At present, the information and control system (I&C) and operation support system (OSS) of the nuclear power plants (NPPs) are designed separately;their structures and functions are independent. So, the compatibil...
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We combined the subgroup method and the method of characteristics for neutron resonance self-shielding calculation, and programmed a resonance calculation code SGMOC. This code is based on the WIMSD format multi-group...
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We combined the subgroup method and the method of characteristics for neutron resonance self-shielding calculation, and programmed a resonance calculation code SGMOC. This code is based on the WIMSD format multi-group data library. The numerical results of SGMOC are in good agreement with those of MCNP, and thus SGMOC has high calculation precision and geometry flexibility. Based on the SGMOC code, we studied two modification methods for the resonance interference effect calculation. The conditional probability method had a correction effect about 30~180 pcm for kinf calculation of UO2 fuel cell. The method by virtue of NJOY code had a correction effect about 20~130 pcm for kinf calculation of UO2 fuel cell.
Based on generalized coarse mesh rebalance (GCMR) method, this paper proposes a new acceleration method for the method of characteristics (MOC) in unstructured meshes: the generalized coarse-mesh finite difference (GC...
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ISBN:
(纸本)9781617820014
Based on generalized coarse mesh rebalance (GCMR) method, this paper proposes a new acceleration method for the method of characteristics (MOC) in unstructured meshes: the generalized coarse-mesh finite difference (GCMFD) method. The GCMFD method, which applies equivalent width of coarse mesh to establish the finite difference discretization, can use unstructured coarse meshes composed of adjacent fine meshes to speed up the MOC iteration. The convergence property of the GCMFD method is controlled by width factor. However, the optimal width factor cannot be given a priori. Method of adjusting width factor automatically is proposed in this paper. Finally, the GCMFD method is adopted in the 3-D neutron transport MOC code TCM. Numerical tests show that the GCMFD, using generalized-geometry coarse meshes, can accelerate the MOC iteration with good speedup.
Based on the mesoscopic finite element model of particle reinforced composites, the effects of stochastic properties of SiC particles on the ratcheting behavior of SiCP/6061Al composites were numerically analyzed by e...
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Based on the mesoscopic finite element model of particle reinforced composites, the effects of stochastic properties of SiC particles on the ratcheting behavior of SiCP/6061Al composites were numerically analyzed by employing a 3D multi-particulate unit cell and using an advanced cyclic plastic constitutive model. In the simulation, a 3D multi-particle unit cell containing the stochastic particle properties was first generated by the random sequential adsorption (RSA) method, and then the effects of the number of particles, the particle arrangement, shape, size and their stochastic distributions on the ratcheting of the composites were discussed by the numerical simulations. The results show that the smaller the particulate size and the higher the proportion of the particles distributing near the surface of matrix as well as the more the number of particulates contained in the unit cell, the higher the resistance to the ratcheting deformation. Meanwhile, the modeled composite with uniform distribution of particle size and location presents higher resistance to the ratcheting deformation than that with random distribution. The assumptions of spherical particle and its uniform distributions in size and location in the 3D unit cell can provide a reasonable simulation to the ratcheting of the particle reinforced metal matrix composites.
Loading pattern optimization (LPO) for a PWR in nuclear power plant contains three parts: fuel assembly location optimization, burnable poison placement optimization, and used fuel assembly orientation optimization. T...
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ISBN:
(纸本)9781617820014
Loading pattern optimization (LPO) for a PWR in nuclear power plant contains three parts: fuel assembly location optimization, burnable poison placement optimization, and used fuel assembly orientation optimization. To solve the former two parts, this paper devises an innovative stochastic evolutionary algorithm - Interval Bound Algorithm (IBA), which can optimize fuel assembly location and burnable poison placement together. IBA just uses the fuel assembly's infinite multiplication factor to get rid of unfavorable patterns and to explore new promising solution space. To solve the last part, this paper applies Estimation of Distribution Algorithms (EDAs), which also belong to evolutionary algorithms. These three parts depend on each other, so it is better not to solve them separately. In order to optimize these parts in a coupled way, we use Symbiotic Co-evolutionary Algorithm (SCA) to incorporate IBA and EDAs. This technique could reflect the real optimization process. Based on these algorithms, the corresponding LPO code of IBALPO is developed. To avoid search direction to offset for inconsistency between the LP search code and the design code, IBALPO directly adopts production core design code to evaluate LPs in a parallel computation environment. Finally, this code system is used to solve a realistic reload problem to show its performance. Obtained results have illustrated that IBALPO is efficient and robust. It can find satisfying LPs in two days using 18 CPUs after evaluating about 10000 LPs for a core containing 157 assemblies.
