HTR-10一回路氦气泄漏率测量方法研究

本文详细介绍了测量HTR-10一回路氦气泄漏率的两种方法--直接测量法和存量衡算法,针对HTR-10一回路参数多变的特性,讨论分析了直接测量法的实用性,并提出了在计算压力壳内氦气平均温度时使用经验公式的方法.结合实际运行参数,分别使用两种测量方法得到的氦气泄漏率的最大相对误差为5.7%,证明了用直接测量法可以准确得到HTR-10一回路氦气的泄漏率,能够以直接测量法得到的测量结果为依据连续监测一回路氦气每天的泄漏量是否小于一回路却剂系统中总氦量的1%.     

中间换热器的传热和阻力特性

中间换热器在高温气冷堆氦气透平间接循环发电系统中是耦合高温气冷堆和氦气透平的关键部件,承担着将高温气冷堆中高温氦气的能量传递到氦气透平回路的任务.中间换热器给氦气透平的设计和运行维护带来方便,但它的传热与阻力性能不可避免地影响循环效率,因此,中间换热器的设计和选型需综合考虑传热效率、压力损失、材料性能和紧凑度等因素.本文介绍了印制板式换热器(PCHE)的主要特点,分析了它在间接循环系统中应用的可行性,重点研究了该中间换热器的传热和流动阻力特性,以及影响PCHE换热效率和压力损失的主要因素.在此基础上,提出了优化中间换热器传热和阻力特性的途径和方法.     

HTR-10GT辅助轴承结构特性研究

在10 MW高温气冷堆氦气透平发电系统(HTR-10GT)中,辅助轴承用于失去磁力轴承主支承后的临时辅助支承,是整个转子系统重要的安全保障.本文综述了辅助轴承的研究现状,针对已建立的辅助轴承实验台架,采用有限元建模分析,讨论了辅助滚动轴承保持架的结构特性,为辅助轴承的结构设计提供了重要参考.     

兆瓦级核电推进系统布雷顿循环热电转换特性分析

闭式布雷顿循环是兆瓦级核电推进系统主要采用的动态热电转换方式，具有结构简单、转换效率高等特点。本文针对兆瓦级核电推进系统的动态布雷顿热电转换方式进行特性分析，具体内容包括：对氦气、氮气、二氧化碳和氙气4种工质及它们以不同比例混合的工质的热物性进行比较，进而对其在兆瓦级核电推进系统闭式布雷顿循环中的换热性能、压力损失系数和透平机械所需级数进行分析；以带有同流换热器和预冷器的直接气体透平循环为研究对象，比较兆瓦级核电推进系统气体透平循环在采用不同比例混合物作为工质时的循环效率，并对参数变化对循环效率的影响进行研究。本研究为兆瓦级核电推进系统气体透平循环在工质选择方面提供了一定的参考，为其设计和控制系统的研究奠定了基础，为以后进行气体透平循环动态性能研究打下了基础。     

反应堆超临界CO2 Brayton循环特性

为达到满意的循环效率,目前的气冷堆氦气透平循环技术需较高的循环最高温度,即需更高的堆芯出口温度,对反应堆压力壳及燃料元件材料有较高要求,同时由于氦气本身的性质,对透平制造也提出了新的要求;而采用CO₂作为循环工质,可保证在热效率相当情况下,降低循环温度,减小透平体积等,提高反应堆的安全性及经济性。根据热力学定律,建立了超临界CO₂透平循环计算模型,并对该动力循环进行了详细的特性研究,得到了决定循环效率的各个参数,并分析了这些参数对循环效率的影响。结果表明,超临界CO₂动力循环在相对氦气循环较低的温度下可达到满意的效率,CO₂是一种理想的循环工质。     

应用于钠冷快堆的超临界二氧化碳动力转换系统研究

超临界二氧化碳（SCO₂）布雷顿循环由于高效、紧凑和可避免钠水反应等特性而成为钠冷快堆的理想动力转换系统。本文以1 200 MWe大型池式钠冷快堆为系统热源，钠回路温度及热负荷为循环系统运行边界，对比研究了不同SCO₂布雷顿循环系统性能和关键设备性能的变化规律。研究发现，级间冷却再压缩循环与钠冷快堆热源特性匹配性最佳，且循环效率最高（40.7%）。进而研究了不同运行参数对级间冷却再压缩循环效率的影响规律，给出了循环系统效率对各关键影响因素的敏感度，发现循环系统效率对冷端参数的敏感度最强，其次为分流比和透平入口参数，对主压缩机级间压比的敏感度最弱。     

无限大芯部热容板翅式回热器动态性能研究

针对高温气冷堆直接氦气透平循环中的板翅式回热器，研究提出一仅考虑回热器芯部热容的集总参数模型，即无限大芯部热容的集总参数模型，并利用四阶龙格 库塔方法求解该模型，求解过程中考虑温度对气体物性的影响。利用该模型，分析了在入口温度、流量阶跃和斜坡扰动下回热器出口温度的响应过程。在此基础上，分析了高温气冷堆直接氦气透平循环中的功率调节过程及透平甩负荷过程时回热器出口温度和芯部温度的响应过程。     

间接氦气透平循环高温堆紧急停堆动态仿真

通过对10 MW高温气冷堆氦气透平发电装置(HTR-10GT)的堆芯、热交换器和透平压气机组等主要设备的数学建模和程序编制,初步建立起了一套模拟该装置瞬态特性的仿真程序.通过对该装置于5s时刻堆内引入0.1$阶跃正反应性引发的紧急停堆事故的瞬态模拟,初步验证了该装置紧急停堆预案设置的安全性和合理性,证明了旁路快开阀的设...     

