闭式循环高温气冷堆氦气轮机的性能优化

1前言高温气冷堆氦气轮机是将氦气轮机与模块式高温气冷堆相结合,利用高温气冷堆产生的高温氦气直接推动涡轮做功进行高效率发电。与目前的蒸汽轮机相比较,氦气轮机发电系统结构紧凑,都安装在一回路压力边界内,采用中间冷却和回热等技术后热效率高。氦气的比热容大(约为空气的5     

我国快堆应用前景分析和探讨

从可持续发展的角度,阐述了快堆在我国核能总体战略中的定位.通过重点分析铀资源对热堆的保障能力、快堆嬗变在核废物最小化中的作用、快堆的成熟性和竞争力等因素,提出我国近期大规模部署快堆的条件还不成熟.从能源安全战略的高度.应重视快堆技术的研发.     

我国亟需尽快启动快堆核能系统的技术开发

本文概述核能对保障我国能源安全从而促进国民经济可持续发展的重要作用,指出我国的压水堆核电技术从第二代向第三代发展,总体上可以说是“今天”核电产业的技术升级工程。快堆及其燃料闭合循环可以充分利用铀资源和实现核废物的最少化,从而保证核裂变能的可持续发展。作者强调,我国核能科技的发展战略不仅要重视“今天”的核电产业的技术升级,更应着眼于“明天”的核能产业的技术开发。尽快启动我国快堆核能系统的技术开发具有极其重要的战略意义。     

闭式循环气轮机装置使用的无气体产生燃料

无气体产生燃料在AIP装置上的应用具有优势,如不会释放燃烧反应气体,不存在燃烧产物排放问题,不会形成排气尾迹。针对闭式循环气轮机装置使用的无气体产生燃料,提出了无气体产生燃料及其氧化剂选择和需满足的技术要求,给出了一些无气体产生燃料及其相应氧化剂的种类和性质,介绍了无气体产生燃料的燃烧方式和燃烧设备,描述了使用无气体产生燃料的闭式循环蒸汽轮机装置和燃气轮机装置的系统组成及工作原理,并对一些应用上问题进行了分析。     

闭式循环柴油机系统的仿真研究

本文基于内燃机热力循环理论，编制了内燃机工作过程仿真程序，针对4102柴油机进行了开式循环和闭式循环的稳态模拟。通过计算结果与试验数据的比较，验证了计算的正确性。并比较了开式循环和闭式循环的各项参数，给出工质中不同含量的二氧化碳对闭式循环柴油机的影响规律。     

闭式注蒸汽燃气轮机循环热效率的估算方法

将实际循环在循环完善程度和设备完善程度方面与理论的卡诺循环进行对比,通过循环的特性参数估算出闭式注蒸汽燃气轮机循环的热效率,并在此基础上给出了中冷,再热和燃煤气的闭式注蒸汽循环热效率的估算公式,同时分析了循环系数和完善系数对循环热效率的影响。     

拟闭式循环柴油机着火过程的研究

简要分析了以“人造大气”工作的闭式循环柴油机所需解决的技术问题和理论问题。针对发动机工作过程的特点，着重就工质成分对拟闭式循环柴油机自然着火过程的影响进行了实验和研究。结果表明，添加氩气有助于缩短冷焰和热焰诱导期，而工质中ＣＯ２浓度的增加则会延长冷，热焰诱导期；在着火滞燃期随工质成分而变化的趋势上，理论计算与实验测量基本相吻合。     

闭式燃气轮机循环的有限时间热力学分析

本文从有限时间热力学观点出发，导出了有限时间约束条件下闭式燃气轮机循环的最大功率及其相应的效率界限和任意功率下的效率界限，即最佳功率、效率关系，借此可分析热阻对闭式燃气轮机循环性能的影响，并实现其有限时间热力学优化．     

