08/29/2008 - 08:03

Nuclear waste repository case studies: Germany

Michael Sailer

Currently, there are 17 nuclear reactors at 12 different sites in Germany. According to a 2002 amendment to the country's 1959 Atomic Energy Act, each reactor has a fixed amount of megawatt hours that it's allowed to produce. When it reaches its limit, the reactor has to be shut down permanently. Therefore, depending on their age and production history, all of Germany's reactors are expected to cease operating between 2009 and 2023.

For disposal purposes, the waste produced by these reactors is divided into two categories--heat-generating waste and non-heat-generating waste. Heat-generating waste includes spent fuel from light water and other nuclear reactors, vitrified high-level waste, and core instrumentation and residues from fuel element cladding after reprocessing. By 2040--a year continuously used in German waste predictions but without any special meaning--Germany will possess 22,000 metric tons of this type of waste. It's currently housed at dry interim storage facilities at each reactor site and four other locations--Ahaus, Juelich, Greifswald, and Gorleben. (See map of "Nuclear Power Plants and Storage Facilities in Germany.")

The storage containers at each interim facility consist of thick-walled, special-cast iron and are built to survive massive aircraft crashes without releasing radioactivity. Within the next 10 years, additional amounts of vitrified glass stemming from reprocessed German-origin spent fuel will be delivered to the Gorleben interim-storage facility from reprocessing plants in France (La Hague) and Britain (Sellafield).

More or less, the non-heat-generating waste is the rest of the country's radioactive waste. It includes low-level waste and most intermediate-level waste--as long as it's not heat-generating. The country doesn't differentiate between waste with long-lived isotopes and short-lived isotopes. Today, some 100,000 cubic meters of conditioned low- and intermediate-level waste resides at the 12 German reactor sites in interim-storage facilities; major interim-storage facilities at Greifswald, Juelich, Karlsruhe, Mitterteich, and Gorleben; and state interim-storage facilities for non-reactor radioactive waste. By 2040, that number is expected to increase almost threefold to 277,400 cubic meters.

Waste with very low radioactivity doesn't need to be specially handled if its radioactivity is below the German clearance levels provided by Berlin's radiation protection ordinance and miscellaneous provisions.

When the decision was made to dispose of all German nuclear waste in deep geologic formations in the 1960s, West Germany and East Germany each began operating a "test disposal facility" for non-heat-generating waste. In West Germany, 124,000 containers of low-level waste and some 1,300 containers of intermediate-level waste were disposed of in the Asse mine. Similarly, East Germany used the Morsleben mine for the disposal of its non-heat-generating waste. Both are located in a salt-dome and have been mined for decades for rock salt and potassium chloride. However, rock instabilities caused by extensive mining activities have led to problems of mechanical stability. Another major safety problem at Asse is that since 1988, 12 cubic meters of salt water has entered the mine daily--an amount that could change in the future. No matter the amount, the incoming brine will be lifted to the surface and discarded at a different facility.

As for the country's heat-generating waste, several salt domes have been discussed since the early 1970s as potential locations for a final disposal facility. (The passage of a 1975 amendment to the Atomic Energy Act stipulated that West Germany was to dispose of its nuclear waste geologically.) In 1977, the West German government and state government of Lower Saxony decided to explore the salt dome at Gorleben, where mining had never taken place. The site-selection process has never been made public, but Gorleben was chosen after several salt domes were compared geologically. Ultimately, an exploration mine at Gorleben was installed, and it operated until October 2000, when exploratory work stopped because of a moratorium established by the federal government--then a coalition of Social Democrats and Greens. This coalition wasn't in favor of the Gorleben site, and the moratorium was introduced mainly to buy time for another solution.

In 1999, the new federal minister of environment installed an advisory group called "AkEnd," whose task was to elaborate a site-selection procedure and criteria for the selection. AkEnd published its final report in December 2002. Although the federal environment minister hasn't formally adopted it, the report has played an important role in the discussions of stakeholders and policy makers. Especially for those in favor of an elaborate site selection, the AkEnd report is proof that such a working selection procedure exists.

Policy process

According to the Atomic Energy Act, the federal government is obliged to build and operate final nuclear waste disposal facilities. In particular, the Ministry of Environment is tasked with implementation and regulation of final disposal. The federal agency for radiation protection, which the Federal Ministry of Environment oversees, acts as the implementer. The state's Ministry of Environment serves as the licensing authority. The German nuclear industry doesn't have direct responsibility for the final disposal of the waste, but the country's "polluter pays" policy forces the industry to underwrite all of the costs for disposal and the preparation activities regarding its respective share in the resulting amount of waste.

Non-heat generating waste: In the early 1980s, a proposal was presented to use the former iron mine Konrad as the final disposal facility for non-heat-generating waste. In 1982, the predecessor to today's federal agency for radiation protection applied for a construction and operation license to the Lower Saxony's Ministry of Environment. But a large debate ensued and it wasn't until 2002 that Lower Saxony approved the license, after which some locals and municipalities took the government to court. Ultimately, the federal government decided to postpone construction until all of the legal obstacles were overcome.

