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CEA ASSESSMENT OF THE SULPHUR-IODINE CYCLE FOR HYDROGEN PRODUCTION
CEA assessment of the sulphur-iodine cycle for hydrogen production
Philippe Carles, Xavier Vitart, Pascal Yvon
CEA, DEN
Gif-sur-Yvette, France
Abstract
The sulphur-iodine cycle is a promising process for hydrogen production using nuclear heat:
• it is a purely thermochemical cycle, implying that hydrogen production will scale with volume
rather than surface;
• it only involves fluids, thus avoiding the often difficult handling of solids;
• its heat requirements are well matched to the temperatures available from a Generation IV
very/high temperature reactor.
These characteristics seem very attractive for high efficiency and low cost massive hydrogen production.
On the other hand, the efficiency of the cycle may suffer from the large over-stoichiometries of water
and iodine and the very important heat exchanges it involves; furthermore, due to lack of adequate
thermodynamic models, its efficiency is difficult to assess with confidence. Besides, the large quantities
of chemicals that need to be handled, and the corrosiveness of these chemicals, are factors not to be
overlooked in terms of investment and operation costs.
In order to assess the actual potential of the sulphur-iodine cycle for massive hydrogen production at a
competitive cost, CEA has been conducting an important programme on this cycle, ranging from
thermodynamic measurements to hydrogen production cost evaluation, with flow sheet optimisation,
component sizing and investment cost estimation as intermediate steps. The paper will present the
method used, the status of both efficiency and production cost estimations, and discuss perspectives
for improvement.
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