A new small-scale nuclear reactors will be built in west Cumbria.
TSP Engineering has said the contract is going to create 750 new jobs at its Workington factory.
The Workington base will become the home of the reactors, known as SMRs.
The company expects to start production of the 'NuCell' this year - with the first reactors set to be manufactured by 2027.
TSP chief executive John Coughlan, said: "This announcement will secure and grow employment within Cumbria across all trades, engineering disciplines and support professions.
"This will be a further support to the nuclear supply chain locally and nationally offering a secure growth path for support businesses and services for decades to come."
Mark Jenkinson, Workington MP, said that this was "fantastic news."
He added: "Manufacturing and design of new nuclear in Cumbria will be another boost to our local skills base – and will help grow jobs and support innovation across the engineering sector in West Cumbria.
"The nuclear industry has its roots firmly established here, and it is great to see that we are building on our strengths and leading the way in innovation."
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