Group 1 - The International Atomic Energy Agency claims that Iran possesses approximately 400 kilograms of uranium enriched to 60%, prompting military actions from Israel and the United States against Iran's nuclear facilities to halt its uranium enrichment process [1] - Uranium enrichment is the process of increasing the proportion of uranium-235 in natural uranium, which is essential for both civilian nuclear power generation and military nuclear technology [1][2] - Natural uranium primarily consists of two isotopes: uranium-238 (99.28%) and uranium-235 (0.71%), with uranium-235 being capable of sustaining a chain reaction and releasing significant energy [1][2] Group 2 - The majority of the world's known uranium resources are concentrated in Australia, Canada, Kazakhstan, Namibia, and Russia, with only uranium deposits containing over 0.05% uranium being economically viable for extraction [2] - The main method for industrial uranium enrichment is gas centrifugation, which separates uranium isotopes based on their slight mass difference, utilizing high-speed centrifuges that can exceed 100,000 RPM [2] - Enriched uranium with a concentration below 20% is primarily used for civilian purposes, while concentrations above 20% are used for military applications, with weapons-grade uranium requiring over 90% enrichment [3] Group 3 - Achieving weapons-grade uranium is only the initial step in a nuclear weapons program, as subsequent challenges include complex weapon design, material development, miniaturization, and testing for reliability [3] - The process of enriching uranium from natural levels (0.7%) to 20% requires significantly more effort than further enriching it to 90%, indicating a critical point in nuclear proliferation [3] - Effective nuclear deterrence necessitates ensuring that a nuclear arsenal can survive an initial strike and maintain a reliable second-strike capability [3]