The recent delivery of advanced nuclear fuel to the Idaho National Laboratory’s Transient Reactor Test Facility marks a major milestone for Project Pele, a first-of-its-kind mobile microreactor prototype designed to provide resilient power for military operations.
The fuel, known as tri-structural isotropic, or TRISO, particle fuel, is made from uranium, carbon and oxygen, formed into a small kernel. This kernel is coated in multiple layers — including silicon carbide — that makes it extremely durable under high heat, radiation and corrosive conditions.
Thousands of these poppy seed-sized particles are combined into compact fuel forms used in advanced reactors like the one being developed under Project Pele by the Department of War’s Strategic Capabilities Office. The first delivery of TRISO fuel for the future demonstration reactor was recently celebrated by INL, the Strategic Capabilities Office, the U.S. Army, BWX Technologies Inc., and the U.S. Department of Energy, who are collaborating on the fuel project.
“This milestone reflects years of dedicated effort by the Office of Nuclear Energy’s Advanced Gas Reactor TRISO Fuel Qualification Program to fabricate and qualify TRISO fuel using world-class capabilities at INL’s Advanced Test Reactor and Materials and Fuels Complex, and Oak Ridge National Laboratory — capabilities that exist nowhere else in the world,” said John Wagner, INL director.
“That investment is now enabling Project Pele to move forward with the speed and confidence our national security demands to accelerate American innovation and demonstrate the leadership that will define this era of nuclear energy.”
The project is significant in its role to help the military, as explained in an INL-produced video the laboratory released.
“We’re thrilled to see the Project Pele microreactor design continue to make forward progress,” added Principal Deputy Assistant Secretary for Nuclear Energy Mike Goff. “This is a great example of how we can accelerate innovation in advanced nuclear fuels and technologies through collaborative partnerships.”
The event featured remarks from leaders from the Department of Energy, the Department of War’s Strategic Capabilities Office and BWXT, along with a ceremonial signing of a commemorative photograph.
It also highlighted the collaborative efforts of federal and private-sector partners in advancing reliable energy solutions for defense applications.
TRISO fuel was first developed in the United States and United Kingdom in the 1960s with uranium dioxide fuel, according to the U.S. Nuclear Regulatory Commission.
In 2002, the Department of Energy focused on improving TRISO fuel using uranium oxycarbide fuel kernels and enhancing its irradiation performance and manufacturing methods in order to further develop advanced high-temperature gas reactors. In 2009, this improved TRISO fuel set an international record by achieving a 19% maximum burnup during a three-year test at Idaho National Laboratory.
The irradiated fuel was then exposed to more than 300 hours of testing at temperatures up to 1,800 degrees Celsius (more than 3,000 degrees Fahrenheit).
These tests exceeded the predicted worst-case accident conditions for high-temperature gas reactors and showed no damage to minimal damage of the particles with full fission product retention.
Critics point out, however, that TRISO is highly expensive to make and the fuel’s structure makes it difficult to reprocess. Another DOE laboratory pointed out this year that TRISO discharges the largest volume of spent nuclear fuels in the industry.