25 Sep 2020, 14:00

What to do with the nuclear waste – the storage question

Germany is in the rare position of knowing almost exactly how much radioactive waste it will have to store because the lifespan of its nuclear reactors is limited and the existing amount of waste is established. But questions over where to store it and how long it will take to load a final repository remain unanswered. [UPDATES explanation of how the search process for a final repository is conducted]

High-level waste

Germany will have to store 1,900 large containers, or around 28,100 m3 (cubicmeters), of high-level radioactive waste by 2080 (See Figure 1), when all its nuclear power stations and many research facilities will have been finally decommissioned and the fuel elements treated at other facilities.

So-called high-level radioactive waste, i.e. the thermogenic (heat generating) remains of the fuel elements, needs to be securely stored for up to several million years until its harmful radioactivity fades. Scientists (nuclear semiotics) are even wondering how future humanoid generations can be warned against the dangerous waste, because languages and symbols may have changed entirely and storage places might be forgotten hundreds of thousands of years from now.

A total of 303,000 m3 of the 600,000 m3 low and medium-level nuclear waste will be stored in a final storage facility in the retired iron ore mine Schacht Konrad, near Salzgitter. The repository is under construction and is scheduled to be loaded from 2022. The government aims to complete this process within 40 years, the Ministry for Environment writes in the “national disposal programme” of August 2015.

 

Heat-generating waste accounts for only a fraction of Germany’s radioactive refuse, but is responsible for 99 percent of the radiation. It is currently held at temporary storage facilities near the nuclear power stations and in central interim repositories in Ahaus (North-Rhine Westphalia), Gorleben (Lower Saxony) and Lubmin (Mecklenburg-Vorpommern). (See Figure 2).

Low and medium-level waste

By 2080, Germany will have to store some 600,000 m3 of low and medium-level nuclear waste with “negligible heat generation” (Figure 1). This waste is largely made up of used parts of nuclear power stations such as pumps, pipelines, filters, contaminated tools, cleaning agents and sludges.

There are currently a multitude of interim storage facilities for radioactive waste with negligible heat generation situated all over the country, near research facilities or operated by the nuclear industry as well as state collection depots in 11 German states.

 

Finding a final repository for high-level waste

After passing a new “Law for finding and choosing a nuclear waste repository” in 2013, the environment ministry set up an expert commission on how the search for a final repository for heat generating waste is administered. The search will continue until 2031. Germany is a “blank map” when it comes to finding a final repository for the highly radioactive waste, environment minister Barbara Hendricks said. Everywhere is a possible location, provided the geological rock formation for an underground repository is favourable.

The expert commission presented its final report in July 2016, sticking to these general parameters. The search procedure will focus on possible storage sites in rock salt, clay rock and crystalline granite. It will thus also include the salt mine at Gorleben where explorations had already begun but were terminated amid large protests from citizens (see below). The nuclear waste is to be stored for one million years in the final repository, but shall be retrievable for the first 500 years, the commission suggests. This is in case a treatment is found to reduce radioactivity earlier (transmutation). The commission, made up from parliamentarians, scientists and NGOs agreed on a general export-ban for nuclear waste.

New search procedure to avoid the mistakes of the past

The commission's much fought over work showed that finding the right site is a difficult one as no community or town in Germany is particularly keen on living next to a cemetery for contaminated waste, Hendricks said. Bavaria’s government, for example, does not tire of pointing out that there are no suitable rock formations to be found in the regional state. And the residents of Salzgitter, near Schacht Konrad, are afraid that the nearby repository will be extended to house even more than the 303,000 m3 of low and medium-level waste. The state of Lower Saxony only agreed to the 2013 site selection law if investigations at Gorleben salt mine were stopped and no further atomic waste containers were sent to the interim storage facility nearby.

