Ceramic Coatings for Clad (The C^3 Project): Advanced Accident-Tolerant Ceramic Coatings for Zr-alloy Cladding

加强核燃料的安全是继续使用和扩大核能的一个重要组成部分。可以提高安全性的一个领域是加强核燃料周围的包层。这种涂层将进一步提高正常反应堆运行条件下燃料的长期稳定性，同时在发生类似福岛事故时提供额外的保险水平。这些新涂层将在锆合金覆层和空气/水之间提供屏障，这将有助于防止冷却剂丧失事故（LOCA）时形成的蒸汽形成氢气，即2011年3月发生在福岛Daichi的过程。利用英国和美国的综合专业知识/知识，一个合作研究小组已经组成，以开发此类涂层。将解决两个选项，一个基于使用氧化物，如氧化锆，而第二个将基于三元碳化物/氮化物基材料，如MAX相。M（n+1）AX（n）相先前已被证明不仅从辐射损伤中快速恢复，而且具有优异的热/腐蚀性能，使其成为该应用的理想选择。为了开发用于当前和未来核反应堆的新涂层，必须制备新涂层，并在一系列反应堆条件下检查其稳定性。该实验方案将处理诸如涂层的制备、涂层与燃料之间结合的稳定性、辐射损害对界面的影响以及强化涂层如何提高燃料对裂变堆芯内高温/高压的稳定性等问题。这些实验还将用于验证腐蚀模拟，提供一种可靠使用模拟的方法。一旦测试，对涂层的最终评估是它们在模拟LOCA事件的条件下的行为。这项工作的结果将用于为现有和未来的反应堆技术开发技术。

Enhancing the safety of nuclear fuel is an important component in the continued use, and expansion, of nuclear power. One area where safety can be enhanced is enhancing the cladding around the nuclear fuel. Such a coating will enhance further the long term stability of the fuel under normal reactor operation, whilst at the same provide an extra level of insurance should an incident similar to that in Fukushima happen. These new coatings will provide a barrier between the Zircalloy cladding and air/water, which will help to prevent the formation of hydrogen gas from steam formed when there is a loss of coolant accident (LOCA), i.e. the process that happened at Fukushima Daichi, in March 2011.Using the combined expertise/knowledge from within the UK and US a collaborative research team has been put together to develop such coatings. Two options will be addressed one based on using oxide, such as zirconia, whilst a second will be based on ternary carbide/nitride based materials, such as MAX phases. M(n+1)AX(n) phases have previously been shown to not only recover rapidly from radiation damage, but also excellent thermal/corrosion properties making them ideal for this application. For the development of new coatings to be used in the current, and future, nuclear reactor fleet, new coatings must be prepared, and examined for stability, under a range of reactor conditions. The experimental programme will address issues such as the preparation of the coating, stability of bonding between coating and fuel, the effects of radiation damage on the interface, and how the enhanced coating increases stability of the fuel to both high temperatures/pressures experienced within a fission core. These experiments will also be used to validate simulations of corrosion, providing a means by which simulations can be reliably used. One final assessment of the coatings once tested, is how they behave under conditions that model a LOCA event. The results from this work will be used in developing technologies for existing and future reactor technologies.