French Commissariat à l'Energie Atomique has been studying the sulfur-iodine cycle for hydrogen production using nuclear heat. The program comprises thermodynamic measurement to assess the efficiency of the cycle, corrosion studies and technological developments, but also large scale component design, plant design, reactor coupling, and cost evaluations. The presentation will provide an overview of the program, highlight recent results, and focus on how they impact the projected hydrogen production cost.

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