The strong demand is expected to last through the week, and the French grid operator RTE has warned the supply could be strained as workers at Electricite de France's (EDF) power plants plan a 24-hour strike on Monday. Six of the company's 58 nuclear reactors are offline. Two reactors recorded unplanned outages over the weekend and have now restarted and are ramping up output. One more reactor is expected to restart on Tuesday.