The Ultra Safe Nuclear Corporation (USNC) has recently delivered uranium nitride coated uranium oxycarbide tristructural isotropic (TRISO) nuclear fuel to the NASA Space Nuclear Power and Propulsion program. USNC states that this demonstrates the “flexibility, precision and value of its Pilot Fuel Manufacturing Facility (PFM). The fuel particles supplied to NASA were small-diameter uranium nitride kernels with a tri-structural zirconium carbide coating surrounded by pyrolytic carbon and layers of porous carbon buffer.
USNC noted that “Past attempts by industry to leverage uranium nitride fuel without tri-structural coatings resulted in failure at temperatures well below predicted or desired performance levels. NASA is optimistic that this more robust fuel form will unlock higher performance regions at lower cost for future space nuclear efforts.”
John Turpin is the Space Nuclear Propulsion Program Manager for NASA. He said, “It's great to see industry stepping up with investment in infrastructure that delivers. Advanced capabilities like the Pilot Fuel Manufacturing facility mean more tools in the nuclear thermal propulsion (NTP) toolbox and that provides a shorter and clearer path to success.”
NTP for spaceflight has several advantages over chemical-based designs. It provides higher efficiency and greater power density resulting in lower propulsion system weight. This would contribute to shorter travel times and lower exposure to cosmic radiation of astronauts. This would be of great benefit to deep space missions such as crewed missions to the Moon and Mars.
Kurt Terrani is the USNC's Executive Vice President for fuel development. He said, “We designed our process and facility specifically to be both scalable and flexible to meet the needs of a rapidly expanding market for advanced coated particle nuclear fuels. I'm proud of the team and our ability to serve and support NASA and its important missions. We are ramping up fast and further to extend the benefits of advanced nuclear fuel solutions here on Earth.”
UNSC claimed that it was able to “leap past lab-scale deployment and set up a single line of production-scale equipment within 15 months by leveraging an experienced team and many technologies both with roots going back to Oak Ridge National Laboratory”.
The PFM is located at the East Tennessee Technology Park at Oak Ridge, Tennessee. It will support USNC in the near term across a number of areas including the manufacture of Qualification Fuel test particles for its Micro-Modular Reactor (MMR). The PFM also works to improve the production-scale equipment and support the licensing activities for the recently announced planned joint venture with Framatome for large-scale production of TRISO-based fuels.
The USNC is headquartered in Seattle, Washington. It is working to demonstrate MMR energy systems at the Canadian Nuclear Laboratories' Chalk River site, in partnership with Ontario Power Generation, and at the University of Illinois. The company is also working on some new projects to deploy its technology elsewhere in Canada and the U.S., as well as Europe.
USNC states that uranium nitride is a candidate particle for high-performance nuclear reactors because of its higher thermal stability and higher uranium density than other nuclear fuels.
USNC added that "The flexibility of PFM allows it to produce a full range of candidate particle fuels - including uranium carbide, uranium nitride and uranium oxycarbide - along with a variety of coatings, including silicon and zirconium carbides."