Ni-based ODS alloys for Molten Salt Reactors

尽管轻水反应堆（用水冷却的核反应堆）历来是最受欢迎的反应堆类型，但核熔毁和氢气爆炸的威胁一直令人担忧，尤其是在2011年福岛第一核电站事故之后。一种比轻水反应堆更安全、更高效的核反应堆设计是熔盐反应堆（MSR），其中熔盐被用作冷却剂，在许多设计中，也被用作液体燃料。无需担心核熔毁，因为燃料已经是液体形式，而且使用液体燃料，反应堆可以在更高的温度下运行，最高可达750摄氏度左右，从而提高反应堆效率。由于与加压水相比，这些熔盐具有更高的体积热容量，因此可制成优良的冷却剂。此外，由于液态盐被用作冷却剂而不是水，因此不存在可能导致氢气爆炸的产氢风险。虽然这些反应堆有许多优点，但它们在材料方面存在重大挑战。熔盐具有腐蚀性，会腐蚀并溶解它所接触到的一些材料，包括许多普通等级的钢。这限制了这些反应堆用于测试反应堆的使用，这些反应堆最初是为核飞机开发的！现在，人们对使用这些反应堆发电很感兴趣，有几家公司正在积极开发新的设计，并致力于建造概念电厂。如果这些反应器要用于商业用途，那么就需要开发新等级的镍合金（在与盐接触时不会受到这种腐蚀）。以前等级的镍合金由于反应堆中核反应产生的氦而发生脆化。这项工作将设计、开发和加工新的镍合金，这种合金含有纳米级的氧化物颗粒，可以有效地捕获氦，捕获它并阻止它导致过早失效。此外，这些颗粒使镍在高温下更强，从而使反应器更有效地运行。通过开发这种材料，我们将加速开发和部署这种更安全、更便宜的反应堆设计。

Although light water reactors (nuclear reactors cooled with water) have historically been the most popular type of reactor, the threat of a nuclear meltdown and hydrogen gas explosion is a continuous concern, especially in the wake of the Fukushima Daiichi nuclear power plant accident in 2011. One nuclear reactor design that is safer and more efficient than the light water reactors designs is the molten salt reactor (MSR) where molten salt is used as a coolant and in many designs, as a liquid fuel. There is no worry of a nuclear meltdown because the fuel is already in liquid form and with liquid fuel, the reactor can be operated at much higher temperatures up to around 750 C leading to a higher reactor efficiency. These molten salts make excellent coolants due to a higher volumetric heat capacity compared to pressurized water. Furthermore, since the liquid salt is used as a coolant instead of water, there is no risk hydrogen production that could lead to a hydrogen explosion. Whilst there are many advantages to these reactors they have major materials challenges. The molten salt is corrosive and will attack and essentially dissolve some materials, including many common grades of steel, it comes into contact with. This has limited the use of these reactors to test reactors, initially developed for use in nuclear planes! There is now much interest in using these reactors for power generation and several companies actively developing new designs and working to build concept plants. If these reactors are to be used commercially then new grades of nickel alloys (which do not suffer such corrosive attack in contact with the salt) need to be developed. Previous grades of nickel alloy have suffered from embrittlement caused by the helium which is produced by nuclear reaction in the reactor. This work will design, develop and process new nickel alloys which contain nano-meter sized oxide based particles which effectively capture the helium, trap it and stop it causing premature failure. In addition these particles make the nickel stronger at high temperature allowing more efficient reactor operation. By developing this material we will accelerate the development and deployment of this safer and potentially cheaper reactor design.