CZ281741B6 - Pressure vessel of a reactor with a cover - Google Patents

Abstract

The reactor pressure vessel (1) is provided with a lid (2) and an arrangement for clamping the reactor shaft (6) housed in the reactor pressure vessel (1) to the lid (2). Between the upper ring (7) of the reactor shaft (6) and the cover (2) of the reactor pressure vessel (1) are arranged such that only the elastic deformation of these clamping elements (10) is possible within a predetermined working path (s). At least one guide rail (8) is provided on the cover (2) of the reactor pressure vessel (1) or on the upper ring (7) of the reactor shaft (6), on which the clamping elements (10) are pushed. ŕ

Description

Reactor pressure vessel with lid

Technical field

The present invention relates to a reactor pressure vessel with a lid and an arrangement for clamping a reactor shaft arranged in a reactor pressure vessel to a lid, wherein parallel clamped elastic clamping elements are arranged between the upper ring of the reactor shaft and the reactor pressure vessel lid. only a flexible deformation of these clamping elements is possible in the predetermined working path.

BACKGROUND OF THE INVENTION

In WWER pressurized water reactors, the reactor shaft carrying nuclear installations is clamped to the reactor pressure vessel lid by so-called compensating tube segments. The purpose of these compensating tube segments is to compensate for the buoyancy forces generated by thermohydraulic processes within the reactor pressure vessel acting on the reactor internals and on the reactor shaft. In this way, stable clamping ratios of the reactor shaft should be provided in order to reduce or eliminate the risk of harmful processes due to wear during operation or to guarantee the safe operation of the nuclear installation. These known compensating tube segments create the clamping forces required for stabilization due to excessive clamping and elastic deformation.

In practice, however, it has been shown that the known compensation tube segments exhibit large plastic deformations already after one year of operation. As a result, damage to the reactor internals is not excluded when these plastic deformed compensation tube segments are used again. In addition, an additional examination of the elastic properties of the already plastically deformed compensation tube segment without further plastic deformation and the consequent reduction of its residual elasticity, i.e. the failure of its elastic properties, is impossible.

In addition, large amounts of heavily radioactive contaminated waste occur when these compensating tube segments are replaced.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a reactor pressure vessel with a lid and an arrangement for clamping the reactor shaft in a reactor pressure vessel that provides stable clamping conditions over a longer period of time.

SUMMARY OF THE INVENTION

This is accomplished by a reactor pressure vessel with a lid and a reactor shaft clamping arrangement disposed in the reactor pressure vessel to the lid, wherein parallel spaced flexible clamping elements are arranged between the upper ring of the reactor shaft and the reactor pressure vessel lid and are arranged such that According to the invention, only the elastic deformation of these clamping elements is possible according to the predetermined working path, which is based on the fact that on the cover of the reactor pressure vessel or on the upper ring of the shaft

At least one guide rail is provided to which the clamping elements are slid.

By this measure, these clamping elements can be easily assembled and disassembled.

In order to avoid plastic deformation of the clamping elements, secure stabilizing clamping ratios are provided over a longer period of operation. In addition, since a plurality of independent spring clamping elements are provided, only those clamping elements which have actually been found to be worn must be replaced during maintenance. This reduces the amount of radioactive waste occurring.

To limit the working path, a mechanical stop is preferably provided on the upper ring of the reactor shaft.

According to a preferred embodiment of the invention, the clamping elements each comprise a resiliently mounted compression stiffening element with a convex end face which is supported by the convex end face on a base rail arranged on the upper ring of the reactor shaft or the reactor pressure vessel lid and provided with concave recesses.

According to a further advantageous embodiment, the clamping elements each comprise a guide sleeve for the push-in reinforcement element, which can be pushed onto the guide rail and provided with a mechanical stop for the push-in reinforcement element.

Finally, according to yet another preferred embodiment, at least one disc spring is provided for resiliently receiving the compression reinforcement element, which is clamped at least indirectly between the guide rail and the compression reinforcement element.

Overview of the drawings

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view of a portion of the pressure vessel in the lid region and the arrangement according to the invention; FIG. 3 and 4, a portion of the lid support ring and a portion of the reactor shaft ring, respectively, seen from below and from above, respectively.

DETAILED DESCRIPTION OF THE INVENTION

In the reactor pressure vessel 1, clamping elements 10 are arranged between the support ring 4 arranged on the lid 2 and the upper ring 7 of the reactor shaft 6, supported on the wall of the reactor pressure vessel 1. These clamping elements 10 clamp the reactor shaft 6 to the cover 2 fixedly screwed to the reactor pressure vessel body 1.

