DE8618773U1 - Device for opening flaps held closed with shear pins on steam generator overflow ceilings in nuclear power plants - Google Patents

Description

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Dr. Helmut Franke

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Description

' Steam generator overflow ceilings in nuclear power plants:

* Device for opening flaps held closed with shear pins on

In nuclear power plants, particularly those with pressurized water reactors of the KWU type, certain incidents make it necessary to open the dampers of the steam generator overflow covers and keep them open.

These overflow covers are primarily designed to open in the event of an overpressure both below and above the overflow covers and to enable pressure equalization. On the one hand, they consist of flaps that open upwards and have the shape of horizontal doors and, on the other hand, of additional flaps integrated into the surface of these flaps that open downwards.

The latter are hinged on one side, around which they can swing downwards, and on the opposite side

held by shear pins. These shear pins break when there is sufficient excess pressure above the flaps and allow the flaps to swing open at the bottom. The flaps that open upwards close after

Pressure equalization again through gravity.

In certain accidents, it is necessary to open and keep open the flaps in the overflow ceiling even without the presence of overpressure in order to allow the H- formed during the accident to rise to the recombiners.

To date, devices have been used to pull up the upward-opening flaps and keep them open. This method is suitable for controlling the accident, but requires complex equipment.

The invention is based on the object of opening and keeping open flaps on the overhead door using simpler and yet reliable devices, regardless of the presence of a pressure difference, without these devices hindering the opening during pressure equalization.

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Helmut Franke
Description

Device for opening flaps held closed with shear pins type damper generator overflow covers “in nuclear power plants:

This object is achieved according to the invention in that the shear pins on the downwardly opening flaps are actuated by electrically, mechanically or pneumatically driven devices, whereby the flaps swing downwards under the force of gravity.

A possible embodiment of the invention is described below. According to this embodiment of the invention, the force required to shear off the shear pin is generated by an air spring bellows which is supported on the flap frame directly or via an intermediate piece and presses directly or via a force-enhancing lever mechanism onto the flap surface, expands when compressed air is introduced and shears off the shear pin.

According to a further development of the invention, flow limiters are installed in the compressed air lines between the collecting line and the branch lines to the individual air spring bellows, which prevent a loss of pressure in the system in the event of leaks in individual branch lines or air spring bellows.

Dr. Helmut Franke A.Z. G 86 18 773*2

$^£&L3±klüi<i'.list of references Device for opening flaps held shut with a safety pin on steam turbine overflow ceilings in nuclear power plants'«

Fig. I: Function with overpressure from below Fig. Hi Function with overpressure from above AUk TTTi n«v4s{'l A~~ 7ii ^ &lgr;&Phi; - Iy 1 &ldquor;&ldquor;&ldquor;&ldquor;&ldquor; rivu jb s J, ■ &kgr;* ouur &igr;u<?re=u£7uu<iivi uyp &sgr;&igr;&igr;

1 upward opening flap

2 downward opening flap

3 hinges of the additional flaps

4 Seer's Fee

5 flap frames

6 Air spring bellows

7 Press-air line - step line

8 Compressed air line - collecting line

9 Current limiter

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Claims (3)

Dr. Helmut Franke Protection claims Device for opening flaps held closed with shear pins on steam generator overflow ceilings in nuclear power plants: 1. Device for opening flaps held closed by shear pins on steam generator overflow ceilings in nuclear power plants, characterized in that the shear pins on the downwardly opening flaps are sheared off by electrically, mechanically or pneumatically driven devices. 2. Device for opening flaps held closed by shear pins according to claim 1, characterized in that the force required to shear off the shear pin is generated by air spring bellows, which are supported on the flap frame directly or via an intermediate piece and press on the flap directly or via a force-enhancing lever mechanism, expand when compressed air is introduced and shear off the shear pins. 3. Device according to claim 1 and 2, characterized in that flow restrictors are installed in the compressed air lines between the collecting lines and branch lines to the individual air spring bellows, which prevent a loss of pressure in the system in the event of leaks in individual branch lines or air spring bellows. · II II II III Ii