Asse mine

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Headframe of the Asse II shaft
Sectional drawing through the Asse-Salzsattel and the mine building of the plant

The Asse mine is a former salt mine in Lower Saxony , which was operated as a research mine from 1965 and on which the final storage of radioactive waste was tested and practiced on a large scale between 1967 and 1978 .

The mine is located in the Asse ridge of the same name, ten kilometers southeast of Wolfenbüttel . After the older of its two day shafts , sunk in 1906, the entire system is also called Asse II .

Since 1965, the facility has been operated on behalf of the federal government by a research facility that was initially called the Gesellschaft für Strahlforschung mbH (GSF) and, after several name changes, now operates as the Helmholtz Zentrum München (HMGU). Research into the final disposal of radioactive waste ended in 1995. From 1995 to 2004, the remaining cavities from the former salt mining were filled. In 2007, the final closure was requested. The closure concept was politically controversial; However, the decision was under certain time pressure, since the mechanical stability of the mine seemed to be secured for only a few years.

After press reports on radioactively contaminated brine in 2008, the operator was accused of having insufficiently informed the supervisory authorities. This was later officially confirmed. In order to be able to close the facility appropriately under nuclear law , it is no longer operated according to mining law , but since January 1, 2009 as a repository according to nuclear law . That is why the Federal Office for Radiation Protection (BfS) has been responsible for the operation and decommissioning of the facility since January 1st, 2009 . With the change of operator, political responsibility fell from the Federal Ministry of Education and Research to the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety . The new operator rejected the closure concept of its predecessor, compared three options for handling the stored materials and presented a plan in January 2010 to retrieve the stored waste.

Location and operation as a salt mine from 1906 to 1964

The salts of the Asse were excreted from the sea in the Zechstein Age , 250 to 230 million years ago ( bar theory ). The formerly flat layers were tectonically unfolded about 110 million years ago to form today's Assesattel. While the flatter north flank has been pushed up from the overburden layers of the lower red sandstone to the surface, the steep south flank consists of sediments of the upper red sandstone and shell limestone and the subsequent overburden layers.

Filling location of the Asse II shaft approx. 490 m below the surface of the earth

In the mining history of the Asse, the potash salt carnallite was first mined , and later rock salt . Particularly intensive mining was carried out in the southwest flank, in which the layers of the overburden are steep. These interventions impaired the state of tension in the salt saddle. Redistributions led to deformations here and in the overburden, which paused up to the surface.

In the years 1894 and 1895, three deep boreholes were carried out for the first time, in which salt deposits were found at a depth of 296 m . In the Asse I mine near Wittmar , potash was mined from 1899 onwards. In the autumn of 1905 there was an inflow of lye from a pre-borehole driven against the salt clay , which increased so much that the pit had to be abandoned in 1906.

Between 1906 and 1908 1.4 km was removed on the corridor of Remlingen m of the shaft aces II to a depth of 765 drilled . Three construction fields were created: in the north for the mining of carnallite (1 million m 3 eruption, 1909–1925), in the south for younger (Leine) rock salt (3.4 million m 3 , 1916–1964), and at a greater depth in the core of the salt dome for older (Staßfurt) rock salt (0.5 million m 3 , 1927–1964). The rock salt mining on Asse II ended in 1964. Part of the eruption was immediately relocated; a cavity volume of a good three million cubic meters remained. In some places the salt barrier to the overburden is only a few meters. In the 1920s, wet backfill was introduced into the potash mines; therefore, the majority of the water currently in the salt dome appears to come from, which collects on the bottom of the soles and, where these have slopes, flows into so-called swamps.

Shaft 3 (Asse III) near Klein Vahlberg was constructed from 1911 onwards, as the mining authorities requested a second shaft for safety reasons. During the work, the system had strong lye inflows and was submerged three times. As a result, the actual salt extraction did not even begin. After the First World War, the work continued and in 1923 it reached the final depth of 728 m. In 1924 the shaft was closed due to the Potash Economic Act, among other things due to the collapse of the demand for potash.

Asse IV is a second day shaft of the Asse II mine and is located in the immediate vicinity of shaft II. It was created by soling and, due to its small diameter, is only suitable for passenger ropes.

Storage phase 1965 to 1978

Goal setting

When the first German nuclear power plants were planned in the 1960s , it was clear that a repository for high-level radioactive waste would be needed after a decade or two . At the International Conference on the Disposal of Radioactive Waste Products in Monaco, it was discussed for the first time that radioactive products in solid form or in containers could be stored in artificial or natural caverns in the ground. Due to the geological conditions in Germany, storage in salt domes was considered the most promising option. There was great confidence that a repository could be put into operation within a few decades. Gorleben was suggested as the location back then . As a prototype for the repository and to clarify the technical issues that were still open, the GSF acquired the Asse II mine from the then owner of Wintershall in 1965 on behalf of the federal government at a price of DM 700,000.

“The aim was to determine and provide the relevant techniques and scientific and technical data for a planned repository in the Gorleben salt dome. The Gorleben salt dome was in the aptitude test. We at GSF should carry out the relevant technologies and scientific studies in the Asse research mine. "

- Klaus Kühn : former operations manager at Asse, 2001

Although the problem of water ingress was known, plaintiffs in court failed with their concerns, and the Asse II mine was declared “dry” and “suitable for the storage of radioactive waste”. In 1972, the then State Secretary in the Federal Ministry of Science, Klaus von Dohnanyi, announced :

"The ingress of water can be ruled out with a probability bordering on certainty."

