System and process for production and collection of radioisotopes
A means for installing material, through a fuel assembly instrument thimble insert, into the existing instrument thimbles in nuclear fuel assemblies for the purpose of allowing the material to be converted to commercially valuable quantities of desired radioisotopes during reactor power operations during a remainder of a fuel cycle and removing the radioisotopes from the core through the reactor flange opening once the fuel assemblies have been removed for refueling. The invention also describes methods that can be used to harvest the irradiated material so it can be packaged for transportation from the reactor to a location where the desired radioisotope(s) can be extracted from the fuel assembly instrument thimble insert.
1. A method of irradiating a target specimen within a nuclear reactor for at least one fuel cycle, to produce at least one commercial radioisotope, the method comprising steps of:
enclosing the target specimen within an elongated tubular housing having an axis along its elongated dimension,
the target specimen being nuclear reactor transmutable to produce the at least one commercial radioisotope,
the elongated tubular housing being closed at a forward end and capped at a rearward end to form a target specimen chamber therebetween within an interior of the elongated tubular housing, and
the elongated tubular housing being sized to slide within an instrument thimble of a nuclear fuel assembly, with the rearward end structured to be driven by a drive cable of an existing moveable in-core detector system;
positioning the target specimen at a preselected axial position within the elongated tubular housing, wherein the target specimen is captured between a forward axial position plug and a rear axial position plug, wherein the forward and rear axial position plugs are structured to seat against an interior wall of the elongated tubular housing to hold the target specimen at the preselected axial position within the elongated tubular housing;
attaching the rearward end to the drive cable;
driving the target specimen positioned within the elongated tubular housing into an instrument thimble of a selected nuclear fuel assembly within a core of a nuclear reactor;
leaving the target specimen within the instrument thimble for the remainder of a fuel cycle of the core, wherein the target specimen while in the instrument thimble is nuclear reactor transmuted to produce the at least one commercial radioisotope;
withdrawing the elongated tubular housing with the at least one commercial radioisotope therein from the core at the end of the fuel cycle;
removing the selected fuel assembly from the core;
while the selected fuel assembly is removed from the core, reinserting the elongated tubular housing with the at least one commercial radioisotope therein at least partially into the core; and
while the elongated tubular housing is at least partially in the core, dislodging from the drive cable at least a portion of the elongated tubular housing that has the at least one commercial radioisotope therein.
2. The method of claim 1 , wherein the dislodging step cuts the elongated tubular housing around a circumference.
3. The method of claim 2 , including a step of transferring the at least a portion of the elongated tubular housing that has the at least one commercial radioisotope therein under water to a spent fuel pool.
4. The method of claim 3 , comprising transferring the at least a portion of the elongated tubular housing in a building housing the spent fuel pool to a shielded package for shipment.
5. The method of claim 1 , wherein positioning the isotope target specimen at a preselected axial position within the elongated tubular housing comprises positioning the target specimen between the forward axial position plug and the rear axial position plug both of which extend across the interior of the elongated tubular housing.
6. The method of claim 1 , wherein the at least one commercial radioisotope comprises one or more materials selected from the group consisting of: Co-60, W-188, Ni-63, Bi-213, and Ac-225.
7. The method of claim 1 , wherein the elongated tubular housing is constructed from zirconium or a zirconium alloy.
8. The method of claim 1 , wherein the forward and rear axial position plugs maintain their axial position due to friction between interfacing surfaces on the axial position forward and rear plugs and the interior wall of the elongated tubular housing.
9. The method of claim 1 , wherein the forward and rear axial position plugs maintain their axial position by fitting in slight recesses in the interior wall of the elongated tubular housing.
10. The method of claim 9 , wherein the forward and rear axial position plugs have an upper and lower surface that extends substantially orthogonal to the axis with an outer, substantially circular wall extending between the upper and lower surface, wherein the axial dimension of the outer, substantially circular wall is sized to fit in one of the recesses.