Koeberg’s radioactive tanks safely cleaned out
The high-risk procedure was completed by Averda South Africa’s Specialised Industrial Cleaning team.
After 40 years the tanks were in need of a wash. Averda managing director Johan van den Berg said the tanks needed to be thoroughly cleaned before they were demolished and disposed of, as they were due for replacement.
“This is a phenomenal achievement by our team from Mossel Bay that services our industrial clients in the region. It was a tough assignment in one of the most hazardous environments one could imagine and they managed to exceed the client’s expectations.”
The project was carried out under contract from Lesedi Nuclear Services and required the Averda team to thoroughly clean two stainless steel tanks that stand 20m high and 12m wide. Van den Berg said the tanks are integral to the nuclear power station’s running, and the radioactive water it has stored could easily have contaminated the structure.
According to Lesedi, there is no record of any other project in which the insides of these tanks have been high-pressure hydro washed to remove radioactive particles and contamination.
The clean-up team spent weeks preparing for the job including a week of safety training before they travelled from Mossel Bay to the Koeberg Nuclear Plant.
“The training had to be in line with Koeberg’s stringent safety procedures and the Averda teams core focus was radioactive contamination and to keep that as low as possible. The high degree of caution was not only to prevent exposure to any radioactive materials or surfaces, but especially because the tanks were still in place alongside the reactors,” he said.
For the clean-up, the team started by suspending a 360° high-pressure nozzle into the tank for 12 hours. Only the following day did team members enter in specialised suits to continue this process with hand-held high-pressure nozzles.
“We could not have been happier with the results, as was Koeberg. The radiation in the tanks before we started was quite high, but when we were done there wasn’t a trace of any remaining radioactive particles,” said Van den Berg.
Averda Mossel Bay branch co-ordinator Mark Golden said that although the possibility of being exposed to radioactive material makes this risky, many other industrial tanks contain residual gases that are far more volatile.
“This is something that’s not visible, so you have to trust your monitors and your training because if the exposure gets too high you have to evacuate immediately,” he said.
A section of the plant was shut down to allow the three-person team to go about their work.
The old tanks were cut into small sections and disposed of at a nuclear disposal site in the Northern Cape.