Nuclear technology plant and method for the pressure relief of a nuclear technology plant
A nuclear plant has a containment shell and a pressure relief pipe connected thereto in which a blowing device and a Venturi washer placed in a container with a washing liquid are connected in series. Even the finest particles or aerosols carried by air are held in the Venturi washer with a very high degree of reliability and the release thereof in environment is excluded in a particularly reliable manner in the case of decompression even associated with seal failures. For this purpose, the size of the blowing device and the Venturi washer are selected in such a way that during the operation of the blowing device a flow rate of liquid in the Venturi washer flowing to the decompressing pipe is higher than 130 m/sec, preferably higher than 180 m/sec.
1. A nuclear plant, comprising:
a containment;
a pressure relief line communicating with said containment and enabling pressure relief in said containment by blowing off a pressure relief gas;
a blower device and a venturi scrubber connected in series in said pressure relief line, said venturi scrubber being disposed in a container with a scrubbing liquid;
said blower device and said venturi scrubber being dimensioned to establish in said venturi scrubber, in an operating state of said blower device, a flow velocity of the pressure relief gas conveyed in said pressure relief line of more than 130 m/s;
said blower device connected upstream from said venturi scrubber;
said venturi scrubber including a venturi tube configured to be passively fed with a scrubbing liquid due to a negative pressure at the constriction of said venturi tube, and
said venturi tube is formed with an entry region configured to be fed with the scrubbing liquid.
2. The nuclear plant according to claim 1 , wherein said blower device and said venturi scrubber are dimensioned to establish a flow velocity of the pressure relief gas of more than 180 m/s in said venturi scrubber.
3. The nuclear plant according to claim 1 , wherein said blower device is a radial fan with a rated speed of more than 10,000 rpm and a pressure of at least 200 mbar.
4. The nuclear plant according to claim 3 , wherein said blower device is rated for a pressure of more than 500 mbar.
5. The nuclear plant according to claim 1 , wherein said venturi scrubber comprises a multiplicity of venturi tubes having outlets, a comparatively large number of said venturi tubes are disposed with the respective said outlets above an intended setpoint level of the scrubbing liquid, and a comparatively small number of said venturi tubes are disposed with an outlet direction directed downward.
6. The nuclear plant according to claim 5 , wherein up to approximately 10% of said venturi tubes are disposed with the outlet direction directed downward.
7. The nuclear plant according to claim 1 , wherein said venturi scrubber comprises a plurality of venturi tubes having a throat cross-sectional area and an inlet cross-section area for the scrubbing liquid, and a ratio of said throat cross-sectional area to said inlet area is less than 10:1.
8. The nuclear plant according to claim 7 , wherein said ratio is approximately 3:1.
9. The nuclear plant according to claim 1 , wherein said venturi scrubber comprises a plurality of substantially round venturi tubes with a throat width of less than about 80 mm.
10. The nuclear plant according to claim 9 , wherein said throat width of said venturi tubes is less than about 40 mm.
11. The nuclear plant according to claim 1 , wherein said venturi scrubber comprises a plurality of substantially flat venturi tubes with a throat width of less than about 100 mm.
12. The nuclear plant according to claim 1 , wherein said venturi scrubber comprises a plurality of venturi tubes with a height to throat width ratio of more than 20.
13. The nuclear plant according to claim 1 , wherein said venturi scrubber comprises a plurality of venturi tubes with a height to throat width ratio of more than 50.
14. The nuclear plant according to claim 1 , which further comprises a scrubbing liquid reservoir connected to said container on a scrubbing liquid side thereof.
15. The nuclear plant according to claim 1 , which further comprises a feedback line connecting a scrubbing liquid side of said container to an interior of said containment.
16. The nuclear plant according to claim 15 , wherein said feedback line is connected via said pressure relief line to the interior of said containment.
17. The nuclear plant according to claim 16 , wherein said container is disposed geodetically lying at least approximately 5 m higher than an exit point of said pressure relief line from said containment.
18. The nuclear plant according to claim 17 , wherein said container is disposed at least 10 m above said exit point.
19. The nuclear plant according to claim 1 , wherein said pressure relief line, said blower device, and said venturi scrubber together form a pressure relief and activity retention system, and wherein an electrical power supply of the system components of said pressure relief and activity retention system, including control systems thereof, is constructed independently of the nuclear plant.
20. The nuclear plant according to claim 1 , wherein said blower device is dimensioned so that, taking into account gases and vapor mixtures and leaks produced during incidents in a core region, a negative pressure of less than 5 mbar in an interior of said containment, a positive head pressure of approximately 500 mbar on a pressure side of said blower device is established during operation of said blower device.
21. The nuclear plant according to claim 1 , which further comprises at least one of a centrifugal drop separator and a fiber separator connected in said pressure relief line downstream of said venturi scrubber.
22. The nuclear plant according to claim 21 , wherein said fiber separator has fibers with a thickness of more than 50 μm.
23. The nuclear plant according to claim 21 , wherein said fiber separator has fibers with decreasing fiber thickness.
24. The nuclear plant according to claim 1 , which further comprises a metal fiber filter with a fiber thickness of up to 5 μm connected in said pressure relief line downstream of said venturi scrubber.
25. The nuclear plant according to claim 24 , wherein said metal fiber filter has stainless steel fibers or sintered filter fibers with pore or fiber diameters of less than 5 μm.
26. The nuclear plant according to claim 1 , wherein the scrubbing liquid in said container has a pH of at least 9.
27. A method for relieving pressure in the nuclear plant according to claim 1 , which comprises:
subjecting the venturi scrubber to a flow velocity of the pressure relief gas conveyed in said pressure relief line of more than 130 m/s; and
connecting said blower device upstream from said venturi scrubber.
28. The method according to claim 27 , which comprises setting the flow velocity to more than 180 m/s.
29. The nuclear plant according to claim 1 , wherein: said venturi tube has at least one feature selected from the group consisting of: a nozzle with a nozzle circumference and an annular slot feed around said nozzle circumference, a throat width of less than 80 mm, a flat construction with a throat width of less than 100 mm, a height to throat width ratio of more than 20.