Innovative Technologies in Thorium-Based Molten Salt Reactors: Comparative Analysis of TMSR-LF1, Copenhagen Atomics Design, and BN-1200M Adaptation

Abstract

Thorium-based molten salt reactors (TMSRs) promise more sustainable nuclear energy by breeding fissile uranium-233 from abundant thorium-232, reducing long-lived waste and improving safety. This review examines three recent developments: China’s 2 MWt TMSR-LF1, which achieved thorium-uranium conversion in 2025 [1];

Copenhagen Atomics’ modular Onion Core® design, validated by two years of continuous salt pump operation in 2026 [2]; and the thorium-adapted BN-1200M sodium-cooled fast reactor, entering preparatory construction in 2025 [3].

Key innovations include online fission product removal, passive safety features, corrosion-resistant materials, and breeding performance.

We compare technical parameters, technology readiness levels, and challenges such as salt corrosion and scalability.

Economic aspects (capital costs, LCOE) and environmental benefits (reduced waste half-life) are discussed. The authors believe these milestones highlight thorium’s potential for cost-competitive, low-carbon power, though further experimental validation remains essential for commercial deployment.