Plutonium is more easily manufactured than highly enriched Uranium if you're just starting out. If you have the industry set up, then it's easy peasy. In the de

Plutonium is more easily manufactured than highly enriched Uranium if you're just starting out. If you have the industry set up, then it's easy peasy. In the developed world there's Uranium enrichment facilities everywhere and in nuclear powers they have HEU up to their ears. Indeed, a lot of modern bombs (which are entirely implosion based) use HEU extensively in their design. Generally, they tend to still use Plutonium in the primary mostly because it saves on size and weight, which is hugely advantageous when it comes to long range ballistic missile delivery. But most compact sub-megaton thermonuclear weapons derive the majority of their yield from HEU in the secondary.