高温气冷堆氦气轮机性能的初步研究

结合了模块式高温气冷堆与气体透平循环技术的高温气冷堆氦气轮机循环是核电领域中的全新概念,为高核电的安全性和经济性提供了新思路,具有很强的竞争优势。首先对高温气冷堆氦气轮机进行了初步研究,表明氦气轮机叶片级数多,叶片高度低。然后应用商业软件NUM ECA对平面叶栅在相同的进出口条件下分别以氦气和空气为工质进行了二维数值模拟计算,并进行了流场分析,揭示了氦气轮机与燃气轮机的区别。     

氦气轮机高温气冷堆(GT-HTGR)

氦气轮机高温气冷堆(GT-HTCR)就是在一回路直接采用氦气闭式循环燃气轮机(CT)的高温气冷核反应堆(HTGR)；氦气既是核反应堆的冷却剂，又是闭式循环燃气轮机的工质；这个闭式循环燃气轮机通常由高、低压压气机、涡轮、预冷器、间冷器、回热器组成，并采用电磁轴承。选择氦气为工质，是因为氦气具有很高的比热和导热系数，同时又是惰性气体。     

用于高温气冷堆发电设备的闭式循环氦气轮机装置

对HTGR-CT发电装置中的氦气轮机装置作了简要介绍．叙述其循环、工质以及影响循环效率的关键因素,并分析HTGR-CT发电装置布雷顿循环系统当前和近期的参数值。针对氦气轮机装置,论述了涡轮、压气机、热交换器、转子、轴承和热氦气管道等主要部件的设计和结构特点,并简要介绍了应用于氦气轮机的材料。最后指出在开发HTGR-CT发电设备中要重视两个关键技术问题：一是开发出用于大功率机组的安全、可靠的磁性轴承;二是免除放射性污染能进行安全运行和有效维护的问题。     

新型布雷顿循环氦气轮机发电系统设计及验证

以功率不低于100 MW的新型布雷顿循环氦气轮机发电系统为研究对象,通过敏感性分析确定了涡轮入口温度、部件效率、压比、堆芯入口温度等主要参数对性能的影响,并开展了总体性能计算、总体结构设计和模化部件试验验证。结果表明:设计的发电系统输出电功率119 MW、发电效率高达47.54%,循环经济性好;最大直径仅5.7 m,相比于传统动力形式的换热设备,结构更紧凑。     

高温气冷堆氦气透平循环工质的热物性

在高温气冷堆氦气透平直接循环中,氦气既是堆芯的冷却剂,又是循环工质。氦气热物性数据来源多样且互相不一致,对目前应用较多的5种氦气热物性参数计算方法进行了比较分析。     

争议高温气冷堆

具有完全知识产权的高温气冷堆技术有可能成为未来我国在世界核电竞技舞台上的重要砝码。然而,对于尚未成熟的此技术,还存在颇多争议。     

高温气冷堆技术研究及展望

概述现有核反应堆的类型,并对气冷堆进行介绍,对高温气冷堆的组成及其历史发展进行重点阐述。目前,高温气冷堆多以氦气为冷却剂,具有独特的技术优势。随着煤炭、石油等传统化石燃料的消耗,世界各国已重新将针对核能的研究与开发提上日程。核能领域目前仍存在一些问题亟待优化,但随着相关技术的发展,核能依然会成为一类重要的能源。     

闭式氦气轮机循环建模及循环特性优化分析

氦气闭式布雷顿循环可用作高温气冷堆热电转换装置,能够有效降低传统核电机组复杂程度,提升热电转换效率。为详细研究氦气闭式布雷顿循环特性,指导工程样机设计,基于Refprop提供的真实气体模型建立了简单、间冷、回热以及间冷-回热四种闭式布雷顿循环数学模型;然后通过对比分析方法,揭示了关键参数变化对循环特性的影响,重点阐述了间冷、回热对循环性能的作用机制。结果表明：1)回热器能够有效回收涡轮出口氦气热量,大幅提升循环热效率,并且能够降低系统达到最佳循环效率所需压比;2)间冷器虽然能够降低压缩系统功耗,但受间冷器流道内压损影响,需综合考虑系统复杂度、研制成本及循环性能等因素确定系统是否需要间冷器。     

