When it’s ready, experiments at Scorpius will be similar to DARHT but with the added complexity of using subcritical amounts of plutonium instead of surrogate materials.

They basically explicitly say that without just coming out and saying it. This kind of hyper fast explosion analysis and photography is a big part of making implosion bombs work properly.

edit: actually they just say it, they don't have to be coy everyone knows the US and other countries study this and it doesn't violate the NTBT because it's sub critical.

essential to the Lab’s stockpile stewardship mission because it helps scientists test and understand the fundamental characteristics of materials and explosive events to inform computational models and analyses without ever detonating an actual weapon.