反应堆堆芯热功率测量方法及其误差分析

通过建立精确的数学模型 ,提出了一种测量核电站压水反应堆堆芯热功率的方法 ,并对该方法进行了误差分析。基于上述方法的KME系统与校验SAPEC系统的比较结果表明 ,该方法完全可以用于核电站堆芯热功率的测量     

特征统计算法(CSA)在堆芯装料方案优化中的应用

针对压水堆堆芯装料优化问题的特殊性,采用了一种更适合于全局优化算法--特征统计算法来求解.本文阐述了该算法的搜索原理以及如何将其应用于堆芯装料优化问题;编制了装料优化程序SCYCLE,应用该程序在2个不同类型的实际堆芯模型上进行了计算,并与其它算法的计算结果进行了比较.结果表明,SCYCLE程序在求解装料优化问题方面具有很高的搜索效率和很好的全局性.     

压水堆核电站堆芯集中参数模型的微机仿真

阐述了PWR核电站堆芯的模型化问题,提适用于微机仿真的核电站堆芯的物理数学模型,将核电站堆芯分为三大块分别建立模型,中子动力学模块,反应性反馈模块,堆芯热力学模块,建立系统传递函数,运用MATLA仿真,得到良好结果。     

CPR1000核电站堆芯出口冷却剂过冷度测量不确定度评定

中国百万千瓦级先进压水堆(CPR1000)核电站反应堆通过堆芯冷却监测系统(CCMS)测量堆芯出口冷却剂的过冷度。本文分析了堆芯出口冷却剂过冷度测量过程中的各种误差来源,对饱和状态下堆芯出口冷却剂温度测量的不确定度进行评定,得到不确定度区间边界随一回路压力变化的曲线,给出了用于判断堆芯冷却状态的堆芯出口冷却剂过冷度测量的误差ε曲线的确定方法,该方法已在CPR1000核电站中得到实际应用。     

应用阶段任务分析法预测秦山核电站应急堆芯冷却系统无效度

应急堆芯冷却系统是核电站工程安全设施的一个组成部分。核电站正常运行期间,它是个待用设备。当发生冷却剂丧失事故时,它向堆芯注入应急冷却水,以确保核电站的安全。本文应用阶段任务分析法建立了应急堆芯冷却系统的综合故障树,求得应急堆芯冷却系统无效度的精确解。介绍了多阶段任务系统无效度的两种近似计算技术,指出当系统含有很多部件时,求精确解是困难的,近似计算技术是有用的。     

轻水堆核电站堆芯熔化分析

本文阐述了开展轻水堆核电站堆芯熔化事故分析的必要性,介绍了堆芯熔化事故计算程序MARCH,并针对轻水堆核电站三种不同工况利用 MARCH 程序进行了计算,结合计算结果讨论了堆芯熔化事故的物理过程。     

AP1000与EPR堆芯中子注量率测量系统的差异性比较和分析

堆芯中子注量率测量系统是核电站监测系统的一个重要组成部分。它主要测量反应堆堆芯的中子注量率分布,监测堆芯功率畸变,积累燃耗数据,对核电站的安全运行及经济性起到重要作用。论文简单介绍了AP1000和EPR堆芯中子注量率测量系统的组成和特点,分析比较了两者之间的差异性。     

SCORPIO堆芯监视系统

【国际原子能机构《报刊文摘》 1998年第 6 2期报道】　经合组织 (OECD)海尔顿反应堆项目开发了一种堆芯监视系统——SCORPIO系统 ,该系统有两种并行的运行方式 :堆芯跟踪方式和预测方式。SCORPIO的主要目的是为反应堆操纵员提供一种实用的工具 ,以提高关于堆芯状态和动态性能方面信息的质量并增加数量。首先 ,该系统可用来探测和防止发生不希望有的堆芯工况 ,从而提高核电站的安全性。其次 ,可使核电站运行更灵活和更有效。该系统现在虽然仅用于西方国家的压水堆系统 ,但其基本概念同样适用于包括 VVER型堆在内的许多其他反应堆。…     