高温气冷堆(HTGR)进行海水淡化的可行性研究

<正> 随着我国现代化建设的不断发展,核能将在能源领域发挥愈来愈大的作用。不断研究更安全可靠的新堆型和开拓核能的应用范围是一项必要的工作。高温气冷堆(HTGR)是一种目前世界上公认的最安全的核动力反应堆。它经历了将近三十多年的研究发展,在技术和工程上都已成熟,并降进入商用化阶段。高温气冷堆能够提供750—950℃的高参数工艺蒸汽,这使得它在化工、石油热采和煤气化、液化等领域有广阔的市场。     

Thermo-economic analysis and optimization of the very high temperature gas-cooled reactor-based nuclear hydrogen production system using copper-chlorine cycle

An improved very high temperature gas-cooled reactor (VHTR) and copper-chlorine (Cu–Cl) cycle-based nuclear hydrogen production system is proposed and investigated in this paper, in order to reveal the unknown thermo-economic characteristics of the system under variable operating conditions. Energy, exergy and economic analysis method and particle swarm optimization algorithm are used to model and optimize the system, respectively. Parametric analysis of the effects of several key operating parameters on the system performance is conducted, and energy loss, exergy loss, and investment cost distributions of the system are discussed under three typical production modes. Results show that increasing the reactor subsystem pressure ratio can enhance the system's thermo-economic performance, and the total efficiencies and cost of producing compressed hydrogen from nuclear energy are respectively lower and higher than that of generating electricity. When the system operates at the maximum hydrogen production rate of 403.1 mol/s, the system's net electrical power output, thermal efficiency, exergy efficiency, and specific energy cost are found to be 38.77 MW, 39.3%, 41.26%, and 0.0731 $/kW·h, respectively. And when the system's hydrogen production load equals to 0, these values are respectively calculated to be 177.25 MW, 50.64%, 53.29%, and 0.0268 $/kW·h. In addition, more than 90% of the system's total energy losses are caused by condenser and Cu–Cl cycle, and about 50–60% of the system's total exergy destructions occur in VHTR. About 60% and 30% of the system's specific energy cost are respectively caused by the equipment investment and the system operation & maintenance, and the investment costs of VHTR and Cu–Cl plant are the system's main capital investment sources.     

Optimization and comparison of two improved very high temperature gas-cooled reactor-based hydrogen and electricity cogeneration systems using iodine-sulfur cycle

To enrich the existing research methods and content, two improved very high temperature gas-cooled reactor and iodine-sulfur (I–S) cycle-based nuclear hydrogen and steam and helium gas turbines electricity cogeneration systems, including the series connection system (SCS) and the parallel connection system (PCS), are proposed and studied. The energy and exergy analysis methods are used to model these two systems, and Aspen Plus is adopted to build the I–S hydrogen production system. The energy consumption and thermal efficiency of the I–S system are analyzed in detail, and the parametric optimization of two improved systems is performed using particle-swarm optimization (PSO) algorithm. Lastly, the performance comparison of the two systems under different operating conditions is conducted. The simulation results show that more than 99% of the energy consumption of the I–S system is occupied by H₂SO₄ section and HIx section, and the system's thermal efficiency is estimated to be in the range of 17.7%–43.3%. After using an internal heat exchange network, a conservative thermal efficiency of 23.7% is achieved. The optimization results show that under zero hydrogen production load, the proposed PCS and SCS can respectively achieve the net electrical power outputs of 172.8 MW and 125.7 MW, the global thermal efficiencies of 49.36% and 35.91%, and the global exergy efficiencies of 51.94% and 37.79%. With the increase of hydrogen production load, the global efficiencies of both systems decrease significantly, but the decreasing rate of PCS is faster than that of SCS. In addition, the performance comparison results indicate that when the hydrogen production load is small or the intermediate heat exchanger's primary side helium outlet temperature is close to the reactor inlet temperature, the PCS would be a better option than the SCS.     

氦气透平压气机组合弹性环密封试验研究

氦气透平压气机采用间冷回热方式的闭式循环,因此高低压压气机以及涡轮进排气口处的密封与外层压力壳间就形成了不同压力的腔室,针对其各不同温度和压力的腔室采用组合弹性环密封.为验证组合弹性环的密封效果,设计了密封试验器和与机组上的组合弹性环完全一致的密封试验件,并在密封试验台上分别采用氦气工质和空气工质进行了试验对比.试验结果表明,组合弹性环具有良好的密封效果,在低压压气机出口进口、高压压气机出口进口以及高压压气机出口涡轮出口3处密封的泄漏分别占设计流量的0.0322‰、0.1035‰、0.1282‰,与空气介质相比,当封前压力为0.6～1.0 MPa时,氦气的泄漏约为空气泄漏的2倍,当封前压力较低时(0.1～0.2 MPa),氦气与空气的泄漏比较接近.     

