Civil engineering group Costain has won a contract from France's EDF to help build the UK's first new nuclear power station for a generation.Costain said it had finalised a deal to design and build the water cooling systems for the new Hinkley Point C nuclear power station in Somerset. The group will design and build three tunnels, around 7 miles in total length and each one about seven metres in diameter, to take water from the Severn Estuary for the nuclear reactor before it is cleaned, recycled and returned.It expects work to begin as soon as possible following the final investment decision.Chief Executive Andrew Wyllie said: "We estimate that this contract will lead to the creation of hundreds of new jobs at Costain alone, including apprentices, specialist technical and engineering roles and programme management."The news came as the UK government announced it had approved a decision to build the station at Hinkley Point, which will cost up to £16billion.The decision, which involves guaranteeing an electricity price to EDF for the power generated at Hinkley Point at nearly twice the current level, has raised concerns that it will lead to higher household energy bills.PW