Wireless sensors unlock the secrets of nuclear waste storage

At the end of last year, Sellafield Ltd saw a breakthrough in nuclear monitoring as Sensor Driven demonstrated its latest smart sensor technology. Live data streamed from within a Special Nuclear Material (SNM) storage extrusion – essentially a Faraday cage designed to contain highly radioactive materials – allowing staff to track temperature and pressure remotely, without exposing personnel to risk. Twenty-five Sellafield staff attended the demonstration, witnessing a technology that could redefine long-term nuclear waste management. 

Solving a Decades-Old Challenge 

Thousands of waste packages at Sellafield, from dry to heat-generating forms, remain stored for decades. Inspecting them is slow and risky: either packages must be removed for manual checks or fitted with in-situ devices in extremely constrained spaces. “Understanding the condition that [these packages] are in is of vital importance,” a Sellafield engineer said. “The smart sensors…enable us to deliver remote wireless sensing without having to put an operator in harm’s way.” 

From Prototype to Proof 

Developed through the Game Changers programme, originally with the support of the Central Technical team before being progressed by SNM, the sensors evolved over 7 years: 

• 2020: Proof that ultra-low-power electronics can survive radiation. 
• 2021: Mk1 prototype with 30-year life and pressure sensing. 
• 2022: Mk2 capable of transmitting wirelessly from plugged extrusions in laboratory tests. 
• 2023: Mk3 miniaturized sensors embedded into canister lids, measuring temperature and transmitting wirelessly; welding methods developed for attachment. 
• 2024–2025: Active trial: sensors deployed in live SNM store, transmitting data in situ over an 18-month period. 

The sensors withstand gamma doses up to 1,500 Gy and neutron exposure equivalent to 75 years, measuring micron-scale pressure changes and temperature, then wirelessly transmitting data through the thick metal of plugged extrusions. 

“Game Changers has been instrumental in making sure that we as a small company can work very effectively with the very large company that Sellafield is. And it has allowed us to create a very genuine collaboration.” said Bernard Stark, Director at Sensor Driven. 

A Game-Changing Demonstration

During the live demo, Ed MacNeil, Technical Adviser at Sellafield Ltd, remarked, “We’ve achieved the impossible here. We’ve got data out of an SNM extrusion…as we speak, there's data coming out of these stores, and we can see what's going on inside.” The miniaturised antennas cleverly use the canister itself to amplify signals, a feat previously thought impossible. 

Three sensors deployed in trial packages have been transmitting data for 3 months, validating predictive thermal models and giving Sellafield unprecedented insight into store conditions. 

Transforming the Industry

The implications are huge: fewer manual inspections, improved safety, and better confidence in the long-term integrity of waste packages. Next steps include scaling to around 100 sensors and extending deployment across facilities. “Now, the next step,” MacNeil added, “can we use this on active products? Because the technology is ready.” 

Wireless sensors like these promise to change nuclear monitoring forever – turning decades of uncertainty into real-time insight.