As far as I know, that is correct, and it is what I assumed. Japan also (I suspect) have a ton of enriched Plutonium, acquired from its many nuclear power plants. Also, if we can get enough Uranium for Reactors, wouldn't it be a lot more than enough for bombs too?
There are two huge problem with Plutonium acquired from energy nuclear reactors, one is that it is bound to other elements, and two you'll have not only Pu 239 but also 238 240 and 241, and that Pu-240 is highly fissile and would simply cause a bomb to pre-detonate and fizzle.
Also Japans Nuclear waste and circuit is controlled by the IAEA like in any other country, that doesn't mean that Japan cannot built a nuclear bomb within a couple of year, but that would against the non proliferation agreement and also the peace treaty they signed with the US. It's almost impossible for any country to acquire nuclear weapons, unless the country is willing to pay the price as North Korea
Getting the plutonium necessary to construct a nuke is *much* easier to get than uranium. Building the nuke, however, is insanely complicated.
Access to uranium = very hard; construction = very easy
Access to plutonium = fairly easy; construction = insanely hard
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