Cavendish Nuclear is testing a new system for mapping radioactive hotspots, which could aid in the decommissioning of redundant nuclear plant. The company is taking advantage of a breakthrough in fast neutron detection technology to develop a lightweight system that combines simple “plug-and-play” electronics with specially developed algorithms. The result is a highly manoeuvrable device that provides rapid and accurate modelling of plutonium deposits inside gloveboxes, pipes and valves used to process nuclear material.

New technology is being tested at the Sellafield fuel cycle site in Cumbria, where the device is being trialled inside the Sellafield nuclear plant which is being prepared for the post-operational clean-out and decommissioning of its complex reprocessing plant.

The standard DISPIM Imaging device – also developed by Cavendish Nuclear – is used currently at Sellafield for mapping alpha contamination. It is heavily shielded and weighs half a tonne. The new ARKTIS S670e detector is much more mobile and weighs just six kilograms, making it easier for workers to carry out scans from a variety of locations.

Cavendish Nuclear identified the potential of the lightweight ARTKIS in 2015 and began developing a compatible data processing capability incorporating the company’s algorithms. This resulted in the Plutonium Hold Up Management System (PHUMS), which combines the slimline ARKTIS detector head with a simple “plug-and-play” laptop housed in a carry-case.

Sellafield Ltd has been working with Cavendish Nuclear for the last 12 months on trials of PHUMS with good results. Paul Little, head of post-operational clean-out of special nuclear materials at Sellafield Ltd, said: "Both the standard DISPIM Imaging device and the new PHUMS system have been used in Special Nuclear Material facilities with comparable results; however the major advantage of the PHUMS technique is its ability to be deployed in areas where the DISPIM technique cannot due to its size and weight advantage. We were happy to help demonstrate this technique and have added it to our toolbox for the characterisation of facilities within special nuclear materials, e.g. cells, vessels and gloveboxes."