10MW高温气冷堆的燃耗测量研究

10MW高温气冷堆的燃耗测量系统是采用非破坏性高纯锗γ谱仪在线监测来确定燃耗值,利用MCNP4A程序对测量系统的衰减因子进行计算,基于核燃料裂变核素的γ射线能谱分析,以137Cs和134Cs核素活度作为测量对象,并对燃耗测量结果进行讨论.     

Commissioning procedures of the 10 MW high temperature gas-cooled reactor-test module

The 10 MW high temperature gas-cooled reactor-test module (HTR-10) commissioning is divided into three stages (A, B and C) and includes 100 test items. The commissioning flow charts of all stages are described in this article. Stage A, the preliminary performance testing before the fuel loading, has been completed now. Hence, each system and component's performance is confirmed. Stage B includes fuel loading, first criticality, physics and low power experiments. HTR-10 attained the first criticality on 21 December 2000, and the succeeding physics experiments have proven the reliability of the physics designs. The commissioning is ongoing, while it is expected to increase the power, generate electric power, incorporate into the grid and rise the power to RP (rated power) by the end of 2002.     

Design of the material performance test apparatus for high temperature gas-cooled reactor

Most materials can be easily corroded or ineffective in carbonaceous atmospheres at high temperatures in the reactor core of the high temperature gas-cooled reactor （HTGR）. To solve the problem, a material performance test apparatus was built to provide reliable materials and technical support for relevant experiments of the HTGR. The apparatus uses a center high-purity graphite heater and surrounding thermal insulating layers made of carbon fiber felt to form a strong carbon reducing atmosphere inside the apparatus. Specially designed tungsten rhenium thermocouples which can endure high temperatures in carbonaceous atmospheres are used to control the temperature field. A typical experimental process was analyzed in the paper, which lasted 76 hours including seven stages. Experimental results showed the test apparatus could completely simulate the carbon reduction atmosphere and high temperature environment the same as that confronted in the real reactor and the performance of screened materials had been successfully tested and verified. Test temperature in the apparatus could be elevated up to 1600℃, which covered the whole temperature range of the normal operation and accident condition of HTGR and could fully meet the test reauirements of materials used in the reactor.     

Analysis on thermophoretic deposit of fine particle on water wall of 10 MW high temperature gas-cooled reactor

The water wall is an important part of the passive natural circulation residual heat removal system in a high temperature gas-cooled reactor. The maximum temperatures of the pressure shell and the water wall are calculated using annular vertical closed cavity model. Fine particles can deposit on the water wall due to the thei‘mophoresis effect. This deposit can affect heat transfer. The thermophoretic deposit efficiency is calculated by using Batch and Shen‘s formula fitted for both laminar flow and turbulent flow. The calculated results indicate that natural convection is turbulent in the closed cavity. The transient thermophoretic deposit efficiency rises with the increase of the pressure shell‘s temperature. Its maximum value is 14%.     

Development of high temperature gas-cooled reactor (HTGR) fuel in Japan

This paper describes experiences and present status of research and development works for the high temperature gas-cooled reactor (HTGR) fuel in Japan. Recently, Very High Temperature Reactor (VHTR) is evaluated highly worldwide, and is a principal candidate for the Generation IV reactor systems. In Japan, HTGR fuel fabrication technologies have been developed through the High Temperature Engineering Test Reactor (HTTR) project in Japan Atomic Energy Agency since 1960’s. In total about 2 tons of uranium of the HTTR fuel has been fabricated successfully and its excellent quality has been confirmed through the long-term high temperature operation. Based on the HTTR fuel technologies, SiC TRISO fuel has been newly developed for burnup extension targeted VHTR. For ZrC-TRISO coated fuel as an advanced fuel designs, R&Ds for fabrication and inspection have been carried out in JAEA. The irradiation with the Japanese uniform stoichiometric ZrC coating has been completed in the cooperation with Oak Ridge National Laboratory of the United States.     

Thermo-fluid investigation on a double-side-cooled annular fuel for the prismatic very high temperature gas-cooled reactor

One of the key issues in the development of the very high temperature gas-cooled reactor (VHTR) is an undesirably high temperature of the nuclear fuels. An increased reactor coolant outlet temperature directly drives an increase of the nuclear fuel temperature. Therefore, a special measure has to be taken to overcome the issue of a fuel temperature in the VHTR. In this paper, a double-side-cooled annular fuel concept for a prismatic type reactor is proposed to solve the fuel temperature issue. A detailed thermo-fluid analysis using a computational fluid dynamics (CFD) code was carried out to investigate the thermo-fluid performances of the proposed fuel design. The CFD results show that the proposed design has superior thermo-fluid characteristics to the existing prismatic fuel assembly designs.     

