Container for radioactive waste comprising L-shaped grooves for fixedly connecting cover without welds

Abstract

A container for holding radioactive waste has a side wall, a floor connected to a lower end of the side wall, and a cover. A set of side-wall formations is provided at an upper end of the side wall and on an inner surface of the side wall, and a set of cover-edge formations is distributed around an outer edge of the cover and fittable with the side-wall formations. Thus, as a result of the interfitting of cover-edge formations with the side-wall formations, the cover can be or is fixedly connected to the side wall without welds.

Claims

1. A container for holding radioactive waste, the container comprising: a side wall; a floor connected to a lower end of the side wall; a cover; a set of side-wall formations at an upper end of the side wall and on an inner surface of the side wall; and a set of cover-edge formations distributed around an outer edge of the cover and fittable with the side-wall formations such that, as a result of the interfitting of cover-edge formations with the side-wall formations, the formations of one of the sets being L-shaped radially open grooves that each have two portions extending perpendicular or substantially perpendicular to one another such that the cover can be or is fixedly connected to the side wall without welds.

2. The container defined in claim 1, further comprising: a support basket inside the container for holding spent fuel elements constituting the radioactive waste.

3. The container defined in claim 1, wherein the floor and the side wall are integrally connected to one another.

4. The container defined in claim 1, wherein there are at least three of the side-wall formations distributed around the inner surface of the side wall.

5. The container defined in claim 1, wherein there are at least three cover-edge formations distributed around the outer edge of the cover.

6. The container defined in claim 1, wherein the formations of the other of the sets are radial projections fittable in the grooves.

7. The container defined in claim 1, wherein the side wall is substantially cylindrical and centered on an axis, one of the portions of each groove extending tangentially and the other of the portions of each groove extending axially.

8. The container defined in claim 7, wherein, in a locking position with the cover axially secured by the formations to the side wall, the formations of the other set each bear upward on a downwardly directed upper face of the one portion of the respective groove.

9. The container defined in claim 8, wherein an upwardly directed lower face of each of the other portions of each groove is angled downward and toward the floor, and lower downwardly directed faces of the formations of the other set are complementarily angled, whereby an upward force on the cover pulls the upper edge of the side wall radially inward.

10. The container defined in claim 1, wherein the cover and side wall form an upwardly open sealing groove, the container further comprising: an annular seal fitted in the groove.

11. The container defined in claim 10, wherein the seal is a metal or elastomeric seal.

12. The container defined in claim 10, further comprising: a compression ring releasably secured atop the cover and formed with an axially downwardly projecting ridge engaging in the groove and pressing the seal against an upper face of the sealing groove and the inner surface of the side wall.

13. The container defined in claim 12, wherein the ridge has a frustoconical lower face facing radially outward and downward and the sealing groove has a frustoconical upper face facing radially outward and upward, whereby the ridge presses the seal radially outward against the inner surface of the side wall when axially squeezing the seal between the lower and upper faces.

14. The container defined in claim 1, wherein the container is a transport or storage container, the cover is a primary cover of the transport or storage container, the container further comprising: a secondary cover fixed to the container above the primary cover seals.

15. A container assembly, comprising a container according to claim 14, wherein the container is a canister loaded with spent fuel elements and received in a transport or storage container that can be or is sealed with the secondary cover over the primary cover.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The above and other objects, features, and advantages will become more readily apparent from the following description, reference being made to the accompanying drawing in which:

(2) FIG. 1A is a perspective view of a container according to the invention;

(3) FIG. 1B is a partial perspective exploded view like FIG. 1A;

(4) FIG. 2 is a top partly sectional view through the container according to the invention in the locking position;

(5) FIG. 3 is a sectional side elevational view of the container; and

(6) FIG. 4 is a cross-section through a seal for the container according to the invention.

SPECIFIC DESCRIPTION OF THE INVENTION

(7) As seen in drawing, a container 1 according to the invention for holding radioactive waste, in this embodiment for holding spent fuel elements 2, has a cylindrically tubular side wall 3, a flat planar floor 4 connected to a lower edge of the side wall 3, and a cover 5 sealing the open upper end of the side wall 3. The side wall 3 is centered on a normally upright axis L, and the floor 4 and cover 5 are axially spaced and extend perpendicular to the axis L. In this embodiment a support basket 11 for holding the spent fuel elements 2 is provided in the interior 10 of the container 1. The floor 4 and the side wall 3 may be unitarily connected to one another.

(8) According to the invention, the side wall 3 has an annular array of formations 7 inside the container in its upper cover-side edge region 6 that are distributed around the inner surface of the side wall 3, and the cover 5 is provided on its outer edge with a complementary array of radially outwardly directed formations 9 that are angularly uniformly distributed around its outer edge. In the locking position of the container 1, the cover 5 is fixedly attached to the side wall 3 due to the interfitting of the cover-edge formations 9 with the formations 7 of the side wall 3. According to the invention, however, the connection between cover 5 and side wall 3 is free of welds.

