DE2641327A1 - RADIAL BURST DEVICE FOR PRESSURE TANK SURROUNDED BY A REINFORCED CONCRETE SURFACE, IN PARTICULAR FOR REACTOR PRESSURE TANK - Google Patents

Description

KRAFTWERK UNION AKTIENGESELLSCHAFT Our mark

76P 9 37 4 FRG

Radial burst protection for pressure vessels surrounded by a reinforced concrete shell , especially for reactor pressure vessels

The invention relates to a radial burst protection device for pressure vessels surrounded by a reinforced concrete casing, in particular for reactor pressure vessels, with heat-insulating pressure bodies distributed over the surface to be protected against bursting, the are distributed both in the circumferential direction and axially parallel around the pressure vessel, and with ring tendons in the form of Steel wires, rods or bands that run concentrically to the longitudinal axis of the container and encircle the pressure hulls, with radial ones Pressure forces of the pressure bodies, which they exert on the container wall in the operating state, due to hoop tensioning of the ring tendons are producible. The reinforced concrete shell can in particular be a prestressed concrete shell and usually serves as a biological one Shield for the reactor pressure vessel (RPV).

Such a burst protection is essentially known from DT-PS 1 542 420. Here, the pressure bodies consist in particular of ceramic support elements. The hoop tension of the ring tendons results from the thermal expansion of the pressure vessel and cannot be adjusted mechanically. A uniform and reliable adjustability is of particular importance for pressure vessels in general and for reactor pressure vessels in particular, if it is to be excluded that the probability of failure increases due to uneven and uncontrolled introduction of force. A nuclear reactor plant is also known (DT-OS 2 334 773), in which the eur burst protection apart from an axial bracing of the pressure vessel by means of hydraulics

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pivotable hook in the radial direction realizes a so-called zero travel burst protection is, in which the pressure vessel in the radial gap between it and the biological shield of a Insulating concrete jacket and a compacted bed of gravel, Ceramic parts or the like. is surrounded. Here the Setting a defined radial gap is relatively difficult. The circumferential stresses of the pressure vessel cannot be reduced.

Based on a radial burst protection for pressure vessels of the type mentioned at the beginning, the invention is based on the object to train the radial burst protection so that a defined Adjustability of the radial force exerted by the ring tendons on the pressure vessel in operational or bursting cases Pressure forces is guaranteed. In particular, the burst protection should be able to reduce the hoop stress of the ring tendons To make adjustable so that both a so-called zero-way burst protection is achievable (in which the reactor pressure vessel in the warm operating state practically has the radial gap zero to the surrounding it has burst protection sheath) as well as a more or less strong takeover of TJmfangssspannungsverbindungen of Container wall is made possible by the ring tendons. One distinguishes between burst protection (no influence on the stress state of the RPV, but only restriction of the effects or consequential damage from a burst event) and burst protection (influencing the stress state of the RPV or the component and thereby reducing the risk of cancellation OB). Here as well as before and In the following, however, the term "burst protection" should also include the term "burst protection", i.e. not exclude it, and vice versa, unless a distinction is expressly made between burst protection and protection against bursting.

According to the invention, the tasks set in a radial Burst protection of the type mentioned at the outset is achieved in that radial tendons which engage the ring tendons, penetrate the concrete casing and can be tensioned from the outside are provided and that the radial forces of the pressure body by adjusting the elongation of the radial tendons and thus the tensile prestress of the Ring tendons are adjustable, and / or that the expansion

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part, which the ring tendons in addition to the expansion already applied by means of the radial tendons due to the radial expansion of the pressure vessel can be canceled by additional mechanical expansion of the radial tendons. By clamping the gate (Increasing the force) and / or releasing (relieving) the force in the radial tendons can be the one introduced into the reactor pressure vessel The force can be changed and the desired values adjusted. One can create a gap in front of a thermal radial Pressure vessel expansion is present, measured by the distance setting of the pressure body and thus the nominal circumferential stress in the pressure vessel wall due to radial expansion restraint when the pressure vessel warms up to operating temperature baw. is located influence in a predefinable way.