内可逆闭式布雷顿循环的功率密度优化

以功率密度——循环输出功率与最大比容之比——作为优化目标。用有限时间热力学方法 ,对恒温热源条件下内可逆闭式燃气轮机循环的高、低温侧换热器的热导率分配进行了优化。由数值算例给出了循环的一些主要特征参数对热导率最优分配和最大功率密度的影响 ,以及功率密度最大时的最佳热导率分配与最佳压比之间的对应关系。     

小型离心式压气机压缩氦气闭式循环的初步研究

介绍了小型离心式压气机闭式循环实验台的组成,并在此实验台上进行了压缩氦气和压缩空气闭式循环的实验,针对实验所得数据进行整理和理论分析,得到了压气机压缩氦气的特性线,并且利用压缩空气和压缩氦气的对比实验结果,初步分析了同一压气机压缩不同工质的相似现象。     

PWR-FBR with closed fuel cycle for a sustainable nuclear energy supply in China

From the thermal reactor to the fast reactor and then to the fusion reactor; this is the three-step strategy that has been decided for a sustainable nuclear energy supply in China. As the main thermal reactor type, the commercialized development phase of the pressurized water reactor (PWR) has been stepped up. The development of the fast reactor (FBR) is still in the early stage, marked by China experimental fast reactor (CEFR), which is currently under construction. According to the strategy study on the fast reactor development in China, its engineering development will be divided into three steps: the CEFR with a power of 65 MWt/20 MWe; the China prototype fast reactor (CPFR) with a power of 1 500 MWt/600 MWe; and the China demonstration fast reactor (CDFR) with a power of 2 500–3 750 MWt/1 000–1 500 MWe. With regards to the fuel cycle, a 100 t/a PWR spent fuel reprocessing pilot plant and a 500 kg/ a MOX fabrication plant are under construction. A project involving the construction of an industrial reprocessing plant and an MOX fabrication plant are also under application phase.     

Utilization of nuclear waste plutonium and thorium mixed fuel in candu reactors

Spent nuclear fuel out of conventional light water reactors contains significant amount of even plutonium isotopes, so called reactor grade plutonium. Excellent neutron economy of Canada deuterium uranium (CANDU) reactors can further burn reactor grade plutonium, which has been used as a booster fissile fuel material in form of mixed ThO₂/PuO₂ fuel in a CANDU fuel bundle in order to assure reactor criticality. The paper investigates incineration of nuclear waste and the prospects of exploitation of rich world thorium reserves in CANDU reactors. In the present work, the criticality calculations have been performed with 3‐D geometrical modeling of a CANDU reactor, where the structure of all fuel rods and bundles is represented individually. In the course of time calculations, nuclear transformation and radioactive decay of all actinide elements as well as fission products are considered. Four different fuel compositions have been selected for investigations: ① 95% thoria (ThO₂) + 5% PuO₂, ② 90% ThO₂ + 10% PuO₂, ③ 85% ThO₂ + 15% PuO₂ and ④ 80% ThO₂ + 20% PuO₂. The latter is used for the purpose of denaturing the new ²³³U fuel with ²³⁸U. The behavior of the criticality k_∞ and the burnup values of the reactor have been pursued by full power operation for ~10 years. Among the investigated four modes, 90% ThO₂ + 10% PuO₂ seems a reasonable choice. This mixed fuel would continue make possible extensive exploitation of thorium resources with respect to reactor criticality. Reactor will run with the same fuel charge for ~7 years and allow a fuel burnup ~55 GWd/t. Copyright © 2016 John Wiley & Sons, Ltd.     

