The salt dome formations are not suited to be a permanent storage site, BfS spokesperson Florian Emrich told daily Frankfurter Rundschau.
“Gorleben has many birth defects that are not compatible with today's open and transparent policies and is therefore controversial,” he said.
Emrich suggested that since Germany's reunification, options for new sites have increased, with potential regions including northern Germany, and the states of Bavaria and Baden-Württemberg.
But it is up to the government to set further guidelines for nuclear waste storage, Emrich said. Currently there is “no criteria that says Gorleben is suitable and none that says it isn't suitable,” he added.
Claims by Kiel Geologist Ulrich Schneider, who said Gorleben could flood, are realistic, the BfS spokesperson conceded.
In May, a leaked internal BfS assessment revealed that Gorleben was developed illegally.
Since work began on the underground facility in the 1980s, only permission for “exploration” has been granted. But even without an official authorisation, the paper said that costs for assessing the salt dome for its suitability had been high because “the construction of the permanent storage depot was begun parallel to the investigation.”
Work at Gorleben has been suspended since 2000, when the government decided to wait until 2010 to resume the controversial project.
The appearance of the documents has confirmed the doubts of nuclear energy opponents, who believed that Gorleben had been earmarked as a permanent storage depot before the safety of the salt dome had been adequately investigated.
Nuclear energy is deeply unpopular in Germany activists often stage protests at Gorleben, which is in the German state of Lower Saxony. The government has approved plans to get rid of its reactors by 2020. But high energy costs and greenhouse gas concerns have some politicians second-guessing the plans.