Unlike fission or fission-fusion nuclear weapons, the nuclear weapon used in the film appears to be an ultra-low yield pure fusion weapon. Pure fusion releases energy like conventional nuclear weapons but doesn't require fissile materials such as Plutonium or Uranium and therefore produce no fallout. This allows the Mobile Infantry to destroy huge Plasma bugs and then immediately rush into the area in the early stage of the Klendathu Offensive.
The weapon system is packed as a smart missile, which is small but extremly maneuverable, and comes with M55 Rocket Launcher, the reusable main launcher. The missile is detonated with a proxy fuse with impact fuse as optional.
- Starship Troopers (film)