- Klaus von Dohnanyi

On the occasion of a specialist visit in 1964, the wording was:

"[...] On the 750 m level there is a collecting basin for magnesium-containing lye, which flows in small quantities, 700 l / day, from old carnallite quarries, and a container to collect the dripping water from the shaft. [...] According to Prof. Mohr, the water supply can be contained by cementing. [...] "

- Viewing note

Initial cost estimate

As early as the end of the 1960s, the Asse operating company was asked by the AEG for an opinion on the suitability for final storage and the magnitude of the future disposal costs. In the reply, she said that she could buy 300 barrels per year without any problems, that she was not yet able to provide binding information on the costs, so that she could then continue:

"However, we estimate that the costs [...] will be around DM 100 per 200 liter drum."

- Society for Radiation Research, 1969

Storage inventory

In accordance with the emplacement permits, only low- and medium-level radioactive waste, defined as waste without any significant heat generation , was stored in the Asse . From 1967 to 1975 no fees were charged. Around half of all containers were stored during this time. From December 1975, the fee regulation for the storage of low and medium level radioactive waste in the Asse salt mine came into force . By the end of the storage, an income of around 900,000 euros was achieved.

Costs of 2 billion euros are planned for the renovation; However, expert estimates range up to 6 billion euros.

The entire access documentation was checked again in August 2008 after public speculation about an alleged storage of highly radioactive material. According to the status report, the following were stored in the Asse:

  1. 125,787 containers with low-level radioactive waste, stored between 1967 and 1978 in various chambers at a depth of 750 meters. The containers are mainly metal barrels with a volume of 100 to 400 liters or concrete containers. The declared total activity at the time of the respective storage was 1.8 · 10 15  Bq. Around 50% of containers are from the reprocessing plant of the then Kernforschungszentrum Karlsruhe , 20% from nuclear power plants, 10% of the then Nuclear Research Center Julich . The containers typically contain mixed and laboratory waste, construction waste, scrap, filter residues and combustion residues. Liquids such as evaporator concentrates, sludge, oils, resins and solvents had to be bound in solids. According to former employees, however, barrels with liquid waste were sometimes accepted and stored in the early days.
    Feed chamber above chamber 8a. The barrels with medium-active waste were drained into chamber 8a through the slide in the bottom
    Control panel of the crane system for draining the barrels with medium-active waste. The screen on the right offered a view of chamber 8a
  2. 1293 containers with medium-level radioactive waste, stored between 1972 and 1977 in chamber 8a on the 511-meter level. Only 200-liter roll-hoop drums were permitted as containers, and the waste materials had to be fixed in concrete or bitumen. The declared total activity at the time of the respective storage was 2.8 · 10 15  Bq. Over 97% of the containers (and thus over 90% of the entire Asse activity inventory) come from the Karlsruhe reprocessing plant. Some of the barrels in Karlsruhe contain waste from the reprocessing itself and thus also fissile material. The limit values ​​for this were 200 g 235 U, 15 g 233 U and 15 g 239 Pu per barrel. These limit values ​​were not even close to being reached; the maximum values ​​were 24 g 235 U, 5.7 g Pu and less than 1 g 233 U per barrel. It was thus estimated that less than 25 kg uranium and 6 kg plutonium were stored on the 511 meter level . In August 2009 the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety announced that due to a "transmission error" the registered amount of plutonium was stated far too low and that around 28 kg of plutonium had actually been stored. Another review of the inventory in 2010 shows a total of 14,800 undeclared barrels. Not around 1,300, as previously assumed, but 16,100 waste containers are stored with medium-level radioactive waste.

When assessing the activity of 4.6 · 10 15  Bq stored in the Asse, it must be taken into account that the majority of the radiologically particularly effective and long-lived alpha emitters occur in low-level radioactive waste. This is why low-level waste is of particular importance for long-term safety and causes the greatest problems. The medium-level waste mainly contains relatively short-lived radionuclides, which are of lesser importance for long-term safety, but cause greater problems in handling and handling (necessary shielding).

More than 25% of the containers come from the last year of storage, 1978, at a time when the end of storage was already foreseeable. At the end of 1978, Germany was almost free of low- and medium-level radioactive waste for days, as all potential deliverers took advantage of the period that was still approved for accepting the waste on the Asse. Since the mine could not be approved as a repository, no more radioactive substances have been stored since then.

Storage method

The metal barrels in which the waste was delivered were always seen as a transport container, not as a permanent barrier. The corrosion of metal drums in a salty environment is only a matter of a few years to decades, depending on the humidity. The first and most important barrier to contain the radioactivity is the salt of the salt dome.

At the beginning of the test emplacement, the barrels with the low-level radioactive waste were placed vertically on top of each other in the former mining chambers in the rock salt. Stacking these containers with the low-level radioactive waste on top of one another represented the second phase of emplacement. In the third phase of the test emplacement, the containers with low-level radioactive waste were tipped over a salt slope into the emplacement chamber and then covered with heaps of salt. In this phase at the latest, it was accepted that barrels could be damaged during storage. The medium-level radioactive waste was also dropped into the storage chamber in its rolling hoop drums. A retrieval of stored waste was expressly not intended.

“Special incidents were reported to the mining authority, such as [1973] the extensive contamination in front of chamber 12 on the 750 m level from spilled barrels [which had fallen from a forklift]. This contamination was properly brought into the storage chamber for radioactive waste by removing the corresponding salt sections. "

- Helmholtz Center Munich, 2008

Research operation from 1979

Research by the Institute for Deep Storage 1979 to 1995

Experimental drilling for a thermal conductivity experiment in rock salt. Such tests were carried out between 1967 and 1995 on the 490 m, 750 m and 775 m levels.
Vehicle in the Asse at a depth of 490 m

In 1976 the Atomic Energy Act was amended and the term “repository” was legally defined for the first time. New storage permits could only be issued after a plan approval procedure with the participation of the public. This process was never initiated. Only in the course of the following years did it become clear to everyone involved that the storages would not be resumed.

