[Delaporte-Mathurin et al. "Advancing tritium self-sufficiency in fusion power plants: insights from the BABY experiment." Nuclear Fusion (2025)]

The BABY experiment represents an important early step toward closing the fuel loop for fusion power by directly measuring how much tritium can be bred in a molten salt blanket under realistic conditions. Using 14-MeV neutrons (as in D-T fusion) to irradiate 100 mL of a lithium salt mixture at ~700 °C, the authors measured a tritium breeding ratio (TBR) of about 10⁻⁴, i.e. a very small but nonzero fraction of tritium generated per tritium consumed. They also found that most of the tritium came out as HT (hydrogen-tritide) rather than TF (tritium fluoride), which was unexpected. While this TBR is orders of magnitude below what would be needed for a commercial fusion reactor to sustain its own tritium supply, the work provides valuable experimental validation of tritium breeding models, highlights important effects like tritium chemistry and permeability losses, and sets the stage for larger-scale experiments (e.g. with 1 L volumes or molten FLiBe salts) to move toward self-sufficient fuel cycles.