IMPRINT – defeat of insider theft in nuclear and radioactive sites

‘Insider threats are perhaps the most serious challenges that nuclear security systems face.’


All cases of theft of nuclear materials where the circumstances of the theft were known were all committed by insiders or with the help of insiders. The IMPRINT project works to create a system where it is easier to detect any shielded or radioactive materials that can be stolen on site.

About the project

The term ‘dirty bomb’ refers to those which use radioactive materials compressed in a small steel enclosure, and are surrounded by explosives. Radiation Portal Monitors can detect these quite easily, but issues arise when someone shields the sources. This gap presents an opportunity to the facility insider to steal nuclear materials from the site.

It is necessary to be able to detect shielded and unshielded Special Nuclear Materials. ‘There is a need for inspection systems that can penetrate high attenuating vehicles, be specific to nuclear and shielding materials that can be stolen from the site.’


IMPRINT will work to fill the gap of existing capabilities inspection systems and enable the detection of shielded or radioactive materials that could be stolen from sites.

The technology used is based on high energy natural atmospheric cosmic ray muon particles. These have the highest known penetration levels and are able to penetrate cargo and vehicles.

Implementation journey

All parts for 4 units were produced and in parallel began the integration of the first detector unit.

The IMPRINT solution is planned to be used as a secondary screening. The system is designed to benefit from the information derived from an earlier x-ray image of the vehicle. This enhanced detection will open new capabilities that are currently not available from any competitors.