Patent Number: 
Section: description

The method for producing a coiled body for irradiating radioactive radiation, starts from the step of forming an elongated tubular metal casing 1 as shown in FIG. 1. For example, this elongated tubular metal casing 1 may be formed by drawing an initial tubular preform (not shown), or by grinding said initial tubular preform, or by drawing said initial tubular preform and then grinding it. Preferably the elongated tubular metal casing 1 will have an outer diameter 2 comprised between 100 and 150 xcexcm, and an inner diameter 3 comprised between 30 and 100 xcexcm. The elongated tubular metal casing 1 is then coiled and to achieve such a coiling, said elongated tubular casing 1 is advantageously filled with a liquid 4 (FIG. 2) and sealed at its ends 5, for example by means of plugs 6. The liquid filled casing 1 is then coiled on a mandrel 7, as shown in FIG. 3, and then, the plugs 6 are withdrawn and the liquid 4 is removed from the coiled tubular casing 11 as shown by arrows 8 on FIG. 4. The coiled tubular casing 11 is then filled with a material 9 capable to irradiate radioactive radiation, as shown by arrows 10 on FIG. 5. The material 9 is in liquid state with its following crystallization in the coiled tubular casing. Crystallization may be achieved by cooling and it may be followed by radiation chemical decomposition. Nitrate crystallohydrate compounds of the material 9 may be used as the material in liquid state. Alternatively, carboxylic acid salts taken with material 9 in mole relation 4:1 may be used as material in liquid state, and palmitic acid may be used as said carboxylic acid salts. Still alternatively, phosphorous-organic acid salts taken with the said material in proportion 4:1 may be used as the said material, with diphenilphosphinic acid being used as said phosphorous-organic acid. Still as a further alternative, mixed salts of highest carboxylic and acetic acids may be used as the said material in liquid state. Then, the coiled tubular casing 11 is sealed at its ends 5, for example by mechanical plugging of elements (not shown) having shape memory. Alternatively, sealing of the coiled tubular casing 11 may be made by laser bonding, or by electronic beam welding, or by optical welding, or by electric arc welding, or by soldering, or by covering the ends 5 and subsequent melting, or still by covering the ends 5 and subsequent annealing. As a variant, the coiled tubular casing 11 may be filled with a gas state decomposition of the material capable to irradiate radioactive radiation and settling of said decomposition in the coiled tubular casing 11. As a further variant, the coiled tubular casing 11 may be filled with the material capable to irradiate radioactive radiation in solid state or in the form of a powder, or in the form of a wire, or coated on a wire. The material may be tightened after filling, for example by an explosion in liquid, or by isotonic pressing, or still by magnetoimpulsive treatment. Where the material is in solid state, filling may be made by covering on the fire. As the material capable to irradiate radioactive radiation, a selection is made from the group of Cerium 144, Strontium 89, Strontium 90, Yttrium 91, Ruthenium 106 or Iodine 125, in active state. Alternatively, the selection may be made from the group of Tungsten 186, Iridium 191, Gadolinium 152, or Ytterbium 168, in non-active state, the material being activated after the step of end sealing of the coiled tubular casing 11. Activation may be made by neutrons in a nuclear reactor. The filled coiled tubular casing 11 may be cut into a plurality of coils before sealing of the ends 5, end sealing being then made on each of the cut coils.