According to The Washington Post, Iran’s production of enriched uranium has increased “dramatically.” The shift occurred after President Trump canceled the Iran nuclear deal that limited Iran’s nuclear pursuits. Nuclear weapons involve energy density and dirty bombs.
The article in The Washington Post said that Iran’s uranium program has ramped up over the last several months. “Inspectors from the International Atomic Energy Agency reported a near-tripling of Iran’s stockpile of low-enriched uranium just since November, with total holdings more than three times the 300-kilogram limit set by the nuclear accord,” the article said. “Iran also substantially increased the number of machines it is using to enrich uranium, the agency said, allowing it to make more of the nuclear fuel faster.”
Nuclear weapons are incredibly intricate and involve advanced knowledge of chemistry, but some of their fundamentals are understandable to anyone.
Nuclear Bombs: Why and How
Nuclear bombs are called “nuclear” because they rearrange the nuclei of atoms. The main reason we develop nuclear bombs is because of their energy density.
“One kilogram of chemical explosives can liberate four million joules,” said Dr. Lawrence Weinstein, Professor of Physics at Old Dominion University. “That’s 10 times less than the energy in gasoline, but that’s because chemical explosives don’t need oxygen from the air and can release their energy much more rapidly than gasoline.”
Dr. Weinstein said this is where we get the definition of a “kiloton,” a unit of measurement in nuclear physics. A kiloton is 1,000 tons of chemical explosive. “That’s a million kilograms, so that’s 4 x 1012 joules,” he said.
In terms of energy density, one kilogram of uranium-235 contains 3 x 1024 nuclei. “We get 200 million electron volts of energy released from each nuclear fission, so we multiply that by 200 MeV, and that gives us 6 x 1026 MeV, which is about 1014 joules,” Dr. Weinstein said. “That’s 30 million times more energy released than is released from a kilogram of TNT. Now, not all of the uranium is going to fission, so we have to divide by a little, but that’s still a lot more.”
Dirty Bombs 101
As forceful as chemical explosions are, not all nuclear weapons are used solely for their release of energy. Dirty bombs have also been developed. For purposes of this discussion, a radioactive substance’s activity is measured in a unit called a curie and a dose of absorbed radiation is measured in rems.
“A dirty bomb is not a nuclear explosion; it uses conventional explosives to disperse radioactive material, spread the radiation over a large area, and contaminate the ground,” Dr. Weinstein said. “For example, if we had 1000 curies of caesium-137 and dispersed it over about a square kilometer—so about 20 football fields—then the dose that we would get would be about 20 millirem a day, or about 10 rem a year.
“Now, of course, it wouldn’t be spread out evenly, but if we just say 10 rem a year, that increases the probability of getting a fatal cancer by 0.5% during your lifetime for each year that we’re exposed.”
This number may seem small, but Dr. Weinstein pointed out that the high dosage isn’t always the only cause for concern.
“The worst effects of Chernobyl and Fukushima were due to evacuation and disruption of life, so it’ll cause lots of fear and panic,” he said. “These are weapons of mass disruption, not mass destruction.”
Dr. Lawrence Weinstein contributed to this article. Dr. Weinstein is a Professor of Physics at Old Dominion University (ODU) and a researcher at the Thomas Jefferson National Accelerator Facility. He received his undergraduate degree from Yale University and his doctorate in Physics from the Massachusetts Institute of Technology.