For boosted fission weapons, the size of the centrally placed initiator is critical and has to be as small as possible; replacement with an external neutron source allows for more flexibility, such as variable yields.
The size of the centrally placed initiator is critical. This is for boosted fission weapons. The size of the centrally placed initiator has to be as small as possible. This is for boosted fission weapons. Replacement with an external neutron source allows for more flexibility. This is such as variable yields.