The plant in southeastern France would then be put in "cocoon" mode stopped, cleaned and ready to restart giving time for a potential acquirer to buy the refinery.

"Workers have voted, not unanimously but at a large majority, to resume work as there has been satisfying progress in negotiations given that LyondellBasell's initial intention was to keep the refinery shut," CFDT union representative Jean-Pierre Bourrelly told Reuters by telephone.

"The refinery will be restarted on Monday until the end of the year and then it will be put in a cocoon until the end of 2013," said Bourrelly, adding workers had "no guarantees" the refinery would restart production after that.

"The process to sell the refinery will follow its course during this period. But then again we are not sure we can find a buyer," Bourrelly said. LyondelBasell's decision on Sept 26 to shut the refinery, which employs 370 workers, and the ensuing strike at the plant threatened to reignite a nationwide protest of French refinery workers, reviving the memory of a month-long stoppage in 2010.

But labour unions later decided not to join the Berre refinery workers' strike.

The European refining sector has been struggling for years due to overcapacity and poor margins, leading Total to shut its Dunkirk plant at the start of 2010 and Petroplus to close its Reichstett plant in eastern France in May 2011.

Copyright Reuters, 2011