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。     

高温气冷堆氦气透平直接循环发电技术进展

模块式高温气冷堆是一种先进的、具有固有安全性的新型反应堆，其冷却剂氦气的出口温度可高达９５０℃，可以采用气体透平发电技术，以提高发电效率。美国和南非分别提出了两种高温气冷堆氦气透平直接循环发电方案。他们所使用的氦气透平技术主要基于现在的重工业燃气透平技术和航空发动机技术。本文介绍了这两种技术的区别及氦气透平机设计制造中存在的问题。同时认为由于气体透平的效率比蒸汽透平高得多，所以氦气透平直接循环发电     

高温气冷堆回热循环及透平机组的初步研究

结合了模块式高温气冷堆与气体透平循环技术的高温堆气体透平循环是核电领域中的全新概念，为提高核电的安全性和经济性提供了新的思路，具有很强的竞争优势。其中，高温气冷堆回热循环是该方案的主流。在高温堆回热循环方案中，氦气透平机组的工作介质为氦气，其物性与空气有很大的不同，因此，氦气透平与燃气透平在热力参数、气动参数、尺寸、级数等方面有着较大的差别。本研究对回热循环以及氦气透平进行了初步分析，并通过与燃气透平的比较，揭示了回热循环与氦气透平的一些基本设计特点。     

高温气冷堆间接联合循环热力学分析

高温气冷堆的堆芯出口温度能达到 950℃ ,可以耦合各种动力转换系统。间接蒸汽 /气体透平联合循环是一个技术发展方向。基于现有的高温堆和动力转换部件技术发展水平 ,提出了四种循环方案 ,分析比较了循环效率。同时 ,对影响循环效率的重要因素做了分析。由蒸汽循环和带有预冷器的氮气透平循环构成的间接联合循环可以作为首选方案。堆芯出口温度为 950℃时 ,循环效率可以达到 4 7%以上。     

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。     

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。     

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.     

高温气冷堆氦气透平直接循环的实际特性研究

清华大学高温气冷堆氦气透平直接循环系统(HTR-10GT)的特性研究已经进行了很多,但大多是针对理论上的布雷登循环作特性研究,没有考虑系统中其他实际因素,如工质泄漏、管道摩擦等。工程中,泄漏是不可避免的问题,泄漏及泄漏位置的不同都会引起系统中参数的变化。主要工作是研究HTR-10GT氦气透平直接循环系统在泄漏条件下的实际布雷登循环特性。研究目的就是在建立泄漏的物理和数学模型的基础上,研究泄漏对工质的热力参数及其效率的影响,对比在考虑有无泄漏时系统循环特性曲线的不同,找出提高系统效率的途径。     

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。     

高温气冷堆氦气透平直接循环的Exergy分析

针对100MW电功率的氦气透平直接循环的设计，对循环各个部件分别进行了热力学第一和第二定律分析。给出了各个部件的输入和产出Exergy公式，计算了Exergy损失分布表，并和按照传统分析方法分析的结果进行了比较。结果表明，一半以上的Exergy损失发生在堆芯部分，而由预冷器、压气机和间冷器组成的压缩系统所占Exergy损失比重，比按照第一定律计算的能量损失份额结果小的多；循环Exergy损失主要原因是能量形式的转换和不可逆换热。系统Exergy效率略高于热效率。     

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.     

Substantiation of the parameters and layout solutions for an energy conversion unit with a gas-turbine cycle in a nuclear power plant with HTGR

Light is shed on questions concerning the application of a direct closed gas-turbine cycle for generating electricity in a nuclear power plant with HTGR. This makes it possible to use such reactor systems for generating electricity and(or) producing hydrogen from water and combine high electricity-generation efficiency of 47–50% with high safety. It is shown that it is advantageous to use a recovery gas cycle with recovery efficiency of at least 95% and intermediate cooling of helium in a compressor. The choice of the configuration of the reactor system is substantiated. The heat-exchange equipment of the gas-turbine cycle should have unique characteristics when placed in vessels with limited size and for operation at high temperatures (up to 600°C) and with a large pressure drop (up to 5 MPa). Approaches to solving the problems studied are elucidated on the basis of a modular helium reactor with a GT-MGR gas turbine.I. I. Afrikantov Special Office Design for Machine Engineering.__________Translated from Atomnaya Énergiya, Vol. 98, No. 1, pp. 24–36, January, 2005.     

