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.

A method of a method of irradiating a target material in a heavy water reactor for the production of an isotope, including the steps of providing a target comprised of a material suitable for producing the isotope by way of a neutron capture event, placing the target in a primary fluid side of the heavy water reactor, and irradiating the target.

A method of a method of irradiating a target material in a heavy water reactor for the production of an isotope, including the steps of providing a target comprised of a material suitable for producing the isotope by way of a neutron capture event, placing the target in a primary fluid side of the heavy water reactor, and irradiating the target.

A method of collecting .sup.3He from a nuclear reactor may include the steps of a) providing heavy water at least part of which is exposed to a neutron flux of the reactor, b) providing a cover gas in fluid communication with the heavy water, c) operating the nuclear reactor whereby thermal neutron activation of deuterium in the heavy water produces tritium (.sup.3H) and at least some of the tritium produces .sup.3He gas by .sup. decay and at least a portion of the 3He gas escapes from the heavy water and mixes with the cover gas, d) extracting an outlet gas stream, the outlet gas stream comprising a mixture of the cover gas and the 3He gas and e) separating the 3He gas from the outlet gas stream.

A method of collecting .sup.3He from a nuclear reactor may include the steps of a) providing heavy water at least part of which is exposed to a neutron flux of the reactor, b) providing a cover gas in fluid communication with the heavy water, c) operating the nuclear reactor whereby thermal neutron activation of deuterium in the heavy water produces tritium (.sup.3H) and at least some of the tritium produces .sup.3He gas by .sup. decay and at least a portion of the 3He gas escapes from the heavy water and mixes with the cover gas, d) extracting an outlet gas stream, the outlet gas stream comprising a mixture of the cover gas and the 3He gas and e) separating the 3He gas from the outlet gas stream.

Irradiation target holders are configured to fit in open locations inside of an operating commercial nuclear core. Holders can be 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 can join 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.

A device and method that enables a specimen that is to be converted into a radioisotope to be inserted into an extended, retractable thimble of a nuclear reactor moveable in-core detector system and be harvested after irradiation either during reactor operation or a refueling outage without damaging the retractable thimble. The specimen is enclosed within the interior of a forward portion of a tubular member having a closed lead end and structured to travel within the retractable thimble. The tubular member is sized to extend from a position above and proximate the desired core elevation the specimen is to be irradiated at to a location above a seal table that the retractable thimble extends through. The specimen is inserted and withdrawn from the core by inserting or withdrawing the tubular member from above the seal table. Desirably, the forward end of the tubular member is divided into several specimen compartments.

A vacuum micro-electronics device that utilizes fissile material capable of using the existing neutron leakage from the fuel assemblies of a nuclear reactor to produce thermal energy to power the heater/cathode element of the vacuum micro-electronics device and a self-powered detector emitter to produce the voltage/current necessary to power the anode/plate terminal of the vacuum micro-electronics device.

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.

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.