Analyses of static energy conversion systems for small nuclear power plants

Abstract

Small, Gas Cooled Reactor (GCR) nuclear power plants with static energy conversion could meet the energy mix in underdeveloped countries, including electricity, residential and industrial space heating, seawater desalination, and/or high temperature process heat or steam for industrial uses. Analyses are performed of one high-temperature GCR and three intermediate-temperature GCR power plants with co-generation options to calculate and compare the total energy utilizations of the plants. Conversion of the reactor thermal power to electricity is accomplished using static energy conversion units comprised of an Alkali Metal Thermal-To-Electric topping cycle and a Thermoelectric bottom cycle, as well as segmented thermoelectric converters. The calculated total energy utilization of these plants of 95% includes low-voltage (∼ 400 V) DC electrical power at a net plant efficiency of up to 32.7%, and co-generation for residential and industrial space heating at < 400 K, desalination at 365 K, and/or high temperature process heat or steam at > 500 K. Results indicate that the intermediate-temperature GCR plants with a small coolant temperature rise of 100 – 160 K in the reactor core could deliver 2–3 times the electricity of a GCR plant with a higher temperature rise of 340 K, and that all plants could provide for both seawater desalination and high temperature process heat/steam concurrently. In addition, depending on the number of co-generation options employed, the fraction of the reactor thermal power used for co-generation in the high-temperature GCR plant is ∼ 10–30% higher than in the intermediate-temperature GCR plants with a smaller temperature rise in the reactor.