Load follow with gen-iv very high temperature gas cooled reactor for the spanish future power mix

Abstract

The future power mix in Spain and most of the European countries is expected to be dominated by renewable sources. The Spanish government has set a policy to eliminate fossil fuels and nuclear power in the following decades by means of increasing the installed capacity of renewable energy, mainly solar PV and wind. The high penetration of these technologies in the power mix may cause a mismatch between demand and production that can be hardly overcome by the use of batteries or other non-thermal storage systems. Very high temperature Gas cooled reactors (VHTR) are one of the most attractive options of Gen-IV reactors for several reasons including the superior safety, near term deployment and high thermal efficiency. But another important advantage is their possibility of load following thanks to the use of gas turbines and the possibilities for thermal storage. In this publication, an innovative design of the thermal cycle of a VHTR is presented. The thermal circuit configuration is modified to maximize the flexibility of the reactor thanks to a molten salt thermal storage and the inherent flexibility of the use of a gas turbine. In addition, the thermal storage can also be fed by a solar field of mirrors. To demonstrate the adaptability of the power plant, the power generation of Spain in a hypothetical future has been used to represent the variability that should be provided by a power plant needed to support the high penetration rate of renewable power. The power plant showed great capabilities for load following hour by hour with changes from 0 to 100% without the need to change the nuclear thermal power. This type of power plants may support renewable sources while guaranteeing the net zero emissions objective.