Topic summary
Implosion bomb
Extracted from the Wikipedia article Nuclear weapon design.
Layer cake
The layer cake was an early design for a weapon using thermonuclear reactions, involving an spherical implosion bomb design that contained alternating layers of fission and fusion fuel. As a single-stage device, it was only capable of generating a limited amount of fusion reactions and could not be scaled up indefinitely, and has been equated with boosted fission weapons. It could, however, provide interim capability for high yields, mostly from the low-cost materials of lithium deuteride and natural or depleted uranium, as opposed to expensive fissile material.