Transformational Challenge Reactor

Demonstrating a faster, more affordable approach to advanced nuclear energy

A Path Forward for Nuclear

The Transformational Challenge Reactor will demonstrate a revolutionary approach to deploying new nuclear power systems. By building and operating an additively manufactured microreactor, the Oak Ridge National Laboratory program will explore solutions to the high costs and lengthy deployment timelines that threaten the future of nuclear energy—the country’s largest source of carbon-free energy.

The Science Behind TCR


ORNL is home to the nation’s most comprehensive materials research program and is a world leader in research that supports the development of advanced materials for energy generation, storage, and use.

Advanced Manufacturing

ORNL is leading the advanced manufacturing renaissance by working with industry, academia, and other agencies to create a digital factory that bridges the gap between systems and software.

Data Analytics

ORNL is developing new characterization technologies through data analytics that are capable of rapidly extracting information from materials.

Modeling and Simulation

The ORNL-based CASL is a collaboration of the nation’s leading scientists, institutions, and supercomputers, with a mission to predict the performance of nuclear reactors through modeling and simulation.

nuclear history

Nuclear Energy

ORNL built and operated the world’s first permanent nuclear reactor, and the impact on nuclear has continued for more than 75 years.

TCR Technology


ORNL is the international leader in development of microencapsulated fuel technologies. The TCR reactor utilizes the uranium nitride TRISO fuel particles developed at ORNL in recent years.


By leveraging ORNL’s core expertise in materials science and neutron scattering, a high temperature moderator, yttrium hydride, is now fully developed to be used in the TCR demonstration.


Leveraging ORNL’s leadership in additive manufacturing of metals and ceramics, the additively manufactured reactor core consists of silicon carbide and stainless steel.


ORNL is leveraging its unique nuclear facilities and the longest reactor operational experience in the world to build and operate a helium cooled gas loop core.