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: 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 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CRDM, wherein the attenuation of the fluid pressure is configured to cause a control rod of the CRDM to be inserted or withdrawn from a reactor vessel of the nuclear reactor, and a control circuit including a plurality of relay interfaces, wherein each relay of the plurality of relay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: 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: 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: 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 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.

Abstract: A detection apparatus includes a resonant electrical circuit supported within an interior of a nuclear fuel rod generates a response pulse in response to an excitation pulse and transmits the response pulse through a cladding of the fuel rod to another location within a reactor in which the fuel rod is housed and without any breach in the cladding. A characteristic of the response pulse is indicative of a condition of the fuel rod. The detection apparatus also includes a transmitter positioned outside the cladding, in the reactor, in the vicinity of the fuel rod and configured to generate the excitation pulse and transmit the excitation pulse through the cladding to the resonant electrical circuit. A receiver is supported within the reactor outside of the cladding and, in response to the response pulse, communicates a signal to an electronic processing apparatus outside of the reactor.

Abstract: A coupler for connecting an irradiation target assembly to a transfer system is provided. The coupler comprises a housing and an inner assembly. The housing comprises a distal end, a proximal end and a side section defining a cavity therein. The side section comprises a plurality of side bores extending into the cavity. The inner assembly comprises an actuator body, a return member for exerting a default axial force on the actuator body, and a plurality of friction members configured to be transversely driven by the actuator body through the plurality of side bores. The actuator body is positioned within the cavity and comprises a first section, a second section and a middle section. A coupling system comprising a coupling insert for a transfer system and a coupler for an irradiation target assembly are also provided.

Abstract: A portable real-time system monitoring device is advantageously capable of autonomously learning the normal behavior of any system and of alerting the user or taking other action when the system becomes unpredictable or otherwise undesirable. No prior knowledge about the system is needed by the device. This is because the device uses a combination of machine learning and statistical process control to autonomously develop its own model of the monitored system and then autonomously monitor the system for unexpected behavior. Therefore, without any prior analysis or model creation, it can be deployed on any system, and it can be reused on any other system after it has been reset. The advantageous device of the disclosed and claimed concept performs this function in either real time or near real-time.

Abstract: The systems and methods of the invention pertain to analyzing steam generator tube data for the detection of wear. Further, the invention is capable of performing a comparison of current tube signal data to baseline or historic tube signal data, e.g., from previous and/or the first, in-service inspection of the steam generator. The systems and methods are automated and can generate results to show potential tube-to-tube contact wear areas as well as the progression of tube-to-tube gap reduction within a steam generator tube bundle. In certain embodiments, the invention is capable of comparing current and historical eddy current data to determine the difference that may be related to degradation or other interested phenomena, and of processing and trending historical comparison results to establish normal variance and detect abnormal variances.

Abstract: Provided herein is a nuclear fuel assembly for a pressurized water reactor. The nuclear fuel assembly comprises: a plurality of nuclear fuel rods configured to contain a fissile material, wherein the nuclear fuel assembly is configured such that a hydrogen to uranium ratio for the fuel assembly, when coolant and the fissile material are present under operating conditions, is at least 4.0. Also provided herein is a method for refueling a pressurized water nuclear reactor comprising a nuclear fuel assembly of the present disclosure.

Abstract: A housing assembly configured to house a reactor is disclosed. The housing assembly includes a plurality of modular walls configured to surround the reactor and a passive temperature control system. The plurality of modular walls includes a first modular wall. The passive temperature control system is coupled to the first modular wall. The passive temperature control system is configured to transfer heat between the reactor and an area around the housing assembly.