It takes 90%+ enriched uranium to produce weapons and 1-5% for an electricity reactor. Apparently, 20% is to produce medical isotopes (U235 being a good neutron source<i>(1)</i>) or for some specialized naval reactors.<p>It's not yet sure if the Iranians really want to make a bomb or just want to show the capability of building one. Unfortunately, the sanctions and threats of war do nothing but entrench those currently in power there.<p><i>(1)</i> There are ways to produce neutrons other than by enriching uranium, like particle accelerators.