Certainly 'self-sufficient' is inaccurate, given the reliance on external inputs.
If other nation states are also not self-sufficient for fissionable materials, and/or other fuel types, then I would also not call them self-sufficient on power generation.
Sure, there are degrees of reliance on providers of fuel types, but no need to muddy the waters about self-sufficiency. (f.e. Australia could be self-sufficient on solar, wind, coal, fission, I suspect - at least in terms of raw materials.)