(9) A plurality of the side-wall formations 7, in this embodiment at least twelve side-wall formations 7, are arrayed around the inner surface of the side wall 3. An identical plurality of complementary cover-edge formations 9, at least twelve complementary cover-edge formations 9, are arrayed around the inner periphery of the cover 5. In this embodiment the side-wall formations 7 that are inside the container on the inner surface of the side wall 3 project radially inward, and are rectangular when viewed from above and from radially inside. The complementary cover-edge formations 9 that are distributed on the outer edge 8 of the cover 5 around the outer surface thereof are L-shaped grooves that each have a portion 20 extending parallel to a longitudinal axis L of the container as well as a portion 21 perpendicular thereto or perpendicular to the longitudinal axis L of the container. These portions 21 extend tangentially on the outer edge of the cover 5. The portions 20 parallel to the longitudinal axis L of the container open downward on the edge of the cover 5, so that the formations/projections 7 can be inserted upward into them.

(10) In order to move the container 1, more particularly the cover 5, from an opening position to the locking position, the projections 7 of the side wall 3 engage in the formations/grooves 9 of the cover 5. Advantageously, the cover 5 is first fitted into the upper end of the side wall 3 so that the projections 7 engage axially upward into the vertical portions 20 of the grooves 9 until the projections 7 abut downwardly facing upper edges 15 of the portions 21 of the grooves 9. The cover 5 is then rotated relative to the side wall 3 so that the projections 7 are trapped in the groove portions 21 that extend perpendicular to the longitudinal axis L of the container. In this position, the projections 7 abut against the groove abutment edges 15 on the upper side of the container, so that the cover 5 is held captive on the container 1 axially of the container 1. Since the angular depth of the tangential groove portions 21 past the downwardly open vertical groove portions 20 is roughly equal to the angular dimension of the rectangular projections/formations 7, there is considerable load-bearing capacity.

(11) Especially in this embodiment as shown in FIG. 3 the portions 21 of the grooves 9 have upwardly directed lower faces 16 that are angled downward toward the interior 10 of the container and the floor 4. It lies within the scope of the invention for the projections 7 to have complementarily angled lower faces. Each of the projections 7 also has a complementarily angled face. The engagement of the projections 7 in the groove portions 21 prevents the side wall 3 from spreading as a result of loads during vertical handling of the container 1. In fact an upwardly directed vertical force applied to the cover 5 will pull in the upper edge of the side wall 3.

(12) It can be seen particularly in FIGS. 3 and 4 that a sealing groove 17 runs around the periphery of the container 1 on the upper end of the container 1 between the cover 5 and the upper edge of the container 3 when the container 1 is in the locking position. The cover 5 has an annular upwardly open recess 25 that runs around its edge, more particularly where its outer edge and upper surface meet to form this sealing groove 17. At least one seal 18 is in the sealing groove 17, in this embodiment is a seal ring or O-ring. Advantageously, this seal 18 is a metal gasket. In this embodiment this recess 17 of the cover 5 has a frustoconical and upwardly directed lower face 26 angled downward and outward toward the side wall 3. The seal 18, more particularly the sealing ring, advantageously rests against this base face 26.

(13) A compression ring 19 sits on top of the cover 5 when the container 1 is in the locking position to compresses the seal 18 in the groove 17. The compression ring 19 is fixed to the cover 5 by screws. It also lies within the scope of the invention for the compression ring 19 extends around the edge of the container 1 and the cover 5. The compression ring 19 has a downwardly projecting annular ridge 27 on its outer edge that advantageously comes into direct contact with the seal 18. In this embodiment, this annular ridge 27 of the compression ring 19 has a frustoconical lower face 28 on its underside that is angled upward and outward toward the side wall 3, oppositely to the groove face 26. By virtue of this arrangement, an effective compression of the seal 18 takes place and an optimal radial sealing is achieved because the seal 18 is compressed axially by the faces 26 and 28 and forced radially outward into good contact with the inner face of the side wall 3. It is also recommended means be provided between the compression ring 19 and the side wall 3 advantageously in the form of fitted keys or wedges or similar elements not shown in the figures that fit into complementary grooves of the compression ring 19 on the one hand and of the side wall 3 on the other hand. This means prevents rotation of the ring 19 relative to the cover 5 and/or side wall 3.

(14) FIG. 4 shows the seal 18 used according to a preferred embodiment that here is a metal gasket. This metal gasket has a core ring 22 made of at least one metal, a nickel alloy or a nickel-based alloy. Alternately, the seal 18 has a tubular inner jacket 23 that consists at least substantially of stainless steel as well as a tubular outer jacket 24 that in this embodiment consists or substantially consists of aluminum. This outer jacket 24 could also be a coating of a noble metal such as silver or gold.