user: Question: What is the rated power for the reactor that ended construction on May 10, 1978?
Columns: ['Reactor Unit', 'Type', 'Average Output', 'Rated Power', 'Began construction', 'Finish construction', 'Commercial operation', 'Close of reactor']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Bugey 1', 'Gas-cooled reactor', '540 MW', '555 MW', 'December 1, 1965', 'April 15, 1972', 'July 1, 1972', 'May 27, 1994']
SQL:

assistant: SELECT "Rated Power" FROM "Table" WHERE "Finish construction" = 'May 10, 1978';