The working principles of both types of solid oxide electrochemical cell are different what defines their influence on the steam cycle when integrated with nuclear reactor. SOE with oxygen ion conduction generates hydrogen inside the steam flow by extracting oxygen, whereas conduction of hydrogen protons results in pure hydrogen and introducing oxygen into the steam at the same time. Both solutions have their pros and cons. Producing hydrogen inside a steam flow, gives certain difficulties with obtaining this gas at adequate purity afterwards. On the other hand, putting oxygen inside the steam cycle may cause with increase of corrosion processes, but amount of oxygen in steam flow is two times smaller than adequate amount of hydrogen.
The operation of solid oxide electrochemical cell can be reversed, thus they can operate inn both modes: electrolysis and fuel cells. Much more work is done according the modelling the fuel cell operation (Solid Oxide Fuel Cells: oxygen ion conductors---inter alia \cite{van_Biert_2019,Wu_2019,Nassef_2019,Lv_2019,Guo_2019,Shen_2019,Ghorbani_2019,Botta_2019,Chaudhary_2019,Mozdzierz_2019,Stoeckl_2019,Xia_2018,Prokop_2018,Lv_2018,Baldinelli_2018,Conti_2019}; and proton conductors---inter alia: \cite{Wachowski_2019,Kultz_Unti_2019,Dzierzgowski_2019,Hakimova_2019} . Modeling attempts according Solid oxide electrolyzers can be found inter alia: \cite{Fogel_2019,Jiang_2019}. Thus we have adapted the fuel cell models (both O=SOFC and H+SOFC) for purpose of the modeling the high temperature electrolysis.
Hydrogen Production in Solid Oxide Electrolyzers coupled with Nuclear Reactors
The analysis considers Pressurized Water Reactors, the scheme is based on two cycles of water/steam and the turbine is powered by non-radioactive steam (see Fig. \ref{424195}). The steam is generated in a special steam generator that allows to obtain saturated steam, rarely slightly overheated. Low parameters of steam requires specific measures to avoid blade erosion. The operation of the turbine in the wet steam area is accompanied by additional energy losses that strongly reduce internal efficiency, in relation to the efficiency achieved in the case of super heated steam, wet steam due erosion causes damage to the flow part, mainly rotating blades. Thus, low steam parameters in the nuclear power plant turbines cooperating with water-cooled reactors, requires modification the thermal cycle of the turbine in relation to the standard steam turbine cycle. The impermissible moisture level of the steam in the turbine, permissible due to the erosion of the flow part and the reduction in efficiency, requires the introduction of external water separators in the thermal system, usually including interstage steam superheated with steam.