Asse's new main task was research and development work for final disposal in the Gorleben salt dome. Techniques for backfilling and closing boreholes, chambers, routes and shafts in a repository were developed and tested. Below the existing mine building , further mine structures were excavated as depth outcrops at a depth of between 800 and 975 meters. There, under conditions very similar to those in Gorleben, four large-scale underground tests were to be carried out in the virgin mountains: demonstration tests for the storage of medium and high-level radioactive waste, an attempt to build a dam structure and an attempt to store Pollux containers on horizontal stretches. All research work is documented in the annual reports of the GSF.

In spring 1992 the Federal Ministry for Research and Technology announced that it would no longer support the large-scale tests in the Asse from January 1, 1993 with project funds. As a result of this decision, the GSF Institute for Deep Disposal was dissolved on June 30, 1995. The Braunschweig branch with a focus on repository research was transferred to the Society for Plant and Reactor Safety (GRS). The attempts were canceled.

The former mine director Günther Kappei wrote in 2006:

“For the highly motivated scientists and miners then [...] a world collapsed. All the enthusiasm, all the euphoria with the awareness to carry out unique development work was destroyed at one stroke. At that time it became clear to everyone involved that the years or decades of work, in which the heart and soul of all those involved was put, had largely been carried out in vain. But it was destroyed even more over time. In the meantime, targeted underground research and development work for the safe disposal of radioactive waste in salt has not been carried out in Germany for 15 years. In 2000, a moratorium on exploration of the Gorleben salt dome was set for a period of at least three and a maximum of ten years until fundamental questions of doubt about safety had been clarified. As a result of these long downtimes, the technology used becomes obsolete very quickly and the laboriously acquired know-how is lost over time. We are currently moving further and further away from the task we set ourselves around 50 years ago to solve the problem of the final storage of radioactive waste. "

- Günther Kappei : 100 years of the Asse mine (PDF; 29 kB). Lecture by the head of the Asse research mine, Günther Kappei, p. 6.

Research projects of other institutions

The Karlsruhe Research Center operates since 1978 in Asse II an important for the disposal attempt to leaching of chemical elements from cement . For this purpose, several barrels in which cement mixed with cesium , neptunium and uranium is surrounded by various liquids were placed on the 490-meter level . In the case of some liquids, strong leaching of the elements was measured and destruction of the cement matrix was observed. The implementation of the test is approved until 2013 [obsolete] , but it is to be terminated early as part of the closure of the plant.

Entrance to the underground laboratory for dosimetry and spectrometry at PTB

The Physikalisch-Technische Bundesanstalt (PTB) first set up an underground laboratory for dosimetry and radiological spectrometry (UDO) on the 925-meter level, then on the 490-meter level. Due to the strong shielding by the overlying rock laboratory is Myonenfluss of cosmic radiation by more than four orders of magnitude compared to the reduced to the earth's surface. The local dose rate due to gamma radiation is less than 2 nSv / h, the neutron flux is negligible. Due to its low background radiation, the laboratory was used to measure the smallest activities with the help of germanium spectrometers. In this context, it was considered the best laboratory in Germany. Furthermore, the laboratory was used for comparative measurements in the European framework for self-effect measurement, energy dependency and linearity of local dose rate probes . In the laboratory, collimated radiation fields could be generated, with the help of which the probes can be calibrated in known radiation fields. The future of UDO is endangered by the closure of the facility and the laboratory was given up by the PTB in 2011. In the rock salt plant Braunschweig-Lueneburg in Grasleben the new underground laboratory could UDO 2 are taken in the summer of 2012.

Preparing for closure since 1995

In April 1991, the Lower Saxony Ministry of the Environment commissioned the responsible authorities to carry out a “risk assessment for the Asse 2 mine”. A corresponding report, which was presented in June 1993, pointed to ongoing rock movements and lye inflows and described a backfilling to be carried out according to mining rules as "absolutely necessary".

The Federal Ministry of Education and Research (BMBF) decided in 1992 to end the research work in the mine. The GSF then developed measures to stabilize the mine and worked on a concept for closure. After political turbulence in the summer of 2008, the Federal Ministries for the Environment (BMU) and Science and Research (BMWF) and the Lower Saxony Ministry of the Environment agreed to withdraw responsibility from the company , which was renamed the Helmholtz Center . The Federal Office for Radiation Protection has been the landlord of the facility since January 1, 2009.

Instability of the pit

Supports and struts are not used in a salt mine ; rather, the extraction chambers are laid out in such a way that the remaining salt framework (the mine building) can bear the weight of the overburden itself. It is taken into account that considerable mechanical tensions build up in the pillars and levitation (horizontal areas between the excavation levels ) , under the effect of which the salt structure yields to a certain extent ( plastic deformation ). This yielding continues into the overburden, which is currently shifting in the Asse by up to 15 centimeters per year.

Due to the high degree of construction and the fact that it has been kept open for decades, the deformation in the Asse has reached such an extent that the stressed salt gradually loses its strength: “The load-bearing system has reacted with creep deformations, plastic deformations and local fracture processes to the registered rock stress and is therefore The Institute for Rock Mechanics (IfG) in Leipzig, which has been continuously monitoring this development since 1996, forecast in 2007 that the loss of bearing capacity will increase from the beginning of 2014 and thus increased displacements in the overburden. These shifts can potentially lead to an uncontrollable increase in the flow of water and make it impossible to keep the mine dry.

As early as 1979, a working group headed by Hans-Helge Jürgens prepared a report on the stability of the mine. This describes the threatening scenario of an uncontrolled inflow of solution from the overburden in the area of ​​the southern flank with a subsequent loss of load-bearing capacity of the mine. The operator of the Asse at the time (GSF) and his advisors rejected this report as unscientific and stated that there were no stability problems with the Asse. Corresponding warnings from the Mining Authority had been issued since April 15, 1965.

Water inflow

Brine is stored in tankers on the site (August 2009)

Water always penetrates a salt mine when the salt barrier that is left around the mine building is breached - by accidentally drilling into the barrier or by cracking the deformation of the salt framework. The Asse is particularly endangered by water because the salt barrier is only a few meters thick in places.

