Simulations of nuclear reactors created by one physicist take toxic radioactive waste and morph it into the hydrogen isotope tritium, which is otherwise rare and expensive. This means that one of the key factors holding back nuclear fusion from revolutionizing how we produce energy is simply cost. But that problem might finally be solved, thanks to nuclear waste. In an effort to reduce radioactive by-products, physicist Terence Tarnowsky from the Los Alamos National Laboratory wants to put nuclear waste to use. Tarnowsky is planning to develop a molten salt reactor that would use lithium salt as a coolant around the nuclear waste being turned into tritium.