“How can we make nuclear reactors that produce more fissionable material then it consumes?”
Nuclear reactors are commonly thought of as non-renewable resources. However, if we invest in technology the resight way, then we can do some very creative things. Since flying neutrons can be absorbed by non-fissionable Uranium 238 and be turned into fissionable Plutonium 239, placing these with Uranium 235 can allow for more fissionable material to be created over time. Reactors that use this process are called Breeder Reactors and have been developed in France.