Abstract: A multi-step chemical and radiolytic process for the production of gas such as hydrogen and oxygen. A highly radiosensitive gas such as carbon dioxide is injected directly into the reaction chamber of a fusion reactor and is molecularly dissociated to form carbon monoxide and pure oxygen when the fusion fuel is burned. The carbon monoxide is then mixed with steam at an elevated temperature to form carbon dioxide and pure hydrogen. The carbon dioxide is recycled and injected into the central reaction chamber to complete a closed-loop process for production of pure hydrogen and oxygen at the expense of water.