Core Design Method Research Articles

Terrace-Shaped Core Design Method for Inductive Power Transfer System Considering Uniform Magnetic Flux Distribution

Terrace-Shaped Core Design Method for Inductive Power Transfer System Considering Uniform Magnetic Flux Distribution

Research on the design method of rural public space based on aesthetic interaction concept

Rural public space is not only the carrier of rural residents ' daily life and public activities, but also the link to maintain villagers ' community feelings and the support of traditional culture. It plays a crucial role in rural construction. At present, designers for the design of rural public space, still stay in the " function " level. Based on the concept of aesthetic interaction , this paper applies the concept of interaction design to architectural design , discusses the feasibility of applying " beauty " as the entry point and " interaction " as the core design method in the design of rural public space , and summarizes a set of reasonable and effective design methods from the three aspects of spatial function compound , in the locality and perceptual guidance .

Design Optimization of V-sector Ball Valve Core

In order to solve the problem that the percentage characteristic of V-sector ball valve is poor at the relatively small opening degree, a design optimization flow of valve core is proposed for the first time. The process uses numerical simulation, sample mean evaluation and area average equivalence to calculate the equal percentage characteristics coefficient RQ of DN65 V-sector ball valve core, and uses experiments to verify the rationality of the process, and further extends it to other models of ball valves. The results show that the original DN65 V-sector Ball valve core does not meet the equal percentage characteristics in the opening area of 28.6 % to 7.1 %. After the optimized design, the equal percentage characteristics coefficient RQ of the ball valve core has been effectively improved, and the level of increase has more than doubled. And the equal percentage characteristics coefficient obtained by test exceeds the optimized design results. Further extended in the DN100 V-sector ball valve core, it is known that this optimization design method has universal applicability; V-sector ball valve core design optimization method is an efficient and reliable valve core design method, can improve the level of Valve core flow control, improve the valve core design ability.

Equilibrium core design methods for molten salt breeder reactor based on two-cell model

Two unit-cell-based core design methods are presented for a molten salt breeder reactor (MSBR) equilibrium core with online reprocessing and refueling: a single-cell method and a two-cell method. The single-cell method adopts a representative single unit cell which has the same fuel-to-moderator volume ratio as the average value of an MSBR core which actually consists of two zones with different ratios. The two-cell method uses two representative unit cells, one for each zone, with each zone having the appropriate fuel-to-moderator ratio. It is demonstrated that the two-cell-based method is able to catch the neutron physics of spectral interaction of the two zones with different neutron energy spectra, whereas the single-cell method cannot accurately predict the breeding ratio nor the resonance escape probability of the MSBR core. A new code system was established using MCNP6/PYTHON script language for modeling of the online reprocessing of molten fuel, and the depletion and online refueling of the MSBR core.

A systematic core design method for reduction of critical boron concentration in APR 1400 with gadolinia-bearing assembly

A systematic core design method is developed to design Gd-bearing fuel assembly having two types of Gd rods, low-wt%-Gd rod and high-wt%-Gd rod. The purpose of the method is to lower the critical boron concentration (CBC) of a preliminary core loading pattern, and consequently to achieve more negative or less positive moderator temperature coefficient (MTC). The proposed core design method is a process of solving a non-linear programming problem stated with a system of equations. In this method, both the ratio of the number of low-wt%-Gd rod to the number of high-wt%-Gd rod (r) and the assembly average Gd wt% (w) are the solution variables of the system of equations. The target function is the amount of soluble boron concentration reduction, ΔCBC, which is correlated with the reactivity change, ΔkFA, per Gd-bearing fuel assembly by a quadratic reactivity equation. The coefficients of the quadratic equations are calculated prior to the determination of Gd-bearing fuel assembly pattern, using the least square method. The constraints required to determine (r,w) are physically realizable Gd rods pattern, Δki close to ΔkFA derived from ΔCBC, etc. An objective function, minf∑i(ΔkFA-Δki), enables a final loading pattern to reach a target CBC. This design methodology is applied to APR 1400. Total six cases with various target CBCs are investigated to validate the proposed method. CASMO-3/MASTER calculations with new design assemblies produce lower CBCs at BOC than target CBCs keeping maximum pin power below the safety limit, and thus show more negative MTC.

Design and Implementation of Dual-Mode Correlator IP Based on SoC

The SoC design is a tendency which the navigation and positioning receiver circuit design, its key technologies, including bus architecture technology, IP core design and multiplexing, in which the correlator IP core design and reuse is crucial for navigation and positioning receiver. This paper describes the operating principles and structures of the SoC bus architecture and navigation-positioning correlator, and the various modules of the correlator and the Galileo/GPS navigation signal are analyzed; On this basis, to design Galileo/GPS dual-mode correlator IP core using SoC-based IP core design method, and to simulate and analyse, it can be easily applied to the navigation and positioning receiver baseband SoC design.

