjet apparatus used in thermal energy (mainly in thermal power plants), comprising a housing, nozzles for supplying gaseous and liquid media, and a chamber (RF patent 6853 U1, IPC F04F 5/02; publ. 16.06. 1998).

The disadvantage of the existing prototype of the inkjet apparatus is that, being used on a steam generator of a nuclear power plant, it does not increase the circulation rate and, as a result, does not provide economic and energy efficiency.

VNIIAES has developed an effective inkjet apparatus. The technical result of the invention is to increase the rate of circulation of feed water on the hot side of the steam generator, leading to an increase in steam production while maintaining its geometric dimensions. In addition, the invention allows:

- negate the loss of steam during condensation compared to the traditional scheme that occurs when the feed water of the steam generator is heated;

- receive more intensive mixing of the coolant in the lowering channels, which reduces the thermal load on the tubular packages;

- to eliminate the breakthrough of steam in the lowering channels;

- level the water level in the steam generator above the hole sheet by trapping water from the area above the hole sheet on the hot side of the steam generator.

The essence of the invention lies in a jet apparatus, which comprises a cylindrical body, placed vertically in the lower channel of the steam generator and connected by a lower part to the guide deflector, a cylindrical nozzle recessed half its length into the upper part of the body with the formation of an annular gap between the cylindrical nozzle and the supply body steam generator feed water into the casing from the area under the hole sheet, tapering channels located inside the walls of the cylindrical nozzle and connected through feed tubes with a distributing manifold with the possibility of feedwater from tapering channels into the housing at an angle of 75 ° to the vertical, while the upper cut of the cylindrical nozzle is connected to a hole sheet that passes the steam generator feed water from the area above the hole sheet to the upper part of the cylindrical nozzle and further into the housing. The housing can have a length of up to 1700 mm to fill the entire length of the lowering channel.

General view of the inkjet apparatus is presented in figure 1.

The inkjet apparatus consists (Fig. 2) of a cylindrical body (1), a cylindrical nozzle (2) for supplying feed water from a distribution manifold, plates (3) for connecting the cylindrical body of the apparatus with a cylindrical nozzle, feed tubes (4), tapering channels ( 5) inside the walls of the cylindrical nozzle (2) (for clarity, the channel is shaded in FIG. 2) and the guide deflector (6). The upper cut of the cylindrical nozzle (2) is connected to the hole sheet (7). The feed tubes (4) supply feed water from the distribution manifold to the narrowing channels (5) connected to them. The shape of the tapering channels (5) inside the walls of the cylindrical nozzle (2) has a spiral shape to create acceleration and obtain a speed of about 10 m / s at the exit of the channels of the cylindrical nozzle, while the inlet in the upper part of the cylindrical nozzle is much wider than in the lower part at the exit (for example, in the upper part there may be 4 mm, in the lower part - 2 mm). The very nature of the narrowing can be both longitudinal and transverse relative to the walls of the cylindrical nozzle. The number of tapering channels in the walls of the cylindrical nozzle (2) is limited only by the geometric dimensions of the cylindrical nozzle (2) of the jet apparatus itself. In the upper part of the cylindrical nozzle (2), the steam generator feed water enters the cylindrical body (1) from the area above the hole sheet (7). In the annular gap between the cylindrical nozzle (2) and the cylindrical body (1), the steam generator feed water enters the cylindrical body (1) from the area under the hole sheet (7). In figure 2, the directional arrows show the motion vector of the feed water of the steam generator from both areas into a cylindrical nozzle (2) and a cylindrical body (1). The guide deflector (6) is designed in such a way as to facilitate the subsequent flow of the mixed stream into the tubular packages (8).

A top view of the proposed inkjet apparatus is presented in figure 3.

When using the proposed jet apparatus, the feed water enters into two rows of distributing collectors located along the body of the steam generator on the hot side of the steam generator, and from them, through the supply tubes (4), is distributed into the jet apparatuses themselves. The number of jet devices depends on the geometric dimensions of the steam generator; for the PGV-1000 steam generator, this number can be from 10 to 20, depending on the number of rows. Inkjet devices are located between the tube bundles - in the lowering channel. The feed water supplied by the supply tubes (4) from the distribution manifold enters the narrowing channels (5) located in the walls of the cylindrical nozzle. At the exit from the cylindrical nozzle (2), the feed water coming out with swirls at an angle of 75 ° to the vertical and at a speed of about 10 m / s at the cut is mixed with a significant part of the steam generator feed water, which enters the cylindrical body as from the upper part of the cylindrical nozzle (2), and from the annular gap between the cylindrical nozzle (2) and the cylindrical body (1) of the jet apparatus. Mixing the feed water from the distributor with the feed water of the steam generator in the cylindrical body (1) of the jet apparatus gives a mono-temperature cross-section flow after exiting the deflector (6) under the tube bundles. The flow, passing through the tubular packets, turns into a steam-water mixture, which rises up and is partially separated by a hole sheet. Above the perforated sheet, the mixture is separated into vapor-water phases by gravitational separation. The steam-water mixture, separated above and below the hole sheet, due to the rarefaction that arises at the cut of the cylindrical nozzle due to the exit of the feed water from the cylindrical nozzle from the distributor at a speed of about 10 m / s, is returned back to the jet apparatus, where the remaining vapor in the separated mixture condenses. The rest of the water flows under the influence of gravity into the lowering channels on the edges of the hole sheet. The separated steam enters the output manifold and then to the turbine.

Thus, thanks to the proposed jet apparatus, a technical result is achieved consisting in removing restrictions on increasing the steam capacity of the steam generator by increasing the multiplicity of feed water circulation on the hot side of the steam generator. This helps to reduce the likelihood of moisture throwing into steam pipelines, reducing the likelihood of sludge deposits on the steam generator tube, as well as the possibility of organizing continuous washing of deposits on the weld seam of the steam generator manifold.

Claims (2)

1. An inkjet apparatus comprising a cylindrical body, placed vertically in the lower channel of the steam generator and connected by a lower part to the guide deflector, a cylindrical nozzle recessed half its length into the upper part of the body with the formation of an annular gap between the cylindrical nozzle and the body for supplying steam water to the steam generator into the casing from the area under the hole sheet, tapering channels located inside the walls of the cylindrical nozzle and connected through the supply tubes to the transfer to collector with the possibility of feeding feed water from the narrowing channels into the housing at an angle of 75 ° to the vertical, while the upper cut of the cylindrical nozzle is connected to the hole sheet, passing the feed water of the steam generator from the area above the hole sheet to the upper part of the cylindrical nozzle and further into the housing. 2. The inkjet apparatus according to claim 1, characterized in that the casing has a length of up to 1700 mm.

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