The advantages that can be achieved with the invention are primarily to be seen in the fact that one of the needs of super-protected reactor systems adaptable radial burst protection was created, with which various radial burst protection concepts without additional effort are realized. So the ring tendons can be dimensioned so that they are capable of the possible bursting (longitudinal crack) of the reactor pressure vessel to absorb forces, in which case the biological shield in prestressed concrete container construction can provide additional security. Here, the ring tendons are expediently so tensioned by the radial tendons and dimensioned the radial gaps so that by a radial expansion restriction of the reactor pressure vessel even in its normal operating state, a more or less large proportion of its circumferential stress occurs the ring tendons is taken over. The expansion of the ring tendons by prestressing the radial tendons has in the main purpose is that - before the ring tendons experience an expansion due to thermal expansion of the pressure vessel - there is a tensile force in the radial tendons. Any change in elongation of the ring tendons (e.g. due to Discharge of the radial tendons, caused by thermal expansion of the pressure vessel or creep deformation of the concrete structure) a change in this pulling force. With commercially available measuring devices (load cell), the change in the tensile force controlled and monitored in the radial tension rods

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den, which is also the respective state of tension of the pressure vessel is detected radially and tangentially.

However, it is also possible to prestress the ring tendons in this way and to dimension the radial gaps so that in the operating state of the reactor pressure vessel only a small part of its hoop stresses is taken over by the ring tendons, in the event of a bursting, both the ring tendons and the prestressed concrete structure of the biological shield act as burst protection, since in the event of a burst the ring tendons are initially expanded against their prestressing force in such a way that a frictional connection from the reactor pressure vessel via the pressure hull, Crossheads, ring tendons and fillers are given to the biological shield. Finally, according to a third burst protection concept provided that the sum of all gap widths between pressure vessels generated by assembly or mechanical expansion and the ring tendons is greater than the radial expansion of the pressure vessel which it experiences when starting from the cold state is brought to operating temperature and operating pressure. This is an actual burst protection for Difference from the actual burst protection. Particularly beneficial it is when in the installed state by subsequent mechanical increase or decrease of the tensile forces of the radial tendons the previously existing stress state of the pressure vessel to be protected can be changed.

The invention takes into account the problems that exist in nuclear reactor construction, where on the one hand the deformation paths of the overall construction due to the appropriate selection of materials for the individual components can no longer be reduced sufficiently and where on the other hand also the tolerances cannot be specified more closely, unless there is a risk of uncontrolled introduction of force should exist in the pressure vessel.

According to a preferred embodiment of the invention, the radial tendons are at least partially provided with load cells on which the ring force of the ring tendons and thus the circumferential tension of the reactor pressure vessel can be read off .

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In this way, the ring force can be controlled or adjusted will. This method also allows tolerance-free assembly of the components of the thermal insulation cooling gap when the gap is already installed Reactor pressure vessel. The existing assembly play is at least equal to the radial expansion of the actuator pressure vessel at temperature and internal pressure, minus the amount to be determined of the radial expansion of the ring tendons through the pressure vessel.

In a further development of the invention, the pressure hulls consist of stackable insulating concrete segments. That way is the Assembly and disassembly of the thermal insulation cooling gap are particularly easy. A particularly favorable embodiment of the pressure body consists in the fact that these are designed as insulating concrete segments that have both a thermal insulation zone close to the container and a Have container-remote cooling zone, the cooling zone of cooling air ducts is streaked. The pressure bodies are preferably provided with molded-in cooling channels, preferably multilayered, which are aligned when stacked on top of each other. These molded Cooling channels are expediently designed as cast steel pipes, which are also suitable for pressure transmission are. The radial tendons are expediently provided with crossheads at their inner ends and the latter at the outer circumference the pressure hull arranged.

Except for the aforementioned pressure hulls between the reactor pressure vessels and crossheads are arranged and meet the puncture of thermal insulation and cooling, according to the invention is also a A second group of pressure bodies is provided which, viewed radially, is arranged between the crossheads and the biological shield and are here loosely, i.e. in the cold state with sufficient radial play, are arranged in such a way that they prevent expansion of the ring tendons. Accordingly, those are from the inner perimeter of the concrete structure, from the outer perimeter of the crossheads and annular chambers delimited by the ring tendon layers with fillings suitable for pressure transmission, preferably insulating concrete radial stones, loosely filled in, with the segment stones serving as an assembly aid for the ring tendon layers by alternately a segment stone and a ring tendon layer can be stacked on top of each other.

