A two-year campaign closes

Clean Core Thorium Energy has announced completion of its nearly two-year ANEEL fuel irradiation testing and qualification campaign at Idaho National Laboratory. ANEEL is a blend of thorium and high-assay low-enriched uranium designed to give existing pressurised heavy water reactors a higher-burnup fuel option without requiring reactor modifications.

The experiment began in 2024 in INL's Advanced Test Reactor with a target of reaching burnup of up to 60 GWd/MTU. Clean Core said the final tests exceeded that goal, more than eight times the typical discharge burnup of traditional PHWR and CANDU reactors.

Three batches, 216 pellets

The campaign tested 216 ANEEL fuel pellets, extracted from the ATR in three batches: the first at the 20 GWd/MTU target, the second at over 45 GWd/MTU, and the final batch now at over 60 GWd/MTU. The staged withdrawal allowed the company to inspect performance incrementally rather than waiting for a single end-point.

Clean Core said its campaign demonstrates thorium-HALEU fuel can achieve burnup levels comparable to pressurised water reactor fuels.

Post-irradiation examination results reported so far are consistent with literature and suggest ANEEL fuel performs well. Some test rodlets showed superior fission gas retention compared with traditional uranium dioxide fuel. The final fuel batch has not yet been analysed, so the highest-burnup data point remains pending.

Why HALEU-bearing fuel qualification matters

ANEEL illustrates a distinct HALEU demand pathway from new-build advanced reactors: retrofitting an existing heavy water fleet with a denser fuel. That route depends less on reactor licensing and more on fuel fabrication and qualification evidence, including irradiation performance data that regulators and utilities can review.

Higher burnup translates into fewer refuelling interruptions and lower fuel-cycle costs per unit of electricity if the fuel can be manufactured reliably at scale. The thorium component is intended to improve in-reactor behaviour while the HALEU fraction supplies the fissile content needed to reach PWR-comparable burnups in a heavy water lattice.

Next step: a commercial reactor

Clean Core said its next step toward commercialising ANEEL is a demonstration irradiation in a commercial power reactor. Chief executive Mehul Shah said the campaign demonstrates that thorium-HALEU fuel can achieve burnup levels comparable to PWR fuels.

That transition, from test reactor to utility host site, is the point at which fuel fabrication supply, transport and licensing arrangements must all be in place.

This article was assisted by AI analysis. Please refer to the original source for official information.