With the final court finding last summer ruling in favor of using the site, detailed planning is now underway, and the Konrad disposal facility is expected to open between 2013 and 2014--despite continued local debate.

Heat-generating waste: Although Gorleben was selected as the disposal site for heat-generating waste 30 years ago, the decision is still subject to significant scrutiny, and opinions about how to proceed differ greatly. The political situation in Germany doesn't make it any easier. Currently, there are five political parties in the country´s parliament--the Christian Democrats and the Social Democrats are the two major parties, while the Left (former communists), the Liberals (generally right-wing), and the Greens are the three smaller parties. Naturally, they each have substantially different views of nuclear power and nuclear waste disposal.

That said, in general, four main arguments about the Gorleben site exist:

  • Local citizen groups and their supporters maintain that Gorleben isn't a suitable site, arguing that there are problems with the geological stability of the salt dome and the past site-selection process.
  • AkEnd suggests that the selection procedure start anew with a "white map of Germany"--in other words, no preselection.
  • The federal minister of environment and the Social Democrats support a selection process that compares Gorleben against a few other select sites. If any of these other sites are identified as having a clear advantage, Gorleben is scrapped. If not, Gorleben remains the disposal site for heat-generating waste.
  • The German nuclear industry and Christian Democrats don't understand why the country should embark upon a new site­-selection process. They believe that since Gorleben was chosen via a valid selection procedure 30 years ago, the exploration of the site should continue as rapidly as possible.

Since the federal government has been based on a coalition of Social Democrats and Christian Democrats since 2005, neither party has been able to push forward its preferred option. Therefore, the result has been gridlock. Most political observers don't expect this to change until the fall 2009 federal elections.

Technical issues

The Konrad disposal site is located in an iron ore layer in the Konrad graben at a depth of 800-1,300 meters. It's overlaid by several hundred meters of highly impermeable Cretaceous claystone and marlstone, which according to demonstrations during the licensing procedure should guard against the release of radionuclides into the groundwater.

In the "conditions for acceptance" of non-heat-generating waste issued by the federal agency for radiation protection, the allowed waste packages are specified as waste drums of 200- and 400-liter volume and containers with those waste drums inside. The conditions also include specifications for the content of radionuclides and the chemical and mechanical form of the waste. Before delivery to the final disposal facility, the waste must adhere to these conditions and be verified by the federal agency for radiation protection, which a majority of the country's existing non-heat-generating waste already does.

Meanwhile, most German geologists agree that salt domes and thick layers of claystone could serve as the final disposal site for heat-generating waste as well. The specific behavior of such geologic formations allows the waste to be completely enclosed after a couple of decades or centuries. According to German experts, the geologic barrier must demonstrate that it's stable enough to hold for at least one million years. Technical barriers such as casks, backfill, and drift and shaft seals are required until the geological barrier encloses the material over time. German experts believe it's easier to predict the behavior of a well-known, investigated geologic repository than that of a human-made system.

Decisions on heat-generating waste packaging and actual disposal options haven't been formally considered yet. But a general outline has been established, and it includes a deposition of the waste packages in horizontal drifts or chambers or in vertical boreholes starting in drifts. Three types of packages are under discussion:

  • Massive iron casks for spent fuel and vitrified glass canisters--e.g., the POLLUX cask. The casks will be loaded at the conditioning plant, and they're suitable for horizontal storage.
  • Massive interim storage casks for spent fuel--e.g., the CASTOR cask. Although an interim cask, they won't be reopened after interim storage; they, too, are suitable for horizontal storage.
  • Steel canisters with thin walls for spent fuel. Like the iron casks, they will be loaded at the conditioning plant; their dimensions are similar to the coquilles in which the vitrified glass is delivered from reprocessing plants. They can be stored horizontally or vertically.

Public response

According to polls, a vast majority of Germans want a solution for nuclear waste disposal as quickly as possible. But polls also show that they don't want a disposal site in their backyard, presenting a tricky situation in a country that has a high population density.

Since 1977, many big demonstrations and other acts of protest against the Gorleben site have taken place. This resistance is organized by local groups who have broad local and national support. In Gorleben, the situation is complicated by the installation of three additional nuclear facilities (an interim storage facility for spent fuel and vitrified glass, an interim storage facility for non-heat-generating waste, and a waste-conditioning plant) literally across the road from the exploratory mine. Their presence and resulting activities--i.e., the transport of vitrified glass to the interim storage facility--have also caused significant protest.

Suggested improvements

In order for Germany to permanently dispose of its heat-generating nuclear waste, the federal government needs to make some clear decisions. Namely, the next coalition government must establish a road map for where and how the waste will be disposed. Until this political element is fixed, suggestions for further improvements are useless. That said, communication between the government and pertinent stakeholders needs to improve. For example, as of now, all discussions are undertaken on an informal basis, without a clear procedure as to how the public can substantively participate. No matter the ultimate governmental directive, the process won't proceed until the communication issues are cleared up.