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Another advantageous development of the invention relates to the burst protection in the nozzle area of the reactor pressure vessel, for which the main coolant lines surrounding and the biological shield penetrating ducts in a partial association of the ring tendons are included, which in the following as well as further features and details of the invention with reference to the several exemplary embodiments Illustrative drawing is explained in which show:

Fig. 1 in an axial section and in detail, a reactor pressure vessel with the radial burst protection according to the Invention showing a main coolant port portion;

2 shows a cross section in the plane normal to the axis of the main coolant connection of the object of Fig. 1, but the right half is shown and the bursting device is shown simplified only with pressure hulls;

3 shows view A from Pig. 2, i.e. the top view of a Section of the main coolant line level;

FIG. 4 in a corresponding representation: to FIG. 1, however, in one smaller section of a variant of the first embodiment shown in Fig. 1, wherein the thermal insulation cooling zone is divided into insulating concrete blocks and separately into cooling elements made of steel;

FIG. 4a shows a cross section of the cooling elements 3b ¹ from FIG. 4 in a detail;

5 shows various assembly states in a schematic representation and dimensioning options for the radial burst protection according to the invention, namely

Flg.5a a state before anchoring the radial tendons in the crossheads;

5b shows the mechanically prestressed radial and ring tendons;

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Pig. 5c the subject after Pig. 5b, but with mounted Insulating cooling elements (the reactor pressure vessel is here still cold);

Pig. 5d the state after the radial expansion of the reactor pressure vessel, when this is applied to the radial burst protection and this widened by, for example, 2 mm Has;

Pig. 5e an embodiment variant in which the originally existing Reduction of the circumferential tension of the pressure vessel was canceled by the fact that the radial tendons were subsequently tensioned, so that there is now a burst protection with no play or with minimal play is and

Pig. 5f another variant of the burst protection, in which Prestressing and subsequent increased lowering of the radial tendons result in a redistribution of part of the im Concrete existing radial pressure forces on the reactor pressure vessel takes place, so that in this there is an increased relief of circumferential stress given is.

The reactor pressure vessel 1 in Pig. 1, for simplification in hereinafter referred to as a pressure vessel, is provided with a radial burst protection, designated as a whole with B. Preferred If the pressure vessel 1 is a reactor pressure vessel, since the burst protection is particularly important here; it however, it can generally be a pressure vessel surrounded by a reinforced concrete casing. The pressure vessel 1 is with a biological shield 2 surrounded in its jacket area. This consists of an essentially hollow cylindrical prestressed concrete structure for example with radial tendons 2a, circumferential tendons 2b and axial tendons not shown in detail. Such a construction is known, for example, from DT-As 1 684-643. Like the concrete structure of the biological Shield 2 looks in detail, is for the invention

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but not of importance; it is essential that it is able to absorb considerable axial, radial and circumferential forces. The radial tendons 2a of the biological shield are with Circumferential tendons 2b positively coupled such that by tensioning the radial tendons 2a by means of the tension nuts 2c, the circumferential tendons 2b can be tensioned. To support the latter, the radial tendons 2a have transverse headers 2d, spacer disks 2f (not shown) between them the individual layers of the circumferential tendons 2b, as well as abutment washers 2e on. The circumferential and radial tendons can be seen distributed over the height of the biological shield 2. Furthermore, as mentioned, the biological shield 2 is made up of axial tendons axially traversed so that it is able to exert axial prestressing forces acting on the reactor pressure vessel 1 a storage, not shown, can be exercised. This storage, the rest of the understanding of the invention does not need to be described in more detail, e.g. from a bottom suspension via spiral springs and consist of a cover-side bracing via pendulum supports.