For the period from 1906 to 1988, 29 saline solution inflows are documented. Some of them have been successfully sealed, some have dried up, some are negligible (less than 0.5 cubic meters per day). According to the Lower Saxony Ministry of the Environment, they are irrelevant for current operational safety.

Between 1988 and 2008, 32 new access points were found. A part is attributed to solution occurrences within the salt saddle from the areas south of the potash mining. Much more important are the tributaries from the side or overburden in the southern flank, in the area of ​​rock salt mining. They are caught on levels 658, 725 and 750 and are currently (2008) 11.8 cubic meters per day. The collected caustic is checked for radioactivity, if the limit values ​​are adhered to, it is transported for days, pumped into tank trucks, brought to the disused K + S AG potash mines ( Bad Salzdetfurth , Adolfsglück and Mariaglück ) and used there for flooding.

Storage basin (covered with foil, right) and removal of the brine on the 658 m level

A sealing of the southern flank does not seem possible. These tributaries come from pathways that have formed as a result of the deformation of the salt dome in the salt barrier and in the surrounding mountains. The danger of such inflows was already pointed out in 1979 in a critical study.

When the Asse was reported nationwide in September 2008, the media did not always make a clear distinction between the problem of liquor inflows from outside and the occurrence of contaminated liquor inside the mine (see below). As a political response, the Environment Minister of Lower Saxony temporarily prohibited the removal of the incoming caustic solution and demanded the establishment of special free measuring points .

Radioactively contaminated brine

On June 11, 2008, the Braunschweiger Zeitung reported that lye in the Asse was contaminated with cesium -137 ( 137 Cs) ( half-life 30 years). This report became politically explosive because the Lower Saxony Ministry of the Environment was unable to answer queries as they knew nothing of such contamination. The Landtag and the Federal Environment Minister then asked the Environment Minister of Lower Saxony for a status report, which was published on September 2, 2008.

On July 4, 2008, Christel Wegner , member of the state parliament, asked detailed questions about the shipment of lye from the Asse nuclear waste storage facility. This inquiry made the fact public that lye from the mine had been brought to closed mines of K + S AG for years. This was not known to the Federal Environment Minister Sigmar Gabriel either. As a result, reserve samples were evaluated, the names of the affected mines announced, and the respective district administrators and the population informed. On December 17, 2008, the request with the answers was published as a state parliament printed matter.

The status report of September 2, 2008, on more than 160 pages, first answers the question of who possessed which information at what time, before technical and legal problems are discussed. According to this report, it was found in the early 1990s that caustic that collected in certain test wells at the bottom of the 750-level had an increased concentration of the radioactive isotope 137 Cs. In September 1995, a contaminated caustic drip point was found in the ridge area of ​​the 775-meter level for the first time. After a change in the Radiation Protection Ordinance, which came into force on August 1, 2001, the 137 Cs activity was above the exemption limits at some measuring points. In agreement with the direct supervisory authority, the State Mining Authority Clausthal-Zellerfeld , from around this time until the beginning of 2008 the contaminated lye was diverted to the 900-meter level, which was no longer open as a traffic route; afterwards the influx largely dried up. In the status report, the Lower Saxony Ministry of the Environment takes the view that a special nuclear license was required for this discharge; However, it also cites the opposite legal opinion of the Lower Saxony mining authorities, which resolutely defend their longstanding administrative practice.

Appraisers were consulted to create the status report. Prof. Mengel ( TU Clausthal ) and Dr. Lennartz ( Forschungszentrum Jülich ) were not satisfied with the operator's statement that the contamination was residues of the storage accident in 1973. Rather, within a few days they found clear indications that the caustic solution was seeping out of the storage chamber 12. Ultimately, the origin of the lye is old backfill from a chamber only thirty meters away, from which moisture migrated into chamber 12 in the decades before it was stored. When it was stored in 1974, the floor of chamber 12 was soaked in alkali. This lye has come into contact with stored substances and is now diffusing into the traffic areas in the immediate vicinity of the storage chamber.

In 2009 the environmental protection organization Greenpeace published a letter from the Federal Office for Radiation Protection (BfS) to the Federal Environment Ministry dated February 29, 1996, in which the BfS considered it “urgently necessary” to “have an analysis of the hazardous situation carried out and here at GRS and BGR should be included. ”The reason given for this was the increased solution inflows and the particular importance of the long-lived alpha emitters Pu-239 and Am-241 stored there . "If the pit were to drown , radiation exposure far above the dose limits of §45 StrlSchV could not be ruled out."

In April 2011, the Federal Office for Radiation Protection again found contaminated caustic not far from emplacement chamber 12. Samples of 240 kBq / l of the radioactive isotope cesium-137 were found in a borehole in the mine. According to the authorities, this was the highest value of cesium-137 to date, which has been measured since the end of storage in 1978. It was well below the handling limit. In the borehole there was around one liter of the radioactive liquor that had leaked from the waste chamber.

Mine gases

The moisture and the solutions and water in the salt dome lead to increased corrosion on the steel barrels stored. This creates hydrogen . In addition, methane is present in large quantities from organic rotting (cleaning rags, animal carcasses) . This could lead to an uncontrollable situation if, at a currently incalculable point in time, more and possibly much larger amounts of water or lye suddenly burst through the overburden. The inflowing solution would dissolve further salts ( carnallite ) in the mine building, which would further decrease the stability of the mine. In addition, a massive increase in corrosion and an associated increase in the formation of hydrogen would also be expected in the event of liquid ingress. In connection with the methane, which is also present, this could lead to a so-called blow-out after 50 years , in which the gases could flow uncontrolled to the surface due to the high gas pressure that is created, carrying radioactively contaminated liquids and sludge with them. The released gases and liquids would quickly escape into the biosphere and cause radioactive pollution there. This problem is not prevented by flooding the pit with the so-called protective fluid, on the contrary: the magnesium chloride solution, which is provided for when the refuse collection fails and is already used for partial backfills, massively accelerates the corrosion of the metals.

