Following a series of experiments, CNL researchers conclude that Active Neutron Interrogation could potentially detect and identify even the most ‘well-hidden’ nuclear materials
(A mock-up of a nuclear warhead core composed of surrogate material sitting in front of a neutron generator and detection system)
A team of applied physics researchers completed a series of experiments testing the accuracy and sensitivity of a nuclear materials detection technique that they concluded could potentially identify even the most well-shielded fissile materials.
Called active neutron interrogation (ANI), this detection technique identifies what material is truly inside a heavily shielded container by exposing the sample of interest to a neutron source, which generates a unique and identifiable signature.
Among the many other techniques and tools needed to get there, ANI falls under a larger, overarching effort to work towards a world without nuclear weapons – a process called nuclear disarmament. Referred to as nuclear disarmament verification (NDV), determining and verifying whether parties are complying with nuclear disarmament efforts, agreements, or treaties is a key part of that process.
ANI works by probing materials of interest with an external neutron source. Neutrons are a type of particle radiation without a positive or negative charge, and because of this, they can penetrate materials easier than other charged particles. When these neutrons reach their target material, they generate a unique, and identifiable signature in return that can be measured.
“The ANI technique, by its ability to measure unique features of nuclear materials, could provide inspectors certainty of either the presence or absence of nuclear materials without transferring sensitive information to a third-party that could jeopardize the security of the disarming state and the non-proliferation regime,” explains experimental safeguards researcher Ghaouti Bentoumi, who’s leading detection and sensor development work at Canadian Nuclear Laboratories.
Last fall, researchers conducted experiments testing ANI’s ability to overcome some of the most challenging “cheating” detection scenarios. In NDV, cheating essentially refers to a situation where the disarming party declares they’ve removed fissile material from something when, in reality, they haven’t. Typically, cheaters “hide” their fissile material in shielded containers made of lead, or steel, for example, in an attempt to avoid triggering detectors.
Following their tests, the team of researchers found that ANI successfully detected and identified several different mock-up nuclear warheads they’d made to represent these challenging cheating scenarios. Their experiments indicated the technique’s potential for NDV applications and laid the groundwork for more efficient and optimized capabilities in this area.
Their work – which is co-funded by the Canadian Safety and Security Program (CSSP) – also supports Canada’s role among the 25 countries participating in the ongoing International Partnership for Nuclear Disarmament Verification (IPNDV) initiative to develop procedures and technologies to address NDV challenges.
This research is co-funded by Atomic Energy of Canada Limited’s (AECL) Federal Nuclear Science & Technology (FNST) work plan program, which connects federal organizations, departments, and agencies to the nuclear science expertise and facilities we have at Chalk River Laboratories. Under this program, our researchers carry out projects designed to support the Canadian government’s core responsibilities and priorities across the areas of health, safety and security, energy, and the environment.