Three-dimensional simulation of a simplified advanced gas-cooled reactor fuel element

The present work involves simulations of a simplified three-dimensional representation of the UK fleet of advanced gas-cooled reactors (AGRs) fuel element using a 30° sector configuration. The computations were carried out using the v²–f formulation which was shown to be one of the most accurate turbulence models in earlier simulations of two-dimensional rib-roughened channels. In the present work main features of the mean flow and heat transfer in the fuel element were identified and discussed. The pressure loss and friction factor were also calculated where good agreement with the experimental correlations was found. Further comparisons were made against simulations of a 2D rib-roughened channel in order to assess the validity and relevance of a ‘2D approximation’ approach. It was shown that although a two-dimensional approach is very useful and economical for ‘parametric studies’, it does not provide an accurate representation of a 3D fuel element configuration, especially for the velocity and pressure coefficient distributions, where large discrepancies were found between the results of the 2D channel and azimuthal planes of the 3D configuration.     

Fuel element design for the 300 MW(e) gas-cooled fast breeder reactor

The fuel element design for a 300 MW(e) gas cooled fast breeder reactor (GCFR) is presented. The design is the result of a program sponsored by Kernforschungsanlage, Julich (KFA) to develop and fabricate a full size fuel element model under extension of an agreement between General Atomic (GA), Kraftwerk Union (KWU), and KFA to exchange information from GCFR irradiation experiments. The resulting fuel element model design was achieved by joint participation between GA and KWU and relies on the experience and knowledge of the two companies. The model, which will be manufactured by KWU using prototypical materials and specifications, except for dummy fuel pellets, will establish manufacturing feasibility and identify areas for future cost reduction improvements. The evolved designs, particularly the fuel rods, are very similar to those employed in the liquid metal fast breeder reactor (LMFBR) programs. These similarities enable the GCFR to use the vast amount of data being generated for the LMFBR programs, with only an incremental development plan needed to verify certain unique features inherent to the use of helium as the primary coolant.     

Studies on disintegrating spherical fuel elements of high temperature gas-cooled reactor by a electrochemical method

Spherical fuel elements of a high temperature gas-cooled reactor were disintegrated through a electrochemical method with NaNO₃ as electrolyte. The X-ray diffraction spectra and total carbon contents of the graphite fragments were determined, and the results agreed with those from simulated fuel elements. After conducting the characterization analysis and the leaching experiment of coated fuel particles, the uranium concentrations of leaching solutions and spent electrolyte were found to be at background levels. The results demonstrate the effectiveness of the improved electrochemical method with NaNO₃ as electrolyte in disintegrating the unirradiated fuel elements without any damage to the coated fuel particles. Moreover, the method avoided unexpected radioactivity contamination to the graphite matrix and spent electrolyte.     

The high temperature gas-cooled reactor as a source of high temperature process heat

The nuclear reactor has established itself as a future major supplier of electrical energy. The industrial market for other forms of energy, however, is almost as large and represents a new potential for the use of nuclear reactors. The high temperature gas-cooled reactor (HTGR) has been developed for commercial application in the electric power generation field. Since the HTGR is capable of delivering process heat in the temperature range of 1000–1500°F, it has many applications that would not be possible at the lower operating temperatures of water-cooled reactors. This paper briefly summarizes the development of the HTGR and outlines its salient technical features. Modifications to the reactor that enable it to be used as a process heat source are discussed. Specific applications are developed for coal gasification, steelmaking, and hydrogen production.     

高温气冷实验堆燃料元件双向探测器的研制

介绍了高温气冷实验堆燃料元件双向探测器的基本原理和实现方法。它以两个并联的感应线圈为敏感元件,通过双通道法采集信号,以８９Ｃ５１单片机为处理核心,系统软件采用循环扫描输入端口的方式获取过球信号,经智能分析、判断,实现了燃料元件的双向检测。     

高温气冷堆氦气轮机基本特性研究

高温气冷堆氦气轮机循环被认为是将来核能发电领域中最有潜力的方案之一。首先对高温堆氦气轮机循环进行分析和优化 ,然后着重从热力学和气体动力学角度研究氦气轮机的基本特性。结果表明 ,氦气轮机有两个主要设计特点不同于通常的燃气轮机 :一个是叶片级数多 ;另一个是叶片高度低 ,这些特性分别由氦气的物性和闭式循环的高压所导致。     

