单脉冲二次监视雷达天线波瓣测量方案研究

对单脉冲二次雷达工作原理作简要介绍,分析天线波瓣外部测量法与内部测量法的优缺点以及波瓣发生变形产生的后果,从而对外部测量法进行相应改进。使用振幅一相位法测试二次雷达天线水平极化图和垂直极化图,并给出幅相不一致和交叉极化影响的解决方法,最终设计了一套二次雷达天线极化测量系统。该系统为民航雷达检测中心的建设提供理论与实践指导。     

汽动给水泵组使用弹性基础时若干问题的探讨

为消除制造厂在汽动给水泵组使用弹性基础时 ,对超临界参数、轴系、欧洲机型与西屋机型、真空吸力以及管道接口等的疑虑 ,进行了上述各项的讨论。讨论结果表明 :汽动给水泵组使用弹性基础是一项先进、成熟、省钱、省时、省空间、易找平、防沉降、抗地震的技术 ,国内、外大量实践证明该技术运行可靠 ,种种疑虑可以完全消除 。     

Synthesis and characterization of Pt on novel catalyst supports for the H2 production in the Westinghouse cycle

This work shows the preparation and physicochemical and electrochemical characterization of Pt based catalysts supported on two different catalyst supports (Vulcan carbon and SiC/TiC) with a 40 wt% Pt content for the depolarized SO₂ electro-oxidation in the hybrid sulfur process, which is a promising approach for the hydrogen production. The Pt based catalysts supported on carbon showed the lowest Pt crystallite size, but the electrochemical surface area of the Pt deposited on the Si_0.9CTi_0.1C was the highest of the three catalysts prepared in the lab under the same operation conditions. The Pt catalysts supported on the novel SiC/TiC based material are promising catalysts for this technology as they showed high catalyst activity and durability in sulfuric acid conditions.     

西屋压水堆运行技术规格书几项修改的跟踪与探讨

简要描述了美国核电厂运行技术规格书的发展过程,对近期跟踪的几项美国西屋压水堆核电厂运行技术规格书的修改做了简要介绍,并对修改的内容进行了探讨。     

新一代压水堆燃料组件技术特点及其在华专利申请

以美国西屋电气公司的Next Generation Fuel燃料组件技术特点为线索,收集了美国西屋电气公司在中国燃料组件技术方面的专利申请和专利文献,从中筛选出与NGF燃料组件技术特点符合的专利申请和专利文献,对其技术方案进行了深入剖析,从中了解西屋新一代压水堆燃料组件技术的发展趋势。     

Hydrogen filter press electrolyser modelled by coupling Fluent<Superscript><Emphasis Type="Bold">®</Emphasis></Superscript> and Flux Expert<Superscript><Emphasis Type="Bold">®</Emphasis></Superscript> codes

Mass production of hydrogen is a major issue for the coming decades particularly to decrease greenhouse gas production. The development of fourth-generation high-temperature nuclear reactors has led to renewed interest for hydrogen production. In France, the CEA is investigating new processes using nuclear reactors, such as the Westinghouse hybrid cycle. A recent study was devoted to electrical modeling of the hydrogen electrolyzer, which is the key unit of this process. In this electrochemical reactor, hydrogen is reduced at the cathode and SO₂ is oxidized at the anode with the advantage of a very low voltage cell. This paper describes an improved model coupling the electrical and thermal phenomena with hydrodynamics in the electrolyzer, designed for a priori computational optimization of our future pilot cell. The hydrogen electrolyzer chosen here is a filter press design comprising a stack of identical cathode and anode compartments separated by a membrane. In a complex reactor of this type the main coupled physical phenomena involved are forced convection of the electrolyte flows, the plume of evolving hydrogen bubbles that modifies the local electrolyte conductivity, and all the irreversible processes that contribute to local overheating (Joule effect, overpotentials, etc.). The secondary current distribution was modeled with a commercial FEM code, Flux Expert^®, which was customized with specific finite interfacial elements capable of describing the potential discontinuity associated with the electrochemical overpotential. Since the finite element method is not capable of properly describing the complex two-phase flows in the cathode compartment, the Fluent^® CFD code was used for thermohydraulic computations. In this way each physical phenomenon was modeled using the best numerical method. The coupling implements an iterative process in which each code computes the physical data it has to transmit to the other one: the two-phase thermohydraulic problem is solved by Fluent^® using the Flux-Expert^® current density and heat sources; the secondary distribution and heat losses are solved by Flux-Expert^® using the Fluent^® temperature field and flow velocities. A set of dedicated library routines was developed for process initiation, message passing, and synchronization of the two codes. The first results obtained with the two coupled commercial codes give realistic distributions for the electrical current density, gas fraction, and velocity in the electrolyzer. This approach allows us to optimize the design of a future experimental device.     

西屋型汽轮发电机组使用弹性基础的探讨

西屋型汽轮发电机组在国外早已使用弹性基础 ,但在国内还没有业绩。西屋机型使用弹性基础后有一些问题需要解决 ,因此 ,西屋机型使用弹性基础后 ,可精确地进行动力分析、可不停机进行机组的对中与调整、可解决基础的不均匀沉降、可节省检修时间、可抗地震等。     

Capabilities of TRANSURANUS code in simulating power ramp tests from the IFPE database

Investigations of fuel behavior are carried out in close connection with experimental research, operation feedback and computational analyses. OECD NEA sets up the “International Fuel Performance Experiments (IFPE) database”, a public domain database on nuclear fuel performance experiments with the purpose of model development and code validation. The objective of the activity (performed in the framework of the IAEA CRP FUMEX-III project) is to investigate the pellet-clad interaction mechanism and the capability of TRANSURANUS code in simulating the phenomena, processes occurring in the fuel rod during the power ramps, with focus on the parameters influencing the cladding failures. The experimental database adopted is the Studsvik PWR Super-Ramp subprogram, part of the IFPE database, which consists of 28 pressurized water reactor fuel rods power ramped at burnup from 28 to 45 MWd/kgU. Relevant results by TRANSURANUS are presented in connection with the experimental evidences. Focus is given on the PCI/SCC failure, demonstrating that the failure threshold, available in TRANSURANUS, results conservative both in case of KWU and W rods.