DE1208833B - Boiling water core reactor with steam-water separators arranged inside the reactor pressure vessel - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. α .:

G21d

German KX: 21 g - 21/24

Number: 1208 833

File number: L 37098 VIII c / 21 g

Filing date: September 23, 1960

Opened on: January 13, 1966

The invention relates to a boiling water core reactor with arranged inside the reactor pressure vessel Devices for separating the vapor-liquid mixture emerging from the reactor core, which consist of guide devices placed on the reactor core that control the flow divide the steam-water mixture into several vertically directed partial flows and these deflect radially and provide the steam discharge pipes opening above the water surface are.

The task of boiling water core reactors is to control the steam-water mixture emerging from the reactor core to separate, remove the steam as dry as possible and the water as free from vapor bubbles as possible to dissipate. The entrainment of water in the steam creates difficulties in the turbine or in the Superheaters, for example due to erosion or the spread of activity. Taken steam bubbles in the water would furthermore the subcooling of the water re-entering the reactor core prevent and thus worsen the operating conditions.

In the case of boiling water nuclear reactors with a low output or in the case of boiling water nuclear reactors with a lower output With a specific load, the desired separation takes place in a more satisfactory manner without any special effort Way by gravity alone, because there is enough time for the steam-water mixture between Drainage from the core and drainage of the separate components is available. at Increase in the specific output, but especially when the absolute output of the Reactor, however, a point is reached at which the separation will not occur without special measures more takes place to a sufficient extent.

In order to achieve the desired deposition in such reactors, one can either by Increasing the water surface, increasing the times available for separation, because this reduces the speeds, or you can install mechanical separators. The first solution has the disadvantage that it enlarges the pressure vessel considerably and thus as a whole an extraordinary agile solution is achieved. In large reactors, the water level is found because of the maximum feasible size of the pressure vessels quickly reached its limit.

A centrifugal water separator for boiling water nuclear reactors has become known in which each fuel assembly box carries the actual separator via a chimney. This consists essentially of boiling water nuclear reactor with within the
Reactor pressure vessel arranged
Steam-water separators

Applicant:

Licentia Patent-Verwaltungs-G. m. b. H.,

Frankfurt / M., Theodor-Stern-Kai 1

Named as inventor:
Dr.-Ing. Heinz Kornbichler,
Falkenstein (Taunus)

from a frustoconical frustoconical perforated sleeve, at the entrance of which a ring of fixed guide vanes is attached. However, these guide vanes whirl through the mixture and thus counteract any separation that has already taken place.
In another known separator, the mixture is fed to several vortex chamber separators, from which the water flows off, while the steam escapes upwards. Here, too, there is the disadvantage of a reduction in the volume of vapor bubbles in the separators. The pressure loss is also relatively large.

The present device avoids these disadvantages by, according to the invention, the guide devices from each of the partial flows branch off further partial flows at different heights and these branch off radially and deflect it downwards, slowing the flow.

The guide devices are designed in such a way that the branched off from each partial flow Water almost horizontally between the neighboring ones, for the rising steam-water mixture provided riser pipes can flow off. Between the guiding devices and the steam room Above the water level pipes are arranged in such a way that the separated steam upwards can be discharged. Means for throttling the currents can also be provided in the guiding devices will. To strengthen the separation

E09 778/289

swirl generators can also be arranged will.

With such a design of the nuclear reactor, the decisive advantage of natural separation remains, namely the low pressure loss, while the disadvantage of the natural separation, namely, the poor functioning at high specific loads, is prevented. Also needs the pressure vessel does not have to be enlarged in diameter, but at most an extension results this vessel, which is less important in terms of design and construction costs.

To further explain the subject matter of the invention, various FIGS. 1 and 2 are shown Embodiments shown schematically.