用于换料方案快速评价的低阶谐波结合线性扰动展开法——理论模型

为解决核电厂装料方案优化搜索过程计算最大和耗时的难题,提出了用于装料方案快速评价的谐波结合线性扰动法.在该方法中,由核燃料倒换所引起的堆芯中子注量率空间分布变化,被区分为局部扰动和全局宏观倾斜两种效应,并分别采用扰动基函数和参考堆芯装载方案的低阶谐波基函数来近似表达.再通过剩余权重方法,将原本大规模矩阵特征值问题的求解转换成有关展开系数的小规模矩阵特征值问题求解,从而实现对堆芯装载方案的快速评价.     

MOX燃料堆芯热工特性及设计限值研究

使用MOX燃料的快堆核电站以其线功率高、燃耗高、堆芯出口温度高等特点,对堆芯热工设计提出了新的问题.本文在对MOX燃料热工性能分析的基础上,给出了主要的热工设计限值,并以电功率870 MW电站为参考,初步分析了其堆芯热工特性和设计裕量.结果表明对于MOX燃料,较高的堆芯热工参数合理可行,且具有足够的裕量.     

Optimal Reactor Strategy for Minimizing Natural Uranium Requirement, (I)

An optimization problem of nuclear power system economics is formulated and solved numerically with the application of linear programming technique. The problem treated here is to determine the optimal long-range reactor strategy that minimizes the total requirement of natural uranium under a restriction imposed on the quantity of excess plutonium. The optimization model and the problem formulation as a linear programming problem are described in Part (I) accompanied by some examples of numerical solution. An analysis of various results of computation will be presented in Part (II) of the present work.     

Artificial neural networks in prediction of mechanical behavior of concrete at high temperature

The behavior of concrete structures that are exposed to extreme thermo-mechanical loading is an issue of great importance in nuclear engineering. The mechanical behavior of concrete at high temperature is non-linear. The properties that regulate its response are highly temperature dependent and extremely complex. In addition, the constituent materials, e.g. aggregates, influence the response significantly. Attempts have been made to trace the stress–strain curve through mathematical models and rheological models. However, it has been difficult to include all the contributing factors in the mathematical model. This paper examines a new programming paradigm, artificial neural networks, for the problem. Implementing a feedforward network and backpropagation algorithm the stress–strain relationship of the material is captured. The neural networks for the prediction of uniaxial behavior of concrete at high temperature has been presented here. The results of the present investigation are very encouraging.     

Mathematical models of optimization problems under creep conditions

This paper concerns the optimization of structures, the state of which is in general determined by the creep of the material. The material of the structure is in the state of steady creep. The relationship of the creep flow rates and the stresses is determined by the exponential function according to the flow theory. The mathematical models of the optimization problem in the static formulation is derived on the basis of the extremum energy principle of the minimum plastic dissipation. The mathematical model of the problem in the kinematic formulation is obtained by way of formal consideration on the basis of the duality theory of mathematical programming. This corresponds to the extremum energy principle of the maximum external power. The mathematical models of the optimization problem in the static and kinematic formulations are a dual pair of mathematical programming problems. The problems for the determination of the minimum volume, the minimum theoretical cost and the period of failure of the structure may be looked upon as particular cases of the problems presented. The design of circular plates with simply supported and clamped edges is presented as numerical examples.     

A nuclear reactor core fuel reload optimization using artificial ant colony connective networks

The core of a nuclear Pressurized Water Reactor (PWR) may be reloaded every time the fuel burn-up is such that it is not more possible to maintain the reactor operating at nominal power. The nuclear core fuel reload optimization problem consists in finding a pattern of burned-up and fresh-fuel assemblies that maximize the number of full operational days. This is an NP-Hard problem, meaning that complexity grows exponentially with the number of fuel assemblies in the core. Moreover, the problem is non-linear and its search space is highly discontinuous and multi-modal.     

