The company, which maintains some of the Britain's railways and roads, said on Tuesday it would buy the nuclear services division of EnergySolutions for $318 million (206 million pounds) to help boost its capabilities in nuclear decommissioning.

Atkins has been steadily building its nuclear offering, with the acquisition of Nuclear Safety Associates last year, to support governments and energy companies that decide to decommission their nuclear projects.

"Energy is the field where we have been most active. It is a great follow up on the success we had on expanding our nuclear business," Chief Executive Uwe Krueger told Reuters.

Shares in the group rose by more than 7 percent in early trade, its best performance in 18 months, and were trading at 1,460 pence by 0909 GMT.

"The acquisition should strengthen Atkins position in nuclear in the UK and provide further decommissioning opportunities in Europe such as Germany," said Liberum analyst Joe Brent, who has a "buy" rating on the stock.

Krueger said the acquisition would enable the company to bid for larger contracts in the United States as well as gain a footprint in mainland China and Japan.

He also said the business would help the group in new markets such as Germany and Switzerland, which plan to decommission their nuclear projects in the coming years.

(Reporting by Li-mei Hoang; Editing by Mark Potter)