Multifunctional backup electricity supply for NPP auxiliary needs based on combined-cycle power plant with hydrogen overheating

Abstract

Approach is suggested of combining nuclear power plant with combined cycle gas turbine unit and hydrogen producing complex which, while operated in normal conditions, give the possibility to increase plant capacity and, in case of complete blackout, to ensure supply of electricity for covering auxiliary needs of the NPP. It is suggested to use hydrogen for overheating generated steam by exhaust gases of the gas turbine plant included in the composition of the combined cycle gas turbine unit. Combined cycle gas turbine unit must be installed beyond the NPP site. Hydrogen is to be generated by electrolysis of water using cheap off-peak energy produced by the NPP during nighttime, following which hydrogen will be efficiently used during the day for enhancing parameters of steam before the gas turbine included in the composition of the combined cycle gas turbine unit.Probabilistic assessment was performed of reliability of the proposed system in the conditions of loss of power supply for the case of joint use of the combined cycle gas turbine unit and emergency electric power supply channels equipped with diesel generators.The proposed system allows ensuring supply of electricity for covering auxiliary needs of the NPP during more than 72h. Use of the steam turbine plant included in the composition of the combined cycle gas turbine unit is possible for covering auxiliary needs of the NPP in case of failure of gas turbine plants. Steam turbine can be operated due to the generation of additional steam during incineration of hydrogen in oxygen. With appropriate modernization the system allows using decay heat released in the nuclear reactor core. It was established that the proposed option of combining NPP with combined cycle gas turbine unit in combination with hydrogen generating complex allows enhancing reliability of supply of electricity for covering auxiliary needs of the NPP in emergency conditions accompanied with loss of electric power supply.