Cavendish Nuclear and Sellafield Ltd test technology breakthrough in mapping of plutonium plant

3D model showing the locations of the PHUMS measurement positions around a suite of gloveboxes

PHUMS detector deployed in close proximity to a shielded glovebox

PHUMS software and hardware is self-contained within a lightweight case

Cavendish Nuclear is testing a new system for mapping radioactive hotspots, which promises to transform 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 algorithms developed by Cavendish Nuclear.

The result is a highly manoeuvrable device that provides rapid and highly-accurate modelling of plutonium deposits inside gloveboxes, pipes and valves used to process nuclear material.

It is currently being trialled inside the Sellafield nuclear plant where preparations are being made for the post-operational clean-out and decommissioning of its complex reprocessing plant.

Janet Fletcher, head of products and services at Cavendish Nuclear said,

“Innovation in the use of technology is transforming the ease with which redundant plant can be mapped for the build-up of plutonium on the inside of pipes, valves, gloveboxes and other kit that is reaching the end of its operational life.

"Sellafield Ltd is an important customer of Cavendish Nuclear and we share a strong desire to innovate to deliver nuclear clean-up safer, faster, at lower cost.”

The standard DISPIM Imaging device - also developed by Cavendish Nuclear - is used currently within Sellafield for mapping alpha contamination. It is heavily shielded and weighs a cumbersome half a tonne.

The new ARKTIS S670e detector is much more mobile and weighs just six kilogrammes, 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.

The result is the Plutonium Hold Up Management System, or PHUMS – a lightweight and highly manoeuvrable set-up that combines the slimline ARKTIS detector head with a simple “plug-and-play” laptop housed in a carry-case.

Sellafield Ltd is very keen to bring innovation to its plans for decommissioning and has been working with Cavendish Nuclear for the last 12 months on trials of PHUMS on its plant.

The results have been impressive, delivering rapid and accurate models of facilities for the presence of plutonium.

Paul Little, head of post-operational clean-out of special nuclear materials at Sellafield Ltd, said,

"We are always keen on making the most of innovation and new techniques to transform the way we work and support us in our mission of safe and cost effective risk retirement.

"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."