The GSF closure concept

The main features of a closure concept have been approved within the framework of main and special operating plans since 1995; parts of the concept have already been implemented on the basis of these operating plans. The actual application to close the mine was submitted to the State Mining Office in January 2007. This application included a final operating plan and a long-term safety certificate . After an initial check, the approval authority decided that the documents submitted were insufficient and requested further evidence.

The plan was to mechanically stabilize the salt dome by filling cavities. Blowing in salt grit led to calming in the mountains, but the counterpressure that can be achieved is not sufficient for permanent stabilization. In order to further minimize the remaining pore volume in the filling material and thereby contribute to the reduction of mechanical stresses, a protective fluid should be introduced. A magnesium chloride solution was provided for this purpose, with the help of which the decomposition of the carnallite due to the sodium chloride solution that had entered was to be counteracted. The closure concept also provided for the construction of flow barriers.

The flooding of the Asse with a protective fluid was presented to the public as the only appropriate procedure from a mining point of view. However, it remained problematic whether this is compatible with the requirements of radiation protection. In accordance with the basic rule of not solving disposal problems through dilution, it is the international standard to store radioactive waste dry. If the emplacement chambers in the Asse are flooded, it is to be expected that part of the radioactive inventory will be dissolved and diffused through the porous filled cavities of the closed mine over the course of centuries. To limit this diffusion, flow barriers should be built. The operator tried to use model calculations to prove that a radiological protection goal that excludes any impairment of the biosphere is achieved over the long term.

Another objection to the flooding is that the cement, in which much of the waste is bound, can react chemically with the incoming water, releasing gas and building up pressure up to the risk of an explosion.

Preparatory work

From August 1995 to April 2004 - with the exception of a few remaining cavities - the old excavation cavities between the 725 and 490 m level were filled with residual salts from the former Ronnenberg potash salt mine . Every working day, 18 railway wagons were brought in. On site, the cavities were tightly filled with a sliding sign up to the roof. A total of around 2.15 million tons of salt heaps were excavated on the southern flank of the Asse II mine.

The original closure concept included:

  • Construction of flow barriers to effectively limit and control the possible future solution movements in the mine.
  • Backfilling of the cavities below the 800 m level.
  • Infeed of magnesium chloride solution as protective fluid.
  • Dismantling of the Asse II and Asse IV shafts.
  • Guaranteeing the safety of the pit through regular maintenance work in the mine building (checks in areas where there is a risk of stones falling, checking the hoist cage, rope and hoisting machine, maintenance of the underground carriageways, monitoring and maintenance of machines and electrotechnical equipment).

After the change of operator on January 1, 2009, the old closure concept was postponed. First, various closure options were considered, from which the aim was to select the relatively best option by the end of 2009.

In January 2010, the Federal Office for Radiation Protection proposed that the nuclear waste should be completely removed from the ailing warehouse. The options of setting the barrels in concrete or moving the barrels to deeper layers had previously been discarded. In a statement dated February 15, 2011, the Association for Radiation Protection rejected an early stipulation that the waste should be retrieved for radiation protection reasons. A period of ten years was set for the retrieval of the stored waste; the costs were initially estimated at around two billion euros in an expert report. At the end of January 2010, the then Federal Environment Minister Röttgen estimated the costs to be significantly higher at 3.7 billion euros.

In 2012 it was announced that the worst-case scenario could not begin until 2036. In 2015, considerations were made to initially concentrate on more easily accessible areas of the mine during the preparatory explorations in order to be able to start retrieval as early as 2023.

An additional Asse 5 shaft is required to retrieve the nuclear waste , as Asse 2 is not suitable for technical reasons. On June 5, 2013, drilling began on the exploratory borehole for shaft 5. The borehole is expected to be 790 m deep and cost around two million euros.

Public participation and comparison of options

Until 2008 the Asse was operated according to mining law . The main difference to operation under nuclear law is that licensing procedures can be carried out without public participation. However, due to growing public pressure and for political reasons, the ministers involved ( Federal Environment Minister , Federal Education Minister , Lower Saxony Environment Minister) decided in 2007 to involve the public in examining the closure application. A comparison of options working group was set up to examine alternatives to the operator's closure concept, and an advisory group was set up in the Wolfenbüttel district .

In addition to flooding with magnesium chloride solution, options have now been mentioned: backfilling with solid material (gravel, Sorel cement ), relocating parts of the nuclear waste within the mine or retrieving the barrels.

Nationwide attention and change of operator

Entrance to the Asse II mine (August 2009)

The publication of the status report and its interpretation, in particular by Federal Environment Minister Sigmar Gabriel, made headlines nationwide. The minister raised serious allegations against the operator and the mining licensing authority. Both would have missed nuclear law standards. The storage of nuclear fuel contradicts previous statements. It is also “unbelievable” that the leak in the mine has been known since 1967 and not just since 1988. Since “grossly negligent” actions have taken place, the question of criminal charges must also be examined. The storage of the nuclear waste barrels took place in damp chambers at that time, as the questioning of employees showed. "There was never a safe Asse repository, rather information on caustic access was deliberately suppressed," criticized Gabriel. He spoke of a "psychological meltdown for the repository debate" and a burden for the search for a suitable location. Asse II is "the most problematic nuclear facility that we find in Europe". Stefan Wenzel MdL, Bündnis 90 / Die Grünen, filed a criminal complaint in July 2007 according to § 327 , § 328 StGB for illegal use of nuclear fuel and other radioactive substances. Green parliamentary group leader Renate Künast filed a criminal complaint against those responsible for the nuclear camp in September 2008. In both cases the investigations were discontinued by the Braunschweig public prosecutor. In 2008 they were resumed for the third time. The renovation should cost around 2.2 billion euros.