-2GB 281741 B6

The clamping elements 10 consist of a guide sleeve 12 which is slid onto a dovetail-shaped guide rail 8 arranged on the support ring 4.

A push-in reinforcement element 14 engages the guide sleeve 12, which is pushed outwardly so that it protrudes from the guide sleeve when the guide sleeve 12 is slid onto the guide rail 8, by a bundle of disc springs 16 resting on the pressure ring 18 on the guide rail 8. 12. The compression stiffening element 14 is provided with a collar 142 which, when the compression stiffening element 14 is fully pushed out, is supported by the ring spring assembly 16 on the annular projection 121 of the guide sleeve 12. The annular projection 121 therefore forms a mechanical stop for the compression reinforcement element 14.

Instead of disk springs 16 or disk spring bundles 16, spring leaf segments or compression spring segments such as coil springs may be provided in the clamping elements 10.

FIG. 1 shows an assembled situation in which a gap with _1f has been formed between the collar 142 and the annular projection 121 corresponding to the bias of the clamping element 10.

A guide pin 20 is provided on the compression reinforcement element 14 to receive the disk spring bundle 16.

The compression stiffening element 14 is provided with a convex face 141 which is supported by a concave recess 91 in the base bar 9 arranged on the upper ring 7 of the reactor shaft 6. By this convex or concave shaping of the surfaces facing each other, centering of the compression reinforcing element 14 is guaranteed.

FIG. 1 shows the maximum possible predetermined working path with the reactor shafts 6. This working path s is formed by mechanical stops not shown in FIG. 1 and limits the possible stroke of the reactor shaft 6 with respect to the lid 2. The working path s is shorter than the spring paths due to the design of the guide sleeve 12 which are limited between the guide pin 20 and the end face of the guide rail 8, or the distance of the lower end face of the guide sleeve 12 from the base bar 9. The disc spring pack 16 is dimensioned such that in the assembled state of the springs 16 and hence of the clamping element 10.

Instead of a guide rail 8 mounted on the lid 2 and intended to receive the clamping elements 10, a guide rail 8 can also be provided on the upper ring 7 of the reactor shaft 6. According to another embodiment, clamping elements can be provided which are encapsulated in segmented guide rails. which are detachably connected in positions adapted for compensating tube segments to the upper ring 7 of the reactor shaft 6.

FIG. 2 shows the maximum possible working path s. In this case, the working path is defined by a mechanical dome stop 30 screwed to the reactor shaft 6.

-3GB 281741 B6

FIG. 3 shows that a plurality of segmented annular guide rails 8 are provided on the support ring 4, on which a plurality of clamping elements 10 are always mounted. These clamping elements 10 are independent units detachably connected to the guide rails 8 fixed to each other. on the support ring 4, these units can be independently checked and replaced individually if necessary.

Similarly, in Fig. 4, several segmented base strips 9 are provided, which are provided with clamping elements 10 with concave recesses 91. In Fig. 4, mechanical stops 30 are also arranged between the individual strips 9.

Claims (5)

PATENT CLAIMS A reactor pressure vessel (1) with a lid (2) and an arrangement for clamping a reactor shaft (6) arranged in a reactor pressure vessel (1) to a lid (2), wherein between the upper ring (7) of the reactor shaft (6) and the cover (2) of the reactor pressure vessel (1) are arranged parallel elastic clamping elements (10), which are arranged such that only a flexible deformation of these clamping elements (10) is possible within a predetermined working path (s). in that at least one guide rail (8) is provided on the cover (2) of the reactor pressure vessel (1) or on the upper ring (7) of the reactor shaft (6), onto which the clamping elements (10) are slid. A pressure vessel according to claim 1, characterized in that a mechanical stop (30) is provided on the upper ring (7) of the reactor shaft (6) for limiting the working path (s). Pressure vessel according to claim 1 or 2, characterized in that the clamping elements (10) each comprise a resiliently mounted compression reinforcement element (14) with a convex end face (141) which is supported by the convex end face (141) on the base. a rail (9) arranged on the upper ring (7) of the reactor shaft (6) or on the lid (2) of the reactor pressure vessel (1) and provided with concave recesses (91). Pressure vessel according to claim 3, characterized in that the clamping elements (10) each comprise a guide sleeve (12) for a push-in reinforcement element (14) slidable on the guide rail (8) and provided with a mechanical stop (121) for push-in reinforcement element (13). Pressure vessel according to claim 3 or 4, characterized in that at least one disc spring (16) is arranged for resiliently receiving the compression reinforcement element (14), which is clamped at least indirectly between the guide rail (8) and the compression reinforcement element (14). 14).