DE1291953B - Welded passage of a pipeline through the wall of a vessel containing gas or steam under high pressure - Google Patents

Description

The invention relates to a welded implementation of a Piping through the wall of a vessel containing gas or steam under high pressure, in particular a pressure vessel for a steam-cooled nuclear reactor.

Used as a pressure vessel for gases or vapors with a pipe connection provided, if the connection point between the pipeline and the Pressure vessel Risk of accident as a result of the pressure medium flowing out of the too quickly Given pressure vessel. Especially in the case of the pressure vessel of a steam-cooled rapid one Nuclear reactor; there must be a rapid drop in pressure due to a loss of coolant. at least be kept within limits until the reactor is switched off, which for example happens by retracting control rods. A heavy loss of coolant, connected with a large pressure drop, if the reactor is not shut down in time, a Cause runaway, which means at least the destruction of the reactor core. The critical times are in the order of a few tens of milliseconds.

The object of the invention is, in a wall duct of the initially called type the outflow speed of the breakage of the weld from the Pressure vessel to limit escaping gas or steam to a permissible value.

This object is achieved according to the invention in that the pressure vessel a discharge pipe surrounding the pipeline with an open free end is attached, whose cross-section and length are dimensioned so that the speed of the Breakage of the weld from the largest possible flow cross-section given at break : escaping gas or steam is limited to a permissible value.

By choosing the length of the downpipe and its inside diameter the course of the pressure drop can be determined by influencing the flow resistance can be influenced at the outlet point. In the extreme case that the pipeline tears off at the welding point and is completely blown out of the discharge pipe, you can determine the time that also elapses when using the drainage pipe, until the pressure in the pressure vessel has dropped to a certain value. It will for dimensioning the downpipe for this time is based on a value, for example sufficient for the emergency shutdown of a steam-cooled reactor to take effect is.

Arrange one at some distance from the open end of the downcomer Wall in such a way that the pipeline is prevented from being blown out of the discharge pipe is, the pressure drop will be much slower than the free The flow cross-section in the discharge pipe is greatly reduced by the pipeline, especially since the pipeline can often be expected to swell or bend.

In the case of a high-pressure hose, it is known to be at a radial distance Provide a protective hose to safely divert the from the high-pressure hose to serve the escaping medium. But this is about the protection of the Around the high pressure hose, not about the limitation of the outlet speed from a container.

The figure shows an embodiment of the invention. A pressure vessel For example, 10 for a steam-cooled nuclear reactor contains water vapor below 200 atm. A pipe 11 is welded to this pressure vessel. With any If the welding point 12 is broken, the superheated steam enters the annular space, which passes through a discharge pipe 13 and the pipe 11 is formed. The superheated steam flows in this annular space turbulent to the open end 14 of the downcomer. The pipeline 11 should be completely tear off, it is possible that it will be blown out of the discharge pipe 13 entirely or inflates inside the discharge tube, as indicated by dashed lines at 15 is. With these considerations it should be noted that after the pipeline has been torn off 11 also shows the end of the pipeline torn off from the pressure vessel 10 is under high pressure, so that with a puff rather than a simple one Blowing out this part of the pipeline is to be expected. Blowing out can be prevented by some distance from the open end 14 of the downcomer a wall 16 is arranged. This wall can be a grid, for example. That Drainage pipe, which is welded or screwed to the pressure vessel 10, must be torn off the pipeline 11 a shock load by this and a strong pressure wave can withstand the escaping medium. It should also be caused by a flutter the torn off pipeline are not destroyed To reduce the impact stress are between the pipeline and the downcomer resilient elements 17, for example Disc springs, arranged. In addition, there is an elastic fastening of the downpipe 13 on the pressure vessel by means of strong bellows.

In the event that the pipeline 11 expands and the discharge pipe 13 not for the total pressure, e.g. B. 200 atm, holes 18 or predetermined breaking points are intended. .

The discharge pipe 13 can be divided lengthways to simplify assembly be.

Claims (3)

Claims: 1. Welded implementation of a pipeline the wall of a vessel containing gas or steam under high pressure, in particular a pressure vessel for a steam-cooled nuclear reactor, d u r c h e k e n n -z e i c h n e t that a pipe (11) surrounding the pressure vessel (10) Down pipe (13) is attached with an open free end (14), the cross section and Length are dimensioned so that the speed of the breakage of the welding point (12) emerging from the largest possible flow cross-section released in the event of a break Gas or steam is limited to a permissible value. 2. Wall duct according to Claim 1, characterized by resilient elements between the pipeline (11) and the drain pipe (13). 3. Wall bushing according to claim 1 or 2, characterized in that that at some distance from the open end (14) of the discharge pipe (13) a wall in such a way is arranged that prevents the pipe (11) from being blown out of the discharge pipe will.