The planned £13bn Wylfa Newydd nuclear power station on Anglesey has been scrapped.
Hitachi suspended work on the project in January 2019 because they said funding negotiations with the UK Government had “hit an impasse”.
Newspaper reports on Tuesday in Japan said that the company was "poised to withdraw" from the project.
And the Isle of Anglesey council said on Tuesday the company had now confirmed in writing it is withdrawing from the project.
Council leader Llinos Medi told BBC Wales: "This is very disappointing, particularly at such a difficult time economically."
The council reportedly received a letter from the Tokyo-based electronics company confirming its decision.
Mrs Medi has asked to meet both the Welsh and UK governments to discuss the future of the site.
Developer Horizon Nuclear, which is owned by Hitachi, said it would not comment.
The development of the two-reactor nuclear site had been expected to be a major source of employment on Anglesey and a boost to the region’s economy.
There had 9,000 workers ready for the construction phase and the suspension was described at the time as a "tremendous blow" to the Welsh economy.
