[Daniel_sk]

Plutonium doesn't explode on itself. Unless you pack it into the complicated mechanism of a nuclear bomb device. Other than that you can do what you want, wrapping it in explosives and firing them will just disperse the plutonium but it will not make a chain reaction.

[hunter-2]

I'm no expert on the subject, but do you think the plutonium being buried under several tons of ice could cause it to explode?

[manwe150]

My layman’s understand is you need a neutron trigger to destabilize it rapidly, as well as a shell to contain it to get a stable chain reaction going. I think you typically need to be at the center of a an exploding star to see that happen just from pressure.

[AareyBaba]

"Radioisotope thermoelectric generator" is what you want to understand. There are plenty of youtube videos on this topic.