HTR-10 GT辅助轴承保持架振动特性研究

在10 MW高温气冷堆氦气汽轮机发电系统(HTR-10 GT)中,辅助轴承作为磁力轴承支承失效后转子的辅助支承装置,是整个转子系统最重要的安全保障.针对辅助轴承的工作特点,采用有限元方法进行了建模分析,研究了辅助轴承中保持架的离心应力和自由振动特性,讨论了不同结构参数对保持架振动特性的影响.结果表明,保持架上的最大离心应力发生在侧梁中点处;在辅助轴承工作状态下,较易引发低频的振动模态;对保持架尺寸以及兜孔数的合理选择有助于提高保持架的性能.     

旁路阀调节对高温气冷堆闭式布雷顿循环瞬态特性影响研究

闭式布雷顿循环是第4代高温堆核能系统的关键技术之一,其典型的动态过程是旁路阀调节。为分析这一过程,建立了循环中关键部件的动态模型,其中压气机在径向平衡模型基础上耦合了对附面层发展的预测,兼顾了计算效率与准确性;换热部件模型基于双曲型守恒律方程,对工质的热物性和参数的快速变化有较好的适应性。在此基础上根据回路的质量守恒和压力平衡原则将各部件的模型耦合,建立了系统的动态模型。由于旁路阀调节是氦气透平发电系统主要的功率快速调节手段,瞬态效应较为显著,以模块式高温气冷堆（HTR-10GT）旁路阀开启后的过渡过程作为算例,分析了主要循环参数的响应特性,并通过分析,给出了降低输出功率的机制。计算结果表明：系统的容积惯性对旁路阀调节的响应速度影响较大,而阀门的开度则决定了系统在末态的输出功率;回热器的温度冲击现象可能发生在调节过程中,但可通过两旁路阀联动的方式缓解;反应堆出口温度变化幅度很小,因此反应堆模型的准确程度对结果基本无影响。     

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.     

超临界二氧化碳再压缩布雷顿循环变工况特性分析

超临界二氧化碳再压缩布雷顿循环是高效紧凑的能量转换方式。目前许多研究在分析循环的特性时，常假设压缩机和透平的效率为恒定，该假设与实际情况差别很大。本文使用MODELICA作为工具，建立了超临界二氧化碳再压缩布雷顿循环模型。对于压缩机和透平，加入了真实压缩机和透平的特性曲线模型。通过模拟计算发现，循环输入功率和循环流量的改变将对循环火用效率和各组件的火用损产生影响。循环偏离设计工况时，适当控制输入功率和循环流量可调节循环输出功率和火用效率。     

Comparison of two models for a high temperature reactor coupled to a gas turbine

This paper presents two independent dynamic models of a nuclear gas turbine power plant. Both the high temperature nuclear reactor (HTR) and its energy conversion system (ECS) based on a direct Brayton cycle have been modelled. One model utilises RELAP5 for the ECS, the other Aspen Custom Modeler (ACM). The reactor model used in both models is a point kinetic model derived from a detailed reactor model. The ECS model is described and compared componentwise, with an emphasis on the turbomachinery. The total plant models are compared with each other by calculating two representative transients: one load rejection transient and one transient with the system at part load.     

直接布雷顿循环气冷反应堆系统运行特性分析

基于Matlab/simulink程序，针对小型直接布雷顿循环反应堆系统，通过模块化思想建立该系统数学物理模型，开发了系统分析程序。通过改变反应堆、透平、压缩机、换热器等关键设备的运行参数或引入阶跃扰动，模拟了系统稳态工况与瞬态变工况运行，得到了关键设备功率、进出口压力、温度等关键参数的变化曲线。结果表明，系统分析程序对小型直接布雷顿循环反应堆系统稳态与瞬态运行特性的模拟结果较合理，能为小型直接布雷顿循环反应堆系统的设计、优化与安全分析提供依据。     

高温气冷堆气体透平循环方式的技术评价

气体透平循环被认为是高温气冷堆发电的发展方向。循环方式包括直接循环，开式间接循环和闭式间接循环，工质包括氦气，空气和氮气，对于每一种循环都进行了热力学分析和优化计算，并对透平压气机进行了气动设计，研究结果表明，氦气直接循环是一个理想的选择，但是基于现有技术水平难度较大，氦气和氮气闭式间接循环是目前比较现实的方案，可以实现气体透平循环的设想并为将来的直接循环做技术积累。     

Feasibility analysis of two-phase MHD energy conversion for liquid metal cooled reactors

A two-phase MHD energy conversion unit is proposed to a liquid metal cooled fast reactor. Using supercritical CO₂ as the working fluid in the gas cycle without considering friction and heat losses, the optimized cycles efficiency is obtained, which is about 5% higher than that of the gas turbine Brayton cycle with the same regenerator/compressor configurations. Based on a simple MHD power analysis and the two-phase homogeneous flow model, the important system operational conditions were estimated. The results suggest that a liquid lead pump of at least 20% of the MHD power output is needed in order to convert the 400 MW reactor heat into electricity at the specified thermal efficiency, unless a mixture foam flow of void fraction greater than 80% is achievable at very high mixture velocity.     

