Most ships use H-Fuel for main power and propulsion, which is a fusion based fuel. Battleships also tend to use MOX, which suggests a battleship weapons array has such a strong power demand that it requires an auxiliary power source. Neither of these are antimatter based. While an antimatter reactor could provide power a few orders of magnitude higher then that of a H-Fuel based one, the fuel reserves are immensely difficult to store, and detonation of a fuel reserve inside a ship would likely waste an entire system (such as the warning of the Nansei card indicates).
Nasty thought: Gallic strike team makes Nansei go -KABOOM-, which cuts off Kusari reinforcements heading to the Taus.
Most antimatter is used in the heaviest anti-capital weapons - SNACs, Razors, Mortars. These have huge power requirements - presumably because antimatter generation is quite a hog on the power systems.
Wide awake in a world that sleeps, enduring thoughts, enduring scenes. The knowledge of what is yet to come.
From a time when all seems lost, from a dead man to a world, without restraint, unafraid and free.
Mostly retired Discovery member. May still visit from time to time.