Design and Verification of a "Soft" eFPGA Using New Method

A novel design methodology for soft eFPGA is proposed. In comparison with the previous soft core design approach, a structured-description strategy is applied and the process of logic synthesis is bypassed in the new design flow. Thus, the capability of processing the bidirectional routing architectures of the mainstream eFPGAs is obtained, while the conventional soft core design method could only handle the eFPGA with directional routing structure. Moreover, the experiment result shows eFPGA designed with this new method is 2 times denser than that designed with the conventional method. To verify this method, a proof-of-concept eFPGA prototype is designed and also presented.

Structural design for dc bushing core based on the material life

In this paper, the design method of dc capacitor bushing core has been studied. According to the derived epoxy/paper composite life model, the bushing core design methods are proposed based on the life of materials, which can make a more reasonable electric field distribution within bushing core. By adjusting the size of plates, the insulation life of innermost and outermost of the bushing core is made to be equivalent, resulting in more efficiency in usage of insulation material. Taking 800 kV dry bushing for example, the optimization size is designed. An iterative algorithm is used to optimize the design of the bushing core to minimize the volume of bushing core, while meeting the maximum designed withstand field strength under the ac and dc voltage.

Design and implementation of an open CNC core at the shop floor level

In this paper, a new CNC core design method, the function-separated design (FSD) method, is proposed to increase the modularity and reconfigurability of CNC systems, simplify the CNC development process, as well as gain a secondary development ability to allow customers or third parties to add or modify NC functions at the shop floor level. With the FSD method, a new CNC core structure is built. In this structure, the CNC core is composed of three main components: engine machine interface, event processor (EP), and system description data (SDD). The engine machine interface provides an interface to machine tools through the parameter settings via a human machine interface (HMI). The EP and SDD are the most important parts. The SDD stores the control rules and modularized NC functions. It is designed as the relatively separated part inside the CNC core. It can also be modified according to the specification changes to access the functions of the CNC core at the shop floor level. To ease the modification of the SDD on the shop floor, the Statechart modeling tool is used to generate a CNC function model; meanwhile, an SDD generator is developed to convert this model into the SDD. The EP is driven by events from the event generator and processes these events by referring to the SDD. The EP always remains the same. With such a structure, the control rules and NC functions of a CNC core can be redesigned or upgraded easily. A case study for implementing a non-circular piston-turning system verifies the feasibility of the proposed design method at the shop floor level.

HTTR環状炉心の炉心解析モデルの検討

It was shown from the annular core critical experiment of the HTTR that its excess reactivity values tend to be overestimated about 3%Δk/k by the HTTR core design method. Therefore, assessment of the calculation model for the annular core of the HTTR was systematically undertaken. The revised model was investigated which was based on the SRAC code system.It was concluded that the multiplication factor of the annular core is considerably affected by the three factors listed below:(1) The Benoist's anisotropic diffusion coefficients(2) The mesh interval in the whole core diffusion calculation(3) The mesh structure of graphite region in fuel lattice cells.The significantly large discrepancy previously reported was reduced down to 1.6%Δk/k by the revised annular core model.

Three-dimensional Core Design of High Temperature Supercritical-Pressure Light Water Reactor with Neutronic and Thermal-Hydraulic Coupling

The equilibrium core of the High Temperature Supercritical-Pressure Light Water Reactor (SCLWR-H) is designed by three-dimensional neutronic and thermal-hydraulic coupled core calculations. The average coolant core outlet temperature of 500°C is accurately evaluated for the first time in the development of the SCLWR-H. The average coolant core outlet temperature is one of the key parameters, which must be accurately determined in order to establish the concept of this unique reactor design. However, it can only be determined by three-dimensional core design method, taking into account the control rod patterns, fuel loading patterns, coupling of the neutronic and thermal-hydraulic calculations, and burnup distribution of each fuel assembly. The R—Z two-dimensional core design method used in previous studies could not model or evaluate such parameters with sufficient accuracy. In this study, a three-dimensional equilibrium core design method for the SCLWR-H is established. This method can accurately evaluate the average coolant core outlet temperature and has permitted a comprehensive equilibrium core to be developed, which satisfies all design criteria. The design criteria are maximum fuel rod cladding surface temperature of 650°C, maximum linear heat generation rate of 39 kW/m, and a positive water density reactivity coefficient.

Three-dimensional Core Design of High Temperature Supercritical-Pressure Light Water Reactor with Neutronic and Thermal-Hydraulic Coupling

The equilibrium core of the High Temperature Supercritical-Pressure Light Water Reactor (SCLWR-H) is designed by three-dimensional neutronic and thermal-hydraulic coupled core calculations. The average coolant core outlet temperature of 500°C is accurately evaluated for the first time in the development of the SCLWR-H. The average coolant core outlet temperature is one of the key parameters, which must be accurately determined in order to establish the concept of this unique reactor design. However, it can only be determined by three-dimensional core design method, taking into account the control rod patterns, fuel loading patterns, coupling of the neutronic and thermal-hydraulic calculations, and burnup distribution of each fuel assembly. The R—Z two-dimensional core design method used in previous studies could not model or evaluate such parameters with sufficient accuracy. In this study, a three-dimensional equilibrium core design method for the SCLWR-H is established. This method can accurately evaluate the average coolant core outlet temperature and has permitted a comprehensive equilibrium core to be developed, which satisfies all design criteria. The design criteria are maximum fuel rod cladding surface temperature of 650°C, maximum linear heat generation rate of 39 kW/m, and a positive water density reactivity coefficient.

