Reaching new areas

AN INNOVATIVE APPROACH TO REMOTELY access hard-to-reach areas to locate and take samples of hazardous nuclear waste has been successfully demonstrated during the UK’s coronavirus lockdown.

REACH is a collaboration project between Createc, Viridian Consultants and the UK Atomic Energy Authority’s Remote Applications in Challenging Environments (RACE) to demonstrate remote deployment of nuclear characterisation tools.

There is a constant requirement in civil nuclear to characterise the environment in areas where worker access is not possible. The project aimed to demonstrate how this problem could be solved by remotely deploying tools (Createc’s N-Visage® technology and Viridian’s laser sampling tool, ViridiScope®) on robots in challenging environments.

“With the REACH project we wanted to create agile robotics and avoid putting humans into these hard-to- reach contaminated areas,” says Pete Rodgers, Createc’s operations manager.

“Tools often have to pass through small openings to enter cells and glove boxes to determine the source of radiometric dose. In addition, different tools must often be deployed using different deployment mechanisms, taking significant time and effort to swap over.”

“If a single deployment system is used, the nature of different tool interfaces can make swapping systems very difficult when wearing protective equipment and potentially result in additional dose to the operator and damage to the equipment itself. This is precisely why we have created this solution.”

REACH is a flexible, easily deployable system providing a range of deployment platforms carrying (initially) a gamma imaging system and a laser sampling tool though a single universal interface.

“We have developed a novel, robust and universal interfacing system. This interfacing system converts a deployment mechanism’s unique connection and services requirements into a universal mounting system that can be used, not just with the current tools, but with a multitude of other sensors,” says Rodgers.

“This mounting system will also be designed to enable quick and effortless swapping of a tool while wearing protective equipment.”

Gamma imaging system

The N-Visage system, developed by Createc over the last ten years, works by locating and quantifying radioactive contamination, rather than simply measuring the radiation itself. It is a gamma imager capable of mapping gamma readings onto 360-degree photos, as well as combining 3D point cloud data with gamma readings, and it has been commercially deployed at Sellafield, and extensively at Fukushima Daiichi.

Combined with Createc’s proprietary integration software, Iris, N-Visage can provide information to teams about safe and unsafe areas in unknown environments in around two hours.

Iris can be used to control the N-Visage robotics and cameras via a simple interface.

Laser sampling tool

ViridiScope, created by Viridian Consultants, is a laser ablation sampling tool which can take a suitable sample from concrete, steel and plaster in around two minutes (see NEI February 2020, p30-31).

An infra-red laser is used to take a sample, for example from a concrete surface, and the ablated material is transported through a nylon sampling line to a filter substrate in a collection pod. The pod can be put directly into a portable gamma spectrometer, or it can be opened and the filter and support counted for gross alpha/beta in a gasless proportional counter.

Using Viridian’s mobile laboratory, isotopic analysis, gamma radiation detection and gross alpha/beta counts can all be completed in around 20 minutes.

The original remit for ViridiScope was that it should be able to operate in areas of high radiation fields. Fo this reason complex and expensive components like the laser source and the safety and control electronics had to be located at a distance from the sampling site and manually operated.

As part of the REACH project, Viridian has developed the capability to take samples inside 6-inch ports.

“The REACH project has been a great opportunity to push ViridiScope’s design to the limit and reduce the size of the laser sampling head, making it more flexible for deployment in those really hard-to-reach areas. Interestingly, with our 

new optical configuration, the performance is even better than with the manually-deployed system,” says Kym Jarvis, Viridian’s managing director.

Development, testing and application

The REACH project has immediate benefit for detailed characterisation of areas such as underground tanks, as well as for reactor inspection and maintenance.

Glove boxes in the civil nuclear sector also present a significant challenge, in terms of narrow port entry and the type of characterisation required – and there are more than 2000 across the UK Nuclear Decommissioning Authority estate.

Currently, the challenges of difficult to access areas are solved with bespoke solutions or human entry, or are indefinitely postponed. This is costly, time-consuming and, in the case of human entry, can pose significant health risks.

Collaborating with Createc and Viridian, RACE developed a universal coupling to allow quick and efficient tool changing between end-effectors. RACE also developed a test cell to demonstrate remote deployment of the end-effectors under a small platform, inside a 6-inch port and through a 6-inch port. Working with N-Visage REACH means gamma hotspots can be identified, sampled and analysed remotely making the process safer, cleaner and faster.

The REACH project has also developed a new approach for completely remote deployment in voids, pipework and difficult to access areas where man access is not possible. The tools developed are able to pass through small openings to enter cells to determine the source of a radiometric dose and take samples.

Teams working on the project overcame a number of challenges.

Createc miniaturised its N-Visage scanner to pass through a standard 10cm nuclear cell penetration. ViridiScope was also shrunk so it could be deployed in pipes and voids as small as 15cm in diameter and at 40m from the control electronics.

A system had to be developed that would allow samples to be taken adjacent to the direction of travel, for example from the inside surface of a pipe. This meant creating both an optical arrangement to turn the laser beam through 90 degrees without losing power and a mechanism to determine whether the head was in contact with the surface. In the case of a curved target surface, the sampling head had to have a similar profile, but still be able to operate on flat surfaces.

A mechanism to reveal when the head is correctly located and ready for sampling was needed for when it is not possible to see the surface, such as inside a pipe. A number of proximity sensors and a feedback system were developed so an operator knows whether the sampling head is correctly positioned, side to side and front to back, without having to see it.

The outer casing, which is likely to become contaminated, also had to be rapidly replaced, without contaminating any of the internal optical components.

Options for deployment include mounting the ViridiScope head directly on a pole, such as to sample inside a pipe. ViridScope has also been mounted on a Kinova arm to deploy through a penetration. This gives flexibility for sampling inside cells and glove boxes.

When the head is mounted on the Kinova robot arm on a Husky platform it provides a flexible, robust system that can be deployed in inaccessible areas such as service ducts and drains.

Other tools that can be mounted on the system include laser scanners, cameras and radiation detectors. With these sensors the unit generates a 3D model, and panoramic images that can be combined with the radiation measurements using the Createc N-Visage algorithms to characterise the contamination across surfaces.

Demonstration and outlook

Funded by InnovateUK, the REACH project took place over three years, finishing in April 2020 with a demonstration at the UKAEA’s RACE base at Culham Science Centre, in Abingdon, Oxfordshire.

“A primary motivation for the further development of the N-Visage system with this REACH project is improving efficiency in nuclear cleanup around the world,” says Matt Mellor, chief executive of Createc.

Discussions are now taking place with Sellafield Ltd for an active REACH demonstration to take place at the Sellafield nuclear site in Cumbria, UK.

While the REACH technology has been developed for the civil nuclear industry it has potential applications in other sectors such as oil and gas and construction. As lockdown eases another event is planned, in a non-nuclear environment, at Createc’s headquarters at Cockermouth in Cumbria.