One Speed Transport Theory Solution for Complete Back Scattering

An in-core fuel management problem is formulated for the equilibrium fuel cycle in an N-region nuclear reactor model. The formulation shows that the infinite multiplication factor k_∞ requisite for newly charged fuel can be separated into two terms—one corresponding to the average k_∞, at the end of the cycle and the other representing the direct contribution of the shuffling scheme and control rod programming. This formulation is applied to a three-region cylindrical reactor to obtain simultaneous optimization of shuffling and control rod programming.

It is demonstrated that this formulation aids greatly in gaining a better understanding of the effects of changes in the shuffling scheme and control rod programming on equilibrium fuel cycle performance.     

Shape optimization of wire-wrapped fuel assembly using Kriging metamodeling technique

In this work, shape optimization of a wire-wrapped fuel assembly in a liquid metal reactor has been carried out by combining a three-dimensional Reynolds-averaged Navier–Stokes analysis with the Kriging method, a well-known metamodeling technique for optimization. Sequential quadratic programming (SQP) is used to search the optimal point from the constructed metamodel. Two geometric design variables are selected for the optimization and design space is sampled using Latin Hypercube Sampling (LHS). The optimization problem has been defined as a maximization of the objective function, which is as a linear combination of heat transfer and friction loss related terms with a weighing factor. The objective function value is more sensitive to the ratio of the wire spacer diameter to the fuel rod diameter than to the ratio of the wire wrap pitch to the fuel rod diameter. The optimal values of the design variables are obtained by varying the weighting factor.     

低泄漏堆芯燃料管理的一种多循环优化方法

提出一种用于指导压水堆低泄漏堆芯燃料管理的多循环优化方法。该方法将多循环优化问题分解为３步优化处理：首先用线性规划确定满足多循环总体目标最优的各个单循环优化目标参数,然后以此为条件,对多循环中相继的各个单循环进行燃料组件的优化布置,最后进行可燃毒物的优化配置。本文着重讨论第一步优化方法,并给出主要计算结果。     

Extension of Load Follow Capability of a PWR Reactor by Optimal Control

The problem of extending that part of the fuel life cycle during which a reactor is capable of sustaining load-follow operation is formulated as an optimal control problem. A two-node model representation of pressurized water reactor dynamics is used, leading to a set of non-linear ordinary differential equations. Differential Dynamic Programming is used to solve directly the resulting nonlinear optimization problem and obtain the trajectories of soluble boron concentration and control rod insertion. Results of computations performed for a reference reactor are presented, showing how the optimal control policy stretches the capability of the reactor to follow an average daily load curve towards the end of the fuel life cycle.     

Optimization of Radioactive Waste Management System by Application of Multiobjective Linear Programming

A mathematical procedure is proposed to make a radioactive waste management plan comprehensively. Since such planning is relevant to some different goals in management, decision making has to be formulated as a multiobjective optimization problem. A mathematical programming method was introduced to make a decision through an interactive manner which enables us to assess the preference of decision maker step by step among the conflicting objectives.

The reference system taken as an example is the radioactive waste management system at the Research Reactor Institute of Kyoto University (KUR). Its linear model was built based on the experience in the actual management at KUR. The best-compromise model was then formulated as a multiobjective linear programming by the aid of the computational analysis through a conventional optimization. It was shown from the numerical results that the proposed approach could provide some useful informations to make an actual management plan.     

蚁群算法在核能动力系统分级故障定位中的应用研究

核能动力系统是一个高度复杂并具有高安全性要求的结构体系,为提高其安全性,故障定位显得尤为重要.蚁群算法是一种新型的优化算法,本文提出将其应用于核能动力系统的故障定位,并将核能动力系统进行分级处理,以一回路主冷却剂简化系统为研究对象,利用VB6.0编程技术设计了核能动力系统故障定位系统.利用文献中的数据对该系统进行了测试,结果表明利用蚁群算法可以准确地对核能动力系统进行分级故障定位.