Classifications

• • G—PHYSICS
  • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
  • G21C—NUCLEAR REACTORS
  • G21C13/00—Pressure vessels; Containment vessels; Containment in general
  • G21C13/02—Details
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E30/00—Energy generation of nuclear origin
  • Y02E30/30—Nuclear fission reactors

Definitions

• the present invention relates to a compression joint for reinforcement of a tubular component, preferably a substan ⁇ tially cylindrical vessel, for example a reactor vessel.
• the joint is designed to superimpose an axially contracting force on the component.
• Compression joints for reinforcement of tubular components are known. These compression joints may consist of a pre- stressed winding of several layers of strip or wire around the location on the tubular component which is desirable to reinforce. The technique is based on the wire or strip being stretched such that a strong contraction takes place around the reinforcement point on the tubular component. The com- pression state which thus arises remains, with a suitable dimension of and tensile stress in the wire, also after the tubular component has been pressurized and loaded. To increase the axial strength somewhat in such a joint, it is also known to make the strip from a thin sheet which is so wide that one turn of the strip covers the reinforcement point satisfactorily. However, this embodiment does not superimpose any axially contracting forces on the tubular component.
• the invention relates to a compression joint for reinforce ⁇ ment of a tubular component, preferably a substantially cylindrical vessel, for example a reactor vessel.
• the compression joint comprises a first sleeve divided into a plurality of parts along axial sec ⁇ tions substantially parallel to the axial longitudinal direction of the component.
• the sleeve is fixed around the component by means of at least one winding of strip or wire of memory metal.
• a second sleeve which is also divided into a plurality of parts along axial sections, is fixed around the component at a certain distance from the first sleeve by means of a winding of strip or wire of memory metal.
• this strip or wire Prior to being wound around the respective sleeves at a tempera ⁇ ture below the transition temperature of the memory metal, this strip or wire has been stretched into a suitable length to achieve the desired compressive stress in the joint after the winding on and a subsequent increase of the temperature of the winding above the transition temperature.
• the sleeves are provided around their periphery with a number of fixing devices for a number of axially arranged tension elements tightened from the fixing devices on the first sleeve to the fixing devices on the second sleeve.
• the above-mentioned type of com ⁇ pression joint can thus also transmit an axially contracting force to that part of the component which is situated between the two sleeves.
• the axial strain on the weld can be reduced by placing the joint such that the tension elements lie across the weld and thus exert a contracting force on the welded- together components.
• the tension elements be made of a material with a lower coefficient of linear expansion than the material in the components. It may then be sufficient that the tension elements, at a low temperature in relation to the working temperature of the vessel, be applied with only a small or no tensile stress around the vessel. The desired tensile stress then does not arise until the tempe ⁇ rature in the vessel is increased.
• Another way is to manufacture the tension elements from memory metal. In that case the memory metal in the tension elements should have a higher transition temperature than the memory metal of the winding. This will cause the sleeve joints around the component to be fixed before the tension elements are activated.
• Figure 1 shows a reactor vessel with an applied compression joint.
• Figure 2 shows a cross section of the vessel wall and a part of a sleeve placed outside the vessel wall.
• Figure 3 shows a part of a sleeve seen from the front with the fixing points formed as tree-shaped recesses.
• Figure 4 shows a package of tension elements with a tree- like shape at their ends.
• Figure 5 shows the package of Figure 4 seen from the side.
• numeral 1 designates the tubular component which here consists of a reactor vessel la.
• the reactor vessel comprises at least two cylindrical parts which are joined together by means of a weld 2 which thus runs around the vessel la.
• the compression joint 3 is applied.
• the compression joint 3 consists of a first sleeve 4 divided into several parts 5 placed around the vessel la on one side of the weld 2.
• Each part 5 is provided at the bottom with a strong lug 6, in which fixing devices 7, not shown (see Fig. 2), for the tension elements 8 are arranged.
• Figure 1 shows only a small number of tension elements 8.
• the parts 5 of the sleeve 4 are fixed around the vessel by means of two windings 9 of wire or strip, suitably consisting of memory metal. Prior to winding around the first sleeve 4, this strip or wire is stretched at a temperature below the tran ⁇ sition temperature of the memory metal into a suitable length for achieving the desired compressive stress in the joint 3 after winding on and a subsequent increase of the temperature of the windings 9 above the transition tempe ⁇ rature.
• the second sleeve 10 consisting of parts 11 and lugs 12, is fixed in a corre- sponding way, also by means of fixing devices 7.
• the parts 11 of the sleeve 10 are fixed with the windings 13, which are only indicated in order to show more clearly what the different parts 11 look like.
• the tension elements 8 can be tightened across the weld 2. Depending on the design of the tension elements 8, this can take place in several different ways.
• FIG. 2 One embodiment of the tension elements is shown in Figure 2.
• lb designates the vessel wall and 2 the weld around the vessel la.
• the figure shows a section I-I through one of the parts 5 of the first sleeve 4 with a lug 6 and fixing devices 7 in the form of threaded holes.
• threaded tension elements 8 in the form of threaded bars.
• the tension elements 8 can be tightened by turning in one direction.
• the tension elements 8 are arranged in double rows to achieve a sufficient tension.
• FIG 3 Another type of tension elements is shown in Figure 3 which shows one part 5 seen from the front.
• the lug 6 tree- shaped recesses 14 are arranged.
• Tension elements 8 of memory metal are provided with a corresponding tree-like shape at their ends.
• These tension elements 8 are suitably made in the form of flat laths as shown in Figures 4 and 5. It is thus possible to fit a package of several of these laths or tension elements 8 into a recess 14.
• the tension elements 8 Before fitting these latter tension elements 8 into the recesses 14 of the lugs 6, 12, the tension elements are tightened below the transition temperature of the memory metal into a suitable length such that the desired tensile stress is obtained above the transition temperature of the memory metal.
• the tran- sition temperature of the memory metal in the windings of the sleeves 4, 10 should be lower than the transition tempe ⁇ rature of the memory metal in the tension elements 8. This is to make it possible for the sleeves 4, 10, upon heating, to be fixed around the vessel la before the tension elements can take up any tensile forces. Otherwise, heating of win ⁇ dings and tension elements must take place in separate stages.

Landscapes

• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Plasma & Fusion (AREA)
• General Engineering & Computer Science (AREA)
• High Energy & Nuclear Physics (AREA)
• Non-Disconnectible Joints And Screw-Threaded Joints (AREA)
• Filling Or Discharging Of Gas Storage Vessels (AREA)
• Butt Welding And Welding Of Specific Article (AREA)
• Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20388127

Family Applications (1)

Country Status (3)

Cited By (1)

Citations (3)

• 1992
  • 1992-12-15 SE SE9203772A patent/SE500878C2/sv unknown
• 1993
  • 1993-11-05 WO PCT/SE1993/000926 patent/WO1994014165A1/en active Application Filing
  • 1993-11-05 RU RU9395114400A patent/RU2086011C1/ru active

Patent Citations (3)

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