US startup makes thorium breakthrough at Department of Energy’s Idaho National Lab

Clean Core Thorium Energy (CCTE) achieved a milestone for its patented Advanced Nuclear Energy for Enriched Life (ANEEL) fuel, which it said has now reached a burnup level of over 45 gigawatt-days per metric ton in the advanced test reactor at the US Department of Energy’s Idaho National Laboratory (INL).

This level, CCTE said, outpaces the capabilities of conventional nuclear fuels used in pressurized heavy water reactors (PHWRs) and CANDU reactors – Canadian pressurized heavy-water reactor design used to generate electric power.

In February, the privately-held, Chicago-based company raised a $15.5 million Series Seed round of financing to advance the ANEEL fuel – a patented blend of thorium and high-assay low-enriched uranium (HALEU) designed to be seamlessly deployed into existing reactors.

The fuel, the company said, uniquely combines thorium with HALEU to offer a safer, more efficient, and proliferation-resistant alternative for existing and future PHWR and other CANDU reactor fleets worldwide.

Thorium, weakly radioactive, silvery-white metal, has been hailed as a safer and cheaper alternative to uranium in nuclear reactors. According to the International Atomic Energy Agency (IAEA), thorium is three times more abundant in nature than uranium, but historically has found little use in power generation due to the significant economic and technical hurdles.

Compared to uranium, thorium can generate a significantly higher amount of energy via nuclear fission, reports have shown.

Over a year of testing

In May 2024, twelve ANEEL fuel rodlets were loaded into the ATR for irradiation to achieve three burnup level targets. The first successful irradiation of four rodlets surpassed 20 GWd/MTU last year, the company said, adding that the second set of four rodlets have exceeded 45 GWd/MTU—six to seven times the average discharge burnup for PHWR/CANDU reactors that are designed to use natural uranium fuel.

The newly irradiated rodlets are currently cooling in the ATR water pool and will soon be transferred to INL’s materials and fuels complex for detailed post-irradiation examination. The final four rodlets will remain in the ATR for continued irradiation, with expected burnup levels exceeding 60 GWd/MTU, CCTE said.

“This second burnup milestone is a transformative moment for CCTE and for the future of nuclear energy,” CCTE Thorium Energy CEO Mehul Shah said in a news release.

“ANEEL fuel is not just demonstrating superior technical performance—it’s proving that thorium-based solutions can meaningfully address global challenges of energy security, nuclear waste, and proliferation,” Shah said. “Our partnership with INL is helping unlock a new era for advanced nuclear fuels.”

The company said these results reflect ANEEL fuel’s potential to redefine performance and sustainability standards in the nuclear industry.

“ANEEL’s performance in the ATR is a strong indicator of the promise thorium-based fuels hold in supporting future energy goals and diversifying the nuclear fuel landscape,” Dr. Michael Worrall, technical lead for the CCTE ATR Irradiation at INL, added.