On November 5, 2008, the Federal Cabinet decided, at the suggestion of Federal Research Minister Annette Schavan and Federal Environment Minister Sigmar Gabriel, to submit the Asse to the Federal Office for Radiation Protection (BfS) from January 1, 2009.

A law passed by the German Bundestag on January 29, 2009 stipulates that the operation and decommissioning of the Asse II mine is subject to the provisions of the Atomic Energy Act . The Federal Office for Radiation Protection, as the new operator, will press ahead with the closure of the facility as part of a nuclear plan approval procedure and is responsible for the provisional continued operation of the facility. The federal government bears the costs for the continued operation and closure of the Asse ( Section 57b Atomic Energy Act). In May 2009 the parliamentary group of the Greens presented a brochure which sheds light on the parliamentary debate of the last decades, the inventory, the role of research and the role of the aces as a prototype for Gorleben.

The Federal Office for Radiation Protection has set up the Asse information center in the Steiger building opposite the mine . The current condition of the mine and the decommissioning concept are shown here using models and computer animations:

In January 2010, the incumbent Federal Research Minister Annette Schavan alleged errors in handling the Asse nuclear waste storage facility. The warehouse was not only used for scientific purposes, especially since the large number of 126,000 barrels stored was not necessary for research. In addition, according to the current state of the art, no more nuclear waste storage facilities would be built there.

Since 2009 an investigation committee of the Lower Saxony state parliament has been dealing with the events surrounding the Asse nuclear waste storage facility. Investigations by the committee revealed that the containers for storing the radioactive material were only designed for a shelf life of three years. It was therefore accepted that they would rot within a short time. Stefan Wenzel, the chairman of the Greens in the parliamentary committee of inquiry into the Asse in the Lower Saxony state parliament, sees this as an indication that the industry has seen a cheap repository in the storage pit that has been declared a research mine from the start.

Salvage Act and Estimated Costs

The law to accelerate the retrieval of radioactive waste and the decommissioning of the Asse II mine (“Lex Asse”) was passed in April 2013 by the Bundestag. The costs are estimated at four to six billion euros. They should not be borne by the operator, but by the federal government.

Cancers on the aces

In 2008 the district of Wolfenbüttel submitted an inquiry to the Lower Saxony epidemiological cancer registry, which has existed since 2000, about the frequency of leukemia around the Asse camp . The cancer registry, which collects data in this area beginning in 2002, did not have enough data to answer the request until 2010. With data from October 1, 2010 it determined that in the period from 2002 to 2009 in the area of ​​the joint municipality of Asse, compared to that of the other municipalities in the surrounding district of Wolfenbüttel, leukemia and thyroid cancers occurred conspicuously and that in the period from 2002 to 2008 the Mortality from leukemia had been strikingly high. The probability of exceedance , with which the determined number of cases would be reached by chance assuming the respective expected value of the comparison area, is 0.30% for the leukemia incidence (18 cases; 8.5 expected), for the incidence of thyroid cancer 0.08% (12 cases; 3.9 expected) and for leukemia mortality 0.86% (11 cases; 4.7 expected). There were no significant abnormalities in other types of cancer or in the other municipalities in the district. It has not yet been possible to verify whether these increases are related to the aces.

The Federal Office for Radiation Protection states that no contamination with radioactive substances was found in the vicinity of the camp. Also from the statistical data no causes and therefore no possible connection to the Asse mine can be proven. It is noteworthy that only men are visibly affected by the increases in leukemia and only women in thyroid carcinoma. Well-known risk factors for leukemia are ionizing radiation, various chemicals (e.g. cytostatics, benzene, pesticides) and some rare genetic changes. The influence of viruses and insufficient training of the immune system in childhood are discussed. Well-known risk factors for thyroid carcinoma are ionizing radiation, especially in childhood (the age of all twelve people affected here is over 30), goiter diseases , especially in those under 50, benign adenomas of the thyroid and genetic disposition. In the case of thyroid cancer in particular, differences in the intensity of diagnostic measures are also conceivable, which lead to different detection rates in early forms. Due to the fact that the majority of reports by laboratory doctors are anonymously only based on age and gender and are not traceable either, those affected or relatives of the deceased were asked to contact their doctors in order to provide more precise information on workplaces required to research the cause Current and previous places of residence and possibly other risk factors can be ascertained. In order to classify the cases more precisely and to identify risk factors, a group of experts was formed by the Wolfenbüttel district, which then came to the conclusion in December 2012 that a connection between the diseases and the camp could not be identified.

Committee of Inquiry

In the state parliament of Lower Saxony, an investigative committee also dealt with the Asse II mine from 2009 onwards. a. clarify what was stored in the Asse and which criteria were created for the selection of Asse II as a research location. The committee presented its final report in October 2012.

Web links

Commons : Schachtanlage Asse  - Collection of pictures, videos and audio files
operator
Accompanying groups
Citizens' initiatives
Official reports
Audio
history

