Numerical Study on Effects of Fuel Mixture Fraction and Li-6 Enrichment on Neutronic Parameters of a Fusion–Fission Hybrid Reactor

This study presents the effects of mixture fractions of nuclear fuels (mixture of fissile–fertile fuels and mixture of two different fertile fuels) and ⁶Li enrichment on the neutronic parameters (the tritium breeding ratio, TBR, the fission rate, FR, the energy multiplication ratio, M, the fissile breeding rate, FBR, the neutron leakage out of blanket, L, and the peak-to-average fission power density ratio, Γ) of a deuterium–tritium (D–T) fusion neutron-driven hybrid blanket. Three different fertile fuels (²³²Th, ²³⁸U and ²⁴⁴Cm), and one fissile fuel (²³⁵U) were selected as the nuclear fuel. Two different coolants (pressurized helium and natural lithium) were used for the nuclear heat transfer out of the fuel zone (FZ). The Boltzmann transport equation was solved numerically for obtaining the neutronic parameters with the help of the neutron transport code XSDRNPM/SCALE4.4a. In addition, these calculations were performed by also using the MCNP4B code. The sub-limits of the mixture fractions and ⁶Li enrichment were determined for the tritium self-sufficiency. The considered hybrid reactor can be operated in a self-sufficiency mode in the cases with the fuel mixtures mixed with a fraction of equal to or greater than these sub-limits. Furthermore, the numerical results show that the fissile fuel breeding and fission potentials of the blankets with the helium coolant are higher than with the lithium coolant.     

斯德哥尔摩高放废物地质处置库国际大会概况

本文对2003年12月在瑞典斯德哥尔摩召开的“地质处置库国际大会：政治和技术进展”会议内容进行了简要小结。这次会议介绍了过去4年中有关国家地质处置计划取得的进展、目前面临的挑战和今后的规划;还对中国高放废物地质处置工作提出了政策、法规、管理体制、长远规划、经费、国际合作以及公众接受等方面的建议。     

汽车发动机用氧传感器的研究

发动机尾气在排出之前要利用三元催化剂对有害成分进行催化处理。其净化率与尾气中的氧含量有关,同时配合节能,通过氧气含量的测定,可实时控制A/F即空燃比(气缸内空气与燃料的混合比例),确保缸内燃料充分燃烧,以尽可能减少尾气中有害气体的含量,由此便可利用氧传感器。文章描述了ZrO2氧传感器的发展现状,介绍了它的结构、工作原理和应用,以及新型稳定剂的添加等关键技术。     

An overview of a nuclear reprocessing plant Human Factors programme

This paper presents a case study of a large Human Factors programme applied in the nuclear fuel reprocessing industry (1987-1991). The paper outlines the key Human Factors issues addressed, as well as the impacts achieved, and gives an indication of the resources utilised (approximately 15 person-years of effort). It also considers the starting point of the programme, in terms of the factors that led to the need for such an extensive programme. Some general lessons learned are given at the end of the paper.     

美军在着火安全燃料方面的研究与应用

介绍了美军在着火安全燃料技术方面的研究与应用,包括燃料性能的调整、改型燃料的研究及首火防护与控制等。     

The conductivity of co-dopant ceria electrolyte

1　IntroductionManyresearchersaregraduallyinterestedinceriaelectrolytesfortheiroutstandingmerits ,especiallyinin termediatetemperaturesolidoxidefuelcell (IT -SOFC) .InIT -SOFCfield ,anode supportedplanarstackisbe comingthemainstream .Therefore ,mechanicalpropertiesofelectrolytesarenolongerimportantfordesiredperfor mance ,andthemainattentionfocusesonhowtoimprovetheionicconductivity .Themainaimsofimprovingtheionicconductivityaretomakethinnerfilmanddevelopnewelectrolyteseriesandco dopantsadd…     

Electrodes modified by electrodeposition of CoTAA complexes as selective oxygen cathodes in a direct methanol fuel cell

