July 15 (Bloomberg) -- Operators of an underground nuclear- waste dump in Germany are trying to shore up the interior faster than it’s being eroded by water leaks, buying time until they determine whether the site should be shut down.

Workers will use cement to reinforce ceilings of chambers in the former salt mine, said Wolfram Koenig, president of Federal Office for Radiation Protection, the atomic regulator. Water has seeped into the site since at least 1988. About 12,000 liters (3,170 gallons) enter daily, forming underground pools that must be covered to avoid contamination so the water can be pumped out safely or used to make cement.

“Essentially we’re trying to buy ourselves time,” Koenig said in an interview at the Asse dump in the northwestern state of Lower Saxony. The waste site is about 31 kilometers (19 miles) south of Volkswagen AG’s headquarters in Wolfsburg.

The Lower Saxony environment ministry today approved a plan to fill the fissures in the walls and ceilings of the chambers and reduce the risk of collapse. The remedial efforts don’t change the fact that the site’s stability is “massively at risk,” state environment minister Hans-Heinrich Sander said in an e-mailed statement.

German Environment Minister Sigmar Gabriel, whose electoral district includes some of the nearby towns, has called Asse a “complete failure” and a “Swiss cheese” full of holes. The cost to shut it down permanently may be as high as 4 billion euros ($5.6 billion), Gabriel said five days ago.

Germany today enacted new rules for storing nuclear waste, including a requirement that high-level radioactive material be stored safely for a million years as well as regulations on how storage technology must be “continually optimized” during the construction of a repository.

Radiation Protection

Koenig’s agency took over as operator in January after the former manager failed to report water seepage and the unauthorized storage of contaminated material. Since then, new rules have forced workers, who previously wore street clothing on the job, to wear radiation monitors. Other precautionary measures for radiation protection in the mine were set up.

Asse stores 126,000 barrels of what the regulator calls “weak” and “mid-radioactive” waste generated by nuclear plants from 1967 to 1978. Koenig and colleagues are weighing three options for closing the site: repackage the waste and store it at another repository; create new chambers at the same facility; or to fill the entire mine with concrete.

Almost two-thirds of Germans are in favor of closing the country’s 17 nuclear power plants, a decision reached by the previous Social Democratic government, according to a Forsa survey commissioned by the environment ministry.

To contact the reporter on this story: Jeremy van Loon in Berlin at jvanloon@bloomberg.net.

Last Updated: July 15, 2009 11:32 EDT