Abstract: Devices, systems, and methods for power generation using irradiators and other gamma ray sources are disclosed herein. In various aspects, an irradiator-based power generation device is disclosed. The power generation device can include a radiator layer configured to at least partially surround an irradiator, wherein the radiator layer comprises a radiator material configured to emit delta radiation in response to exposure to gamma radiation; an electrical insulation layer configured to surround the radiator layer, wherein the electrical insulation layer comprises an electrical insulation material configured to allow delta radiation to penetrate therethrough; and a collector layer configured to surround the electrical insulation layer, wherein the collector layer comprises a collector material configured to collect delta radiation.

Abstract: A power sensor system for monitoring a subcritical neutron generator is provided. The power sensor system comprises a self-powered sensor insert. The self-powered sensor insert comprises an insert thimble and a detector assembly. The insert thimble includes an outer housing, a power generator configured to produce an electrical power based on an incident radiation and a first electrical interface electrically connected to the power generator. The detector assembly includes a solid state radiation detector able to provide a detector signal directly proportional to a neutron flux level, a transmitter configured to wirelessly output a transmitter signal based on the detector signal and a second electrical interface configured to electrically couple to the first electrical interface. A power monitor system comprising a power sensor system and a control system and a method for optimizing a subcritical neutron generator are also provided.

Abstract: A cladding for housing enriched nuclear fuel in a nuclear fuel assembly is provided. The cladding comprises a base layer comprised of Zirconium alloy and a coating for the base layer. The base layer has a wall thickness of less than 1 millimeter. The coating comprises a primary layer comprised of Chromium or a Chromium alloy. The primary layer has a thickness in the range of about 5 to about 50 microns. A fuel rod for a nuclear reactor core and a method for producing a fuel rod are also provided.

Abstract: Devices, systems, and methods for delivering delta radiation using prompt neutron capture gamma radiation are disclosed herein. In one aspect, a device for delivering delta radiation can include a neutron generator, an electron emitter, and an irradiation target. The neutron generator may be configured to generate a neutron flux field. The an irradiation target can include an irradiation target material having a high thermal neutron cross section and can be configured to emit gamma radiation in response to exposure to the neutron flux field. The electron emitter can be configured to emit delta radiation in response to exposure to the gamma radiation. In some aspects, the irradiation target and the electron emitter can be configured to be positioned between the neutron generator and a surface of an object to deliver the delta radiation to a target region within the object.

Abstract: An enclosure for producing a radioisotope from an irradiation target material in a thimble guide tube of a nuclear reactor core is provided. The enclosure is comprised of an enriched material and defines a cavity therein. The cavity of the enclosure is configured to house the irradiation target material. A target assembly for producing synthetic radioisotopes and a method for producing pharmaceutical radioisotopes with a target assembly are also provided.

Abstract: A target assembly for producing synthetic radioisotopes of Cobalt is provided. The target assembly comprises an enclosure and an irradiation target material. The enclosure defines a cavity therein and is comprised of an enriched material configured to have a short half-life upon being exposed to a neutron flux. The irradiation target material is comprised of a precursor to Cobalt-60. A method for producing a target assembly is also provided.

Abstract: An in-core detector configured to measure a power distribution in a nuclear reactor is disclosed herein. The in-core detector includes a housing configured to be placed within a predetermined location of the nuclear reactor and a plurality of a gamma detectors. Each gamma detector of the plurality of gamma detectors includes a Schottky diode including an active semiconductor region and a Schottky contact, an Ohmic contact, a photoelectron source material configured to transfer electrons to the active region upon contact with gamma radiation, and a first and second lead. The plurality of gamma detectors are positioned within the housing such that each gamma detector of the plurality of gamma detectors is radially offset relative to an adjacent gamma detector of the plurality of gamma detectors, such that the first and second leads of each gamma detector are offset relative to the first and second leads of the adjacent gamma detector.

Abstract: A hydraulic control unit (“HCU”) configured to control a control rod drive mechanism (“CRDM”) configured to control the nuclear flux produced by a nuclear reactor is disclosed herein. The HCU can include a plurality of valves configured to attenuate a fluid pressure within the CRDM, wherein the attenuation of the fluid pressure is configured to cause a control rod of the CRDM to be inserted or withdrawn from a reactor vessel of the nuclear reactor, and a control circuit including a plurality of relay interfaces, wherein each relay of the plurality of relay interfaces is electrically coupled to a valve of the plurality of valves, a controller electrically coupled to the plurality of relay interfaces, and a communications circuit communicably coupled to a header controller, wherein the communications circuit is configured to transmit and receive signals between the controller and the header controller.

Abstract: An apparatus for removing irradiated Co-60 capsules from a plurality of burnable absorber rodlets. The apparatus comprises a solenoid that induces an electromagnetic flux into a Co-60 capsule and locks the Co-60 capsule in parallel with the apparatus. The apparatus is slideable along a longitudinal axis of the burnable absorber rodlet and causes the Co-60 capsule to overcome a plurality of forces exerted on it.

Abstract: A heat pipe configured to remove heat from a nuclear reactor core is disclosed herein. The heat pipe can include an inner housing defining an inner volume configured to accommodate a heat source and an outer housing configured about the inner housing and the heat source. A wick can be positioned between at least a portion of the inner housing and at least a portion of the outer housing, wherein the wick can include a capillary material, and wherein the wick can define an intermediate volume between the inner housing and the outer housing. A working fluid can be positioned within the intermediate volume, wherein the working fluid can evaporate at a first end of the heat pipe and condense at a second end of the heat pipe adjacent to a heat exchanger, and wherein the wick can return condensed working fluid to the first end of the heat pipe.