The radial burst protection B consists of heat-insulating pressure bodies 3, covering the surface to be protected against bursting 1a of the pressure vessel 1 are distributed, both in the circumferential direction (see. Fig. 2) and axially parallel based on the axis 1 'of the pressure vessel 1. In addition, the radial Burst protection B ring tendons 4 in the form of steel straps, which run concentrically to the container axis 1 'and the pressure hulls 3 surrounded. The radial forces P ^, in particular the radial pressure forces of the pressure bodies 3, which they exert on the container wall 1b in the operating or bursting state can be generated by hoop tensioning of the ring tendons 4, i.e. the hoop tension of the ring tendons is converted into corresponding radial forces P, transformed. 1c is still in FIG. 1 Main coolant line stub designated, to which a coolant line 5 is connected with a partition 5a, so that the ■ Line 5 has both a feed line 5.1 and a return line 5.2 includes. The ring tendons 4 can be seen on the

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Height of the pressure vessel 1 Provided in a plurality of ring packets 4a arranged at an axial distance from one another, each packet 4a has individual tape layers 4b. Instead of the ribbons or Tape layers 4b could also be used with steel wires or steel rods.

According to the invention now engage the second group of the ring tendons 4, which are radially inside the biological shield 2 and are arranged radially outside the wall 1b in an annular space S2, the radial tendons 6, which penetrate the prestressed concrete shell 2 and can be tightened from the outside (nuts 6a, Washers 6b). This second group of radial tendons 6 is kit crossheads 6c of their inner ends on the outer circumference of the Pressure body 3 arranged. That is, with the burst protection arrangement shown in Fig. 1 (cold state of the pressure vessel 1) follows the wall 1b, seen radially outwards, bit Radialapalt

UBd

B ^ the arrangement of the pressure bodies 3 / the jacket of the crossheads 6c, which are designed as steel bodies and have a recess 6d and a bore 6e, the bore 6e continuing in the jacket tube 6f of the radial tendons 6 and the head 6g of the radial tendons in the recess space 6d 6 is arranged, so the latter grip behind the crossheads with their heads 6g non-positively. Between the crossheads 6c and the biological shield 2, the aforementioned annular space S2 is formed with individual annular chambers 7 in which, in addition to the annular tendons 4, fillers 8 are also arranged between the individual packets 4a, as will be explained below. Depending on the state of tension of the ring tendons 4 and the operating state of the pressure vessel 1, there are further gaps s «between the fillers β and the crossheads 6c and s _r , between the fillers 8 and the biological shield 2. The columns s- and s _r _ are, however, irrelevant for the stress state of the pressure vessel in operating states. By specifying a gap width s ^ by the whole amount or part of the radial pressure vessel expansion Δ r ^, which the latter experiences when heating to operating temperature, the circumferential nominal tension in the pressure vessel 1 can now, for example. its wall 1b pretend, and this happens due to the radial expansion of the wall 1b when it is at operating temperature

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heated (transient process) or located (stationary).

For this purpose it is advantageous if the radial tendons 6., as shown, load cell kit 6h. are provided on which the ring force of the ring tendons 4 and thus the hoop stress of the pressure vessel 1a can be read. The bias in the radial tendons can be made so that in the warm operating state of the pressure vessel 1, when its peripheral stress due to hindered thermal expansion completely or partially taken over by the ring tendons 6 1st, the tensile force in the radial tendons 6 goes to zero.

The pressure body 5 are advantageously made of stackable Iaolierbetonaegmenten, according to Pig. 1 from those both a thermal insulation zone 3a close to the container and a Have cooling zone 3b remote from the container, the cooling zone 3b being traversed by cooling air channels 5c. These are preferred Cooling air ducts 3c concreted in several layers in the pressure body 3, see Flg. 2, in such a way that the cooling channels at the upper " stack the pressure body 3 are aligned with each other.

Pig. 4 shows a variant in which the pressure bodies 3 * consist of separate insulating concrete blocks 3a '(thermal insulation bodies) and steel segments 3b ¹ (heat sinks). In addition, only one row of cooling channels 3c ^{1 is} provided in the heat sinks 3b ^1. The cooling channels 3c ¹ are expediently produced by welding steel pipes and steel sheets. This results in an axially continuous cooling channel system within the pressure body 3 '»which can be connected on its inlet side to the pressure side of a fan (not shown) via a common inlet channel and on its outlet side via a collecting channel (also not shown) to the suction side of the fan.

