Applus+ Radiation Protection team were approached by Subsea Environmental Services to provide support in the recycling of 1,400 km of potentially radioactive telecommunications materials pulled up from the sea bed. Subsea is an environmentally conscious company that works to keep the sea bed ‘clean’ and is involved in, amongst other things, the removal and recycling of many thousand kilometres of undersea cables. The challenge was carried out in close collaboration with the Dutch government.
Under the sea between Europe and America, there lies a vast network of coaxial telecommunications cables at depths of between 3 and 7 km. These very thick cables date from the 1950’s and have long since fallen out of service. They needed to be checked for radioactivity before they could be recycled. Subsea Environmental, the prime contractor for this project, relied on the help of a Dutch ship which was specially equipped for bringing the cables to the surface.
Five sources of radioactivity
The telecommunications cables contained a number of repeaters (or amplifiers) and investigations established that these definitely contained traces of radiation. The import of such materials must always be reported to the relevant national authorities which, given the Dutch government’s close involvement in this project, happened smoothly and efficiently. What did cause a problem, however, was that since the original supplier of the repeaters was no longer in existence, additional information was unavailable. As a result the repeaters had to be analysed and, after the thick steel sections were removed it was discovered that the construction contained no less than five sources of radioactivity.
Delivering a solution
In total, there were some 125 repeaters along the 1,400 km of cabling, so a detailed plan was drawn up. With the close collaboration of a scrapmetal recovery and handling organisation, as well as that of the Dutch government, the desired result was achieved to the client’s full satisfaction.
Supporting a better environment
Applus+ was able to respond rapidly to the client’s requirements, which included retaining as much material as possible for recycling, thereby protecting the environment from unwanted waste. For each repeater, we were able to recycle around 600 kg of steel, 20 kg of copper and around 30 kg of usable electronic scrap material. There were 38 kg of radioactive waste collected from the 125 repeaters (a total of 625 sources). All tubes containing Ra226 were disposed of as radioactive waste. In 2015 a second landing and processing of repeaters was performed. From 44 repeaters, 176 tubes, each containing approximately 100 kBq H3 (Tritium), were extracted. All further remains from the 44 repeaters could be recycled normally. So as to be able to continue carrying out this specialist work, all involved parties are now working on obtaining licences for the future landing and processing of these kinds of repeaters.