The recent arrest of three men in Slovakia charged with trying to sell enriched uranium has renewed interest in “dirty bombs.” These are conventional bombs that have been wrapped with radioactive material. When the bomb detonates, the material is dispersed over an area making it unfit for use and possibly causing anybody in the area to suffer radiation poisoning.

It’s a scary topic, but the recent incident raises several questions.

1. How suitable is enriched uranium for making dirty bombs? My understanding is that it isn’t very suitable at all: A dirty bomb dispersing enriched uranium might spread terror among the uninformed but would not deliver a significant dose of radiation. In a short time, the fear level should drop as people see that there isn’t a threat.

Here’s one typical quote on the non-lethality of enriched uranium:

Alexander Glaser, a researcher at Princeton University’s Program in Science and Global Security, said any discussion of dirty bombs in this case was “off topic.”

“Even naturally occurring uranium would be more effective than this in making a dirty bomb,” he said.

2. Why, then, are some people fanning the flames? This, for example, is from an article today in an Israeli publication:

A “dirty bomb”, which is essentially a low grade nuclear weapon, is far less lethal than an atomic bomb, but can still lead to massive casualties and injuries should it be employed. … Only last Wednesday, three suspects were arrested at the Slovak-Hungarian border after trying to sell roughly a pound of enriched Uranium, typically used as fuel in nuclear facilities. Enriched Uranium is a prime ingredient for “dirty bombs” and other nuclear weapons.

In fact, a dirty bomb isn’t any grade of nuclear weapon. It’s a conventional explosive with radioactive stuff packed around it. In particular, it doesn’t produce any nuclear blast effect and it doesn’t produce any additional radiation.

3. One thing we all agree on is that there is a lot of real dirty bomb material floating around the world, much of it from medical use. If there is so much of it, and if making the bomb is trivially easy once you have it, why hasn’t anybody done it?