Demonstrators take part in a protest to ask for the closure of the nuclear power plant of Fessenheim, in Fessenheim, France, June 26, 2011. Anti-nuclear protestors from France, Germany, and Switzerland demanded on Sunday the closure of France's oldest nuclear plant which is located at the French-German border along the Rhine river. [Photo/Agencies]

FESSENHEIM, France - Thousands of demonstrators formed a human chain outside France's oldest nuclear power plant on Sunday to demand the site be closed as the government mulls whether to extend its life by a decade.

The plant at Fessenheim, in Alsace, has become a flashpoint in the renewed debate over nuclear safety in France following the Fukushima disaster In Japan.

Its location near the German border has also made Fessenheim a point of tension between France, which is heavily reliant on its 58 nuclear reactors and has defended their safety, and Germany, which has decided to abandon nuclear power.  

Ecology Minister Natalie Kosciusko-Morizet said on Friday there would be no decision until a report from the nuclear safety watchdog was submitted in early July and the results were in from safety tests set up in the wake of Fukushima.

Some 5,000 mostly German demonstrators stretched out over four or five km outside the plant on Sunday in a protest organised by French, Swiss and German associations, supported by France's socialist and green parties.

The No. 1 reactor at Fessenheim has been in service since 1977. The plant is operated by French power group EDF .

The demonstrators fear the site is vulnerable to earthquakes and flooding, whilst EDF and the French nuclear safety authority say this has been taken into account in the plant's design and that risks are regularly reassessed.