Nuclear Weapons 690 - Newly Developed Technique Can Tell Whether A Building Has Been Used To Store Highly Enriched Uranium
The detection of radioactive materials is an important area of research. The ability to tell whether or not a shipping container contains radioactive materials is of great importance in preventing the smuggling of nuclear materials that may be used by terrorists for dirty bombs or actual atomic bombs. New tools and procedures are being developed all the time.
A newly published paper explains how tiny samples of building materials like tile or brick can be used to determine whether a building has ever been used to store high enriched uranium which could be used to make nuclear weapons.
Robert Hayes is an associate professor of nuclear engineering at North Carolina State University who authored the new paper. He said “We can now use the housing structure itself as part of any nonproliferation monitoring efforts. This work details the theory to test building material samples to differentiate between the forms of uranium used in nuclear power and the HEU that's used to develop nuclear weapons.”
The new method only requires a tiny sample of relevant building material for testing. (A one-inch cube is sufficient.) The testing process is similar to the process used for determining radiation exposure with dosimeter badges worn by workers in radioactive environments. It is as if a small sample of building material is acting as a dosimeter badge.
Hayes says, “Our technique allows us to determine how much radiation a material has been exposed to, in addition to the very types of radiation a material has been exposed to. Because different radionuclides have different radiation fields, these measurements allow us to determine which nuclear materials were stored near whatever building material we're sampling.”
Although this process is very new, agencies responsible for nuclear monitoring are already interested and following Hayes’ work with great interest, Hayes says, “We're optimistic that this will be a valuable tool in the nonproliferation monitoring toolbox, but we need to address some existing questions.”
Hayes goes on to say, “For example, the radiation signature will vary depending on where the nuclear material was stored in relation to whatever sample we're testing. If our sample was from brick that was right under a uranium storage container, the signature will be different than if the container was located 20 feet away, horizontally. Theoretically, these properties of the signature would be consistent over any gridded array of the same building material. Sampling such an array would then allow us to reconstruct not only what material was stored at a site, but precisely where it was stored. That's something we're working on now.”
Hayes’ paper is titled “Potential Retrospective Uranium Enrichment Determination Using Solid State Dosimetry Techniques on Ubiquitous Building Materials.” It was published in the Journal of Nuclear Materials Management.
With growing concerns about international smuggling of radioactive materials by terrorist, the ability to test buildings that might have been used to store high enriched uranium will be a welcome addition to the capabilities of authorities charged with preventing the smuggling of radioactive materials.