While it is possible to design a bomb without access to knowledge the atomic powers keep secret[1], if you get it wrong it&#x27;s a really costly mistake to make, both in materials and time. Documentation for a tested design seems very valuable.<p>[1] the US military had a pair of physics PhDs try to design a bomb sometime in the 60s, and apparently they succeeded, but that is only one data point. Not sure if there is any public knowledge about other states&#x27; nuke programs.