How can Polonium 210 leak from a sealed container?
The alpha particles emanating from Polonium 210 produce such an immense amount of heat as they bounce off the walls of their container that in a few weeks a gram of Polonium 210 can self-heat to 600 degrees Celsius. That is why the Soviet Union planned to use Polonium 210 to heat its Lunar module. The self-heating property also exerts pressure on its container and over time can breach the seal.
