Safety Concept of Nuclear Cogeneration of Hydrogen and Electricity

There is a significant potential for nuclear combined heat and power (CHP) in quite a number of industries. The reactor concepts of the next generation would be capable to open up, in particular, the high temperature heat market where nuclear energy is applicable to the production processes of hydrogen (or liquid fuels) by steam reforming or water splitting. Due to the need to locate a nuclear facility near the hydrogen plant, an overall safety concept has to deal with the question of safety of the combined nuclear/industrial system by taking into account a qualitatively new class of events characterized by interacting influences. Specific requirements will be determined by such factors as the reactor type, the nature of the industrial process, the separation distances of the industrial facility and population centers from the nuclear plant, and prevailing public attitudes. Based on the Japanese concept of the GTHTR300C nuclear reactor for electricity and hydrogen cogeneration, theoretical studies were conducted on the release, dispersive transport, and explosion of a hydrogen cloud in the atmosphere for the sake of assessing the required minimum separation distance to avoid any risk to the nuclear plant's safety systems. In the case of sulfur-iodine water splitting, the accidental release of process intermediates including large amounts of sulfur dioxide, sulfur trioxide, and sulfuric acid need to be investigated as well to estimate the potential risk to nuclear installations like the operators' room and estimate appropriate separation distances against toxic gas propagation. Results of respective simulation studies will be presented.