The HTGR gas turbine plant with dry air cooling

The development of the HTGR gas turbine power plant as a future evolution of the HTGR is one of the most promising solutions to the interrelated power generation and environmental problems. The HTGR gas turbine can make dry air cooling economical and can make possible increased flexibility and economy in power plant siting. The simplification and size reduction of the overall plant imply lower capital costs. Cycle parameters and plant layout for a typical HTGR direct-cycle gas turbine plant of 1100 MW(e) output are described. For safety reasons all the primary equipment is integrated inside the prestressed concrete reactor vessel. Four parallel loops are contained in eight vertical PCRV cavities located around the core cavity. Alternative design configurations and parameter choices are discussed. The advantages and the development potential of the direct cycle with regard to heat rejection and cost are discussed. The possibility of profitably using the gas turbine thermal discharge for operating a seawater distillation plant is pointed out.     

A system analysis tool with a 2D gas turbine modeling for the load transients of HTGRS

This paper presents the operational performance and transient response of a high temperature gas-cooled reactor (HTGR) with an emphasis on the gas turbine through a two-dimensional approach. For its operational and transient simulation we use a GAMMA-T in which the system code, GAMMA, is coupled with the two-dimensional turbomachinery model. We also implement several models into the GAMMA-T: the reactor kinetics model, the bypass valve model, and the models of the core, the heat exchangers, the gas turbine, and the piping. The estimations of compressor and turbine performances are based on a two-dimensional axisymmetric throughflow method that is capable of predicting both the transient and steady-state behavior of the power conversion system (PCS). To demonstrate the code capability, we investigated the two representative transients of GTHTR300, which is a 600 MW direct cycle helium cooled reactor consisting of a prismatic block type core, a horizontal single-shaft configuration of turbomachinery, a recuperator, and a precooler: a loss of heat rejection transient corresponding to the failure of the precooler water supply, and a 30% load reduction transient from nominal operation with bypass control. The simulation results demonstrated the controllability and operational stability for the plant.     

高温和超高温气冷堆动力转换方案研究

动力转换单元是高温和超高温气冷堆的重要组成部分。本文对高温和超高温气冷堆的动力转换单元进行研究。从4个关键参数（反应堆出口温度、反应堆入口温度、压缩比和主蒸汽参数）入手,对5个循环方案进行比较分析。综合考虑各种工程因素,上位循环为简单氦气透平循环、下位循环为有再热的蒸汽轮机循环的联合循环方案是具有竞争力的,其中下位循环在高温气冷堆范围是亚临界参数循环,在超高温气冷堆范围是超临界参数循环。联合循环可实现高温和超高温气冷堆热量的高效率转化,且反应堆入口温度在反应堆压力壳材料允许的范围内,具有足够的安全性。     

安全经济高效的先进能源

具有第四代安全经济特性的核电应该是人们期待的先进的清洁低碳能源。高温气冷堆是当今研发的第四代核电堆型之一,但现有的设计还存在需要排除的严重的安全隐患。堆芯不熔化,不等于说不会有严重事故发生。需要吸取国外球床高温堆和柱状高温堆两种实验堆型运行的经验教训、扩展安全观念和应对安全低概率事件,确保反应堆不出现后果极其严重的放射性释放事故。当热电转换系统采用与燃气蒸汽联合循环耦合应用的技术以后,会发挥高温堆所长,更大地提升转换效率,形成一种高安全低投资和高效率的双燃料清洁能源,可用于大堆或小堆的应用环境,可满足电力系统基本负荷和调锋负荷的需要。在工程设计上采取一系列改进和创新措施,包括釆用规则床模块化及地下反应堆设计以后,可在提高反应堆核心部位安全防卫能力的同时,防范低概率事件,成为一种新的安全经济高效的先进能源。