Limiting/eliminating formation of cracks in bottom of nuclear reactor tank, comprises passing curved segments of first chamber through core plate, assembling segments around a tube, and fixing segments one another and at the tank bottom

摘要

The process for limiting or eliminating the formation of cracks in a bottom of a nuclear reactor tank, comprises passing curved segments of a first chamber (48) through a core plate until a location around a tube (36) is fixed to the bottom of the tank surrounding a penetration, assembling the segments around the tube for forming an enclosure, fixing the segments one another and at the bottom of the tank, passing a second chamber (60) through a hole of the core plate and contacting with the first chamber, and evacuating water in the first and second chambers. The process for limiting or eliminating the formation of cracks in a bottom of a nuclear reactor tank, comprises passing curved segments of a first chamber (48) through a core plate until a location around a tube (36) is fixed to the bottom of the tank surrounding a penetration, assembling the segments around the tube for forming an enclosure, fixing the segments one another and at the bottom of the tank, passing a second chamber (60) through a hole of the core plate and contacting with the first chamber, evacuating water in the first and second chambers thus providing a dry environment, and descending a welding head through the second chamber for producing a weld around the tube or on the bottom of the tank. The first chamber has a diameter larger than a diameter of the hole. A pair of segments is formed in an exclusive way with different configuration to form a hemispherical shape of the tank bottom. The hemispherical bottom has a vertical axis passing by its point. The segments have higher edges in a horizontal plane perpendicular to the vertical axis, and conical lower edges for adapting itself to a slope along the hemispherical bottom. Forming a clip in the form of two distinct parts, passing separately the distinct parts of the clip through the hole, fixing the clip at the place of welding of the bottom, and coupling the clip and the segment to maintain an inner surface of the bottom of tank. The bottom of the tank comprises mechanical casings for control rods.