Materials for fusion & fission power

据预测，到2012年，英国的发电能力将不再足以满足需求。可靠的几千兆瓦新电力来源将对社会稳定和经济实力至关重要。已经提出了核聚变和先进裂变发电厂，运行年限可能在2025年(先进裂变)到2050年(聚变)之间。它们有可能在未来几代人的时间里实现大规模、清洁、无二氧化碳的发电。然而，除非解决一些非常困难的材料科学问题，否则它们将不会可行。建造核电站核心部件的结构材料必须在高温下具有高强度和韧性，并在受到高能中子辐射破坏的情况下保持良好的性能数十年。中子撞击原子的位置，扰乱了材料精心设计的微结构，并产生了许多微小的晶体缺陷，使材料更加脆弱。与目前核电站中的中子不同，这些中子有足够的能量来引发变形反应：这导致了两个问题。首先，许多通常用于强合金中的元素无法使用，因为它们的变形产物具有数千年的高放射性，因此我们必须使用非常有限的元素范围来设计新的强合金。其次，大多数反应中都会产生氦，增加了辐射损伤的脆化效应。中国没有快中子设施，即使是慢中子试验堆，使用起来也非常昂贵，而且一次运行需要数年时间。为了快速开发关键的新材料，我们需要现在就采取行动。我们可以使用计算机模拟辐射诱导的缺陷是如何形成的，它们如何表现，以及它们如何相互作用来改变材料的性质。在实验上，离子辐照可以在几个小时内产生与快中子相同的损伤类型，而且不会产生难以处理的放射性样品；但受影响的材料量很小--只有1/1000毫米厚。我们已经开发出新的技术来测试在这些薄层中制作的样本，并可以使用先进的显微镜来观察辐射损伤。这个项目将进一步发展建模和实验，并将它们结合使用，以便实验为模型提供信息并测试它们的预测。牛津大学、利物浦大学、索尔福德大学、UKAEA Fusion和CEA的研究人员将在一个大型项目中合作，组成专门的小型研究团队，开发创新的建模和实验方法，致力于研究对钢和钨新合金应用至关重要的问题：辐射损伤如何使某些元素集中在晶界，使它们变得脆弱；辐射如何影响合金中包括的纳米级氧化物颗粒，以提高高温强度并吸收氦和氢。该项目将在微观结构尺度上取得重大进展，在微观结构尺度上操作材料特性，并将根据实验数据验证模型的预测。它的成功将大大加快新材料的开发，这些材料对于聚变和新一代裂变能源的商业实现至关重要。它将帮助英国领导新材料的科学发展，并为未来的裂变和聚变计划培训未来的专家。这些进展还涉及其他重要的结构完整性问题(例如脆化、延性-脆性转变、应力腐蚀开裂和合金强度)。该项目的领导者目前领导着世界领先的研究工作，这些领域将形成这个综合项目。他们与国际核聚变和英国核裂变社区有很好的联系，他们的代表将就该计划的方向提供建议，并将迅速实施其结果。

It has been predicted that by 2012 the UK's electricity generating capacity will no longer be enough to meet demand. Reliable new sources of multi-gigawatt electrical power will be vital for social stability and economic strength. Nuclear fusion and advanced fission power plants have been proposed, with possible years for operation in the range 2025 (advanced fission) to 2050 (fusion). These have the potential for large-scale, clean, CO2-free power generation for generations. However, they will not be viable unless some very difficult materials science problems are solved. The structural materials from which the power plants' core components will be built must have high strength and toughness at high temperatures, and retain good properties for decades despite being subjected to radiation damage from high-energy neutrons. The neutrons knock atoms from their positions, scrambling the materials' carefully-designed microstructures, and produce many small crystal defects which make the materials more brittle. The neutrons, unlike those in current nuclear power plants, have enough energy to cause transmutation reactions: this causes two problems. First, many elements ordinarily used in strong alloys cannot be used, because their transmutation products are highly radioactive for thousands of years, so we must design new strong alloys using a very restricted range of elements. Second, helium is produced in most reactions, and adds to the embrittling effects of the radiation damage.There are no fast-neutron facilities, and even slow-neutron test reactors are very expensive to use and take years for a single run . To develop the critical new materials quickly, we need to act now. We can use computer modelling of how the radiation-induced defects are formed, how they behave and how they interact to change material properties. Experimentally, ion irradiation can be used to produce the same damage types as from fast neutrons, in a few hours and without producing hard-to-handle radioactive specimens; but the amount of material affected is tiny - a layer 1/1000 mm thick. We have developed new techniques to test specimens made in these thin layers, and can use advanced microscopy to look at the radiation damage. This project will develop modelling and experiment further, and use them together so that experiments provide information to models and test their predictions. Researchers at Oxford, Liverpool and Salford Universities, UKAEA Fusion and the CEA will work together in a large project to form specialist small research teams developing innovative modelling and experimental methods, working on a problems critical to the applications of new alloys of steel and tungsten: how radiation damage can concentrate some elements at grain boundaries, making them brittle; how radiation effects on nanometre-sized oxide particles included in the alloys for high-temperature strength and to soak up helium and hydrogen.The project will make major advances in innovative experimental and modelling techniques operating at the microstructural scale where materials properties are determined, and it will verify the models' predictions against experimental data. Its success will significantly speed development of the new materials that are essential for the commercial realisation of fusion and new-generation fission power. It will help the UK to lead scientific developments in new materials and to train future experts for future fission and fusion programmes. The developments are also relevant to other important structural integrity issues (e.g. embrittlement, ductile-brittle transitions, stress corrosion cracking, and alloy strength). The project's leaders currently head world-leading research efforts in the areas which will form this integrated project. They are well-linked into the international fusion and UK fission communities, representatives of which will advise on the programme's direction and will speedily implement its results.