Abstract: A method for sealing a leak between a control rod drive (CRD) stub tube (3) arranged in a reactor wall (2) and a tubular CRD housing (1) extending through the CRD stub tube (3) and the vessel wall (2). According to the invention, this sealing is obtained by deforming a suitably shaped element of memory metal below the transition temperature of the memory metal in such a way that it can be inserted, in the form of a sleeve (5) or a ring, into or around the CRD housing (1) where said housing passes through the vessel wall (2), or alternatively replace part of the CRD housing (1) at the passage through the vessel wall (2). Then when the memory metal is heated to above the transition temperature, it strives to resume its original shape which shall then have been such that the desired seal is obtained.

Abstract: The invention relates to a sealing joint for pipes (3) or pipe sockets (2) in, for example, a nuclear reactor. The joint comprises at least two sealing bodies (4, 5) contacting each other in a contact surface (8) and provided with through holes (6, 7). The holes (6, 7) are delimited by envelope surfaces (9, 10) and form a tubular channel (11) through the sealing bodies (4, 5) and the contact surface (8). The sealing bodies (4, 5) are displaceable in relation to each other along the contact surface (8). Around the channel (11) a sealing member (12) is arranged between the sealing bodies (4, 5). Each one of the sealing bodies (4, 5) is divided into at least two discs (4a, 4b; 5a, 5b, respectively) in a plane intersecting the associated envelope surface (9, 10) along a closed curve. Between the discs belonging to a sealing body (4, 5), a slot (13 ) has been provided which is delimited by the associated envelope surface (9, 10). A flexible sealing ring (13a) is inserted into the slot (13).

Abstract: The invention relates to a sealing sleeve for sealing a leak in, for example, a pipe, a pipe socket or the like in a nuclear reactor. The sleeve comprises a bellows-like mid-portion (1) with annular ends, at least these or part of these (2) being made of a memory metal with a suitable transition temperature. At a temperature above the transition temperature, that part of these annular ends which consists of memory metal has been given an inner diameter suitable for achieving sealing around the relevant pipe section on each side of the leak. The mentioned part of the ends has thereafter, at a temperature below the transition temperature, been deformed into a diameter which permits the sleeve to be freely fitted onto the pipe. In fitted position, the sleeve is then heated to above the transition temperature, the memory metal then striving to recover its previous shape and shrinks the sleeve so as to obtain sealing.

Abstract: A fuel assembly for a boiling water reactor comprises four bundles of vertical fuel rods (5). The bundles are surrounded by a common fuel channel (2) and each provided with a top tie plate (10) and a bottom tie plate (11). The four bottom tie plates are supported by a common supporting plate (18) which is inserted into, and supported by, the inlet sleeve (15) of the fuel assembly. Each bottom tie plate (11) includes an annular horizontal contact surface (24) abutting the supporting plate, and a non-round guide portion which is arranged, with no mentionable play, in a corresponding, non-round, through-hole (19) in the supporting plate (18).

Abstract: A fuel asembly with a fuel channel (2) which surrounds a plurality of fuel rods (1) and which is divided, by means of a stiffening device (3) of cruciform cross-section and four wings (5), into four sub-channels (4) each of which comprises a bundle of fuel rods.Each fuel channel side has a plurality of stamped, inwardly-directed projections (6) arranged vertically one after the other, said projections being welded to one and the same stiffening wing. Each one of the wall portions located between the projections (6) defines, together with two adjacently positioned projections and a portion of the stiffening wing, a communication opening between two bundles located on one side each of the stiffening wing.

Abstract: A fuel assembly is disclosed which comprises a fuel channel (1) with square cross-section supported by an inlet sleeve (22) having at its lower part an inlet opening for a flow of coolant flowing through the fuel assembly. The inlet sleeve (22) is made of stainless steel and is mechanically connected to a transition sleeve (21) made of thick zirconium alloy sheet, which is welded to the more thin-walled fuel channel (1).

Abstract: A metallic, annular sealing device for closing an annular passage between a high-pressure chamber (2) and a circular cover (3) therefor. The sealing device comprises two coaxial, solid rings (17, 18) which are arranged with an intermediate circular gap. An upper (22) and a lower (21) hollow metal ring are each made with a circular gap. The edges of the gap of the upper hollow ring are welded to the solid rings (17, 18) at the upper portion of the gap defined between the solid rings, whereas the edges of the gap of the lower hollow ring are welded to the lower portion of the gap defined between the solid rings. Thus, the hollow rings (21, 22) communicate with each other.

Abstract: A fuel assembly for a boiling water reactor comprises a plurality of fuel rods (2, 2'), which constitute four partial bundles and are surrounded by a fuel channel system (1) comprising one partial tube for each partial bundle. Each of the four partial bundles rests on a bottom tie plate (19) and is positioned with respect to the others by means of a common top tie plate (31), which is provided with a lifting loop (33) which is sufficiently strong to be able to lift the four partial bundles simultaneously, a major part of the lifting force being transmitted to said bottom tie plates via a plurality of supporting fuel rods (2').

Abstract: A boiling water reactor fuel assembly is provided with an elongated, vertical stiffening device having four stiffening wings (4) which are each attached to a wall of the fuel box. Each stiffening wing has at least one vertically directed passageway for water. The stiffening device has a cruciform cross-section and is composed of four elongated members (6, 6', 6", 6'") of L-shaped cross-sections.

Abstract: A fuel assembly for a boiling water reactor comprises a plurality of vertical fuel rods (1) and is furnished with a fuel channel device. The fuel rods are arranged with their lower ends resting on a bottom plate and positioned by means of a plurality of spacers (6) attached to the casing. The freedom of movement of the fuel rods in the upward direction is limited by means of a top plate (12) arranged above the upper end surfaces of the fuel rods (1).

Abstract: A boiling water reactor fuel assembly is provided with an elongated, vertical stiffening device having four stiffening wings which are each attached to a wall of the fuel box. Each stiffening wing has at least one vertically directed passageway for water.

Abstract: A coupling assembly for joining an inlet nozzle with a conduit assembly extending concentrically therein, to provide a fluid-tight and thermally insulated flow passageway for introducing cold water into a nuclear reactor pressure vessel and the like.The coupling assembly comprises a protective sleeve surrounding the conduit assembly and wedged into abutting contact with an end portion of the conduit assembly and an inner surface of the inlet nozzle to form a fluid-tight seal therebetween. A fluid insulating medium having a decreasing temperature gradient is positioned between a portion of the protective sleeve and the surrounding inlet nozzle to create a similar decreasing temperature gradient within the inlet nozzle, in order to protect the nozzle against thermal shocks resulting from the difference in temperature between the relatively warm reactor pressure vessel surrounding the inlet nozzle and the relatively cold water flowing through the inlet nozzle.

Abstract: The present invention relates to an improved attachment assembly for clamping a nuclear reactor foot ring into engagement with a surrounding support wall while allowing for thermal expansion of the foot ring.

Abstract: A yoke-like attachment assembly for connecting a lifting hook with a lid portion of a nuclear reactor pressure vessel or the like, comprising a plurality of separate coupling assemblies extending parallel to each other between the lifting hook and lid, wherein each coupling assembly is capable of supporting the entire weight of the lid in the event of the failure of the remaining coupling assembly. Each coupling assembly includes a pair of spaced sheet-metal lugs, each mounted on a support plate assembly, with at least one bolt interconnecting the spaced lugs with the lifting hook positioned therebetween. Each support plate assembly is attached to a separate beam which, in turn, is attached to the lid.