A machine-learning tool learns from sensors' data of a nuclear reactor at steady state and maps them to controls of the nuclear reactor. The tool learns all given ranges of normal operation and responses for corrective measures. The tool may train another learning tool (or the same tool) that forecasts the behavior of the reactor based on real-time changes (e.g., every 10 seconds). The tool implements an optimization technique for differing half-life materials to be placed in the reactor. The tool maximizes isotope production based on optimal controls of the reactor.

A coolant having a set temperature is fed into the nuclear reactor core of a medical neutron source, which is in a subcritical state. The nuclear reactor core is transitioned from the subcritical state to a critical state until the nominal power of the nuclear reactor is achieved. A neutron output channel is opened in order to conduct a neutron therapy session, and the operation of the reactor is maintained at nominal power while the neutron therapy session is conducted. At the end of the session, the neutron output channel is closed at the same time as the reactor core is transitioned to a subcritical state. The temperature of the coolant entering the core is maintained unchanged and equal to a set temperature, both when the core is transitioned to a critical state and during the operation of the nuclear reactor at nominal power.

A method for harvesting activated irradiation targets (16) from an instrumentation tube system (12) of a nuclear reactor comprises the steps of: Coupling the instrumentation tube system (12) to a discharge tube (38) having an apex (50), an exit port (40) and a lock element (44) between the apex (50) and the exit port (40); Passing the activated irradiation targets (16) from the instrumentation tube system (12) into the discharge tube (38) and blocking movement of the activated irradiation targets (16) out of the discharge tube (38) by means of the lock element (44); Separating a predefined quantity (16) of the activated irradiated targets (16) from another quantity (16) of the targets (16) in the discharge tube (38); Coupling the exit port (40) to a storage container (42) and releasing the lock element (44) to pass the predefined quantity (16) of the activated irradiation targets (16) under action of gravity into the storage container (42); wherein said separating step comprises passing the predefined quantity (16) of the activated irradiation targets (16) over the apex (50) and retaining the other quantity (16) of the targets (16) in the discharge tube (38) by means of the apex (50). Systems for generating radionuclides and harvesting activated irradiation targets adapted to the above method are also provided.

A method for harvesting activated irradiation targets (16) from an instrumentation tube system (12) of a nuclear reactor comprises the steps of: Coupling the instrumentation tube system (12) to a discharge tube (38) having an apex (50), an exit port (40) and a lock element (44) between the apex (50) and the exit port (40); Passing the activated irradiation targets (16) from the instrumentation tube system (12) into the discharge tube (38) and blocking movement of the activated irradiation targets (16) out of the discharge tube (38) by means of the lock element (44); Separating a predefined quantity (16) of the activated irradiated targets (16) from another quantity (16) of the targets (16) in the discharge tube (38); Coupling the exit port (40) to a storage container (42) and releasing the lock element (44) to pass the predefined quantity (16) of the activated irradiation targets (16) under action of gravity into the storage container (42); wherein said separating step comprises passing the predefined quantity (16) of the activated irradiation targets (16) over the apex (50) and retaining the other quantity (16) of the targets (16) in the discharge tube (38) by means of the apex (50). Systems for generating radionuclides and harvesting activated irradiation targets adapted to the above method are also provided.

A nuclear reactor is operated with irradiation target holders fit in open locations inside of an operating commercial nuclear core and placed with ends at vertical bottom and top of the core or any position therebetween to directly expose holders to nuclear fuel reactions. Holders have ends and overall shape that are joined with existing reactor structures, while fitting closely with fuel and moderator and being easily removable from the same. Holders are fabricated of any reactor-compatible material that will retain irradiation targets and daughter products. Holders securely retain irradiation targets and daughter products of any shape or phase throughout reactor operation. Holders can be installed during reactor outages and irradiated during operation without risk of movement or interference with operation. After a desired period of operation and irradiation, holders can be harvested from the core independent of other core structures and fuel.

Target assemblies are provided that can include a uranium-comprising annulus. The assemblies can include target material consisting essentially of non-uranium material within the volume of the annulus. Reactors are disclosed that can include one or more discrete zones configured to receive target material. At least one uranium-comprising annulus can be within one or more of the zones. Methods for producing isotopes within target material are also disclosed, with the methods including providing neutrons to target material within a uranium-comprising annulus. Methods for modifying materials within target material are disclosed as well as are methods for characterizing material within a target material.

Target assemblies are provided that can include a uranium-comprising annulus. The assemblies can include target material consisting essentially of non-uranium material within the volume of the annulus. Reactors are disclosed that can include one or more discrete zones configured to receive target material. At least one uranium-comprising annulus can be within one or more of the zones. Methods for producing isotopes within target material are also disclosed, with the methods including providing neutrons to target material within a uranium-comprising annulus. Methods for modifying materials within target material are disclosed as well as are methods for characterizing material within a target material.

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.

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.

Disclosed are a radioisotope activity surveillance system and methods. The system includes a fuel rod assembly having a plurality of nuclear fuel rods and a target assembly having a top nozzle including an orifice plate and at least one target material rod fixedly coupled to the orifice plate. The least one target material rod is slidably disposed within the fuel rod assembly. A sensing assembly defines an opening sized and configured to receive the target assembly therethrough. The sensing assembly includes a self-powered detector assembly to detect radioisotope activity of the target rod material. Also disclosed is a method for measuring a self-powered detector signal to calculate radioisotope activity of a target assembly and a method for analyzing total activity of a desired radioisotope.