Nuclear Forensics - Tracking Radioactive Threats

Nov 1, 2014

The Rock Doc, Kirsten Peters
Credit Washington State University

How do you catch and prosecute someone illegally trafficking nuclear materials? You could catch them uranium-handed… except that granite also contains traces of uranium. That’s the challenge of nuclear forensics: telling what’s evidence of nuclear material, and what’s just background noise. WSU’s Nathalie Wall is a chemist who handles nuclear forensics. The Rock Doc, Kirsten Peters, brings us her story.  

As a kid, I read the Sherlock Holmes stories and the mysteries of Agatha Christie. As an adult, I wrote four mysteries that focused on a Quaker heroine solving crimes she happened across in her religious community. As a geologist, I’ve read about real-life criminal investigations that involved samples of sand and soil.

But it wasn’t until I talked with Dr. Nathalie Wall of the chemistry department at Washington State University that I got my head around forensic science that relates to radioactive materials.

Here’s what she said to me: “The basic definition of forensics is that it gives you information about the past. The best known type of forensics is the criminal kind.”

Nuclear forensics is the study of radioactive materials found on places like a suspect’s hand. The goal is to develop information about such things as the source of the nuclear material. One part of the research Wall does is to help develop techniques that can be used for prosecution of people linked to illegally transporting or trafficking in radioactive substances.

As Wall told me, “You can’t arrest someone just for having a trace amount of uranium on their hands. There is uranium in granite, so a person can pick up trace amounts of it just from handling rocks.”

That’s part of the reason why it can be much more complicated to make a legal case against a person for dealing in radioactive materials than it can be to prove other kinds of criminal case.

“The cool thing about nuclear chemistry is that radioactive elements come in sets,” Wall said to me. “If you find a specific suite of elements of different proportions, you can potentially tell where the material came from and what it’s been used for.”

Wall’s work is in the chemistry of various radioactive elements. She collaborates with people who make sophisticated devices for testing trace samples of materials.

“Just as the TSA may swipe your hand to see if you’ve touched conventional explosives,” Wall said, “our goal is to develop tests for trace amounts of radioactive isotopes. Part of the challenge is to make the tests both accurate and fast.”

Wall got a start in the research world working on nuclear repositories and contaminated sites. Nuclear forensics has been a recent addition to her work.

“From a chemist’s point of view, it’s all the same story,” Wall said.

Wall’s work is part of a broader who-done-it effort that’s important to all of us. I’m glad she and others like her are at work on real-life investigatory techniques that can stop terrorists. 

Dr. E. Kirsten Peters, a native of the rural Northwest, was trained as a geologist at Princeton and Harvard. This column is a service of the College of Agricultural, Human, and Natural Resource Sciences at Washington State University.