TARGET IRRADIATION SYSTEMS FOR THE PRODUCTION OF RADIOISOTOPES
A target well of a target delivery assembly for use in an irradiation system operative to allow irradiation of a radioisotope target via a vessel penetration of a fission reactor. The target well includes an outer tube and an inner tube disposed therein so that an annulus is formed therebetween. The target is positioned in the inner tube during irradiation. At least one flow channel extends between a bottom end of the outer tube and a bottom end of the inner tube. An elevation piston is slidably disposed within the inner tube to elevate the target, the elevation piston including a one-way check valve allowing flow in a downward direction and preventing flow in an upward direction.
1 . A target well of a target delivery assembly for use in an irradiation system which is operative to irradiate a radioisotope target via a vessel penetration of a fission reactor, comprising:
a tube defining an interior in which the target can slidably move, the tube having an upper portion, a lower portion, and a constriction disposed therebetween; and
an elevation piston slidably disposed within the lower portion of the tube, the elevation piston being reciprocatively movable in the lower portion of the tube to selectively elevate the target,
wherein the constriction of the tube defines an aperture having an inner diameter that is less than an outer diameter of the elevation piston, thereby preventing passage of the elevation piston from the lower portion to the upper portion of the inner tube.
2 . The target well of claim 1 , further comprising a central tube disposed within the upper portion of the inner tube so that an annulus is defined therebetween.
3 . The target well of claim 2 , further comprising at least one flow aperture defined in a bottom end of the central tube adjacent the constriction.
4 . The target well of claim 2 , further comprising a hydraulic supply in fluid communication with the annulus so as to supply propellant medium into the at least one flow aperture to thereby further elevate the target.
5 . The target well of claim 1 , further comprising a force-limiting device located in the lower portion of the tube.
6 . The target well of claim 1 , further comprising a hydraulic supply operative to cause upward movement of the elevation piston.