8 results about "Fuel cycle" patented technology

This invention provides a method, system, device, and medium for assessing the availability of a neutron detector, relating to the field of commissioning and maintenance technology for external nuclear instrumentation systems in nuclear power plants. The assessment method includes: obtaining the high-pressure characteristic curve of the neutron detector for the current fuel cycle; obtaining the plateau slope of the neutron detector for the current fuel cycle based on the high-pressure characteristic curve; obtaining the voltage margin of the high-pressure characteristic curve of the neutron detector for the current fuel cycle based on the high-pressure characteristic curve, the current power level of the reactor, the upper limit of the power level to be measured by the neutron detector, the operating voltage of the neutron detector, and the upper limit of the low-pressure region voltage of the neutron detector; and determining the availability of the neutron detector based on the plateau slope and the voltage margin of the high-pressure characteristic curve. The assessment method, system, device, and medium provided by this invention can comprehensively assess the current availability of the neutron detector and predict its remaining service life without changing the external nuclear instrumentation system equipment.

The application provides an engine preheating and fuel circulating heating system suitable for extremely cold environment, which comprises an engine, a coolant heater, an oil tank divided into a main oil cavity and a sub oil cavity, a fuel heater and a sub oil cavity oil suction element. The system stores low-grade diesel in the sub oil tank for preheating and stores conventional diesel in the main oil tank to reduce cost. The coolant heater heats the coolant, and the fuel heater heats the diesel in the main oil tank by using the heated coolant. The system also has an oil valve and a driving motor, which can flexibly switch the main oil tank and the sub oil tank to supply oil. In addition, the application also provides a heating method, which comprises the steps of preheating the coolant, starting the engine with low-grade diesel, circulating heating and melting the waxed diesel, and switching to conventional diesel oil supply. Compared with the prior art, the application has significant advantages in cost-effectiveness, engine starting performance, heating efficiency, risk of diesel waxing and system flexibility, and is suitable for stable operation of the engine in extremely cold environment.

This invention discloses a simulation method for differential refueling in a pebble bed reactor based on a semi-Lagrange fixed-grid backtracking algorithm, relating to the field of fuel cycle calculation technology for high-temperature gas-cooled reactors. The method includes: calculating the macroscopic burnup depth and poison nucleus density of fuel spheres in each grid of a homogenized pebble bed using a core diffusion program; calculating the backtracking distance of each grid based on the flow velocity in the channel where each grid is located and the time step used in each refueling step, and determining the position before backtracking; calculating weighting coefficients based on this backtracking position, and updating the macroscopic burnup depth and poison nucleus density of fuel spheres in the calculation grid using a cubic spline interpolation function; and finally correcting the calculated macroscopic burnup depth and poison nucleus density using a correction equation. This invention solves the numerical dispersion and oscillation problems existing in traditional methods, significantly improving the smoothness and stability of core physics field calculations under differential refueling conditions.

A self-contained, offshore, underwater nuclear power plant is housed within a hull mounted to the seafloor. An electric line extends from the offshore power plant to an onshore electric load to power the electric load. The body of water provides a heat sink for the power plant, and protection from surface weather, waves, and currents. The hull mounts to the seafloor via a dampener that reduces the transfer of seismic activity from the seafloor to the hull. The hull and power plant may be manufactured at an onshore facility and transported to an offshore location of operation on the seafloor. After completion of a fuel cycle, the hull and power plant may be transported from the offshore location of operation to an onshore maintenance / refueling facility for refueling, repair and later, when obsolete or damaged, for decommissioning.

The present application relates to an aero-engine fuel system icing test device and test method. The aero-engine fuel system icing test device includes a supercooled water manufacturing unit to generate liquid water at a set temperature; a supercooled water and fuel collision unit for injecting liquid water at a set temperature into fuel to generate water-containing fuel or ice-containing fuel; a fuel storage unit for storing fuel; a circulation control and heat exchange unit for heating and cooling the fuel in the fuel storage unit; and an ejector pump connected to the circulation control and heat exchange unit and the supercooled water and fuel collision unit through fuel pipelines. The ejector pump is connected to the inlet pipeline of the engine, and is used to suck the water-containing fuel or ice-containing fuel in the fuel pipeline into the inlet pipeline of the engine. The present application provides an aero-engine fuel system icing test device and test method, which can achieve transient icing verification and steady-state icing verification.

The invention relates to a fuel circulation method of a pebble-bed high-temperature gas cooled reactor, and relates to the field of nuclear energy engineering. The method comprises the following steps: adding fuel elements with low enrichment degree and high mixing ratio into a reactor container, and simultaneously unloading all fuel elements loaded in an initial loading reactor core in the reactor container. Sequentially adding a low-enrichment-degree fuel element and a low-enrichment-degree high-mixing-ratio fuel element into the reactor container, simultaneously unloading a part of fuel elements at the bottom of the reactor core during each addition, and circulating for a first set time; and adding low-enrichment-degree pure fuel elements to the top of the reactor core, and simultaneously unloading the fuel elements which are loaded in the reactor core in a staggered manner. And adding a low-enrichment-degree and high-enrichment-degree mixed fuel element to the top of the reactor core, simultaneously unloading a low-enrichment-degree pure fuel element at the bottom of the reactor core, and circulating for a second set number of times. Through stepped fuel replacement and staggered loading design, the axial power distribution of the reactor core is effectively flattened, the hot-spot temperature is reduced, the fuel utilization rate and the operation economy are improved, and the device is adaptive to a non-stop refueling system.

The present application relates to aviation fuel control technical field, specifically, it is a kind of aviation fuel control system and control method thereof;Including fuel circulation system and electrical measurement and control system, electrical measurement and control system is used to control the temperature, flow and pressure of circulating fuel in fuel circulation system;Fuel circulation system includes first regulating valve group, explosion-proof electric heater group, heat preservation assembly, pump group, second regulating valve group and temperature measuring assembly, product export is sequentially connected first regulating valve group, explosion-proof electric heater group, heat preservation assembly and pump group between product import, and product import and product export end are equipped with temperature measuring assembly;The pipeline connected between first regulating valve group, explosion-proof electric heater group and the pipeline connected between pump group, product import are communicated, and the pipeline of this communication is connected second regulating valve group;The present application can control the temperature, pressure and flow of fuel into the product under test, help to improve the stable fuel condition for the combustion test of product, improve the accuracy of combustion test.

The application discloses a kind of nuclide composition analysis methods of spent fuel assembly, comprising: respectively obtaining the rod position data of AO control rod group and mechanical compensation control rod group in each fuel cycle in each burnup point in core.According to the rod position data of AO control rod group in each fuel cycle in each burnup point, obtain the calculation segmentation number N of AO control rod group.According to the rod position data of mechanical compensation control rod group in each fuel cycle in each burnup point, obtain the maximum burnup depth ratio Z of mechanical compensation control rod group k . According to the calculation segmentation number N of AO control rod group insertion and the maximum burnup depth ratio Z k , the burnup of each axial segmentation of the spent fuel assembly is calculated to obtain the nuclide composition of each axial segmentation of the spent fuel assembly.The present method can analyze the nuclide composition of spent fuel assembly, and the analysis result is accurate.The application also discloses a kind of nuclide composition analysis devices of spent fuel assembly.