UPDATE 1-British Energy's Hinkley B4, Torness unit 2 stop

(Recasts, adds details of other outages)

LONDON, Jan 5 (Reuters) - British Energy BGY.L is working on the restart plans for the four nuclear power reactors that shut down between Friday and early Monday morning, a spokeswoman for the company said.

British Energy's 610-megawatt Hinkley B8 reactor in southwest England tripped at 0009 GMT on Monday, after the 625-MW Torness 2 unit in Scotland stopped unexpectedly on Saturday afternoon and two others tripped on Friday.

The spokeswoman said that the causes of the trips were unrelated and that the shutdowns would be short.

"They are unrelated, they are minor issues and we are working on restart plans for all of them," she said. The Hinkley Point B7 reactor shut down unexpectedly on Friday afternoon, just hours after the company's 555-MW Dungeness B21 reactor in southeast England tripped.

Four other reactors, at the Hartlepool and Heysham power stations, have been shut for over a year for age-related problems and are expected to restart early this year.

The company only usually starts work on restart plans once repairs or maintenance work is completed.

(Reporting by Daniel Fineren/Nina Chestney)