Patent Number: 
Section: claims

1. An irradiation target harvesting system comprising:at least one storage container for receiving activated irradiation targets from an instrumentation tube system of a nuclear reactor;a discharge tube having an exit port configured to be coupled to the storage container; anda lock element provided in the discharge tube for blocking movement of the activated irradiation targets to the storage container;wherein the discharge tube comprises a first discharge tube section, a second discharge tube section and an apex formed at a conjunction of the first and second discharge tube sections,wherein the first and second discharge tube sections are directed downward from the apex,wherein the exit port is arranged at an end of the first discharge tube section,wherein the second discharge tube section is coupled to the instrumentation tube system, andwherein the discharge tube comprises a T-junction located between the lock element and the exit port, wherein the T-junction is configured for supplying and discharging pressurized gas into and out of the discharge tube. 2. The irradiation target harvesting system according to claim 1, wherein the exit port comprises a valve element for pressure-tight sealing the discharge tube. 3. The irradiation target harvesting system according to claim 1, wherein the first discharge tube section, the second discharge tube section and the apex have a shape of an inverse U. 4. The irradiation target harvesting system according to claim 1, wherein the lock element is at a first level, wherein the second discharge tube section has a base point opposite to the apex and the base point is at a second level, and wherein the first level is higher than the second level. 5. The irradiation target harvesting system according to claim 1, wherein the harvesting system comprises one or more magnets arranged at the first discharge tube section between the apex and the lock element. 6. The irradiation target harvesting system according to claim 5, wherein the one or more magnets are selected from a permanent magnet and a solenoid. 7. The irradiation target harvesting system according to claim 1, wherein the lock element comprises a magnetically or mechanically operated restriction element. 8. A radionuclide generation system comprising:an instrumentation tube system of a nuclear reactor including at least one instrumentation finger extending into a core of the nuclear reactor wherein the instrumentation tube system is configured to permit insertion and removal of irradiation targets into the instrumentation finger;a target drive system configured to insert the irradiation targets into the instrumentation finger in a predetermined linear order and to remove the irradiation targets from the instrumentation finger;a core monitoring system and an instrumentation and control unit linked to each other and configured to calculate an optimum axial irradiation position and time for the irradiation targets based on the actual state of the nuclear reactor as provided by the core monitoring system; anda target harvesting system according to claim 1. 9. The radionuclide generation system according to claim 8, wherein the target drive system is pneumatically operated. 10. The radionuclide generation system according to claim 8, wherein the target harvesting system comprises one or more magnets arranged at the first discharge tube section between the apex and the lock element and the lock element and the one or more magnets are remotely controlled by the instrumentation and control unit. 11. A method for harvesting activated irradiation targets from an instrumentation tube system of a nuclear reactor, wherein the method comprises the steps of:coupling the instrumentation tube system to a discharge tube having a first discharge tube section, a second discharge tube section and an apex formed at a conjunction of the first and second discharge tube sections, an exit port and a lock element between the apex and the exit port, wherein the first and second discharge tube sections are directed downward from the apex;passing the activated irradiation targets from the instrumentation tube system into the discharge tube and blocking movement of the activated irradiation targets out of the discharge tube by means of the lock element;separating a predefined quantity of the activated irradiated targets from another quantity of the activated irradiated targets in the discharge tube;coupling the exit port to a storage container and releasing the lock element to pass the predefined quantity of the activated irradiated targets under action of gravity into the storage container;wherein said separating step comprises passing the predefined quantity of the activated irradiation targets over the apex into the first discharge tube section and keeping the other quantity of activated irradiation targets in the second discharge tube section or the instrumentation tube system by means of the apex. 12. The method according to claim 11, further comprising a step wherein the other quantity of the activated irradiation targets separated from the predetermined quantity of activated irradiation targets is transferred from the second discharge tube section into a position in the instrumentation tube system prior to removing the storage container from the exit port. 13. The method according to claim 11, further comprising a step wherein irradiation targets and one or more dummy targets are inserted into the instrumentation tube system, wherein the dummy targets are made of an inert material that is not substantially activated under the conditions in the core of an operating nuclear reactor, and wherein the irradiation targets and the dummy targets have different magnetic properties. 14. The method according to claim 13, wherein the dummy targets inserted into the instrumentation tube system are ferromagnetic, and the irradiation targets inserted into the instrumentation tube system are non-magnetic or paramagnetic. 15. The method according to claim 14, further comprising a step wherein the dummy targets and/or the irradiation targets are exposed to a magnetic field when in the first discharge tube section. 16. The method according to claim 13, further comprising a step wherein the dummy targets and/or the irradiation targets are exposed to a magnetic field when in the first discharge tube section. 17. The method according to claim 13, wherein the irradiation targets are separated from the dummy targets by selectively removing one of the irradiation targets and the dummy targets from the discharge tube, the method further comprising the steps of exposing the irradiation targets or the dummy targets to a magnetic field, opening the lock element, and releasing one of the irradiation targets or the dummy targets from the discharge tube while keeping the other one of the irradiation targets or the dummy targets in the first discharge tube section by the action of the magnetic field. 18. The method according to claim 17, wherein the step of separating the irradiation targets from the dummy targets further comprises driving one of the dummy targets or the irradiation targets back into the instrumentation finger or a holding position in the instrumentation tube system while retaining the other one of the dummy targets or the irradiation targets in the first discharge tube section by means of the magnetic field.