Trapped, Trapped? How about pureed? Well, they said they were trying to enrich URANIUM-——now they know what critical mass means——maybe. At the very least they are learning about high powered machinery-—the hard way. Famous last words: Hey Parveez-—try to spread out those shiny bricks when you stack them——woops.
It’s extremely unlikely that this was a nuclear explosion in the conventional definition.
It may be a kinetic event or conventional explosion that dispersed nuclear material.