Power flattening study of ultra‐long cycle fast reactor using thorium fuel

This paper presents a design study of power shape flattening for an optimized ultra‐long cycle fast reactor with a power rate of 1000 MWe in order to mitigate the power peaking issue and improve the safety with a lower maximum neutron flux and reactivity swing. There are variations in the core designs by loading thorium fuel or zoning fuels in the blanket region and the bottom driver region of ultra‐long cycle fast reactor with a power rate of 1000 MWe. While it has lower breeding performance in a fast breeder reactor, thorium fuel is one of the promising fuel options for future reactors because of its abundance and its safety characteristics. It has been confirmed that the thorium fuels, when loaded into the center region of a reactor core, lower the power peaking factor from 1.64 to 1.25 after 20 years and achieves a more flattened radial power distribution. This consequently reduces the maximum neutron flux and the speed of the active core moving from 3.0 cm/year to 2.5 cm/year on the average over the 60‐year reactor operation. It has been successfully demonstrated that the three‐zone core is the most optimized core, has the most flattened radial power shape, and is without any compromise in the nature of long cycle core, from the neutronics point of view, in terms of average discharge burnup and breeding ratio. Copyright © 2016 John Wiley & Sons, Ltd.     

A proper spent nuclear fuel management strategy could enhance the continuity of nuclear power in the Spanish energy mix

This article presents two economic analyses performed with the Mariño model, which was specially designed to analyse the costs of different spent nuclear fuel (SNF) management strategies in the real Spanish context. These analyses are: (a) a Monte Carlo study for those strategies and (b) the effects of a longer operational lifetime for the Spanish nuclear power plants (NPPs) on the costs of spent nuclear fuel (SNF) management. For the first analysis, a triangular distribution for the different unitary costs was assumed and the data and assumptions from numerous studies were used to obtain the values required for the distribution. The second analysis was performed for the current official shutdown dates for the NPPs, and the results were compared to other operational lifetime scenarios. The main assumption for these scenarios was a progressive shutdown of the reactors, in order to avoid numerous shutdowns in a few years. These scenarios were proposed for 40 to 60 years of mean operational lifetime of the reactors. The results show that, for all scenarios analysed, the additional electricity production due to longer operational lifetimes compensate the extra costs caused by the larger amount of SNF to be managed. Additionally, for the current SNF management strategy, a progressive shutdown at 40 years of mean operational lifetime has shown to entail lower costs than the official shutdown scenario. However, a strategy without a centralised interim storage facility would be the most economically favourable one for all the scenarios analysed.     

Performance modeling and analysis of spent nuclear fuel recycling

The rapid expansion of nuclear energy in China has intensified concerns regarding spent fuel management. However, the consequences of failure or delay in developing approaches to managing spent fuel in China have not yet been explicitly analyzed. Thus, a dynamic analysis of transitions in nuclear fuel cycles in China to 2050 was conducted. This multi‐disciplinary study compares the environmental, security, and economic consequences of choices among ongoing technology development options for spent fuel management. Four transition scenarios were identified: the direct disposal of PWR (Pressurized Water Reactor) spent fuel, the recycling of PWR spent fuel through PWR‐MOX (Mixed Oxides), the PWR‐MOX followed by fast reactors, and the recycling of PWR spent fuel using fast reactors. Direct disposal would have the lowest cost of electricity generation under the current market conditions, while the reprocessing and recycling of PWR spent fuel would benefit the Chinese nuclear power program by reducing the generation of high level waste (67–82%), saving natural U resources (9–17%), and reducing Pu management risk (24–58%). Moreover, a fast reactor system would provide better performance than one‐time recycling through PWR‐MOX. The latter also poses high risks in managing the build‐up of separated Pu. Copyright © 2015 John Wiley & Sons, Ltd.     

West Germany's efforts to close the nuclear fuel cycle: Strategies for radioactive waste management

West Germany's efforts to reach a mature nuclear economy by [closing] the [back end] of the nuclear fuel cycle are discussed with special emphasis on radioactive waste management strategies. the radioactive wastes that would be generated in a closed nuclear fuel cycle are described. A brief discussion is given of the motives that underlie the current international disagreement regarding the desirability of, and the need for, closing the nuclear fuel cycle. West Germany's concept for closing the nuclear fuel cycle is outlined including institutional arrangements and responsibilities. A discussion of radioactive waste classification follows. Expected volumes and inventories of radioactive wastes are pointed out. Current practices, and research and development work in the treatment and disposal of radioactive wastes are outlined. A final section is devoted to the history, circumstances and implications of the current requirement for a [solution] for the back end of the nuclear fuel cycle as a precondition for continued expansion of nuclear power in West Germany.     

