The patent involves a more efficient method of immobilising radioactive sludge in a cement matrix.
Nuclear power plants store used fuel canisters in cooling water ponds to enable radiation levels to decrease before the fuel is reprocessed. The storage process leaves a radioactive sludge in the pond which can be immobilised by mixing it with cement for safe, long-term storage. The immobilisation process operates on a batch-wise basis.
Costain developed an improved process to enable the cementation of larger quantities of radioactive sludge more quickly and reliably than at present. The proposed process could deliver a six-fold increase in the number of drums filled per week from two to twelve, according to Costain.
The approach was developed by process engineers Jaswinder Singh and Lee Scott and they were jointly awarded a Costain innovation award in 2006. The company decided the technique was sufficiently innovative to apply for a patent. The application was granted after a comprehensive examination process by a Patent Office examiner.
“We are extremely pleased to have been granted our first nuclear patent”, said nuclear process sector director Paul Campbell. “This is one of a number of our novel approaches to the problems encountered when decommissioning nuclear plant.”
“This demonstrates the importance Costain places on developing innovative solutions to address complex challenges faced by the industry,” said Costain Energy & Process managing director Charles Sweeney.