That said, it is a risky proposition for even the most well-versed lawyer to expound on nuclear technology, so I will confine my explanation of the nuclear fuel cycle to a simple series of steps.
1. Mining: Uranium ore is extracted from the ground. As it occurs in nature, uranium is predominantly made up of the uranium-238 isotope. Only about 0.7 percent is uranium-235, which is “fissile,” meaning it can sustain a nuclear chain reaction.
2. Milling: The ore is processed, by grinding and chemical leaching, to produce “yellowcake,” a uranium concentrate.
3. Conversion: The yellowcake is transformed, through a series of chemical processes, to uranium hexafluoride (UF6) gas, the feedstock for centrifuge enrichment. The UF6 at this stage is still considered “natural uranium,” since the relative concentrations of U-238 and U-235 have not changed.
4. Enrichment: As the UF6 is fed through centrifuges, the concentration of U-235 is increased, correspondingly decreasing the concentration of U-238. Enrichment makes the uranium more capable of generating nuclear energy.
5. Fuel fabrication: The enriched uranium is converted into powder, processed into ceramic pellets, and inserted into fuel rods, which are then arranged into fuel assemblies that will power a reactor core.
6. Storage: After being used in the reactor, the depleted nuclear fuel—now mostly U-238, with not enough U-235 remaining to sustain the reaction—is usually stored in a “spent fuel pool.” Depleted fuel also contains about 1 percent of fissile plutonium, created as a by-product in the reactor.
7. Reprocessing: Since only a small percentage of the nuclear energy is used up in a normal reactor cycle, some countries recycle the spent fuel, recovering (or “separating”) the uranium and plutonium for reuse.
The gas centrifuges used in uranium enrichment[4] resemble tall, skinny metal cylinders with inlet and outlet piping attached. They spin at enormous speeds—more than twenty thousand revolutions per minute, fast enough that the atoms of uranium-238, three nucleons heavier than uranium-235, move to the outside of the tube and can be separated out as they exit. When multiple centrifuges are lined up in a row, or in a “cascade,” the UF6 gas passes from one to the next and is gradually “enriched” to a higher percentage of U-235. Since U-235 makes up only a tiny percentage of natural uranium, it takes a very large volume of incoming feed material to produce even a very small volume of enriched product. This requires the centrifuges to spin for weeks and months at a time, which means they are not easy to design or construct and can be made only of special metals that can withstand the stresses.
Most light water reactors, which use nuclear fuel to produce electricity, require uranium enriched to about 3.5 percent U-235. “High-enriched uranium,” or HEU, refers to any enrichment level above 20 percent. Uranium enriched to 90 percent or greater is usually considered weapons grade; however, many research reactors worldwide also use 90 percent enriched uranium fuel for peaceful purposes, such as to produce medical isotopes.
Contrary to the most common misconception, steps 1–7 are all elements of a peaceful nuclear fuel cycle. Despite what is at times implied in the press, uranium enrichment (or, for that matter, plutonium separation) does not inherently signal the intent to develop nuclear weapons. Since plutonium and HEU are the nuclear materials that can be used most directly in nuclear weapons, the two most proliferation-sensitive aspects of the fuel cycle are correspondingly reprocessing, in which plutonium is separated, and enrichment, which can make HEU. But both HEU and plutonium can also be used in reactor fuel, to generate electricity. Thus none of these fuel cycle operations is “illegal”; they are all within the rights of any member of the NPT. There are, of course, caveats: the relevant facilities and activities must be “declared,” or reported, to the IAEA, and safeguards must be in place to verify that the nuclear material involved is accounted for and has not been diverted for use in weapons.
Roughly a dozen countries have significant nuclear fuel cycle operations. A fair number of non-nuclear-weapon states therefore have stockpiles of plutonium (separated out through reprocessing spent nuclear fuel), or HEU, which could readily be applied to a nuclear weapons program. And as more countries industrialize and nuclear knowledge spreads, still more governments are likely to consider the economic and other strategic advantages that come with owning the nuclear fuel cycle.
This is where the plot thickens. With the spread of nuclear technology comes an increased proliferation risk. Thus those states that already have the nuclear fuel cycle do not want to give it up but would prefer that no other countries acquire it. The have-nots resent this stinginess. And indeed, under the NPT bargain, the haves who possess peaceful nuclear knowledge and technology are obliged to share it. The have-nots resent, most of all, that the nuclear-weapon states have failed to keep their part of the bargain, to negotiate “in good faith” and “at an early date” toward nuclear disarmament. The haves enjoy a status that other countries might well envy, since nuclear weapons have become synonymous with political clout and power and an insurance against attack.
In hindsight, the emergence of the first clandestine nuclear programs in Iraq and North Korea in the early 1990s perhaps should have been no surprise. With the cold war winding down, the balance of power between the Soviet Union and the United States could no longer be relied on to maintain a relative peace. Countries not explicitly protected under a “nuclear umbrella,” such as that provided to members of NATO or other U.S. allies, might understandably have been experiencing an increasing sense of insecurity. What better insurance policy than to develop nuclear weapons in secret?
This was the context in which Iraq’s nuclear program was discovered at the end of the 1991 Gulf War. While the United States had mentioned Iraq’s emerging nuclear ambitions as one of many reasons for military action,[5] in fact very little was known about Iraq’s actual nuclear capabilities before the war. Some in the U.S. intelligence community reportedly presumed that Iraq had nuclear weapons ambitions—based on, among other indications, attempts made by Iraq to acquire nuclear enrichment components and other nuclear technology from a number of European countries.[6] No such information, however, had been presented to the IAEA. In the month or two before the war, a number of media outlets began making wild and unsubstantiated reports about Iraq’s specific nuclear capabilities.[7] But perhaps the best indication of the extent of prewar Western intelligence is that the United States was reported to have had only two nuclear sites on its list of targets to bomb, whereas, in the postwar inspection, as many as eighteen nuclear sites would be identified by the IAEA. In fact, it was Saddam Hussein’s invasion and occupation of Kuwait that provided the primary justification for the U.S.-led coalition to invade.
On April 3, 1991, less than two months after the end of the war, the UN Security Council issued a sweeping set of terms with which Iraq was to comply. Naturally, this included obligations such as respecting the Iraq-Kuwait boundary, returning Kuwaiti property, and compensating Kuwait for injury, damage, and loss. But a major part of the resolution was devoted to the council’s demands that Iraq rid itself of weapons of mass destruction.
In the nuclear arena, Resolution 687 called on Iraq to come clean—to declare fully all of its nuclear facilities and its weapons-grade nuclear material. It asked the IAEA Director General to carry out immediate inspections based on Iraq’s declarations and to develop a plan within forty-five days to destroy or remove from Iraq any nuclear-weapon-related capabilities. The resolution also established UNSCOM, the United Nations Special Commission, which was charged with a similar mission related to Iraq’s biological and chemical weapons programs and long-range missile delivery systems.[8]
5
Soon after the bombing commenced, on January 16, 1991, President George Herbert Walker Bush said the following on national television: “We are determined to knock out Saddam Hussein’s nuclear bomb potential.” Quoted in David Albright and Mark Hibbs, “Iraq and the Bomb: Were They Even Close?”
6
“Early Western Assessments: What Did We Know and When Did We Know It?” Federation of American Scientists, retrieved at www.fas.org/nuke/guide/iraq/nuke/when.htm.
7
A good example was that of William Safire, claiming in the