Antares Mark-0 Reactor Pilot Program Reaches Criticality Under DOE Pilot
Antares said its test reactor at Idaho National Laboratory reached criticality on Thursday under the antares mark-0 reactor pilot program. The Mark 0 is still not generating power, so the milestone shows the nuclear reactions inside the hardware can sustain themselves before the full system is switched on.
Idaho National Laboratory and Mark 0
Criticality means the reactor’s nuclear reactions had become self sustaining. It does not mean the reactor had started to generate power. That distinction is the practical one for anyone watching federal reactor development, because the machine has crossed a physics threshold without moving into electricity production.
Antares said the Mark 0 reactor is not connected to the power-generation portion. It is being used to validate the company’s modeling of the physical conditions in its reactors and to generate safety data for licensing applications. For engineers, that means the unit is serving as a test bed for whether the design behaves in the way the company says it will.
DOE reactor acceleration effort
Just over a year ago, the Trump Administration issued an executive order to accelerate the development of nuclear power in the US. The order directed the Department of Energy to have three different reactor designs reach criticality in a bit over a year, and Antares is now the first new design to do it under that effort.
The milestone also narrows the gap between paper design and operational use. Antares said attempts to run the entire system, including electrical generation, are expected next year, which means the current step is validation rather than delivery of power.
TRISO, sodium, and nitrogen
Antares is basing its design on TRISO fuel, which uses tiny pellets with a uranium oxide core surrounded by several layers of carbon and a hard ceramic shell. The company’s design adds a graphite sheath, uses sodium to take heat from the reactor to a heat exchanger, and then transfers that heat to pressurized nitrogen, which drives a turbine in a closed Brayton cycle setup.
The unresolved question is whether the next phase moves from a working test reactor to a full system that can produce electricity next year. Antares also said it is working with the Department of Defense’s Project Pele program for a mobile nuclear reactor and has received support from NASA, which puts the Mark 0 inside a wider federal testing network rather than a finished commercial product.
