November 24, 2014 is a looming deadline for Iran, Israel, the United States and the world over its nuclear weapons program. Just hours ago, the International Atomic Energy Agency [IAEA] released a report summarized by its conclusion: “The Agency is not in a position to provide credible assurances about the absence of undeclared nuclear material and activities in Iran, and therefore to conclude that all nuclear material in Iran is in peaceful activities. Iran has not provided any explanations that enable the Agency to clarify the outstanding practical measures, nor has it proposed any new practical measures in the next step of the Framework for cooperation.”
Under Secretary of State Wendy Sherman, leading the international negotiations, has described the back and forth as “a forest of distrust.” At the same time, she declares, “Our bottom line is unambiguous … Iran will not, shall not obtain a nuclear weapon.” In the background, media revelations disclose secret correspondence between the Obama White House to Iran’s Supreme Leader Ayatollah Ali Khamenei — kept even from Congressional leaders and America’s closest allies and Israel. Washington is struggling to enlist Tehran in the faltering campaign against the Islamic State. This process has juggled agreed numbers of centrifuges — a limit of 4,000 … or is it 10,000 … or is it something in between? Centrifuges are a critical component because each vertical cylinder slowly but steadily distills uranium into a highly enriched weapon-ready state.
However, as the world ponders Iran’s dash to enrich more kilograms of uranium, the underlying concern is not so much about the enrichment process itself, but the end product: a nuclear warhead. Iran has been developing its warhead for some sixteen years. That design is nearly perfected.
Compare the process to gunpowder. To use gunpowder, you need load it into a cartridge, load the cartridge and a bullet into a rifle, and then find a marksman. Iran has nearly mastered all those steps — but in nuclear terms.
Four technological achievements are key to completing Tehran’s nuclear weapon:
1) accretion of enough nuclear materials, highly enriched to weapons-grade or 90 percent; 2) machining that material into metal for a spheroid warhead so it can fit into a missile nosecone; 3) developing a trigger mechanism to initiate the atomic explosion at a precise moment during missile reentry; and, of course, 4) a reliable delivery system.
Start with the nuclear material. Experts estimate that a single bomb would require approximately 25 kilograms of Highly Enriched Uranium, or HEU, with a U-235 concentration of at least 90 percent. Much of Iran’s nuclear enrichment remains at 3.5 and 20 percent levels. But the numbers are deceiving. Enriching to 3.5 percent is 75 percent of the task of reaching weapons-grade. Once Iran has reached 20 percent, it has gone 90 percent of the distance. Indeed, Iran’s President Hassan Rouhani made a 2005 speech in his capacity as National Security Advisor in which he declared, “a country that possesses fuel cycle technology can enrich uranium —and the country that can enrich uranium to about 3.5 percent will also have the capability to enrich it to about 90 percent.” Today, Iran possesses enough nuclear material for a fast “break-out” that would finish the job, creating enough for five or ten bombs, in about six weeks.
Second, that HEU must be metalized and shaped into a dense spheroid compact enough to fit into a missile nosecone. Iran has mastered the metallurgical techniques using other high-density metals such as tungsten, which have been test-detonated in a special chamber to measure their explosive character.
Third, the spheroid must be detonated. Iran’s warhead design employs a R265 shock generator hemisphere drilled with 5mm boreholes that are filled with PETN— pentaerythritol tetranitrate, an organic high explosive favored by terrorists. When triggered with precision, the PETN array can cause a massive synchronized implosion. That will fire an internal exploding bridgewire which will in turn actuate an embedded neutron initiator to detonate the atomic reaction—and