Cracks on 12 giant fans in a clean-up plant are threatening to close Britain’s largest power station and could lead to multi-million pound claims for damages.
The booster fans which are 4m in diameter drive the exhaust gasses from the 4,000MW coal-fired power station at Drax, South Yorkshire, through its attached flue gas desulphurisation plant. If the FGD unit is out of action, the power station risks exceeding its sulphur emission limits.
According to an engineer close to the project, manufacturer Howden Sirocco had been aware of hairline cracks on the impeller blades (which with the drive shaft weigh 35-tonnes on each unit) for the past two years. As the cracks were too small to see with the naked eye and were not noticeably enlarging, it was deemed safe to continue operating the plant.
But a catastrophic failure of a similar unit at a power station in Italy last November in which the impeller was destroyed led to the closure of the Drax units.
National Power has applied to the Environment Agency to increase Drax’s permitted annual sulphur emissions from 100,000 tonnes to 270,000 tonnes while the fans are repaired.
The generator said that if it failed to secure consent for the increase, it would have to close the station for the duration and use less-efficient and more polluting coal-fired plant elsewhere.