10 MW高温气冷实验堆吸收球停堆系统设备热态试验

碳化硼吸收球停堆系统是10 MW高温气冷实验堆的第二停堆系统,其功能是,在控制棒失效时,吸收球落入反射层的吸收球孔道,以达到紧急停堆的目的.介绍了在堆外、空气介质、150 ℃工作温度条件下,对吸收球传动机构设备进行的热态考验、传动试验和落球试验.结果表明,吸收球停堆系统7套设备均达到了传动机构工作正常、落球时间在3 min之内、球位指示正确等设计要求.7套设备安装到10 MW高温气冷实验堆上之后,在堆上进行了氦气介质下的热态落球试验,其结果达到设计规范的要求.     

Current status and future development of coated fuel particles for high temperature gas-cooled reactors

The coated particles were first invented by Roy Huddle in Harwell 1957. Through five decades of development, the German UO₂ coated particle and US LEU UCO coated particle represent the highly successful coated particle designs up to now. In this paper, current status as well as the failure mechanisms of coated particle so far is reviewed and discussed. The challenges associated with high temperatures for coated particles applied in future VHTR are evaluated. And future development prospects of advanced coated particle suited for higher temperatures are presented. According to the past coated fuel particle development experience, it is unwise to make multiple simultaneous changes in the coated particle design. Two advanced designs which are modifications of standard German UO₂ coated particle (UO₂^∗ herein) and US UCO coated particle (TRIZO) are promising and feasible under the world-wide cooperations and efforts.     

A simplified mathematical dynamic model of the HTR-10 high temperature gas-cooled reactor with control system design purposes

A simplified mathematical dynamic model of the HTR-10 high temperature gas-cooled reactor is developed based upon the fundamental conservation of fluid mass, energy and momentum. The model is formulated for coupling reactor neutron kinetics with reactivity feedback and reactor thermal-hydraulics. The reactor is nodalized to employ the lumped parameter modeling methodology, which is mathematically described by differential algebraic equations (DAEs). The developed model is implemented on a personal computer using the MATLAB/Simulink tool. A lot of numerical simulation experiments are investigated and discussed. The transient results show that the model can properly predict the reactor dynamics and can serve as the basis for the model-based control system design.     

采用虚拟场景技术的高温气冷堆仿真系统研究

仿真系统对10 MW高温气冷堆的堆芯、主回路系统和蒸汽发生器等部件进行分析计算,模拟稳态和瞬态过程。采用虚拟场景技术,按高温气冷堆的实际结构建立三维虚拟场景,用户可在虚拟场景中漫游观测,实时查看仿真计算状态;同时可对仿真数据结果进行分析并以二维、三维图形显示。该仿真系统不仅对高温气冷堆的工程设计、安全分析和人员培训有重要作用,且可以对HTR-10主控室的操作人员进行现场支持及各项研究提供帮助。     

Parametric studies on different gas turbine cycles for a high temperature gas-cooled reactor

The high temperature gas-cooled reactor (HTGR) coupled with turbine cycle is considered as one of the leading candidates for future nuclear power plants. In this paper, the various types of HTGR gas turbine cycles are concluded as three typical cycles of direct cycle, closed indirect cycle and open indirect cycle. Furthermore they are theoretically converted to three Brayton cycles of helium, nitrogen and air. Those three types of Brayton cycles are thermodynamically analyzed and optimized. The results show that the variety of gas affects the cycle pressure ratio more significantly than other cycle parameters, however, the optimized cycle efficiencies of the three Brayton cycles are almost the same. In addition, the turbomachines which are required for the three optimized Brayton cycles are aerodynamically analyzed and compared and their fundamental characteristics are obtained. Helium turbocompressor has lower stage pressure ratio and more stage number than those for nitrogen and air machines, while helium and nitrogen turbocompressors have shorter blade length than that for air machine.     

Development of a new decay heat removal system for a high temperature gas-cooled reactor

The heat removal capacity of a RCCS is one of the major parameters limiting the capacity of a HTGR based on a passive safety system. To improve the plant economy of a HTGR, the decay heat removal capacity needs to be improved. For this, a new analysis system of an algebraic method for the performance of various RCCS designs was set up and the heat transfer characteristics and performance of the designs were analyzed. Based on the analysis results, a new passive decay heat removal system with a substantially improved performance, LFDRS was developed. With the new system, one can have an expectation that the heat removal capacity of a HTGR could be doubled.