Two Paths to a Nuclear Bomb Iran has historically pursued work on both uranium- and plutonium-weapons programs, Western ocials say. The 2015 nuclear deal set temporary limits on a wide range of Iran's nuclear work and committed Tehran to never work on nuclear weapons. Here's how far down those paths Iran is. Creating weapons-grade nuclear fuel Uranium 1 Low-grade uranium ore is 2 Centrifuges are set up in 3 Enriching uranium to 5% is the 4 It takes roughly 200 kg to 250 kg of 20% mined and chemically treated cascades to enrich the uranium. most time-consuming part of enriched uranium to produce the 25 kg of to produce a concentrated The sophisticated process can producing weapons-grade material. 90% enriched uranium, the amount needed yellowcake. After a conversion take years to establish. Iran Iran on Monday exceeded its for a bomb. Iran has reached 20% purity in process, it is fed into produced around 20,000 basic permitted 300-kg stockpile of the past but has never enriched above that centrifuges. centrifuges but is doing research uranium enriched to 3.67%. level. The enriched uranium is converted to Weaponizing nuclear fuel on more advanced machines. uranium metal for weapon use. Deploying the nuclear fuel in a Centrifuges weapon presents technical challenges, many of which Iran isn’t believed to have mastered. Detonating the 5% enriched Uranium Yellowcake Uranium 20% weapon requires a fission ore hexaflouride uranium 90% reaction. The nuclear payload 25kg must be attached to a missile, and the payload must be able 200-250 kg to withstand reentry through through earth's atmosphere as Plutonium it descends to its target. 1 Heavy-water reactors produce plutonium as a waste 2 To create pure plutonium, the plutonium 3 The pure plutonium is melted into a liquid Nuclear payload product. Iran never finished its Arak heavy-water reactor so it waste is chemically separated and extracted form that is poured into a mold designed for never produced plutonium. Under the 2015 deal, it agreed to from radioactive spent-fuel assemblies at a use in a nuclear weapon. remove the Arak reactor core and build one that would reprocessing plant. produce less plutonium. Re-entry vehicle Deuterium oxide Natural Plutonium waste uranium Reprocessing plant Pure plutonium Pure plutonium Plutonium Weapon Heavy-water reactor liquid mold Roque Ruiz/THE WALL STREET JOURNAL.