DE2339922A1 - Primary circuit secondary containment - for light water reactor system - Google Patents

Abstract

Secondary containment for primary circuit pipework comprising an outer enclosing pipe which in the event of a rupture inhibits loss of coolant and obviates emergency reactor shut-down. Used in light water reactors, giving economic enhanced reactor safety.

Description

Licentia
Patent-Verwaltungs-GmbH 6 Prankfurt 70, Theodor-Stern-Kai 1

ί ¹ 73/19

June 26, 1973 gray / white

Core reactor piping.

In most nuclear power plants - especially in all nuclear power plants with light water reactors to which the following considerations refer - is the highly radioactive nuclear fuel of three barriers surround: the first barrier is the fuel cladding, which is intended to prevent fission products from entering ^ the primary system of the Get reactor plant; the second barrier is formed by the reactor pressure vessel and the connected primary system; the third

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Barrier is a containment that holds those parts of the plant in which the main radioactive inventory of the nuclear power plant is located.

Besides the mentioned safety barriers there are also most of them other of the devices necessary for the safety of the reactor, two or more independent systems are provided

In the event of an accident involving a coolant leak from the primary system are connected, protective devices are activated that shut down the reactor and close the passage through the containment and emergency cooling of the reactor core.

For the design of the emergency cooling systems, boiling water reactors a complete rupture of the largest pipeline connected to the reactor pressure vessel is assumed (largest to be assumed Accident "GAU") »with the additional assumption that the pipe ends displaced or shifted as a result of the accident so that the coolant can flow out freely from both ends.

A total loss of coolant, in addition to the damage directly caused by the coolant leak, would be inevitable The result is that the fuel cladding of the uncooled fuel elements would burst. With the help of the emergency cooling system, it can be done reliably prevent the reactor core from melting together, however, are these systems are technically and financially expensive.

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The object of the invention is therefore to ensure the security of the To design the reactor important, in particular the coolant leading, nuclear reactor pipelines so that an accident or incident as a result of the outflow of the medium flowing in it is largely avoided.

In the case of a nuclear reactor line that is surrounded at a distance by a second tube (protective tube), this object is achieved by that to prevent the free escape of the in the inner .Rohrleitung pressurized medium, the protective tube, which extends over the entire area to be protected and in normal Operating condition is depressurized, is sealed at both ends, so that in the case of rupture of the inner one. Pipeline this through the outflowing medium is connected to the second pipeline, the second pipeline being designed so that it can function the inner pipeline, causing a loss of medium

is avoided.

From DT-OS 20 09 848 pipelines are in nuclear reactors known, which are surrounded by a protective box at a distance, but this protective box has the task of protecting the pipelines from impacts As it is open at its ends, it can contain any medium flowing out of the pipeline do not catch; it is also unsuitable in terms of its dimensions, the puncture of the pipeline passing through it to take over.

The same applies to a feed opening known from DT-AS 1 489 857 for a nuclear reactor in which a pipeline from a

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closed singing room is surrounded, which is here for isolation purposes serves.

The advantages of the invention can be seen in the fact that in the event of a leak or a rupture of a pipeline that is important for the safety of the reactor, a free outflow of what is in the pipeline? en medium is prevented by means of the surrounding pipeline enables a reduction in the effort for the safety devices, in particular, there can be almost no loss of coolant, which means that the reactor can be shut down normally, the emergency cooling systems do not have to be put into operation and there is no damage occur due to the escaping coolant; the cross-section on which the design of the emergency cooling systems is based is thus reduced.

An embodiment of the invention is shown in the drawing and described in more detail below.

On the reactor pressure vessel 1 shown, only those are shown in cross section large lines are drawn, namely the main steam line 2 and the feed water lines 3. The right main steam line is shown in section, so that the outer protective tube 4- and its connection with the inner pipe 2 via the wall of the reactor pressure vessel 1 can be seen.

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Claims (1)

-5- ί1 73/19 claims 1. Nuclear reactor pipeline spaced from a second pipeline (Protective tube) is surrounded, characterized in that that to prevent the free escape of the in the inner pipeline under. The medium under pressure Protective tube, which extends over the entire area to be protected and is depressurized in normal operating condition, on both Ends is tightly closed, so that in the event of the breakage of the inner pipeline, this through the outflowing medium with the second pipeline is connected, wherein the second pipeline is designed so that they the function of the inner pipeline can take over, whereby a loss of medium is avoided. 2 Pipeline according to Claim 1, characterized in that that spacers are provided between the walls of the two pipes. 509810/0019 Blank page