Engineering news
Some workers at Rolls-Royce Marine Power Operations were exposed to potentially dangerous levels of radiation
Rolls-Royce Marine Power Operations has been fined £200,000 and ordered to pay costs of £176,500 after it lost a radioactive source at its Derby plant, exposing several workers to potentially harmful levels of gamma radiation.
The company, a subsidiary of Rolls-Royce, manufactures components for nuclear submarines and uses radioactive sources containing Ytterbium -169 to test welds during its industrial radiography work.
On 3 March 2011, one of the sources, a capsule the size of a screw, was lost for approximately five hours at the Sinfin Lane site.
Leicester Crown Court heard that on the day of the incident, the source was being used in a specially built radiography enclosure. But during the work, it became detached from its holder and ended up in the component on test.
Significant failings meant the loss of the source was not detected by the safety features of the radiography enclosure or by the radiographer in charge of the work.
It was instead discovered by welders working on site, who spotted the capsule and removed it for examination, passing it amongst themselves and exposing them to gamma radiation. The danger was only noticed when radiographers arriving for the next shift identified the component - but only after some of them had also held it.
The room was then cleared and made safe.
A joint investigation by the Health and Safety Executive (HSE) and the Environment Agency found that some of the workers’ hands had been exposed to up to 32 times the annual permitted dose of radiation.
The investigation also found Rolls-Royce did not have a suitable and sufficient risk assessment for the gamma radiography work. Inadequate procedures and deficiencies in training meant it did not have robust and effective controls to manage the risk of using high activity radioactive sources.
Speaking after the hearing, David Orr, HSE’s specialist inspector of radiation, told the hearing: “Gamma radiation emitted by this type of radioactive source is harmful to human health. Rolls-Royce is fully aware of the danger it poses and has a clear duty to protect staff from harm. However the company failed its duty of care on this occasion, losing control of the source without realising it.
“There was no effective surveillance of it for five hours and the exposure of workers to radiation, including some who were not involved in the industrial radiography work, was considerably in excess of the annual permitted dose.”
Rolls-Royce Marine Power Operations was fined £200,000 and ordered to pay £176,500 in costs after it pleaded guilty to breaching the Health and Safety at Work Act, the Management of Health and Safety at Work Regulations 1999, Regulation 11 of the Ionising Radiation Regulations 1999 and three counts of breaching the Environmental Permitting Regulations 2010.