NASA’s Plutonium Problem Could End Deep-Space Exploration

[DetlefK]

1. How a plutonium-battery works:

It's the thermoelectric effect.

You need two wires, made from different metals, e.g. iron and copper.
Connect them on one end.
Heat that point, e.g. with a piece of plutonium that's lukewarm from radioactive decay, but make sure that the other ends of the wires are unaffected.
The temperature-difference leads to a shift in electron-density, which is visible as an electric voltage between the untampered ends of the wires.
Connect an electronic device, e.g. a lamp, to the loose ends of the wires and it will run as long as the temperature-difference is upheld.