Design and licensing of UKAEA IP 2m box

Abstract

Croft Associates Ltd (Croft) was contracted by the United Kingdom Atomic Energy Authority (UKAEA), Winfrith in 2006 to design, manufacture, test and license an intermediate level waste industrial package transport packaging (UKAEA 2 m Box Design no. 3954) for decommissioning waste from the Dragon and steam generating heavy water reactors at Winfrith. The package had to meet the requirements of the existing UK. Nuclear Decommissioning Authority (NDA) (Nirex) 2 m Box specification. The UKAEA 2 m Box is intended for on-site storage at Winfrith and possibly another site for 50 years and subsequent transport to the NDA repository without further processing. The design of the box closure includes a leak testable sealing system which is capable of being replaced at a later date (e.g. before shipment), by the removal of the lid and replacement of seals remote from the box location. Initially the specification for the UKAEA 2 m Box called for rating for gross weight of 40 t, but this was raised to 50 t as it was realised that the efficient use of the capacity of the box would result in a 50 t gross weight. Two prototype 2 m Boxes were produced; one being provided with 100 mm of concrete shielding, and the other being provided without any shielding. The shielded box was filled with simulated waste and a concrete grout cap fitted and the resulting 50 t package was dropped onto the massive target at Winfrith from a height of 300 mm (this being the regulatory test height). The test showed that the box performed as expected; meeting all requirements. In particular: there was no loss of shielding and no effect on the containment system that would reduce its effectiveness.     

Mobile Agent-Based Management in the INSERT Project

This paper describes work carried out atUniversity College London to evaluate the use of MobileAgents (MA), written in Java, in network and systemmanagement. The work draws on experience fromconventional management systems based on ISO CommonManagement Information Protocol (CMIP) andInternet Simple Network ManagementProtocol (SNMP). These systems make use of theconcept of a Managed Object (MO). The paper describes the way in which the MOconcept has been translated into a form suitable forMA-based management and how the features of the Javalanguage may be used to express management information and to implement MOs. A platform has beenimplemented which allows MOs to be instantiated,controlled and stored. The platform also allows the easyproduction of MAs, their launching into the system and their subsequent management. Details of theplatform implementation are given and an initialassessment of performance is presented.     

Influence of hydrogen levels on porosity and mechanical properties of Mg alloy castings

Abstract

The effects of hydrogen levels on microstructure of porosity and mechanical properties of magnesium alloy castings were investigated. The hydrogen content of AZ91 alloy melt under Ar+HFC-134a mixed gas protection was 103 cm³ kg^?1, which was less than that of 139 cm³ kg^?1 under flux protection, therefore the effect of gas protection was better. The porosity ratio in microstructure of castings melted under gas protection was 1˙8%, which was also less than that of 2˙6% under flux protection. The hydrogen content of melt under flux protection and degassed with Ar gas was 70 cm³ kg^?1, and the corresponding porosity ratio in microstructure of castings was only 0˙6%. The density of the samples was increased with decreasing hydrogen content. The tensile strength of AZ91 alloy casting sample under flux protection and degassed with Ar gas was 21% higher than that of undegassed one, and the elongation was also 50% higher.     

Water modelling of level fluctuation in thin slab continuous casting mould

Abstract

A water modelling experiment was conducted to study the meniscus instability in a continuous thin slab casting mould using particle image visualisation. The results show that the level fluctuation, circulation centre position and jet impinging depth are unsteady and periodic with a similar period. The probability distributions of the fluctuating meniscus and wave height have been obtained with the highest frequency near the average position. The flow pattern and meniscus profile may be momentarily asymmetrical, and the phase difference of level fluctuation in the two sides of mould centreline is a half period. The average meniscus profile, the highest and lowest meniscus positions are generally symmetrical about the mould centreline. The wave height mainly depends on the jet impinging depth and circulation centre position. The wave height increases as the jet impinging position rises and the circulation centre approaches to the submerged entry nozzle.     

