Why Iran's claim of not seeking a nuclear weapon lacks credibility?
Iran has said that it'll continue uranium enrichment, which has reached 60%, but claimed it'll not produce a nuclear weapon. As per IAEA, 20% enriched uranium is mostly used in naval propulsion reactors, nuclear weapons and some research reactors, while most commercial reactors use low-enriched uranium, below 5%, as fuel. Uranium enriched to 90% is deemed weapons-grade.