Horizon, which was bought by Japanese firm Hitachi last year, revealed it was going for the smaller option as it officially branded the project “Wylfa Newydd” – Welsh for “New Wylfa”.
When Hitachi took over the scheme in November 2012, the company said it would build two or three 1,300MW Advanced Boiling Water Reactors at each of two sites: Wylfa and Oldbury, in Gloucestershire.
It is working up designs for two units at Wylfa to be set out in detail in the second half of 2014.
Alan Raymant, chief operating officer, said 2014 would be “one of the busiest years on the project so far” as Horizon goes through a second round of design safety checks and launches a public consultation.
Subject to regulatory approval, major on-site work is scheduled to start in 2018.