The generation of a nuclear core loading distribution includes receiving a reactor core parameter distribution associated with a state of a reference nuclear reactor core, generating an initial fuel loading distribution for a simulated beginning-of-cycle (BOC) nuclear reactor core, selecting an initial set of positions for a set of regions within the simulated BOC core, generating an initial set of fuel design parameter values utilizing a design variable of each of the regions, calculating a reactor core parameter distribution of the simulated BOC core utilizing the generated initial set of fuel design parameter values associated with the set of regions located at the initial set of positions of the simulated BOC core and generating a loading distribution by performing a perturbation process on the set of regions of the simulated BOC core to determine a subsequent set of positions for the set of regions within the simulated BOC core.

A method to determine a global core reactivity bias and the corresponding estimated critical conditions of a nuclear reactor core prior to achieving reactor criticality. The method first requires collection and evaluation of the inverse count rate ratio (ICRR) data; specifically, fitting measured ICRR vs. predicted ICRR data. The global core reactivity bias is then determined as the amount of uniform reactivity adjustment to the prediction that produces an ideal comparison between the measurement and the prediction.

A computerized system for modeling reactor fuel element and fuel design to determine the thermo-mechanical performance thereof includes a processor coupled to memory, the memory configuring the processor to execute a fuel element analysis and an output configured to communicate data that describes the thermo-mechanical performance of the fuel element and fuel design based on the fuel element performance analysis. The processor is configured to estimate the mechanical behavior of a fuel by creating separate variables for the open and closed porosity components, conducting a routine for the open and closed porosity components that processes the current state of the fuel and updates the current state and forces of each of the open and closed porosity components, and combining the updates for the current state and forces according to a weighting; and estimate the creep and swelling behavior of a cladding.

A nuclear fuel simulation method is provided that includes: step (a) for receiving an input of data on the order in which nuclear fuels are moved; step (b) for extracting, from the data, information on nuclear fuels, the coordinates of locations from which nuclear fuels are unloaded, and the coordinates of locations into which nuclear fuels are loaded; and step (c) for simulating the information extracted in step (b) according to a flowchart of the data. The present invention has an advantage in that it is possible to accurately and quickly verify all fuel movement works requiring the unloading and loading of nuclear fuels by receiving an input of a huge amount of data on the order in which nuclear fuels are moved and systematically verify an error that may occur during a simulation according to a flowchart, which enables the workload of about three man-days, required per cycle for each reactor, to be done in three man-hours, thereby achieving a significant reduction in working time.

A method for managing the movements of nuclear fuels is provided that includes: (a) loading a storage status map in which storage racks of an SFPR where spent fuels are stored and an NFS where new fuels are stored are mapped; (b) assigning the storage locations of nuclear fuels and the colors thereof in the storage status map; (c) receiving a pattern type input of tasks for designating the order in which nuclear fuels are moved and the locations to which the nuclear fuels are moved, and generating a movement flowchart; and (d) updating the storage status map according to the level at which the movement flowchart has progressed. The present invention has an advantage in that it is possible to quickly create a nuclear fuel movement flowchart by automating all fuel movement works requiring the unloading and loading of nuclear fuels, which enables the workload of about 30 man-days, required per cycle for each reactor, to be done in three man-hours, thereby achieving a significant reduction in working time.

A system is provided that determines optimal movements of fuel assemblies in a nuclear reactor, such as a traveling wave reactor (TWR). Such a system may be capable of modeling core operations and fuel moves in parallel to determine optimal fuel cycle moves responsive to one or more constraints, including, but not limited to core criticality and location of a deflagration wave within an operating reactor core. According to one embodiment, the optimal solution may be determined using a branch search to simulate possible fuel moves.

A computer-assisted method for determining an optimal core-loading pattern for a nuclear reactor core. Positions of nuclear fuel assemblies are tested to assign optimal positions and to load the reactor. The reactor core includes cells positioned symmetrically to axes of symmetry and a standard assembly for insertion into each cell. Standard assemblies are distributed by the number of previous production cycles. Groups of cell positions symmetric to the axes of symmetry are identified, and symmetric positions are counted. Families of standard assemblies having similar burnups are formed, wherein the standard assemblies correspond to positions in a group. The loading pattern of standard assemblies in initial positions is tested by numerical simulation, then the positions are swapped while maintaining the previously formed families of assemblies. The swapped positions loading pattern is tested by numerical simulation. This is repeated until at least one candidate pattern for loading the reactor is obtained.

A computer implemented method for simulating an operation of a reactor core includes determining an initial state of the reactor core; calculating a nodal target power distribution and/or the target 3D neutron flux distribution; obtaining an actual power distribution and/or the actual 3D neutron flux distribution of the nuclear reactor core; determining a difference between the target power distribution and the actual power distribution of the nuclear reactor core and/or determining a difference between the target 3D neutron flux distribution and the actual 3D neutron flux distribution of the nuclear reactor core; determining modal expansion coefficients using a Fourier modal decomposition based on the determined difference and applying a Modal Generalized Perturbation Theory to the modal expansion coefficients for determining a 3D cross-section distribution perturbation causing the determined difference; and determining a 3D adaptation distribution for the determined difference based on the determined 3D cross-section distribution perturbation.

A method of operating a nuclear fission reactor. The reactor comprises a reactor core, and a coolant tank containing coolant, the reactor core comprises an array of fuel assemblies. Each fuel assembly extends generally vertically and comprises one or more fuel tubes containing fissile fuel. The fuel tubes are immersed in the coolant. The method comprises monitoring and/or modelling fuel concentrations and/or fission rates in each of the fuel assemblies; and in dependence upon results of the monitoring and/or modelling, moving fuel assemblies horizontally within the array, without lifting the fuel tubes from the coolant, in order to control fission rates in the reactor core. A nuclear reactor implementing the method, and fuel assemblies for use in the method are also disclosed.

A method of determination of a nuclear core loading pattern defining the disposition of fuel assemblies. The method includes defining at least one potential core loading pattern and calculating predictive bowing of the fuel assemblies at the end of the operation cycle for each potential core loading pattern. The calculation is carried out by an automatic learning algorithm trained on a training data set that includes a plurality of other core loading patterns. The set also includes, for each of the other core loading patterns, measurements of bowing of fuel assemblies at the end of operation cycle. The method also includes evaluating the at least one potential core loading pattern based on the predictive bowing calculations and at least one predetermined criteria. The method further includes selecting one of the potential core loading patterns based at least in part on the evaluating.