Evaluation of alternate power conversion unit designs for the GT-MHR

General Atomics in the USA and Experimental Design Bureau of Machine Building (OKBM) in the Russian Federation have jointly developed a nuclear power plant design, the gas turbine modular helium reactor (GT-MHR). There have been considerable improvements during the last 10 years, which resulted in a more effective, efficient and safe design. The existing design is based on a 600 MW(t) reactor cooled by helium at a pressure of about 7 MPa. The power conversion unit (PCU) uses reactor outlet helium with a temperature of 850 °C in a direct Brayton cycle to achieve the cycle efficiency of about 48%. The PCU consists of a gas turbine, a recuperator, a precooler, low-pressure and high-pressure compressors, an intercooler, and a generator. The turbomachine (TM) includes the turbine, compressors and generator mounted on a single vertical shaft. TM shaft rotation speed is 4400 rpm. The shaft of generator is connected to the turbine shaft by a flexible coupling. The required grid frequency of generated electricity is achieved by a converter. All PCU components are enclosed in a single vessel. TM uses radial and axial electromagnetic bearings (EMB) for support. Catcher bearings (CB) are provided as redundant support for the TM rotor in case of EMBs failure. Several alternative PCU designs were analyzed on the basis of current progress in technologies, new world experience, and experience accumulated in the process of GT-MHR design development. Results of these analyses will be taken into account when a final PCU design is selected.     

Investigation of alternative layouts for the supercritical carbon dioxide Brayton cycle for a sodium-cooled fast reactor

Analyses of supercritical carbon dioxide (S-CO₂) Brayton cycle performance have largely settled on the recompression supercritical cycle (or Feher cycle) incorporating a flow split between the main compressor downstream of heat rejection, a recompressing compressor providing direct compression without heat rejection, and high and low temperature recuperators to raise the effectiveness of recuperation and the cycle efficiency. Alternative cycle layouts have been previously examined by Angelino (Politecnico, Milan), by MIT (Dostal, Hejzlar, and Driscoll), and possibly others but not for sodium-cooled fast reactors (SFRs) operating at relatively low core outlet temperature. Thus, the present authors could not be sure that the recompression cycle is an optimal arrangement for application to the SFR. To ensure that an advantageous alternative layout has not been overlooked, several alternative cycle layouts have been investigated for a S-CO₂ Brayton cycle coupled to the Advanced Burner Test Reactor (ABTR) SFR preconceptual design having a 510 °C core outlet temperature and a 470 °C turbine inlet temperature to determine if they provide any benefit in cycle performance (e.g., enhanced cycle efficiency). No such benefits were identified, consistent with the previous examinations, such that attention was devoted to optimizing the recompression supercritical cycle. The effects of optimizing the cycle minimum temperature and pressure are investigated including minimum temperatures and/or pressures below the critical values. It is found that improvements in the cycle efficiency of 1% or greater relative to previous analyses which arbitrarily fixed the minimum temperature and pressure can be realized through an optimal choice of the combination of the minimum cycle temperature and pressure (e.g., for a fixed minimum temperature there is an optimal minimum pressure). However, this leads to a requirement for a larger cooler for heat rejection which may impact the tradeoff between efficiency and capital cost. In addition, for minimum temperatures below the critical temperature, a lower heat sink temperature is required the availability of which is dependent upon the climate at the specific plant site.     

熔盐堆超临界二氧化碳布雷顿循环系统与热力学分析

熔盐堆（MSR）能实现在线填料和后处理,出口温度较高,应配备一种与之出口温度相匹配的创新型循环方式,且可达到较高的循环效率。本文基于中国科学院上海应用物理研究所设计的小型模块化熔盐堆（smTMSR-400）设计超临界二氧化碳（SCO₂）布雷顿循环系统,使用控制变量法分析了分流比、压缩机/透平效率、主压缩机出口温度、低温换热器换热温差/阻力对SCO₂布雷顿循环系统的影响。分析结果表明:①存在最佳分流比使低温换热器两侧温差相等;②相较于压缩机效率,等幅度的透平效率提升可使系统循环效率和?效率更高;③主压缩机出口压力增大为系统带来正面影响,但循环效率/?效率与其斜率都逐渐降低;④换热器换热温差和流动阻力都为系统循环带来了可量化的负担: 换热温差每增加10 K,循环效率降低1.85%,?效率降低2.70%;流动阻力每增加1 MPa,循环效率降低6.58%,?效率降低10.22%。最后根据分析结果和系统?流变化设计了5种物理参考方案。