Power cycle assessment of nuclear high temperature gas-cooled reactors

This century power engineering is facing up to one of the greatest challenges ever posed to humankind: the achievement of a sustainable energy system. In order to respond to this challenge, nuclear technology is designing a new generation of power plants termed Generation IV, among them high temperature gas-cooled reactors stand out for their potential capability to achieve an excellent thermal performance. This paper investigates the thermal and economic performance of several direct Brayton cycle configurations that could be used in future HTGRs, with special attention to the effects of inter-cooling and reheating. Among the hypotheses and assumptions taken, the adoption of the PBMR reactor parameters and settings as a reference is particularly important. All inter-cooled layouts have shown thermal efficiencies near or even higher than 50%, which means a substantial improvement with respect to non-intercooled baselines with no economic penalties. Reheating has been shown not to affect remarkably the thermal or economic plant performance under base-load operation, but it provides the plant with such a flexibility that allows its operation under the “load-follow” regime without heavily taxing the thermal or economic performance. Anyway, use of a multiple axes configuration instead of a single one seems to worsen plant economics and not to entail any thermal benefit.