Based on the present MODE-G control strategy, an improved new core control strategy is developed for the initial cycle utilizing gadolinium burnable poisons. With the relaxed axial offset control (RAOC) procedure to l...
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Based on the present MODE-G control strategy, an improved new core control strategy is developed for the initial cycle utilizing gadolinium burnable poisons. With the relaxed axial offset control (RAOC) procedure to limit the core axial offset (AO) in a band region, load follow operations are simulated under the improved core control strategy and the simulation results are compared with those obtained using MODE-G control strategy. Additionally, a preliminary evaluation of the impact of the an ejected rod with the improved core control strategy is performed. It is shown that the improved core control strategy can control the core axial power distribution more satisfactorily and effectively.
A new hexagonal fuel assembly(FA) design which has two rows of fuel rods between the hexagonal moderator channels is proposed for the thermal supercritical water cooled reactor(SCWR). The two-row hexagonal fuel assemb...
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A new hexagonal fuel assembly(FA) design which has two rows of fuel rods between the hexagonal moderator channels is proposed for the thermal supercritical water cooled reactor(SCWR). The two-row hexagonal fuel assembly concept is first and foremost considered for the performance of uniform moderation and sufficient moderation, and with the respect of structural performance and thermal-hydraulic performance. The physical performance of the two-row hexagonal FA with acceptable configuration is investigated. The results show clearly that a better balance between uniform moderation and sufficient moderation can be obtained in the two-row hexagonal fuel assembly. The design objective of the local power peaking factor less than 1.10 can be achieved under the condition of using the same enrichment fuel and containing no burnable poison.
At present, the information and control system (I&C) and operation support system (OSS) of the nuclear power plants (NPPs) are designed separately; their structures and functions are independent. So, the compatibi...
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ISBN:
(纸本)9781424479573
At present, the information and control system (I&C) and operation support system (OSS) of the nuclear power plants (NPPs) are designed separately; their structures and functions are independent. So, the compatibility, availability and dependability of them are not desirable, and the comprehensive advantages of them are not to exert fully. In order to resolve these problems, this paper presents a new idea that designing and developing the I&C and the OSS coordinately, so that their structures and functions are integrated. Firstly, this paper reviewed the evolution and application status of the OSS. And then, the realization methods and forms for the integrated system are analyzed. At last, the hierarchy and architecture of the integrated system which have the double-functions of the I&C and OSS is founded. Analysis and study is also carried out in terms of the hierarchy and characteristics of the integrated system.
To solve the reactor loading pattern optimization problem in realistic nuclear power plants, this paper presents a new optimization method - Interval Bound Algorithm, and introduces the origin of the algorithm and des...
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To solve the reactor loading pattern optimization problem in realistic nuclear power plants, this paper presents a new optimization method - Interval Bound Algorithm, and introduces the origin of the algorithm and describes its implementation procedure. Based on this algorithm, the corresponding parallel loading pattern optimization code of IBALPO is developed using Fortran95. Finally, this code system is used to solve a realistic and difficult reload problem to show its performance, and a better pattern is obtained compared to the one searched by experienced engineers.
The absence of radiolytic-gas bubbles strongly affects the steady operation of Aqueous Homogeneous reactors (AHRs), and because of the buoyancy and collision effects, the bubble behavior and their steady distribution ...
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The absence of radiolytic-gas bubbles strongly affects the steady operation of Aqueous Homogeneous reactors (AHRs), and because of the buoyancy and collision effects, the bubble behavior and their steady distribution in the reactor is always hard to predict. Now, computation methods of AHRs always use a function to express the bubble distribution approximately. Related investigation shows that in CFX, using Multiple Size Group (MUSIG) model, the multi-phase simulation results predict the bubble behavior well, and tally with the experimental results of an AHR. This paper firstly introduces the neutronic and thermal-hydraulic couple code FMCAHR_CFX, and in the last chapter, FMCAHR_CFX is used for a preliminary analysis of a simple AHR.
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