Study on B-stage properties of wafer level underfills

The flip-chip on organic substrates has relied on the underfill to enhance the solder joint reliability. The invention of wafer level underfill technology has greatly improved the production efficiency of the flip-chip process. Nevertheless, because of the unique curing characteristics of the wafer level underfill, there is a need for a fundamental understanding of the underfill curing process. In this study, we have explored two underfill formulations and have investigated their curing properties and the gelation behavior. The B-stage feasibility of these two underfills was investigated based on modeling of the curing process and characterization of the material properties. It was found that the epoxy/anhydride formulation was not suitable for wafer level underfill application, due to its low degree of cure at gelation and its low Tg after the B-stage. The underfill formulation based on epoxy/anhydride system was optimized for good dicing property and curing latency in a reflow process. A successful wafer level underfill material and process were demonstrated.     

A compact planar distributed tactile display and effects of frequency on texture judgment

This paper describes the development of a planar distributed tactile display and the evaluation of the results of its effectiveness for displaying textures. The tactile display is composed of a 6 × 5 pin array actuated by 30 piezoelectric bimorphs. The distance between each pin's centers is 1.8 mm. Vertical excursion of each pin is controlled over a 0–0.7 mm range. Perceptual experiments were conducted to evaluate the performance of the system under three conditions: active touch, passive touch with vibration and passive touch without vibration. The experimental results showed that vibrational stimuli helped subjects discriminate tactile patterns. Measurements of the error rate during discrimination tasks were used to find an optimal vibration frequency for stimuli presented at a constant sensation level (32 SLdB above threshold). The experiment was repeated, this time holding the energy transferred mechanically to the fingertip tissue constant. At low frequencies, we found that the passive stimulation allowed subjects to discriminate just as well as active touch of static stimuli did. The results suggested new possibilities for displaying texture using passive touch, constant energy and spatially varied vibration frequency.     

Mechanical design assessment approaches of actual spent fuel and HLW transport package designs

Abstract

In recent years, BAM Federal Institute for Materials Research and Testing finalised the competent authority assessment of the mechanical and thermal package design in several German approval procedures of new spent fuel and high level waste package designs. The combination of computational methods and experimental investigations in conjunction with materials and cask components testing is the most common approach to mechanical safety assessment. The methodology in the field of safety analysis, including associated assessment criteria and procedures, has evolved rapidly over the last years. The design safety analysis must be based on a clear and comprehensive safety evaluation concept, including defined assessment criteria and constructional safety goals. In general, for new package designs, the implementation of experimental package drop tests in the approval process should be obligatory. Additionally, pre- and post-test calculations as well as components or material testing could be important. The extent to which drop tests are necessary depends on the individual package construction, the materials used and identified safety margins in the design.     

济钢1700热轧卷取模型的应用与完善

详细介绍了济钢1700 ASP的卷取模型的系统组成和控制原理;结合济钢1 700ASP现场实际情况,阐述了卷取模型的应用调试方法;并针对实际生产过程中出现的涉及到卷取模型的各种问题,给出了相应的解决思路和完善方案.     

Slab quality improvement by controlling mould fluid flow

Abstract

Cleanliness of steel is a primary requirement for flat products. It is obtained with minimum of defects by controlling the liquid flow characteristics in the mould and fluctuations over the meniscus surface. Liquid flow in the mould region is due to the momentum of the pouring stream which in turn is related to the clogging of submerged entry nozzle and argon flow in the mould. This makes control of liquid steel flow dynamics in the mould important. The mould level fluctuation index, flow fraction or clogging percentage and optimised gas flow models have been developed and are correlated for minimised surface fluctuations throughout the casting sequence. Tundish weight, casting speed, casting section and immersion depth of the nozzle which primarily change the flow profile inside the mould are the key operational variables considered for model calculations. The operational parameters were adjusted to follow the developed models criteria for different casting conditions. Online application of these operational control models contributed to stabilise the mould fluid flow and have helped in decision making for pumping, flushing and tube changing. The present paper describes the mathematical approach adopted in calculation of optimum casting parameters for controlling flow of liquid steel, nozzle clogging and gas injection rate at JSW Steel Ltd. This has resulted in considerable reduction in mould level fluctuations and production of superior quality slabs even at higher casting speeds.     

线路装耦合地线后耐雷水平计算与过电压分析

鉴于在导线下方架设耦合地线 (CGW )既可增加地线对导线的耦合程度 ,降低绝缘子串上的电压 ,又可对雷电流起分流作用 ,提高输电线路的耐雷水平 ,介绍了装设CGW后输电线路耐雷水平计算的方法 ;并结合实际线路 ,利用EMTP软件对线路雷电过电压进行电磁暂态仿真。计算结果表明CGW可有效提高线路耐雷水平