Next-gen reactors will enhance safety and sustainability
Nuclear energy provides 20 percent of U.S. and more than 10 percent of world electricity, as well as 55 percent of America’s carbon-free clean energy — supplying year-round electricity regardless of weather or season. It plays a key role in protecting our clean air, strengthening energy security, and spurring the economy. It’s also vital for the production of medical isotopes for health care diagnostics and treatment.
Nuclear technology has been used since the 1950s for power generation, yet technology advances are still required to fully realize its multidimensional potential to address global energy and environmental issues. Continuous innovation is crucial to enhance safety and security, improve fuel sustainability, develop diverse applications besides electricity generation, and complement renewable energy for carbon-free energy production.
The next-generation, or Generation IV, reactors are being designed to achieve a high measure of safety, sustainability, and competitive economics. These reactors include light-water reactors, such as small modular reactors and microreactors with applications like providing power for space travel; gas-cooled high-temperate reactors; and fast breeder reactors. The next-gen reactors can be integrated with renewable generating sources, are less expensive than their predecessors, burn nuclear waste as an energy resource, and are “walk-away” safe.
The most likely Generation IV reactor to be commercialized — as it has mature technology and has been under R&D for more than 30 years — is the Very High Temperature Reactor (VHTR). It has various applications in addition to generating electricity, such as processing heat for chemical reactions and for other industrial uses.
One safety aspect that needs further study for this reactor is an accident scenario leading to depressurization of the reactor vessel and loss of forced cooling of the core. In a depressurization accident, there is a possibility that the building oxygen can enter and oxidize the graphite core leading to melting of the core and release of radioactive material to the environment. A Purdue team has proposed novel experimental research supported by modeling and numerical analysis. The goal is to develop a scaled experimental facility to study a VHTR building response in the event of a depressurization accident, and get first-of-a-kind data on the oxygen concentration distribution to validate reactor safety codes and Computational Fluid Dynamics (CFD) models.
A project team led by Purdue is designing and constructing the facility. Our partners include Texas A&M University; Framatome , a leading company in the nuclear industry; and Imperial College in London. Funding for U.S. collaborators is provided by the U.S. Department of Energy, and UK partners are being supported by the UK Engineering and Physical Sciences Council.
Purdue team plans to integrate experimental data and analytical predictions from running the test facility to better understand phenomena and system behavior in accident scenarios. The results should be useful not only to reactor designers and vendors but also to regulators.
The VHTR will play a major role in clean energy solutions with low or no carbon emissions. It can complement photovoltaic, wind and other renewable energy sources by providing much-needed large-scale storage, and it can power the chemical industry with clean, high-temperature heat.
Safety and nuclear waste are on the public’s mind when we talk about nuclear energy. The VHTR addresses these concerns with its unique design and operation, featuring walk-way passive safety systems, accident-tolerant nuclear fuels, and high fuel burnup to reduce nuclear waste.
Shripad T. Revankar, PhD
Professor and Director of Multiphase and Fuel Cell Research Labs
School of Nuclear Engineering
College of Engineering, Purdue University