Use of Alcan's Al-B4C metal matrix composites as neutron absorber material in TN International's transportation and storage casks

Abstract

Major issues in the area of transportation and/or storage of radioactive materials are reliability and safety of engineering components. Among the functions to be undertaken, transportation and storage systems shall allow the criticality control of the transported matter, the control of its temperature, as well as the capacity to withstand the mechanical stresses due to normal, incidental and accidental conditions of use. In most cases, criticality control requires the use of an internal arrangement made of a neutron absorber material, which must also have high thermal conductivity properties to ensure the temperature control. When, as in many AREVA-TN International applications, the design takes credit of the neutron absorber material as a structural component, it must show high mechanical performance. Alcan's Al-B₄C metal matrix composites (Al-B₄C MMCs) meet all the above mentioned requirements, due to their special capability of capturing neutrons, their light weight, and their superior thermal conductivity and mechanical properties. The significant advantage of Alcan's technology is its flexibility with regards to a wide range of boron carbide contents and matrix alloys (from AA1XXX to AA6XXX). This enables the adjustment of the properties to the exact needs of the design. TN International presently uses extruded and/or rolled Al-B₄C MMC parts in several of its internal arrangements. The present paper gives an overview of the manufacture processes of Alcan's Al-B₄C MMCs, from the mixing of B₄C into liquid aluminium to the extrusion and rolling operations. It describes the methods and results for the qualification tests in terms of the neutron absorption, thermal, physical and mechanical properties of the material. Finally, details are given on the use of Alcan's MMCs as a neutron absorber with enough credit for structural material in TN International's TN24 designs.     

2—THE SYSTEMATIC OPTIMIZATION OF THE AQUEOUS COMPRESSION-JET WOOL SCOUR. PART II: SCOURING TRIAL FOR OPTIMUM PRODUCTION CAPACITY

A factorial experiment performed on the aqueous compression-jet scour with three independent variables is reported. These variables were the feed-rate of greasy wool, the speed of the layer of wool, and the jetting pressures. The wools were processed to gilled slivers, on which mean-fibre-length determinations were made. The effects of the independent variables on the dependent variables of residual grease and dirt and mean fibre length (the last-named being a measure of the degree of entanglement of the scoured wool) were evaluated. The results obtained indicated the operating conditions to be used to achieve the optimum production capacity.     

GPS、GPRS车辆监控系统的ARM终端设计与实现

介绍一种基于GPS和GPRS结合的车辆导航和远程监控系统。GPS模块输出的信息数据通过32位RISC CPU的ARM处理器运行的GIS显示出车辆的当前位置及各种信息,实现自主导航,同时,利用GPRS无线通信模块将车载终端GPS模块的信息通过无线网络发送到远程数据服务中心,实现远程的实时监控和调度。     

33—THE SNARLING OF HIGHLY TWISTED MONOFILAMENTS. PART II: CYLINDRICAL SNARLING

An account is given of an experimental investigation of the cylindrical snarling of highly twisted monofilaments.

The theory underlying cylindrical snarling is set out, and an expression is derived for calculating the critical twist level at which normal snarling will be replaced by cylindrical snarling. Experiments on rubber filaments are described, and it is shown that there is good agreement between the theoretical and experimental results. Further experiments, in which the specimen was allowed to contract freely or forced into other forms, are also described.

It is shown from these experiments that it is difficult to establish the true equilibrium behaviour, since the situation appears to be dominated by frictional effects or by direct barriers to relative movement.     

24—A CRITICAL COMPARISON OF EMPIRICAL TESTS OF THE EXTENSIONAL RESILIENCE OF TEXTILE FIBRES: PART III: COMPARISON BETWEEN RECOVERY TESTS AND THE PERFORMANCE OF CARPET-LIKE CONSTRUCTIONS

A series of polypropylene-fibre continuous-filament yarns was used to manufacture a set of simplified carpet-like structures. Recovery and wear tests on these samples are described and the results compared with those of single-filament recovery tests discussed in Parts I and II of this series. It is concluded that single-filament testing can indicate very poor or very good yarns, although unconsidered effects dominate the performance of intermediate samples.     

Applying non-destructive techniques to inspect preserved egg products by decay rates

Preserved eggs are a special Asian food. Traditionally, the gelling of preserved eggs is tested intuitively by feeling the slight vibrations that occur when the preserved egg is tapped with a finger. However, the effects of extended tapping and individual subjectivity lead to inaccurate results. This study thus attempts to devise a scientific method for inspecting the gelling of preserved eggs. Regression analysis of the peaks of the time response starting at 50 ms following the trigger yielded an exponential tendency line that indicates the decay rate of vibration theory. Distinct vibration analysis revealed that a decay below 80 represents complete gelling. Receiver operating characteristic curve analysis reveals an area under curve of 0.963, a cut-off point at 0.000 (x axis) and 0.882 (y axis), and a decay rate of 84.7995. The accuracy was 96.7%. This method provides a foundation for future development of an automatic preserved egg inspecting system.     

IMBR-A/O工艺对生活污水脱氮除磷的研究

采用自行设计的A/O一体式膜生物反应器对生活污水的脱氮除磷进行了研究.结果表明:硝化菌受pH值影响较大,通过投加小苏打来控制硝化O段pH值为6.5～7.0,使其满足硝化菌生长的范围,此时,NH4 -N的去除率达99%以上,出水浓度基本稳定在0.5mg·L-1以下;由于反硝化A段的DO值较高,使反硝化细菌受到抑制造成了系统出水TN值较高,但也能达到80%以上的去除率;TP的去除是由于取样污泥带出了部分磷以及微生物生长消耗了部分磷.