Sandia National Laboratories has developed a groundbreaking prototype using "bruising" materials that display evidence of tampering with containers of nuclear material. The innovative device, created by engineers at Sandia, goes beyond simply detecting tampering and boldly shows the damage, like battle scars. Heidi Smartt, a Sandia electrical engineer and project lead, explained, "Our first idea was to create a 'bleeding' material where it was extremely obvious that it had been tampered with. Then we made a new device using these materials where the damage is obvious for people to see. No one has ever done this sort of concept for international nuclear safeguards before."
The prototype devices are puck-shaped and turn dark brown when damaged or when the wire loop threaded through them is pulled out. The color-changing solution used in the devices contains a chemical called L-DOPA, which reacts with oxygen to produce melanin, the brown chemical that gives human skin, hair, and eyes their color. If someone drills a hole in the device or attempts to pull out the embedded wires, oxygen leaks in and reacts with the color-changing solution, turning it brown. Over time, the "bruise" grows.
The Sandia prototype devices are about the size of a stack of seven U.S. half dollar coins, the same size as the metal cup seals used by the International Atomic Energy Agency (IAEA) since the 1960s. The IAEA relies on tamper-indicating devices to detect if containers of nuclear material have been opened or tampered with. Inspectors need to carefully examine these devices and their wire loops for evidence of tampering, which is time-consuming and subject to human error. The purpose of the Sandia prototype is to reduce the time and subjectivity of these inspections.
Cody Corbin, a Sandia materials chemist, explained the process of making the filling for the prototype devices. The team adds water to a mixture of clear and colored water beads, blends them until they are small bits, and then soaks them in the color-changing solution. The mixture is then poured into 3D-printed cases and sealed. The unique colors of the bead bits provide an anti-counterfeit aspect, making it difficult for someone to replicate a puck.
The team is currently testing dozens of pucks under various conditions to mimic different environments they could be used in. This includes testing them at temperatures ranging from -22 degrees to 150 degrees Fahrenheit and subjecting them to intense UV light to age the materials faster. Last year, the team filed a patent on the color-changing material and recently filed a patent continuation on the tamper-indicating device itself. They may seek additional funding to test the devices in the field and explore partnerships with corporations to license and commercialize the technology.
Smartt believes that these devices can add value to any industry concerned with the tampering of their packaging. She said, "I think we can really add value in that visually obvious aspect of our devices; that's a totally new thing. There are a lot of other possible uses for these loop seals too."
The research on bruising materials was funded by Sandia's Laboratory Directed Research and Development program, while further development and device prototyping were funded by the National Nuclear Security Administration's Office of Defense Nuclear Nonproliferation.