Individual evidence

  1. ↑ a b Federal Ministry for the Environment, Nature Conservation and Nuclear Safety: Cabinet decides to change operator for Asse. Joint press release with the Federal Ministry of Education and Research. November 5, 2008. Retrieved July 29, 2018 .
  2. ↑ Federal Office for Radiation Protection: Asse II. Accessed July 29, 2018 .
  3. ↑ a b Dipl.-Ing. E. Albrecht: The expansion of the rock salt mine Asse II for the storage of radioactive residues . Ed .: Ring Deutscher Bergingenieure . No. 4/1972 . Society for Radiation and Environmental Research mbH, Munich.
  4. ↑ a b Marc Lewandowski: The Braunschweig-Schöningen Railway - Part 5, connection railway Asseschacht. Archived from the original on February 7, 2012 ; accessed on July 29, 2018 .
  5. ↑ 100 years of the Asse mine ( Memento from January 31, 2012 in the Internet Archive ) (PDF; 29 kB) . Ceremonial lecture by the head of the Asse research mine, Günther Kappei.
  6. ↑ Rock- mechanical state analysis of the load-bearing system of the Asse II mine - short report ( Memento from June 17, 2009 in the Internet Archive ) (PDF; 2.2 MB) , page 7. Institut für Gebirgsmechanik GmbH, 2007.
  7. ↑ a b Status report of the Lower Saxony Ministry for the Environment and Climate Protection on the Asse II mine , page 27. Lower Saxony Ministry for the Environment and Climate Protection, Hanover 2008.
  8. ↑ Frankfurter Rundschau, July 16, 2009
  9. ↑ The course already set under Adenauer on Braunschweiger-Zeitung.de (accessed on November 5, 2014)
  10. ↑ Visit to the Asse mine of Wintershall AG in Reutlingen. ( Memento from December 19, 2014 in the Internet Archive ) (PDF; 824 kB). Location. Participant, January 29, 1964. Remlingen near Wolfenbüttel.
  11. ↑ cit. n. Frankfurter Rundschau of July 16, 2009
  12. ↑ Greenpeace: Inspection Note, No. 12. (PDF; 824 kB) Greenpeace.de, March 3, 1964, p. 4 , accessed on July 29, 2018 .
  13. ^ NDR magazine : DM 100 disposal costs per barrel published on June 19, 2009, loaded on May 15, 2014
  14. ↑ See also: Asse inventory report 2010 ( Memento from April 25, 2013 in the Internet Archive ) (PDF; 1.0 MB)
  15. ↑ n-tv article from September 10, 2010: Ten times more medium-level radioactive waste: Asse is significantly more contaminated
  16. ^ Status report of the Lower Saxony Ministry for the Environment and Climate Protection on the Asse II mine , pages 93–128. Lower Saxony Ministry for Environment and Climate Protection, Hanover 2008.
  17. ↑ a b Asse mine - survey of former employees ( memento of August 28, 2008 in the Internet Archive ) . Helmholtz Center Munich, 2008.
  18. ↑ Status report
  19. ↑ Die Asse Chronik - On dealing with nuclear waste in Lower Saxony . Parliamentary group of Bündnis 90 / Die Grünen in the Lower Saxony state parliament, 2008.
  20. ↑ Nuclear power More plutonium in the Asse than previously known - NDR online, accessed on August 29, 2009 ( Memento from August 29, 2009 in the Internet Archive )
  21. ↑ Federal Ministry for the Environment, Nature Conservation and Nuclear Safety: More plutonium in Asse than previously assumed , press release 281/09, August 28, 2009
  22. ↑ Garbage in the Asse more radioactive: inventory reveals errors - taz. September 2010
  23. ↑ a b c 100 years of the Asse mine ( Memento from January 31, 2012 in the Internet Archive ) (PDF; 29 kB) . Lecture by the head of the Asse research mine, Günther Kappei, p. 4.
  24. ^ Federal Office for Radiation Protection: "The yellow barrel" ( Memento from October 26, 2014 in the Internet Archive ). Low and intermediate level waste: where from? Where? (Text version). Retrieved October 19, 2012
  25. ^ Asse - History - Research and Development Work ( Memento from November 29, 2014 in the Internet Archive ) . Helmholtz Center Munich, 2008.
  26. ↑ Long-term corrosion and leaching experiments on cemented 1: 1 containers in the Asse mine - sampling and evaluation 2003 (PDF; 701 kB). Research Center Karlsruhe, 2004.
  27. ↑ Press release of the Environment Minister of Lower Saxony (FDP) from November 13, 2012
  28. ^ S. Neumaier, R. Zwiener, J. Böhm (eds.) (2003): Experiments in the underground laboratory UDO of the PTB in the mine Asse II Review and Perspectives, NW-Verlag, PTB - Dos - 0043, 100pp, ISBN 978-3 -89701-959-1
  29. ↑ UDO: Underground Laboratory for Dosimetry and Spectrometry ( Memento from January 2, 2005 in the Internet Archive ) . Physikalisch-Technische Bundesanstalt, 2006.
  30. ↑ EURADOS: Calibrations of ODL probes at low local dose rates ( Memento from January 10, 2005 in the Internet Archive ) . Physikalisch-Technische Bundesanstalt, 2006.
  31. ↑ Expert opinion ( Memento from January 19, 2012 in the Internet Archive ) (PDF; 9.6 MB)
  32. ↑ Three-dimensional rock mechanical model calculations for the stability analysis of the Asse mine ( Memento from July 19, 2011 in the Internet Archive ) (PDF; 20.4 MB) . Institute for Mountain Mechanics GmbH, Leipzig 2006.
  33. ↑ Rock- mechanical state analysis of the load-bearing system of the Asse II mine - short report ( Memento from June 17, 2009 in the Internet Archive ) (PDF; 2.2 MB) . Institute for Mountain Mechanics GmbH, Leipzig 2007.
  34. ↑ Hans-Helge Jürgens, Katrin Hille: Asse II salt mine nuclear waste dump: Endangerment of the biosphere due to insufficient stability and drowning of the mine building (PDF; 13.1 MB)
  35. ↑ Mining Office warned of nuclear waste as early as 1965 in Asse Braunschweiger Zeitung, September 30, 2009.
  36. ↑ Status report of the Lower Saxony Ministry for Environment and Climate Protection on the Asse II mine , p. 11. Lower Saxony Ministry for Environment and Climate Protection, Hanover 2008.
