How do chemical explosives differ from nuclear explosives?

Chemical and nuclear explosives differ fundamentally in the physical processes they use to release energy.

Chemical explosives function by undergoing extremely rapid chemical decomposition, which produces a large volume of expanding gas in a very brief period. These are categorized as either detonating (high) explosives, such as TNT or dynamite, which create high pressure, or deflagrating (low) explosives, such as black powder, which burn rapidly. They are the standard for most engineering and military applications.123

Nuclear explosives release energy through nuclear fission, nuclear fusion, or a combination of both. Unlike chemical reactions, these involve changes to the atomic nucleus. In fission, a critical mass of material like uranium or plutonium triggers a runaway reaction. Hydrogen bombs utilize a fission primary to trigger a fusion secondary, releasing significantly more energy than atomic bombs or any chemical explosive.45