Thorium molten salt reactors
Thorium salt reactors have been researched since the late sixties and have been proven to work, and damn cheap and safe to run, you could run your whole life on just $100 of thorium from food to electricity and vehicle etc. Salt reactors rely on high heat, low pressure and with the melting point of salt at 800 degrees any pressure loss not only stops the thorium reaction but the salt also solidifies and clogs up any holes or cracks in the system preventing a meltdown in the normal sense. Thorium reactors are very efficient using nearly all of the thorium % wise. Waste from archaic reactors we still use can also be added to the reactors to further brake them down. Waste from thorium reactors is minute compared to nuclear reactors in use today that only use 3% of the fuel, the rest is waste that can take thousands of years to degrade.