Core design options of an ultra‐long‐cycle sodium cooled reactor with effective use of PWR spent fuel for sustainable energy supply

In this work, 350MWe ultra‐long‐cycle sodium‐cooled reactor cores are designed to supply electric energy over ~60 Effective Full Power Years (EFPYs) without refueling and with an effective use of Transuranics (TRU) and uranium from large pressurized water reactor (PWR) spent fuel stocks. The core employs the axial blanket‐driver‐blanket (ABDB) burning strategy, which was recently proposed by the authors to achieve an ultra‐long‐cycle length with self‐controllability under unprotected accidents. In particular, a thorium–uranium fuel cycle is considered to remove the heterogeneity of the fuel assemblies for design simplification and to improve the core performance parameters by selectively adding thorium into both blanket and driver fuels. The results show that the use of TRU nuclides from PWR spent fuel leads to significant extension of the fuel cycle length, but considerable increase of burnup reactivity swing. In addition, these results also indicate that the uranium–thorium mixed fuels both in the lower blanket and driver considerably improve the inherent safety of the ultra‐long‐cycle core by reducing burnup reactivity and sodium void worth; this makes it possible to simplify the previous heterogeneous fuel assembly design with improved core performances. Copyright © 2016 John Wiley & Sons, Ltd.     

The economic competitiveness of promising nuclear energy system: A closer look at the input uncertainties in LCOE analysis

In this study, we aimed to provide important information about the potential economic benefits and risks of nuclear electricity generation associated with existing and prevailing nuclear technologies and to examine the economic effects of nuclear fuel cycle strategies in Korea. An economic analysis model that evaluates the overall life‐cycle costs of nuclear energy systems coupled with multiple fuel cycle options was specially developed by using the levelized cost of electricity (LCOE) as the fundamental methodology. This model is capable of identifying a range of techno‐economic uncertainties underlying each individual nuclear energy system taking into account the state of the art in fuel cycle technologies. It can also quantify and incorporate the resulting impacts into a system‐wide LCOE distribution for each fuel cycle option based on Monte Carlo probabilistic simulation. We analyzed and discussed examples of the economic performance of 13 promising candidates for nuclear energy systems integrated with extensive fuel cycle technologies (including one direct disposal and 12 specific reprocessing and recycling fuel cycle options). We also conducted a sensitivity analysis to investigate the major sensitivity factors of the system component cost in each fuel cycle option and their impacts on individual economic performances. Furthermore, a closer look at the techno‐economic uncertainties of advanced fuel cycle technologies in a break‐even analysis offers evidence of the potential economic feasibility and cost‐reduction opportunities in the reprocessing and recycling options relative to the direct disposal of spent nuclear fuel.     

我国核裂变能可持续发展战略研究

本文从科学技术的角度,分析我国国民经济增长对核能发展的需求,探讨我国核能的近中期发展战略构想,指出为实现其发展战略目标而应重点研究的关键科学技术与问题,并提出一些相关的政策建议,为国家制定核能中长期发展规划提供参考。     

Future regional nuclear fuel cycle cooperation in East Asia: Energy security costs and benefits

Economic growth in East Asia has rapidly increased regional energy, and especially, electricity needs. Many of the countries of East Asia have sought or are seeking to diversify their energy sources and bolster their energy supply and/or environmental security by developing nuclear power. Rapid development of nuclear power in East Asia brings with it concerns regarding nuclear weapons proliferation associated with uranium enrichment and spent nuclear fuel management. This article summarizes the development and analysis of four different scenarios of nuclear fuel cycle management in East Asia, including a scenario where each major nuclear power user develops uranium enrichment and reprocessing of spent fuel individually, scenarios featuring cooperation in the full fuel cycle, and a scenario where reprocessing is avoided in favor of dry cask storage of spent fuel. The material inputs and outputs and costs of key fuel cycle elements under each scenario are summarized.