The minimal amount of nuclear material needed for a sustained nuclear chain reaction is called the critical mass, which depends on the material’s properties, shape, density, and surroundings. For example, a bare sphere of highly enriched uranium-235 requires about 50 kg to reach criticality under normal conditions.
The drones can carry up to 100kg for 700km, which I understand that includes the weight of the containment.
And how many kg do they have, total, at 60%? And what’s critical mass for 60%? And when do you think they’re going to find time to get it to 90% - after they get it out of the collapses tunnels?