Coolant life at BNFL’s machine shop in Preston has been extended by switching from a water-based coolant to an oil product developed by Shell called Sitala, according to Shell.

BNFL’s machine shop manufactures 1000 fuel rod containers each week for the UK’s Magnox plants. In the past it has used a water-based coolant, but the magnesium material being machined caused the coolant to separate and become more alkaline, giving it a lifetime of only eight weeks.

The process has recently moved to a new building with a centralised coolant distribution system and the company introduced the new coolant. Because it does not separate and its pH level remains constant it can be filtered and returned to the machines. The new coolant has a lifetime of 14 months.