In Pig. 4, in addition to FIG. 1, there is also a gap s _r4 between the bodies 3b ¹ and 3a ¹ due to manufacturing tolerances; 1 hit. A lightweight concrete known under the name Leca-Beton has proven to be a suitable insulating concrete for the pressure body 3 and the segments 8. The annular chambers J are from the inner circumference

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of the prestressed concrete 2, delimited by the outer circumference of the crossheads Sc and by the ring tendon facets 4a and, as mentioned, are loosely filled by radial concrete blocks 8. The clearance between the radial stones 8 and the gaps b ~ and s _ are dimensioned in such a way that the thermal movement of the pressure bodies 3, the crossheads 6c and the ring tendons 4 within the ring zone S1 is not hindered and only when the desired thermal expansion of the pressure vessel 1 occurs or in the case of failure of the pressure vessel the rigid BSW. The aforementioned sienente is firmly attached to the biological shield 2, so that, according to a preferred embodiment, the latter is used as a supporting dumbbell. As already mentioned at the beginning, there are various dimensioning options, which will be explained in more detail below with reference to FIG. 5.

From Pig. 1 it can be seen that because of the greater density of the Radial clamping elements 2a and 6 in the area around the main coolant line 5, the biological shield 2 expanded in the form of a line 2f is so that for dls anchoring of the radial tendons 6 additional space is available. 1 to 3 show that the main coolant lines 5 are surrounded by cladding tubes 9 made of steel are, which penetrate the biological shield 2 and in a partial bond Bl, B2 of the ring tendons 4 and the radial tendons 6 are included. The annular space S3 between line 5 and cladding tube 9 is of thermally insulating not shown Elements and rings filled in as burst protection for the pipeline 5; also can in this annular space S3 Cooling channels can be arranged for discharging the cooling air from the cooling channels 3c, the cooling air initially being in an annular space S4 collects in the outer area of the nozzle 1c. The cladding tubes 9 are each provided with a flange 9a remote from the container, which according to FIG Fig. 3 has a rectangular shape, in the partial bracing B1 and B2 of the associated adjacent ring tendons and radial tendons 4, included, wherein in the cold state the cladding tube 9 with its end 9b near the container or the corresponding end faces protrudes beyond the crosshead 6c by a few millimeters and thus the zone of the pressure vessel 1 close to the nozzle extends beyond the pressure body when the container is stretched, the force closure is more likely than the rest cylindrical part. Because the gap s - smaller than the gap

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If the pressure vessel 1 expands radially under pressure and temperature, the cladding tube 9 is first displaced radially via the pressure body 4, the string tendons of the braces B1, B2 tensioning and the flange 9 at the point sg a Gap opposite the biological shield 2 or the reinforcement inserts 2g, 2g ¹ forms. During this first radial partial movement, the radial tendons 6 of the partial braces Bt, B2 are first stretched by the amount of the protrusion Bc. The resulting tensile force in the radial tendons acts via the cladding tubes 9 on the pressure vessel 1 and can be measured with the help of τοπ load cells 6h. During the further stretching movement, the crossheads 6c with the radial tendons 6 and 6 ″ are displaced radially so that the tensile stress in the radial tendons of the partial braces B1, S2 can no longer increase in the course of this second radial partial movement. In this way, the defined Pressure force exerted by the cladding tube 9 via the associated pressure body 4 on the socket area 1c of the pressure vessel 1. The cladding tubes 9 are centered on the inner circumference of wall rings 10 and are supported in their axial direction, with those in the area of the flange 9a of the cladding tube 9 arranged reinforcement insert 2g ', which surrounds the cladding tube 9, is to be referred to as a wall ring. These wall rings 10 and 2g ¹ are embedded in the concrete of the biological shield 2. They also serve as a reinforcing insert to avoid stress peaks that occur during the production of the biological shield occur with the radial clamping process Ühlleitung denotes which, like the main coolant lines 5, open into the interior of the pressure vessel 1. The pressure bodies 4 and possibly also the segments 8 are preferably made of sheet metal so that any abrasion cannot penetrate outward into the cooling circuit, the sheet metal coating of the pressure body 3 (not shown) being connected in a suitable manner to the steel pipes of the cooling channels 3c. The radial stones 8 not only fill the annular spaces 7 in a loose stack, but also serve to support the annular clamping bundles 4a during their assembly.

