Patent Number: 061954063
Section: description

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the figures of the drawings in detail and first, particularly, to FIG. 1 thereof, there is seen a pressurizer 1, which usually forms part of a nuclear power plant with a pressurized water reactor, where it is connected to a hot part or system 12 of a primary circuit through a volume-compensation line 2. If the pressure in the primary circuit were to be too high, water, which can be branched off from a cold part of the primary circuit, is sprayed into the pressurizer 1. To this end, a spray line 3 leads from the cold part or system 13 and ends in the pressurizer 1. A spray valve 4 with a controllable or ON/OFF actuator 5 is disposed in the spray line 3 outside the pressurizer 1. The spray valve 4 is controlled according to the pressure in the primary circuit. Water levels 6a, 6b for zero load and normal operation of the nuclear power plant are indicated in the pressurizer 1. Heater rods 11 are disposed in a lower section of the pressurizer 1. The spray line 3 runs from outside a casing 7 of the pressurizer 1 through a wall of a lower cylindrical part of the casing 7, into an interior of the casing 7, at an oblique angle with respect to the wall. Inside the casing, the spray line 3 runs continuously upward and ends at its geodetically highest point. The spray line 3 is guided along an inner wall surface of the casing 7. The spray line 3 has spray nozzles 8 in the region of its highest point. This portion of the spray line 3 which has the spray nozzles 8 is directed upward at an angle. Water is advantageously sprayed into the pressurizer 1 from its upper region through the use of this configuration. Nevertheless, when the spray valve 4 is closed it is impossible for any part of the spray line 3 between the spray valve 4 and the spray nozzles 8 to become empty. Consequently, it is also impossible for any steam to penetrate into the spray line 3 and condense therein, and there is no possibility of temperature fluctuations or exposure to radiation in the spray line 3. In particular, the spray line 3 inside the pressurizer 1 is only exposed to a slight pressure difference between its interior and its exterior, so that a relatively thin spray line 3 is sufficient, yet there is no risk of the spray line being fractured. Even in the unlikely event of a fracture of the spray line 3 inside the pressurizer 1, the small pressure difference means that there is no possibility of secondary damage caused by recoil effects. FIG. 2 is an enlarged view of a portion of FIG. 1 which shows the structure that allows the spray line 3 to be guided through the wall of the casing 7 at an oblique angle. Inside the casing 7, the spray line 3 is connected to the wall of the casing 7 by clamps 9, which allow the spray line 3 to move in axial direction but do not allow it to rotate. Due to the small pressure differences between the interior and the surroundings of the spray line 3, a relatively thin-walled spray line 3 is sufficient inside the pressurizer 1. A larger wall thickness is required outside the pressurizer 1. A fixed point 10 for the spray line 3 is disposed in the region of the inclined passage through the wall. FIG. 3 shows another embodiment for guiding the spray line 3 through the wall of the casing 7. The FIG. 3 embodiment differs from the embodiment according to FIG. 2 only in that the spray line 3 is guided through the wall at right angles thereto. Although this requires a more complex path for the line as compared to the embodiment according to FIG. 2, the region where it is guided through the wall is simplified. FIG. 4 shows the most advantageous way of guiding the spray line 3 through the wall of the casing 7. The spray line 3 is guided through with slight curvatures at right angles to the wall of the casing 7, in a dome-like part 7a of the casing 7, which closes off the casing 7 at the bottom. In this embodiment, the spray line 3 is also disposed in an inexpensive, stable manner inside the pressurizer 1 over as long a distance as possible. This is because the spray line 3 cannot be guided into the pressurizer 1 directly from below, since that is where the heater rods 11, which are also shown in FIG. 1, are disposed.