How Can We Tell If a Country Is Making Nuclear Power Or Nuclear Weapons?

Bombs or Power?: Centrifuges are usually arranged in a triangular cascade; the layout tips inspectors to its purpose. Weapons require heavily enriched uranium, so the triangle is long and narrow; power takes more fuel, so the cascade is short and fat. McKibillo

From Popular Science:

It's all about enrichment.

Just about everyone insists that Iran’s nuclear program is aimed at building weapons. Iran claims it only wants nuclear power. So how do weapons inspectors get at the truth? They study the country’s supply and treatment of uranium, one of the most abundant nuclear materials on the planet.

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