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The following is a brief description of the construction of the radial burst gate explained on the basis of a radial expansion restriction of the pressure vessel 1 of 2 mn. It is assumed that that the biological shield 2 has already been completed, in exact positions in planes of about 40 cm axial distance, the Htillrohre 12 (see. Pig. 1) for the radial tendons 6 are installed. The prefabricated ring clamping bundles 4a are successively with the interposition of the segment stones 8 on the inner circumference of the biological base 2 stacked one on top of the other, i.e. lifted. The radial tendons 6 are threaded through the cladding tubes 12 in the biological shield 2 and each against the associated crosshead 6c screwed. The geometry of the crossheads 6c is chosen so that the tendon anchorage 6g does not protrude beyond the inner surface of the crossheads and that all ring clamping bundles 4a lie on top of one another with the segment stones 8 interposed. In parallel to this work you can on the outside of the burst protection or biological shield

2 the nuts 6a of the radial tendons, which are designed as steel rods are to be rotated against the anchorage without the To stretch radial tendons 6. This creates a mean distance over the circumference between the respective ring clamping bundle 4a and the concrete surface can be measured and adjusted, which is 11.5 mm according to FIG. 5a. Fig. 5a shows a preliminary stage of the aforementioned

not assembly in which the Radialipannglleder 6 still / on the crossheads are anchored. In the assembled state after the mechanical prestressing of the radial tendons according to FIG. 5b, the Pressure vessel 1 lifted. Then, as shown in Fig. 5c, the assembly of the thermal insulation cooling gap takes place, i.e. the insertion of the Pressure hulls 3. In this case, the pressure hulls 3 are pushed against the crossheads 6c with a clearance of 9 mm relative to the pressure vessel 1. This game can be adjusted with a plus tolerance with individual sheets in front of the respective crosshead 6c; at With a minus tolerance, there is the possibility of expanding the corresponding ring tensioning bundle 4a via the radial tensioning elements 6. The height of a pressure body 3 corresponds to that of the associated crosshead 6c, in order to place a defined stress on the pressure body

3 to ensure.

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The reactor pressure vessel is used after the assembly described above 1 brought up to pressure and temperature, it experiences a radial expansion of 11 mm in the illustrated embodiment. The free Play of 9 mm is bridged, and the ring clamping bundle 4a are expanded radially by a further 2 mm, whereby the pressure vessel 1 a rotationally symmetrical preload. During the stretching process the pressure bodies 3 are also shifted by 2 mm (see FIG. 5d). This causes the ring tension bundle 4a to expand in the radial tendons 6 a defined drop in the existing Traction. With the help of the load cells 6h on the outer anchorages, the arithmetical amount of the force control and monitor.

The tensioning process takes place in the area of the partial bond B1, B2 as already explained above.

Fig. 5e shows a special case of the radial burst protection, which shows that any state of pre-tensioning of the pressure vessel can be released after any operating time by releasing the compression of the pressure vessel by subsequently tightening the radial tendons. This increases the radial and circumferential stresses of the concrete structure. In this special case, the gap width s * q is equal to or greater than zero. However, it is preferred to work with a zero-travel burst protection (gap sv * = 0) or with at least partial relief of the pressure vessel 1 with regard to its circumferential tensile stress due to the radial expansion restriction already described. An enlargement of the pressure vessel pre-tensioning is shown in Fig. 5f, whereby subsequent release of the radial tendons 6 compared to Fig Shield 2 existing compressive stress on the pressure vessel 1 takes place.