Abstract: A system configured to monitor the structural health of reactor vessel internals of a nuclear reactor is disclosed herein. The system includes a memory configured to store historical information associated with past performance of the nuclear reactor, and an anomaly detection subsystem including a control circuit configured to receive a signal from a sensor. The anomaly detection subsystem is configured to determine, via the control circuit, a characteristic of a vibrational response of the reactor vessel internals based, at least in part, on the signal; access, via the control circuit, the historical information stored in the memory; compare, via the control circuit, the determined characteristic to the historical information stored in the memory; and determine, via the control circuit, a condition of the reactor vessel internals based, at least in part, on the comparison of the determined characteristic and the historical information.

Abstract: A radioactivity measurement device for measuring an activity level of a radioisotope source is provided. The radioactivity measurement device comprises a housing and a self-powered detector. The housing comprises an outer shell and an inner shell, wherein the inner shell is adapted to house an insertable radioisotope source, and wherein the outer shell and the inner shell are configured to form a hollow annular region. The self-powered detector, positioned within the hollow annular region of the housing, comprises at least one tubular emitter configured to provide a source of electron emission proportional to a radioisotope activity level of the insertable radioisotope source and at least one tubular collector configured to sink the electron emission. A radioactivity level measurement system comprising at least one radioactivity measurement device, a shipping cask incorporating the radioactivity level measurement system and a method for shipping the shipping cask are also provided.

Abstract: A radioisotope production capsule is described. Each capsule includes generally an inner container for housing one of a target material and a neutron moderator, an outer container surrounding the inner container for housing the one of the target material and the neutron moderator not housed by the inner container, and cladding for isolating the target material from the neutron moderator. One or more modular capsules are placed in each of a plurality of plug fingers. Each single plug finger loaded with one or more capsules is inserted into a guide thimble of an array of guide thimbles in a fuel assembly.

Abstract: A covering for reinforcing a base layer of a nuclear fuel cladding is provided. The covering comprises a first layer configured to cover a first portion of the outer surface of the base layer of the nuclear fuel cladding, a second layer surrounding the first layer and the base layer and a third layer surrounding the second layer. The first layer comprises a fiber based material, the second layer comprises an interfacing material and the third layer comprises Chromium. A reinforced cladding for nuclear fuel and a method for producing a reinforced nuclear fuel cladding are also provided.

Abstract: A spacer grid specifically designed for accident tolerant fuel utilizing fuel rods with SiC cladding for implementation in pressurized water reactors. The spacer grid design allows for ease of SiC fuel rod insertion during the fuel assembly fabrication process by providing a smooth contact geometry. The co-planar support allows the fuel rods to be rotated axially more freely at the grid location than a conventional six-point contact geometry used in existing fuel assembly designs. The fuel rod support cells are attached at their corners which are shared between adjacent support cells.

Abstract: Nuclear fuel rods are disclosed. The nuclear fuel rods include a substrate and a chromium alloy coating layer applied to the substrate. The chromium alloy coating layer comprises chromium (Cr); a element or compound selected from the group consisting of yttrium (Y), lanthanum (La), thorium (Th), zirconium (Zr), titanium (Ti), hafnium (I-lf), molybdenum (Mo), tungsten (W), vanadium (V), rhenium (Re), ruthenium (Ru), cobalt (Co), aluminum (Al), carbides, borides, intermetallics, and combinations thereof; and interstitial elements up to 1500 ppm, wherein carbon (C), oxygen (O), and nitrogen (N) are each 500 ppm or less.

Abstract: A method for transitioning a nuclear reactor during initial cycle startup to a power generating state is disclosed. The method includes setting the nuclear reactor to a zero power state, eliminating lower power physics tests (LPPTs) for a current cycle of the nuclear reactor based on a predetermined set of criteria, and setting the nuclear reactor to the power generating mode without performing the LPPTs, based on the reconciliation. The eliminating includes predicting, using a first design code, a first set of values for factors of the LPPTs, developing, using data from past cycles of the nuclear reactor, empirical formulas for the factors of the LPPTs, predicting, using the empirical formulas, a second set of values for the factors of the LPPTs, and reconciling the first values with the second values.

Abstract: An improved retention system for retaining fuel rods in a fuel assembly is disclosed. The retention system includes a plurality of first engagement surfaces on the bottom nozzle of a fuel assembly. There is at least one engagement surface for each fuel rod. A second engagement surface is formed on the bottom end plug of each fuel rod. The first and second engagement surfaces are configured for engagement with each other for axially and laterally retaining each fuel rod within the fuel assembly. Debris deflectors may also be provided to deflect debris from coolant channels surrounding the fuel rods.

Abstract: An elongate fuel element is described that has a silicon carbide cladding enclosing a fuel, such as UO2, wherein the fuel is dimensioned relative to the cladding to define gaps at each lateral end of the enclosure sufficiently large such that upon swelling in use, the fuel does not increase the strain on the cladding beyond the limits of the claddings strain tolerance. The lateral gaps at the ends of the fuel allow lateral expansion during swelling that reduces the strain on the cladding.

Abstract: An igniter apparatus which generates a high speed buoyancy induced vortex to funnel hydrogen and air from the surrounding onto the “igniter core” where an “igniter core” heats up to the auto ignition temperature by the exothermic catalytic oxidation of hydrogen on its surface. Water (vapor) is formed as the product, which inhibits the oxidation reaction, if not stripped away from the catalyst surface. The high velocity of the vortex ensures the stripping of the boundary layer of steam that is formed by the reaction, thus ensuring more active sites are available for hydrogen oxidation. The vortex is formed by channeling an upward draft into a vortex by guided fins. The upward draft is formed by a plate, which is also coated with a hydrogen recombination catalyst. The plate becomes hot by the same catalytic oxidation reaction in the presence of air containing hydrogen.