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，可能的运行年份在2025年（先进裂变）到2050年（聚变）之间。这些有潜力为几代人提供大规模、清洁、无二氧化碳的发电。然而，除非一些非常困难的材料科学问题得到解决，否则它们将不可行。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，并在遭受高能中子辐射损伤的情况下保持数十年的良好性能。中子将原子从它们的位置上撞下来，扰乱了材料精心设计的微观结构，并产生了许多小的晶体缺陷，使材料更脆。中子与目前核电站中的中子不同，它有足够的能量引起嬗变反应，这就产生了两个问题。首先，许多通常用于强合金的元素不能使用，因为它们的嬗变产物具有数千年的高放射性，所以我们必须使用非常有限的元素来设计新的强合金。其次，氦在大多数反应中产生，并增加了辐射损伤的脆化效应。没有快中子设施，即使是慢中子试验反应堆，使用起来也非常昂贵，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引起的缺陷是如何形成的，它们是如何表现的，以及它们是如何相互作用来改变材料特性的。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。我们已经开发了新技术来测试这些薄层制成的标本，并可以使用先进的显微镜来观察辐射损伤。该项目将进一步发展模型和实验，并将它们结合使用，以便实验为模型提供信息并检验其预测。牛津大学、利物浦大学和索尔福德大学、UKAEA Fusion和CEA的研究人员将在一个大型项目中合作，组建专业的小型研究团队，开发创新的建模和实验方法，研究对新型钢和钨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，使它们变脆；辐射如何影响纳米级的氧化物颗粒，使合金具有高温强度并吸收氦和氢。该项目将在确定材料特性的微观结构尺度上的创新实验和建模技术方面取得重大进展，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发展，这些新材料对核聚变和新一代裂变能源的商业实现至关重要。它将帮助英国引领新材料的科学发展，并为未来的裂变和聚变项目培训未来的专家。这些进展也与其他重要的结构完整性问题相关（如脆化、韧脆转变、应力腐蚀开裂和合金强度）。该项目的领导者目前在将形成这个综合项目的领域领导世界领先的研究工作。他们与国际核聚变和英国核裂变团体有着良好的联系，这些团体的代表将对项目的方向提出建议，并将迅速实施其成果。

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.