Nuclear energy conversion with stacks of graphene nanocapacitors

The efficiency of conventional techniques used to harvest energy in nuclear reactors lies around 35 percent. This limit exists because the nuclear energy is converted to electrical energy via heat engines. We study an alternative approach where the kinetic energy of nuclear reaction products is directly converted into electric energy in a stack of charged capacitors with a gap size of 500 nm and graphene electrodes. Graphene is expected to be chemically and mechanically stable in high radiation environments because it’s tensile strength of 130 GPa is very large, about 100 times larger than most metals. The dielectric strength of such nano-capacitors exceeds 1 GV/m, because avalanching is suppressed at small gap sizes. In a 1 GV/m electric field charged nuclear reaction products, such as 5.6 MeV alpha particles, come to rest in of a stack with 5000 nano capacitors. We show that during the deceleration process more than 90 percent of kinetic energy of charged nuclear reaction products is converted to electric energy and stored as electric energy in the stack. Each stack is 2.5mm thick and produces a high-voltage DC current. A device with a 1 Ci 241Am source is expected to generate 22 mW of electric power.