The nuclear reactor at Sizewell power station in Suffolk has ben shut down.
The plant produces enough electricity to supply two million homes. It's being taken off-line for 6 weeks while engineers carry out work to remove spent fuel rods and replace them with new ones. Serena Sandhu reports.
More top news
It will be a dry day and very warm with bright and sunny spells.
Armed officers will be on patrol at major infrastructure sites across Essex and the county will see more police patrols.
The major party leaders' campaigns for the General Election will remain suspended on Wednesday following the Manchester terror attack.