[Procyon]

You don't need a detonation, which would be noisy and attract attention by the blast damage. Instead, you could have a thermite bomb that melted the radioactive material and spewed it into the atmosphere (similiar to a Chernobyl or uncontained Three Mile Island incident). The affected area would be many square miles. And a real mess to clean up.

[Protect the Bill of Rights]

Nasty...