Security concerns at existing facilities for waste with negligible heat generation at Morsleben and in the old salt mine Asse, which will cost several billion euros to be fixed, have undermined the trust in the safety of nuclear waste repositories. The situation is particularly dire at Asse, where over 200,000 m3 of low and medium-level waste have to be retrieved from instable mine shafts partially flooded with groundwater (influent saline solutions), causing concerns that radioactive elements could contaminate the drinking water nearby. Getting the leaking radioactive barrels, which were deposited in 1967, out of Asse cannot be attempted until 2033, the ministry said.

It is not clear where the Asse waste will then be stored. Minister Hendricks suggests in the new waste disposal programme that the final repository for high-level waste should also be able to accommodate the 200,000 m3 from Asse. Critics claim this will make finding a final repository even more difficult because storing heat-generating waste and low and medium-level waste together requires different conditions and, above all, much more space.

"The search can begin"

In March 2017, Germany’s parliament, the Bundestag, approved a joint bill introduced by the governing coalition of CDU/CSU and SPD, as well as the Green Party, to authorise the search for a final repository. The law states that the public would be “extensively involved” through “transparent participation procedures” before the search's planned conclusion in 2031. “More than 30,000 generations will be affected by a nuclear technology that we’ve only used for 60 years,” Hendricks said in a speech preceding the decision in parliament.

The main body in charge of conducting the search is the Federal Company for Radioactive Waste Disposal (BGE) which prepares the reports and conducts the stakeholder participation events. It is supervised by the Federal Office for the Safety of Nuclear Waste Management (BASE) which reports to the environment ministry.

The BGE has to follow the rules set out by the Site Selection Law of 2017 and accompanying regulations. Its first task was to prepare the “Interim report on sub-areas” (Zwischenbericht Teilgebiete) that devises a first map of possible locations for the final waste disposal site. This report is presented on 28 September 2020.

To arrive at the interim report, the BGE collected existing geological data from the states and used it to exclude unsuitable areas by looking at a set of criteria:

Exclusion criteria: The area may not be prone to volcanic activity, earthquakes or have been damaged by mining activities.

Minimum requirements: The future site of the repository has to be located in either salt rock, crystalline rock or clay rock. The covering rock layer above the storage area must be at least 300 metres thick. The surrounding rock must be at least 100 m thick. The storage area must be of a certain size that also allows for retrieving the waste if it should become necessary. No water may be able to enter the repository. All of these criteria will have to hold true for one million years.

Geo-scientific criteria: (to differentiate between areas that are equally suitable under the first two sets of criteria): The surrounding rock must be able to dissipate heat and keep radiation from getting out. The chemical composition of the rock may not interfere with the waste containers.

Further process: After having presented the interim report, the process will continue with citizen and stakeholder participation elements as of October 2020  that will become part of the next report on the chosen regions.

The BGE will then make a suggestion as to which of these regions should be further explored (above ground). The federal parliament (Bundestag) and the chamber representing the states (Bunderat) will decide if the BGE’s recommendation is valid. If this is the case, surface exploration (including exploratory drilling) will begin, followed by another decision by Bundestag and Bundesrat identifying regions to be explored further by building exploratory mines.

The BGE will then propose a location for the final repository, which will become law if Bundestag and Bundesrat agree. If this is completed by 2031, the repository mine can be constructed.

How to find a space to store dangerous nuclear waste forever in Germany

Storing the waste in its final destination

After a site decision is made, the final repository for heat-generating waste should be built by 2050 when the first containers with used fuel elements are to be deposited there. The process of transporting and storing thousands of casks in the final repository will take until 2090 or 2100, the environment ministry said in 2016.

However, the experts from the parliamentary storage commission anticipate the finding and building of the final repository to take decades (35-61 years) so that the loading and sealing of the repository could be expected to last “well into the next century”, the report says.

All texts created by the Clean Energy Wire are available under a “Creative Commons Attribution 4.0 International Licence (CC BY 4.0)” . They can be copied, shared and made publicly accessible by users so long as they give appropriate credit, provide a link to the license, and indicate if changes were made.

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