Reliable computational modelling of boiling for high-void and the critical heat flux

高空隙沸腾和临界热通量的可靠计算模型

• 批准号: EP/X039927/1
• 负责人: Marco Colombo
• 金额: $ 40.45万
• 依托单位: University of Sheffield
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FX039927%2F1
• 关键词: Reliable; computational; modelling; boiling; void

Meeting 25% of the electricity demand by nuclear energy is one of the pillars of the UK government's strategy for a secure and net-zero UK energy sector by 2050. In the near future, increasing nuclear installed capacity will rely on building new water-cooled fission reactors, which already represents 90% of the worldwide operating fleet. Water-cooled reactors rely on boiling to efficiently transfer the large amount of heat produced in the core and power the steam turbine generating electricity. The "critical heat flux" (CHF) is a limit on the maximum amount of power that can be safely generated in the reactor. If exceeded, the rate of steam generation is so intense that it can blanket the heating surface (e.g., the fuel rods in the reactor core), compromising the heat transfer capabilities of the system. Temperatures can increase up to the melting of the heating surface, making CHF a major risk to the integrity of the reactor and the safe containment of its radioactive inventory. However, our knowledge of the physics of boiling is still limited, and we are therefore forced to rely on empirical correlations, developed years ago from full-scale, expensive experimental CHF measurements, for the assessment of the reactor thermal limits. Due to the empirical nature of these models, overly conservative engineering margins are adopted, and reactors are forced to operate at a power that is only ~75% of the predicted CHF limit.In this project, we will develop higher-fidelity, innovative computational models of boiling built from physical principles and capable of high accuracy. With these models, reactor thermal limits will be established with less conservatism, enabling reactors to operate at higher power levels and provide affordable, reliable and carbon-free electricity to our future society. The project will specifically improve two key areas of nuclear reactor thermal hydraulics: prediction of CHF at pressurized water reactor high pressure (~ 16 MPa) operating conditions, and external passive cooling of the nuclear reactor vessel, a key strategy to mitigate the progression of rare but dangerous reactor accidents.With heating and cooling applications responsible for around 40% of global CO2 emissions, improvements in heat transfer through boiling will benefit many other sectors, such as cooling and micro-cooling applications in high power density electronics. In these areas, advancement and further improvement of equipment and efficiency will be dependent on the availability of the advanced and reliable modelling capabilities that this project will develop.

通过核能满足 25% 的电力需求是英国政府到 2050 年实现安全和净零英国能源部门战略的支柱之一。在不久的将来，增加核电装机容量将依赖于建设新的水冷核电站。裂变反应堆已占全球运行机队的 90%。水冷反应堆依靠沸腾来有效转移堆芯产生的大量热量，并为汽轮机发电提供动力。 “临界热通量”（CHF）是反应堆中可以安全产生的最大功率的限制。如果超过，蒸汽产生的速度会非常快，以至于会覆盖加热表面（例如反应堆堆芯中的燃料棒），从而损害系统的传热能力。温度会升高直至加热表面熔化，使 CHF 成为反应堆完整性及其放射性库存安全的主要风险。然而，我们对沸腾物理学的了解仍然有限，因此我们被迫依赖多年前从全面、昂贵的实验 CHF 测量中开发出来的经验相关性来评估反应堆的热极限。由于这些模型的经验性质，采用了过于保守的工程裕度，反应堆被迫以仅预计 CHF 极限的 75% 左右的功率运行。在这个项目中，我们将开发更高保真度的创新计算模型根据物理原理建立的沸腾模型具有高精度。通过这些模型，反应堆的热限制将更加保守，使反应堆能够在更高的功率水平下运行，并为我们未来的社会提供负担得起的、可靠的和无碳的电力。该项目将具体改进核反应堆热工水力学的两个关键领域：压水堆高压（约16 MPa）运行条件下CHF的预测，以及核反应堆容器的外部被动冷却，这是减缓稀有核反应进程的关键策略。加热和冷却应用约占全球二氧化碳排放量的 40%，通过沸腾改进传热将有利于许多其他领域，例如高功率密度电子设备中的冷却和微冷却应用。在这些领域，设备和效率的进步和进一步改进将取决于该项目将开发的先进且可靠的建模功能的可用性。