11 claims
5 figures

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Claims (11)

Claims 1. Radial burst protection for a "reinforced concrete shell" Surrounded pressure vessels, in particular for reactor pressure vessels, with heat-insulating pressure bodies distributed over the surface to be protected against bursting, both in the circumferential direction and are distributed axially parallel around the pressure vessel, and with ring tendons in the form of steel wires, rods or bands that run concentrically to the longitudinal axis of the container and span the pressure body, with radial pressure-Her aft e of the pressure hull, which this in the operating state on the Exercise the container wall by means of hoop tensioning of the ring tendons can be produced, characterized in that the ring tendons (4) engaging and penetrating the concrete casing (2) and externally tensionable radial tendons (6, 6) are provided and that the radial forces of the pressure body (5) by adjusting the elongation of the radial tendons (6, 6 ') and thus the tensile prestressing of the ring tendons (4), wu / aksc dk8 is the proportion of elongation that the ring tendons (4) can do in addition to that achieved by means of the radial tendons (6, 6 ') experience already applied expansion by the radial expansion of the pressure vessel (1), can be canceled by additional -.- mechanical expansion of the radial tendons (6, 6 ¹ ). : 2. Burst device according to spoke 1, characterized in that in the installed state by subsequent mechanical increase or decrease · of the tensile forces of the radial tendons (6, 6.-V). the previously existing voltage state of the one to be protected Pressure vessel (1) is changeable. 3. Burst device according to claim 1 or 2, characterized in that that the sum of all the gap widths generated by assembly or mechanical expansion between the pressure vessel (1) and the Ring tendons (4) is greater than the radial expansion of the Pressure vessel (1) that he experiences when he is cold starting is brought to operating temperature and operating pressure. . 8098 1 1/0458 OiIQlNM. INSPECTED ο - * - 76 P 9 3 7 4 FRG 4. Burst device according to one of claims 1 to 3, characterized in that the radial tendons (6, 6 ¹ ), at least partially, with load cells (6h) are provided, on which the tensile force of the radial tendons (6, 6 ') the ring force of Ring tendons (4, 4 ') and thus also the circumferential stress of the reactor pressure vessel (1) can be read off. 5. Burst device according to one of claims 1 to 4 »characterized in that that the pressure body (3) consist of stackable insulating concrete segments. 6. Burst device according to one of claims 1 to 5 »characterized in that that the pressure bodies (3) are designed as insulating concrete segments, which both have a thermal insulation zone close to the container (3a) and a cooling zone (3b) remote from the container, the cooling zone (3b) being traversed by cooling air ducts (3c). 7. Burst device according to claim 6, characterized in that the pressure body (3) with molded-in axial cooling channels (3e), are preferably multilayered, which when stacked on top of each other align with each other. 8. Burst device according to one of claims 1 to 7, characterized in that the radial tendons (6, 6 ¹ ) are each provided at their inner ends with crossheads (6c) and the latter are arranged on the outer circumference of the pressure body (3). 9. Burst device according to claim 8, characterized in that from the inner circumference of the concrete shell (2), from the outer circumference of the Crossheads (6c) and ring chambers (7) bounded by the ring tendon layers (4) with filling material suitable for pressure transmission (8), preferably with insulating concrete segment stones, are loosely filled, the segment stones (8) as an assembly aid serve for the ring tendon layers by alternating a segment stone and a ring tendon layer on top of each other are stackable. . 809811/0458 3 '* " 76P 9 3 7 4 FRG 10. Burst device according to one of claims 1 to 9, characterized in that the main coolant lines (5) surrounding and the reinforced concrete casing (2) penetrating ducts (9) in a partial association (B1, B2) of the ring and radial tendons (4 ', 6 ') are included and for this purpose with a. The cladding tube flange (9a) remote from the container forms an abutment for the other end of the radial tendons (6 ¹ ) engaging the ring tendons (4 ') of the relevant sub-structure (B1, B2), the cladding tube end (9b) close to the container facing the container wall ( 1a) has a radial protrusion 4r over the transverse head (6c) and the thermally serving container (1) first moves the cladding tube (9) by Ar with tensioning of the partial assembly (B1, B2) and thus radial bracing of the container nozzle area and with further thermal expansion of the container (1), the crossheads (6c) are also displaced from the pressure hulls (3) and the rest of the radial and ring tendon terband (6, 4) is tensioned without the tensile force in the radial tendons (6 ¹ ) of the sub-structure ( B1, B2). 11. Burst device according to claim 10, characterized in that the cladding tubes (9) embedded in the concrete casing (2) Wall rings (10, 2g ') are centered and guided. ■ 8 098 1.1 / 0458