By Inti Landauro 

PARIS--French state-controlled power utility Eléctricité de France SA, or EDF, made a preliminary offer for the reactor unit of nuclear-engineering firm Areva SA of EUR2 billion ($2.2 billion) as part of the latest attempt by the government to restructure the country's nuclear industry.

EDF Chief Executive Jean-Bernard Levy said earlier this past week that an offer would be forthcoming. The company made its nonbinding bid to buy the nuclear-reactor unit of Areva on Friday, a person close to the matter said. The amount will be negotiated and increase, the person said.

The French utility has stepped in to take over some of Areva's assets following requests from Economy Minister Emmanuel Macron. Officials at both Areva and EDF have said the government will have the ultimate say. More than 80% of the two companies' shares are held by the government. French President François Hollande will meet June 3 with Mr. Macron and other top officials to discuss the issue.

The minister advocated a tie-up between the two companies after Areva sank deeper into losses last year, dogged by a tough market for nuclear reactors since the Fukushima disaster in Japan, poor investment decisions over the past decade and cost overruns on two projects in France and Finland. The initiative from the government is the latest in a long effort to reorganize France's nuclear sector, which has lost ground to competitors from Russia, South Korea and the U.S.

Areva has booked four consecutive annual net losses, culminating with a EUR4.8 billion loss last year.

The person close to the matter said EDF wants to avoid liabilities with two Areva projects in Finland and in France, which ran into cost overruns so wide they threatened the company's survival. The French utility operates the world's largest fleet of nuclear reactors and is one of Areva's largest customers.

The preliminary offer is lower than what some analysts had expected.

Analyst Pierre Boucheny at brokerage Kepler Cheuvreux estimates earnings before interest, taxes, depreciation and amortization on Areva's reactor construction and servicing business amounted to a loss of about EUR1 billion over the past five years. The nuclear-fuel manufacturing business has been slightly profitable over the period, he said.

Mr. Boucheny estimates the reactor unit might be worth between EUR3.5 billion and EUR4 billion given the unit's outlook and the fact EDF wouldn't take on liabilities related to the nuclear reactor being built in Finland.

The other large French power utility, Engie, formerly known as GDF Suez, is also interested in some of Areva's assets. Its chief executive, Gerard Mestrallet, said his company might be interested in taking a stake in Areva's nuclear-reactor servicing unit.

Write to Inti Landauro at inti.landauro@wsj.com

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