Radiating confidence

With the need to detect sources of radiation stronger than ever, one UK company has adapted existing technology to monitor sheep still affected by Chernobyl’s fallout. George Coupe reports

One morning in 1986, the UK woke up to the news that the next rain, when it came, would bathe the country in the fallout from the Chernobyl disaster. It was a shocking reminder of the dangers of atomic radiation.

Since then, for many different reasons including the threat of international terrorism, the need to detect sources of radiation, illicit and otherwise, has only grown stronger.

Recently Corus Northern Engineering Services (CNES) the only UK manufacturer and supplier of radiation portal monitors, adapted its existing technology for the Food Standards Agency (FSA) to monitor sheep still affected by Chernobyl’s fallout.

The group recently beat nine other European companies to win the FSA contract for 40 handheld sets after making a series of alterations to its existing Redeem PRM 100-C handset to meet some of the specific challenges of testing sheep in the wind and rain of upland country.

After Chernobyl, the fallout deposited large amounts of radiocaesium over parts of Scotland, Cumbria and North Wales. Since then, sheep grazing in these areas have been monitored for caesium and their movement and sale are still restricted.

The FSA had been using a set of ageing monitors, but the process was awkward and laborious, requiring a probe to be held on the rump of a sheep for 10 seconds. Someone else had to record the number of radiation counts while the ratemeter automatically reset itself. This procedure had to be repeated three times for each sheep.

Rod Crust, business development engineer for Redeem, said CNES made significant changes to the design and functionality of existing handsets. ‘We reduced the unit weight from 3kg to one: the new software was much more sophisticated [than current FSA handsets] we designed it to detect caesium 137 only, and it makes the 10-second count automatically,’ he said.

The handle of the Redeem PRM 100-C was re-designed and a special grip added to cope with slippery conditions and rainfall. The display menu and software were also simplified, said Crust.

The PRM 85-C, as it is known, was trialled in the field against competing Belgian and Israeli systems and CNES received a £130,000-plus order for 40 handsets this February.

CNES is the only company in the UK that makes equipment for monitoring all types of radioactive sources. Under the brand name Redeem, it supplies a range of products including installed systems for monitoring passing vehicles and pedestrians at ports and airports, as well as handheld devices for environmental and security screening.

The technology’s history goes back 20 years when Corus, British Steel as it was then, was concerned with the problem of orphan sources of radiation getting lost in the metal recycling chain. The group developed a highly sensitive detection technology to provide more protection against the risk of industrial isotopes accidentally entering its plant and furnaces.

Over the years the company has refined and adapted the technology for a range of markets outside the metals sector. This has attracted interest from around the world, and enabled the group to challenge its established foreign rivals. CNES is now the only UK manufacturer and supplier of radiation portal monitors, and it claims to be the first in Europe to produce a system as compact as Redeem.

Crust said that in the 1980s British Steel believed the conventional plastic-based radiation detectors used to scan scrap coming into its plants, were not sufficiently sensitive to detect all sources of gamma radiation. ‘It would have had a big effect on our business if this had got into the steel or gone up the stacks from the furnaces,’ he said.

Gamma radiation from industrial isotopes is attenuated by the surrounding scrap metal and it was decided that a more sensitive system should be developed; it differed in two important ways from the old.

First, instead of mounting scanners only on either side of wagons as they came into the plant, two more scanning heads were used above and below the trucks to provide all-round coverage.

Second, rather than the plastic-based sensor technology, reckoned to be about 20 per cent sensitive to gamma radiation, the new system employed crystal scintillators, with a sensitivity of 60 per cent. Software changes also helped, with algorithms developed especially to process the signals from low-energy, gamma shielded sources.

The system was also capable of making a spectroscopic analysis of the energy levels in the scrap load, which enabled British Steel to identify what type of isotope might be concealed within. ‘This system was eventually rolled out to all the Corus sites, and was sold to other companies in the metal sector,’ said Crust.

Later, a second-generation vehicle monitoring system was developed for more commercial purposes. Further software developments made it possible to identify the position of a radioactive source in a load and the isotope recognition capability was further improved. ‘This was really important, because if somebody has got to go in and get it, they need to know what it is and where it is,’ said Crust.

To date, the portal monitors have sold well in the metal recycling sector, but the company has also worked hard to adapt and promote the devices for a range of other industries. CNES said Redeem can be used for a variety of tasks from checking for radioactive contamination in soil and at landfill sites to providing security at cargo ports and nuclear power plants. Other potential applications include public buildings and transport.’

However, the greatest challenge has been to win a slice of the growing and highly lucrative security market. CNES has worked hard on this front, and come close to winning some major contracts. The company has incorporated number-plate recognition and other visual monitoring systems to its products, as well as falling barriers to prevent the onward progress of suspect vehicles. Audible and visible alarms can also alert security staff discreetly and remotely.

CNES’s steady progress resulted in an invitation to compete to supply a £100m Home Office project, ‘Programme Cyclamen’, to install radiation detection equipment at all UK ports. As a result of that project CNES added neutron detection to its product range. Originally Redeem was designed to pick up gamma radiation, whereas neutron detectors are necessary to find fissile nuclear materials used in atomic weapons.

Another important feature the company added to the monitors was a naturally occurring radioactive material (NORM) filter. This allows the system to identify illicit radioactive sources in loads that naturally emit radiation, such as cement or medical products. ‘There are concerns that isotopes could be hidden in bulk loads such as fertiliser, that are already radioactive. So we developed the system further to be able to determine what the normal level should be,’ said Crust.

This constant improvement looked as if it could have paid off when Redeem was trialled by the US government. ‘We sent two spectroscopic portal monitors to the Nevada test site. The project was to provide the US with portal monitors for border entry. We got down to the last three,’ said Crust.

He said the company is now hoping to win orders from eastern Europe on the potential terror smuggling routes from the Middle East and central Asia. This is not to say that CNES is desperate for customers; it has already sold 60 systems this year to the metals industry, said Crust.

‘Corus ordered three spectroscopic portals, with the NORM facility, for its sites, which is a £500,000 order for us.’ Two years ago, CNES sold 20 pedestrian monitoring systems to the UK nuclear power industry.

Constant innovation and adaptation has made the company stronger, and put it in a position to challenge rival systems from Canada, the US and Russia. It has done best when adapting its products to suit specific customer requirements, such as the sheep monitor for the FSA. According to Crust, it was this rather than the price that was the clincher for the agency. ‘I was told after we won the contract, that we were not the cheapest,’ he said.