Each Mars Rover uses 5 kilograms of plutonium 238. (Plutonium 239 is the one that is used in nuclear bombs.) Per https://www.wired.com/story/nasas-mars-rover-

Each Mars Rover uses 5 kilograms of plutonium 238. (Plutonium 239 is the one that is used in nuclear bombs.) Per https://www.wired.com/story/nasas-mars-rover-will-be-powered-by-us-made-plutonium/ https://www.wired.com/story/nasas-mars-rover-will-be-powered... we currently have a lab dedicated to producing it, and it makes 3.5 pounds per year. Per https://www.npr.org/2011/11/08/141931325/the-plutonium-problem-who-pays-for-space-fuel https://www.npr.org/2011/11/08/141931325/the-plutonium-probl... the cost of getting the lab restarted was a bit shy of $100 million. And once running fully it costs millions of dollars to run. At those cost points it would be cheaper to deliver you a brand new fridge each month for the next 20 years than to deliver you a single fridge using plutonium to run without external electricity for the same 20 years. Not to mention that the plutonium itself is toxic.