Dynamic simulation of a space gas-cooled reactor power system with a closed Brayton cycle

Space nuclear reactor power (SNRP) using a gas-cooled reactor (GCR) and a closed Brayton cycle (CBC) is the ideal choice for future high-power space missions. To investigate the safety characteristics and develop the control strategies for gas-cooled SNRP, transient models for GCR, energy conversion unit, pipes, heat exchangers, pump and heat pipe radiator are established and a system analysis code is developed in this paper. Then, analyses of several operation conditions are performed using this code. In full-power steady-state operation, the core hot spot of 1293 K occurs near the upper part of the core. If 0.4 $ reactivity is introduced into the core, the maximum temperature that the fuel can reach is 2059 K, which is 914 K lower than the fuel melting point. The system finally has the ability to achieve a new steady-state with a higher reactor power. When the GCR is shut down in an emergency, the residual heat of the reactor can be removed through the conduction of the core and radiation heat transfer. The results indicate that the designed GCR is inherently safe owing to its negative reactivity feedback and passive decay heat removal. This paper may provide valuable references for safety design and analysis of the gas-cooled SNRP coupled with CBC.     

Thermal model for the optimization of a solar rotary kiln to be used as high temperature thermochemical reactor

The present study focuses on a thermal model describing a rotary kiln reactor. Several applications can be foreseen for this reactor, for example high temperature heat storage for thermal solar power plants. The energy is provided by concentrated solar radiation that heats up the cavity walls. A thermal model, describing the reactor behavior, is developed and validated. Particular attention is given to the radiation model, which constitutes the most important heat transfer. An innovative way of modeling the reactor aperture through a fictive surface at an imposed equivalent temperature leads to a significant decrease of the simulation time, without decreasing the precision of the solution. The model is validated by comparison first with other models, which make different assumptions and second with experimental results. After the validation, the model can be used for simulating the behavior under different operating condition or to define the possible improvements by a change of the reactor geometry such as the insulation’s thermal conductivity or thickness.     

Life cycle assessment of nuclear hydrogen production processes based on high temperature gas-cooled reactor

Conventional hydrogen production technologies mostly fossil fuels as energy and material basis. The rapid development of nuclear energy in recent years offers a new opportunity. Clean electricity and process heat generated by nuclear reactors can provide energy for hydrogen production, effectively reducing the environmental burden. This study used life cycle assessment (LCA) method to sort out the inputs and outputs of the nuclear hydrogen production processes and analyze the environmental impacts based on local data in China. In this study, we constructed frameworks for two nuclear energy-based processes and created four different scenarios to compare the effect of energy efficiency. Six indicators were used to quantify the environmental impact. The results showed that: (1) electrolysis cell manufacturing and spent fuel disposal generate the largest emissions in hydrogen production. (2) S–I cycle is sensitive to heat transfer efficiency, while high-temperature electrolysis is more sensitive to power generation efficiency; (3) The environmental impact of high-temperature electrolysis (without carrier gas) is slightly lower than that of S–I cycle, but the advantage will disappear as energy efficiency increases. At present, high-temperature electrolysis offers a clean alternative to conventional technologies for hydrogen energy and hydrogen economy. The S–I cycle might have a better prospect in the future. Our study results will provide a scientific assessment of the possibilities of developing nuclear energy for hydrogen production in China and help to make some decisions and policies.     

基于不同启动方式的1 000 MW超超临界汽轮机高温部件低周疲劳损耗研究

为了解汽轮机寿命损耗情况,对汽轮机高温部件寿命影响因素进行分析。基于低周疲劳理论,建立汽轮机高温部件寿命损耗分析模型,采用定量计算方法分析1 000 MW超超临界机组冷态、热态启动方式下高温部件温度偏差变化情况,计算各边界条件下高温部件等效热应力及寿命损耗,并进行敏感性分析。结果表明：汽轮机低周疲劳寿命损耗率对高温部件温度偏差较为敏感,随着温度偏差的升高,汽轮机寿命损耗率大幅升高;相同的温度偏差出现在不同温度区间时,对汽轮机寿命损耗的影响亦不同,高温区间的温度偏差对寿命损耗率影响较大。汽轮机高温部件寿命评估可以为机组启动期间升温速度控制提供技术支持,降低汽轮机寿命损耗,提高机组运行安全性。