Device for securing active zone of the nuclear reactor with pressurized water

 

(57) Abstract:

Usage: in devices for fastening equipment installed inside a pressure vessel of a nuclear reactor containing the annular elastic element. The essence of the invention: each of the annular segments of the elastic element is made in the form of helical springs, which fits planted cylindrical rings. 5 Il.

The invention relates to a device for fastening internal equipment of a nuclear reactor, namely, devices for securing active zones in the reactor with pressurized water and washed by the cooling fluid.

It is known device [1] to secure the active zone containing the reference cylinder, mounted on the flange on the pressure vessel of a nuclear reactor, the elastic element is disposed between the flanges of the support and the pressure cylinder, biasing the lid of the reactor. The elastic element is made of pipe and contains several ring segments secured to the upper surface of the flange of the support cylinder. The compression of the elastic element is in the sealing of the connector receptacle. This creates a clamping force, which, along with the t of the reference cylinder to the support and keep it from surfacing when exposed to a pressure drop of coolant.

A disadvantage of the known device is that during the transition to the loading of the reactor fuel assemblies with a frame made of zirconium alloy instead of fuel assemblies with stainless steel frame is a significant reduction in the force generated by compression springs in the heads of fuel assemblies unit pressure pipes as output when the operating temperature of the heat carrier Zirconia framework of the fuel Assembly is extended to 12-15 mm less than the corresponding channel, formed by the reactor internals are made of stainless steel 08KH18N10T (value movements taken for VVER-1000 reactor with a length of fuel 3.5 m).

When the reduction of the pressing force from the spring units of fuel assemblies there is a need to compensate for pressure support and pressure cylinders by increasing the force from the elastic element. Otherwise, the internals will break away from the supports that are given to vibration as their own, and fuel assemblies, and regulators, i.e., significantly reduced the reliability of the reactor.

The weakening of the pressure vessel internals to the supports can also occur and exposure.

In the limited space allowed in a nuclear reactor for placement of the elastic element, the increase of the pressing force can be achieved, for example, by increasing the wall thickness of the toroidal ring segment. In this case, simultaneously with the increase of linear load decreases the amount of elastic deformation (both relative and absolute), and also decreases the relaxation resistance of such pipes, which necessitates early (before the end of the fuel company) replacement of the elastic element.

The aim of the invention is to increase the carrying capacity of the elastic element, retaining the reference cylinder with an active area of ascent, without increasing the dimensions of the elastic element, reducing the vibration of the internal elements of the device and the active zone during the transition to fuel loading with zirconium frame.

The device according to the invention is characterized by the fact that each of the annular segments of the elastic element is made in the form of helical springs, which fits planted cylindrical rings.

In Fig. 1 shows a diagram of a nuclear reactor, a longitudinal section; Fig.2 section a-a in Fig.1; Fig.3 section b-B in Fig.1; n is ASS="ptx2">

The reactor device for securing the support cylinder with the active zone comprises a vessel 1 under pressure, the sealing cover 2. In the vessel 1 is mounted on the flange 3 of the supporting cylinder 4 with an active area containing the fuel assemblies 5. Between the flange 3 of the reference cylinder and the flange 6 of the pressure cylinder communicating with the end cover 2, has elastic element containing the number of ring segments 7, secured to the flange 3. Each of the segments 7 includes a cylindrical helical spring 8, which is mounted with tension cylindrical ring 9. The vessel 1 is equipped with a suction inlet 10 and the outlet pipe 11 and forms with the wall of the support cylinder 4 and lowering the channel 12 of the brine circuit in the reactor.

The device operates as follows.

The cold fluid enters the pipe 10, having a buried channel 12 through the holes in the bottom of the supporting cylinder, enters the active zone, takes heat from the fuel assemblies 5 and heated, goes through the pipe 11 from the reactor. During the flow of coolant through the reactor pressure decreases and the pressure difference at the inlet and outlet is the force that pushes the supporting cylinder up, if the reference weight kg condition for keeping the supporting cylinder and teplovidelyaushy assemblies from significant movements (causing deterioration and destruction under the influence of the flowing fluid. When sealing the main connector cover 2 through the flange 6 of the pressure cylinder and the elastic segment 7 passes on the flange of the support cylinder, the required contact force, deforming the spring 8 and the ring 9. Since the spring 8 and the ring 9 are made of high strength spring material (for example, of heat-resistant corrosion-resistant alloy HNTR), the elastic element with the same dimensions as the pipe in the prototype (for example, utilized in the industrial production of steel pipe ONT), can withstand much greater linear load than the prototype (2-4 times).

Thus, the proposed design of the elastic element makes it possible to increase the contact force of the reference cylinder to the required size without increasing its size, that provides the necessary reliability of the reactor.

Device for securing active zone of the nuclear reactor with pressurized water containing the reference cylinder, mounted on the flange on the pressure vessel, the elastic element comprising a number of adjacent ring segments secured to the upper surface of the flange of the support cylinder, cooperating with the flange of the pressure cylinder, biasing the end cap receptacle Pavlichenko springs, which fits planted cylindrical rings.

 

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