State-of-the-art British imaging technology has been deployed at Japan's crippled Fukushima nuclear plant to overcome problems that Japanese engineers declared to be insurmountable.
Designed by Cumbria-based Createc, N-Visage cameras have been mounted on remote-controlled drones and caterpillar-tracked robots that can navigate the insides of the three reactor buildings that suffered melt-downs after an earthquake and tsunami hit Fukushima in 2011.
Coupled with unique software, the £200,000 system is able to create a real-time, three-dimensional image of the area being surveyed and identify "hot-spots" of radioactivity.
More than four years after the second-worst nuclear accident in history, radiation levels within the structures remain too high for humans to enter.
That has severely hampered efforts to determine the problems that need to be solved to safely decommission the reactors and clean up the site. Experts have already estimated that process will take three decades but progress to date has been slow.
Tokyo Electric Power, the operator of the plant, was only able to confirm on Thursday previous suspicions that nearly all the fuel from the No. 1 reactor at the plant has melted and fallen into the containment vessel. Two more reactors appear to have experienced similar fates and Tepco is now conducting further tests to confirm that assumption.
"There was some scepticism from Tepco when we were first introduced to their representatives in the UK in April 2012, but they very quickly saw the possibilities", said Dr Matt Mellor, director of Createc.
"One of their guys said it was like finding a Picasso in the loft because their experts had told them that what we do was impossible", he added.
Working in tandem with nuclear unit of Hitachi-GE Nuclear Energy, Createc engineers first visited the Fukushima plant in 2013.
"It was a shocking sight", said Dr Mellor. "Even more than a year after the tsunami, the damage to the reactors was clear. Vehicles were still laying around the site, fences had been crushed, storage tanks had been flattened and radiation levels in the immediate area of the reactors was still very high.
"Nuclear sites are usually tidy and organised because they have to be, so it was clear this was going to be a major challenge from the outset", he added.
As well as using remote-controlled vehicles to get the N-Visage system into the damaged buildings, engineers drilled holes through the roof and lowered imaging equipment into the interior.
Createc has permitted Japanese nuclear engineers to undertake a "virtual walk" through the plant and has mapped areas with the very highest concentrations of radiation, which will in the future enable engineers to shield and isolate such "hot spots".
"It has blown the socks off the engineers at Fukushima," said Pete Woolaghan, a director of Createc. "We have been able to give them an accurate and exact image of the dose environment that they are faced with, which is enabling them to formulate plans with far more certainty and safety.
"Previously, they were working with educated guesses".
The N-Visage system has been deployed at plants that are undergoing decommissioning processes in the UK, including Sellafield, and has attracted interest from the US nuclear industry.
The Japanese government has this month announced plans to decommission five nuclear reactors, the first time that Japanese plants will have been dismantled. With limited experience and capabilities in this specialist area, Createc and other British firms are anticipating an increase in opportunities in Japan.
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