Improving security for storage of dangerous materials

New technology safeguards radioactive weapons and waste

Safe storage of nuclear weapons and waste is critical for national security and environmental health. Specialized seals are used to prevent tampering.

WSU researcher Hergen Eilers has developed a seal technology that adds a layer of security beyond what’s found in existing seals. His technology also allows for simple visual inspection to verify that a storage site is secure.

How the seal works

Dr. Eilers’ seals are composed of nano-particles embedded in a polymer. He uses a wavefront-modulated laser, which can control scattered light. When the laser interacts with the seal, the light is scattered by the particles. The reflected light then interacts with a holographic waveplate which is designed to visually display a unique pattern. The particles are much smaller than those used in current seals, allowing for more complex patterns that are harder to mimic.

Tampering destroys the unique relationship between the seal and the wavefront laser, resulting in the disappearance of the reflection pattern. Imagine, for example, that you wanted to check on the security of stored nuclear waste. If the holographic pattern on the seal remains visible, then there has been no tampering.

Added security

Existing seal technologies require more complicated verification methods. In addition, many seals are limited to displaying one reflection pattern. In contrast, Dr. Eilers’ seals can be used in conjunction with lasers of different wavelengths, polarizations, and other variables. As a result, one seal could reflect 10 different images when combined with different types of lasers. In order to conceal tampering, a person would have to replicate all 10 images. This level of complexity—which makes images nearly impossible to replicate—is made possible by the seal’s small particles and light scattering properties.