The reactor core 1 - consisting of a large number of fuel elements - is located in the reactor pressure vessel 2 1 Form steam bubbles. Since the density of the heated water and that of the steam is lower than the density of the colder water, the steam-water mixture rises and flows through a multi-cell chimney 3 into the steam-water separator 4. This separator consists, for example, of several stacked bell-shaped sheets 5, 6, 7 (see Fig. 1). It is known from experience that the steam content is greatest in the middle of a steam flow, while the steam content is lower at the pipe walls. If the pipe wall is interrupted at suitable points, the free pipe end is washed around by a portion of the flow which has a lower vapor bubble concentration. The part that is now deflected and directed downwards has such a low speed that the vapor bubbles still contained in it find enough time to rise. The bell shape of the pipe sections 5,6 and 7 are the. rising bubbles are fed back into the main stream, while the water content is fed to the downward-directed water cycle. If several bell-shaped pipe sections are connected one behind the other, it is possible in this way to withdraw a large part of the water content from the steam-water mixture without the natural circulation being disturbed by a large pressure loss. The separation of the remaining water at the upper end is then possible in a simple manner by means of baffle plates 9 and fine dryers 12 known per se. The steam that escapes through the pipe connection 11 then collects in space 10.

The in F i g. 2 is based on the same separation principle. - "

In the reactor core 1, which is located in the reactor pressure vessel 2, the coolant is heated in such a way that a steam-water mixture is formed. This mixture rises due to its lower density and reaches a chimney 3, which can also be omitted. The chimney or the reactor core is followed by the arrangement for separating and deflecting the steam-water flow, which consists of suitably shaped sheets such as 4, 5, 6 and 7. The mixture is divided into partial flows by the metal sheets 5 and 6, among other things, with each partial flow being guided radially outwards and / or downwards through separation ducts 7. With this arrangement, too, the deflected and downwardly directed portion has a lower speed, so that the vapor bubbles contained in it find sufficient time to rise. In order to be able to lead the vapor bubbles already separated from the lower part of the separating arrangement upwards without the rest of the current flow being disturbed, there are steam discharge pipes 8 in the separating arrangement Drops of water that are still entrained are ejected. The steam then collects in space 10 and can escape through pipe connection 11.

To support the vapor deposition, it can be advantageous in special cases, for example at the upper end of the tubes 8, instead of the baffles 9, swirl separator, not shown here to be provided.

To vary the buoyancy, it can also be advantageous to have the individual partial flows already from the To lead the reactor core separately.

To get the right flow velocities for the outflowing water in the individual separation channels to achieve, in particular to the entrainment of steam due to excessive speeds To prevent certain points, suitable throttling points can also be installed.

Claims (5)

Patent claims: 1. Boiling water nuclear reactor with facilities arranged within the reactor pressure vessel for separating the vapor-liquid mixture emerging from the reactor core, which consist of guide devices placed on the reactor core, which control the flow of the Divide the steam-water mixture into several vertically directed partial flows and these radially deflect, and provide the steam discharge pipes opening above the water surface are, characterized in that the guiding devices of each of the substreams branch off further substreams at different heights and these radially and afterwards deflect below, slowing the flow. 2. boiling water nuclear reactor according to claim 1, characterized in that the guide devices consist of parallel, side by side and vertically arranged tubes, which consist of assemble bell-shaped pipe sections with the larger opening facing downwards are stacked. 3. Boiling water nuclear reactor according to claim 1, - "" characterized in that the guide devices made of concentrically arranged, from the outside to the inside at increasing heights Ending hollow, mushroom-shaped baffles and consist of different heights of steam discharge pipes from the convex with respect to the reactor core curved upper edges of the baffles up into the space above the Lead water surface. 4. boiling water nuclear reactor according to one or more of claims 1 to 3, characterized in that that above the steam outlet openings arranged above the water surface Guiding devices baffle plates are arranged. 5. Boiling water nuclear reactor according to one or more of claims 1 to 4, characterized in that that before the steam outlet opening from the reactor pressure vessel steam drying devices are arranged. Documents considered: German Patent No. 931170; German Auslegeschriften No. 1082 992,1031899; French Patent No. 1048157; British Patent No. 820,466. 1 sheet of drawings 509 778/289 1.66 © Bundesdruckerei Berlin