The oxygen reduction reaction (ORR) at cobalt tetraazaanulene (CoTAA) modified electrodes was investigated. As a first approach, modified electrodes were prepared by electrodeposition of CoTAA on glassy carbon (GC). The modification of the GC surface was monitored by u.v.–vis. differential reflectance spectroscopy (UVDRS). The recorded spectra (i.e., absorbance as a function of wavelength and time) showed that the electrodeposition of CoTAA at 0.8 V vs Ag|AgCl, that is, at a potential where the TAA ligand is oxidized to TAA⁺, seems to produce a thin polymer film. Starting from these preliminary results, porous rotating disc electrodes (RDEs) were prepared by electrodeposition of CoTAA (0.8 V vs Ag|AgCl, 1 min) on graphite powder embedded in a recast Nafion^® film. The use of a porous RDE allowed comparison of the activity and selectivity of Pt nanoparticles and CoTAA for the ORR under experimental conditions close to those of a fuel cell cathode, that is, at the catalyst|Nafion^® interface. The activity towards the ORR of a porous electrode modified by electrodeposition of CoTAA is not affected when methanol is present in the electrolyte phase, whereas a noticeable decrease in the activity of Pt-based oxygen cathodes was observed under the same conditions. Half-cell life tests showed that CoTAA-modified electrodes and Pt-based electrodes have a comparable stability over a period of 90 min.     

The influence of baking fuel on residues of polycyclic aromatic hydrocarbons and heavy metals in bread

The influence of fuel type used to bake bread on the spectrum and concentrations of some polycyclic aromatic hydrocarbons and heavy metals in baked bread was assessed. Bread samples were collected from different bakeries operated by either electricity, solar, mazot or solid waste and their residue content of PAHs and heavy metals was assessed. The total concentration of PAHs detected in mazot, solar, solid waste and electricity operated bakeries had an average of 320.6, 158.4, 317.3 and 25.5 μg kg⁻¹, respectively. Samples collected from mazot, solar and solid waste operated bakeries have had a wide spectrum of PAHs, in comparison to that detected in bread samples collected from electricity operated bakeries. Lead had the highest concentrations in the four group of bread samples, followed by nickel, while the concentrations of zinc and cadmium were the least. The concentration of lead detected in bread samples produced from mazot, solar, solid waste and electricity fueled bakeries were 1375.5, 1114, 1234, and 257.3 μg kg⁻¹, respectively. Estimated daily intake of PAHs based on bread consumption were 48.2, 28.5, 80.1, and 4.8 μg per person per day for bread produced in bakeries using mazot, solar, solid waste and electricity, respectively. Meanwhile, the estimated daily intake of benzo (a) pyrene were 3.69, 2.65, 8.1, and 0.81 μg per person per day for bread sample baked with mazot, solar, solid waste and electricity, respectively. The daily intake of lead, based on bread consumption was 291, 200.5, 222, and 46.31 μg per person per day for bread sample baked with mazot, solar, solid waste and electricity, respectively. The present work has indicated the comparatively high level of daily intake of benzo (a) pyrene and lead in comparison to levels reported from many other countries and those recommended by international regulatory bodies. It is probable that residues detected in bread samples are partially cereal-borne but there is strong evidence that the process of baking and the gases emitted are responsible for most of the contamination load.     

基于MSP430单片机的燃运胶带保护仪的设计

针对由15条胶带组成的燃运煤系统,文章介绍了一种基于MSP430单片机的综合保护仪及其硬件电路和软件设计。该保护仪能实时检测每条胶带机的电压、电流和胶带线速度等参数,并根据这些参数判断胶带工作是否异常。通过RS485总线与上位监控机进行通信,实现了对15条胶带的远程监控和参数查询。运行结果表明,该保护仪在燃运保护监控系统中有一定的使用价值。     

改性粉煤灰脱硫剂增湿脱硫工艺

研究利用开发的改性粉煤灰脱硫剂，通过模拟试验装置，采用干喷增湿的方法进行正交试验，根据正交试验得出影响脱硫效率的因素及作用大小，并进行了单因素分析和讨论。