RELEASE: Risch Celebrates Historic Milestone at INL, Idaho Leadership in Nuclear Energy

FOR IMMEDIATE RELEASE
June 4, 2026

Contact:
Madison Hardy
Janessa Tolman

First Nuclear Reactor Achieves Criticality at the Idaho National Laboratory in Nearly 50 Years

WASHINGTON – U.S. Senator Jim Risch (R-Idaho) today celebrated the first new nuclear reactor to achieve criticality, or demonstrate a fission chain reaction, at the Idaho National Laboratory in nearly 50 years.

The Antares R1 Mark-0 Reactor Project is the first of three advanced microreactors expected to go critical ahead of the 250^th anniversary of America’s founding on July 4^th. The project supports efforts by Senator Risch to accelerate the development and commercialization of next-generation nuclear technologies.

“Today’s achievement at the INL adds another chapter to Idaho’s proud leadership in nuclear innovation,” said Risch. “The Antares Reactor Project is only the beginning. In the coming months, multiple microreactors will go critical at the INL in a move that will be central to fortifying America’s place as a global leader in nuclear energy, strengthen our security, and power the future. Congratulations to the INL and the Antares team on this remarkable accomplishment.”Senator Risch is the founder and co-chair of the Senate Advanced Nuclear Caucus, which amplifies the essential role nuclear energy plays in the U.S. and explores emerging nuclear technologies. He has spearheaded legislation to increase domestic energy production, enhance national security, and keep the United States at the forefront of nuclear advancement. Earlier this year, Risch introduced the ARC Act to accelerate investment in and encourage completion of new commercial nuclear reactors by mitigating the risk of project cost overruns.

About Jim Risch

Jim Risch proudly represents the people of Idaho in the United States Senate. He currently chairs the Foreign Relations Committee and sits on the Committee on Energy and Natural Resources. Risch previously served as Governor, Lieutenant Governor, and State Senator. For the latest press releases and constituent services visit risch.senate.gov.