Nigel Cann, delivery director at Hinkley Point C, said the circumstances surrounding the fatality will be investigated and that work at the site has been stood down.
He said: “We are very sad to confirm that one of our team was involved in a fatal construction traffic incident this morning during planned work activities.
“The incident is being investigated by the police and the Health and Safety Executive, and we will co-operate fully with the authorities.
“Work at the site has been stood down and we are offering support to colleagues affected by this tragic event. Our thoughts are with his family, friends and colleagues at this very difficult time.”
The force said: “Sadly, despite the efforts of the ambulance service, the man died a short time later.
“His next of kin have been informed and our thoughts are with them at this difficult time.
“We’re liaising with the Health and Safety Executive and our enquiries into the incident are ongoing.”