The "major contract" will support site development work and allow Horizon to assess the best construction timetable for Wylfa, according to the company’s chief operating officer Alan Raymant. It will also feed into public consultations and support Horizon’s supply chain development strategy.

Horizon said that it plans two supplier events next week (in Llandudno and Gloucester) to share information about the project with potential suppliers. It also said that it has recently invited expressions of interest for "a small number" of procurement opportunities.

"We’ll be looking for suppliers to demonstrate they can deliver to time, cost and quality. We’ll also look for suppliers to be innovative in their proposals, making best use of the expertise locally, regionally and nationally," Raymant said.

Horizon Nuclear Power, which Hitachi purchased from Germany’s RWE and E.on last year, plans to build two to three 1300 MW-class ABWR-based nuclear power plants at Wylfa and Oldbury, with the first unit coming online in the early 2020s.

In April, Hitachi-GE signed agreements with UK nuclear regulators for them to carry out a generic design assessment of Hitachi’s ABWR reactor design.