385. 大型高速炉炉心の核的ディカップリング特性

It was made clear by critical experiments (called JUPITER) that nuclear characteristics of large-sized fast reactor cores were quite different from those of small-sized cores. For instance, radial neutron flux distributions are significantly changed by perturbations, control rod reactivity interaction effects are large, etc. These phenomena are interpreted to be commonly caused by the spatial neutronic decoupling of large core. The changeability and instability of flux distribution, which might cause a power peaking and a flux tilting, is a new problem for the development of large core. The paper shows measured results of static decoupling characteristics, interprets them physically, and considers a reactor physics system of large core. The paper also investigates a nuclear core design method, in which the decoupling characteristics are taken into account. A neutronic stability is a new requirement for the nuclear design of large core, which the design policy is to promote and secure together with the performance and the safety. The more tightly coupled the core, i.e., the smaller the degree of decoupling, the better the neutronic stability.

Physics Benchmark Experiments and Analysis for Reflector-Control-Type Small Fast Reactors at TOSHIBA Nuclear Critical Assembly

New physics benchmark experiments were successfully accomplished in order to study the basic characteristics of a reflector controlled small reactor 4S and to validate core design methods using Toshiba NCA critical facility. The experience gained through the analyses provides rationality of nuclear design methodology and nuclear library. Continuous Monte Carlo transport calculation method using JENDL3.2 enables core designers to predict reflector control characteristics with high reliability. Prediction accuracy for burn-up characteristics is needed for further design activity.

Spatial Neutronic Decoupling of Large Fast Breeder Reactor Cores: Application to Nuclear Core Design Method

Space-dependent nuclear characteristics, measured by critical experiments on large-size fast breeder reactor (FBR) cores, were reviewed and interpreted. It was observed that radial neutron flux distributions were significantly distorted by perturbations, control rod reactivity interaction effects were large, and the point kinetics was not valid. These physical behaviors are enhanced as the spatial neutronic decoupling increases. To obtain stable and benign nuclear characteristics and to make the kinetics as close to the point kinetics as possible, it is necessary to reduce the spatial decoupling. This is an important issue that must be taken into account in the nuclear design for large FBR cores.A new nuclear core design method for large FBR cores is proposed in which neutronic stability is considered at the same time as performance and safety for the optimization of core design. The neutronic stability is improved by reducing the spatial decoupling and by taking into account the spatial higher harmonics.

High-Order Finite Difference Nodal Method for Neutron Diffusion Equation

A nodal method has been developed which accurately and rapidly solves the three-dimensional neutron diffusion equation in both Cartesian and hexagonal geometries. To reduce the number of unknowns in comparison with the interface current method in favor of short computation time and a small computer memory requirement, this method employs the finite difference method (FDM) as its global neutron balance solution method. In the global neutron balance solution, the coupling coefficients are modified in such a way as to conserve the nodal interface neutron currents which are obtained by a local neutron balance solution method fit to each geometry. To validate the method developed here, it has been applied to neutron diffusion calculations for reactor cores, typical of Cartesian and hexagonal geometries, with different core sizes, assembly pitches, core configurations, control rod patterns, etc. For a large FBR (hexagonal geometry), for example, errors in power distribution and control rod worth by the method are less than 1/2 and 1/10, respectively, compared to an ordinary FBR core design method, while the computation time is 1/8 that of the latter method.

Optimized Automatic Reload Program for Pressurized Water Reactors Using Simple Direct Optimization Techniques

An efficient reload core design method, applicable to a commercial pressurized water reactor, has been developed. The objective of the reload core design is to achieve the maximum cycle length. The optimization of the reload core design is effected in three stages: 1. Use a linear programming method to find an optimum beginning-of-cycle (BOC) k∞ distribution, which yields maximum keffat the end of cycle when depleted by the Haling power distribution. Individual fuel assemblies are then loaded into the core using the optimum BOC k∞ distribution as a guide.2. Compute the optimum burnable poison requirements in parts per million/billion and their corresponding boron carbide weight percents for the fresh fuel assemblies using the gradient projection method.3. Deplete the optimum design using an accurate analysis.The application of the method to Three Mile Island Unit 1 (TMI-1) cycles 5 and 6 has shown that an optimum loading pattern for maximum cycle length is a low-leakage core. Compared with the TMI-1 loading patterns, the optimization has yielded an increase in cycle length by 12 effective full-power days (EFPDs) in cycle 6 and 41 EFPDs in cycle 5 plus saving about $3 million in fuel cost. The reason for the greater improvement in cycle 5 is that the cycle 5 loading pattern was a high-leakage core and the optimum design is a low-leakage core. The computer time required for computing one reload core design is ∼400 s on the IBM-3090 computer.