Nuclear worries increase as German dump mine floods

An old potash mine in north Germany containing nuclear waste is flooding at a rate of 12 cubic metres a day and throwing up all sorts of questions about safe keeping of nuclear leftovers for a million years.

The design for nuclear waste storage in the now flooding Asse II potash mine near Wolfenbüttel, about 80 kms southeast of Hannover, is the same as for the specially dug salt mine at Gorleben, seen as the likely permanent repository.

Forty years after dumping in Asse II started, massive problems are appearing, though nuclear waste storage was researched there from 1967 to 1992.

The federal environment minister, Sigmar Gabriel, in whose electorate the research mine is located, has said he wants to be more thoroughly informed on how radioactive waste is handled.

Anti-nuclear activists will perceive that as a sick joke because they accuse the Social Democrat of caving in on safety concerns to the nuclear lobby and its conservative political backers.

At any rate, Gabriel has demanded a comprehensive report about Asse II from the Lower Saxony state environment ministry which has the supervisory responsibility for Asse II. Lower Saxony has a conservative government headed by a decidedly pro-nuclear premier.

Lower Saxony state politicians are demanding a parliamentary inquiry. Especially Greens, Social Democrats and The Left condemn the handling of nuclear waste as irresponsible.
People have been protesting since Asse II began operating as a trial repository in 1967.
Since public discussion began last year about a concept to close it down by flooding it completely the alarm signals have got clearer.

The old potash mine is not only seen as in danger of collapsing, it has also now emerged that the brine that occurs in all salt rock has become radioactively polluted in an as yet unknown procedure. The contamination is higher than permitted maximums.

"When the brine comes into contact with the nuclear waste any number of chemical reactions can occur,” warns Rolf Bertram, professor emeritus for physical chemistry.
Many local residents and nuclear opponents fear that the contaminated brine will get into drinking water supplies.

It appears that the operator of the mine dump, the Helmholtz-Zentrum in Munich, has carried out works in it without a permit. The inquiry is to establish whether authorities also made mistakes.

Nuclear opponents throughout Germany feel vindicated by the Asse II happenings. "Asse II shows yet again that the final repository theme is still unclear,” says Alex Burger, spokesman of The Greens in the state of Bavaria.

"What’s happening in the Asse II can happen at all other locations for final repositories,” warns Peter Dickel, spokesman for Arbeitsgemeinschaft Schacht Konrad, a group resisting another planned final nuclear dump in a former iron ore mine in Salzgitter, about 15 kms west of Wolfenbüttel as the crow flies, 65 kms southeast of Hannover.

Since 1987 the Arbeitsgemeinschaft Schacht Konrad has been trying with litigation, protests and information to stop nuclear waste being put in both Asse II and Schacht Konrad.

In 1991 they collected almost 300,000 objections against the Salzgitter dump. Despite this, the old iron ore mine is being made ready as a national final repository for weak and medium radioactive waste. Storing is to begin in 2014.

Dickel is disquieted not just by the problems as such, but also by the way they’re being responded to: "Ministries and authorities squabble over responsibilities, dangers are played down and, worst of all, important information is not revealed.

“This is about waste that could damage people, animals and plants for a million years.”
“Why are we talking about Asse II, have we got too much time?” was the rhetorical question that opened a discussion by the group resisting dumping in the Gorleben experimental mine, about 150 kms northeast of Hannover.

“Quite the contrary,” answered Gerhard Harder, opening a meeting of the Bürgerinitiative Umweltschutz, “time is running out for us because the moratorium on Gorleben is running out.” He meant the government-ordered stop of further exploration of that mine’s suitability as a repository.

Harder said the meeting was called specifically to address the linkages between Asse II und Gorleben; what was happening in the old potash mine at Wolfenbüttel mustn’t be allowed to happen in Gorleben as well.

For years Asse II was seen as the prototype for Gorleben, now Asse II opponents are fighting to have the radioactive waste lifted out of it before it’s too late.

Every day 12 cubic metres of water are pouring into the pit uncontrollably. The pit is in danger of being submerged. So far the water is being caught and pumped out.

It’s now become public knowledge that the water is contaminated with cesium-137, strontium, radium und plutonium.

The Helmholtz Zentrum placates, insisting there’s no danger to people or the environment, although small amounts of the brine are already being caught at the level where nuclear waste is stored.

Was this dilemma predictable? Prof. Werner Schneider, guest speaker at the Gorleben meeting, said when the potash mine was turned into a nuclear dump in 1967 it was already foreseeable that brine would flow.

He mapped the region as a geologist and emphasised that from his scientific perspective there were clear indicators for the precarious situation: the sinkholes (or dolines in geology-talk) on the edge of the salt deposit.

On one side the deposit lacks a water-impervious clay layer. The biggest danger for any salt mine is water inflow, Schneider said. The brines behave very aggressively.

Where there is nuclear waste in the shafts or chambers, the brine behaves very aggressively, he said, which raises the obvious suspicion that some of the drums containing it are already corroded.

“The porosity of the overburden rock was known from the outset. That this was ignored in storing nuclear waste is ethically zero.”

Engineer Udo Dettmann of the Asse II resistance group aufpASSEn e.V. (a play on words meaning watch out) deplored that all disasters were only revealed by incessant research.
The Helmholtz Zentrum was also juggling around with the cesium-137 concentration, he said.

The centre claims that most of it was below the permitted level of 10,000 Becquerels per kilogram, which meant that the radiation protection rules didn’t apply. In actual fact, said Dettmann, at some collection points the concentrations exceed the permitted level by three to eight fold.

From 1967 to 1978 124,494 highly radioactive drums and 1,293 medium active ones were stored in Asse II.

A large proportion of the drums were simply tipped in and already damaged by that. Brine has been seeping into the salt deposits since 1988.

The plan is to flood the entire mine with a magnesium protective fluid to prevent the disastrous interaction between the brine and the waste.

The Helmholtz Zentrum euphemistically calls this method “wet storage”. Flow barriers are to prevent the nuclear waste drums being inundated too quickly.

Construction of the first three flow barriers was completed a few months ago.

If the shafts and with them the waste drums are really to be flooded, they’ll rust away even faster, in a few decades. Contaminated salt solutions would seep into the ground.

Only just recently a study by the government radiation protection agency, BfS, caused furore in the region when it calculated how fast fluids and gases could exit from the mine.

Already 150 years from now contaminated gases could escape into the biosphere in a concentration many times greater than the now set maximum levels.

Despite the obvious failure of the Asse II dump, the Helmholtz Zentrum still unashamedly touts it on its website as a research field.

Asse II was to officially remain a research mine but the political tussles about it did not at any time stop researchers from using the potash mine as a laboratory – for Gorleben.

Until recently the operators of Asse II have been emphasising its pilot function for Gorleben.

Prominent advocates of Gorleben as a final repository, such as mining professor, Klaus Kühn, are still undeterred in recommending aqueous rock as a final repository medium. Kühn was even still certifying Asse II safe when the brine was already flowing.

Wolfgang Ehmke of the Gorleben opposition told the meeting, “In Gorleben there were brine nests and inexplicable water inflows in the phase of digging the shafts. Geologists warned of the water flows and the porous overburden rock.

“The trust in scientific and political honourableness in final repository research is being totally destroyed.”