  37. ^ Status report of the Lower Saxony Ministry for Environment and Climate Protection on the Asse II mine , page 12. Lower Saxony Ministry for Environment and Climate Protection, Hanover 2008.
  38. ↑ Hildesheimer Allgemeine Zeitung of August 16, 2008, p. 17.
  39. ↑ Semi-annual report on the status of the BMBF decommissioning projects and the BMBF-funded R&D work on “Decommissioning / dismantling of nuclear facilities” ( digitized version ). Research Center Karlsruhe, 2007.
  40. ↑ Asse II salt mine nuclear waste dump: Endangerment of the biosphere due to insufficient stability and drowning of the mine building (PDF; 13.1 MB) . Asse Group, Hans-Helge Jürgens, Braunschweig, January 1979.
  41. ^ Status report of the Lower Saxony Ministry for Environment and Climate Protection on the Asse II mine , / MN 6.4.1-1, p. 79. Lower Saxony Ministry for Environment and Climate Protection, Hanover 2008.
  42. ↑ Status report of the Lower Saxony Ministry for Environment and Climate Protection on the Asse II mine . Lower Saxony Ministry for Environment and Climate Protection, Hanover 2008.
  43. ↑ Christel Wegner: Small inquiry from Christel Wegner. (PDF; 38 kB) In: Landtag printed matter. December 17, 2008, accessed December 20, 2008 .
  44. ^ Letter from the Federal Office for Radiation Protection. Published on www.greenpeace.de (accessed December 12, 2015)
  45. ↑ Radiation protection officers report increased radioactivity in Asse Spiegel Online, April 14, 2011
  46. Jump up ↑ Asse - Further reports - Increased cesium activity in a control well
  47. ^ Björn Schwentker: Aces under pressure. Gases could be produced by water ingress. In: Deutschlandfunk.de. February 19, 2010. Retrieved July 29, 2018 .
  48. ↑ Telepolis: The Asse test repository is drinking faster and faster from September 18, 2009
  49. ↑ Ralf E. Krupp: Flow and Transport Model, Long-Term Safety Asse II (PDF; 772 kB), Open Letter to the Working Group on Options Comparison (AGO), December 29, 2009, Burgdorf
  50. ↑ verbuddelt and forgetting - Radioactive waste at the research camp Asse II in Remlingen ( Memento of 28 September 2007 at the Internet Archive ) . In: Braunschweiger Uni-Zeitung, edition WS0607-4, in the Internet Archive
  51. ^ Asse - History - Backfilling ( Memento from February 27, 2013 in the Internet Archive ) . Helmholtz Center Munich, 2008.
  52. ↑ Federal Office advocates retrieval of Asse waste from Frankfurter Allgemeine Zeitung, January 15, 2010
  53. ↑ Asse nuclear waste storage facility is to be cleared ( memento from January 16, 2010 in the Internet Archive ) NDR, January 15, 2010
  54. ^ Association for Radiation Protection eV: Retrieval of the waste from the Asse II mine. (PDF; 57 kB) February 15, 2011, archived from the original on August 9, 2014 ; Retrieved April 30, 2013 .
  55. ↑ Nuclear waste is being removed from Asse Frankfurter Allgemeine Zeitung, January 15, 2010
  56. ↑ Joachim Wille: Asse grave of billions. Frankfurter Rundschau, January 28, 2010, accessed on May 29, 2012 .
  57. ↑ Ailing salt dome: recovery of the Asse nuclear waste could not begin until 2036. Spiegel-Online, May 29, 2012, accessed May 21, 2015 .
  58. ↑ Wolfgang Riek: Asse: Nuclear waste recovery ten years earlier? HNA-Online, April 15, 2015, accessed May 21, 2015 .
  59. ↑ Drilling started for exploration for a new salvage shaft near the Asse. BfS, June 5, 2013, accessed on June 6, 2013 .
  60. ↑ September 2, 2008 - NUCLEAR WASTE "It's the GAU"
  61. ↑ Gabriel: Asse nuclear waste storage facility “GAU for the final disposal debate”  ( page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. @1@ 2Template: Toter Link / www.heute.de   . www.heute.de, September 2, 2008.
  62. ↑ Test report intensifies the repository debate . Der Spiegel, September 2, 2008 (accessed September 2, 2008).
  63. ^ Expensive renovation, Süddeutsche Zeitung , 11./12. October 2008, p. 7
  64. ↑ Draft law of the federal government to amend the Atomic Energy Act of January 15, 2009, page 9 ff.
  65. ↑ Buried for all eternity ?! The nuclear waste disaster in the Asse and its consequences , Vi SdP: Stefan Wenzel, MdL, parliamentary group leader Bündnis 90 / Die Grünen in the Lower Saxony state parliament; May 2009
  66. ↑ Asse repository - information directly on site , September 21, 2018
  67. ↑ taz: Schavan admits errors (January 15, 2010).
  68. ↑ Hannoversche Allgemeine: Schavan: Nuclear waste in Asse not only for research (January 23, 2010)
  69. ↑ SPD votes for Asse investigation committee. In: ndr.de. April 28, 2009, archived from the original on May 1, 2009 ; Retrieved February 11, 2010 .
  70. ^ Susanne Schrammar: Cheap disposal, cross-party. In: Deutschlandfunk.de. February 11, 2010. Retrieved July 29, 2018 .
  71. ↑ Law of April 20, 2013 ( Federal Law Gazette I p. 921 ). The Act added Section 57b to the Atomic Energy Act .
  72. ↑ Spiegel Online: Marodes Asse repository: Bundestag adopts law on nuclear waste recovery from 28 February 2013
  73. ↑ Section 57b (6) Atomic Energy Act: "The federal government bears the costs for continued operation and decommissioning."
  74. ↑ a b Epidemiological Cancer Register Lower Saxony: Evaluation of the EKN on the cancer incidence in the municipality of Asse (PDF; 541 kB) . Oldenburg: EKN, 2010
  75. ↑ Lower Saxony epidemiological cancer registry: Evaluation of the EKN on the incidence of cancer in the communities of Cremlingen, City of Wolfenbüttel, SG Baddeckestedt, SG Oderwald, SG Schladen, SG Schöppenstedt and SG Sickte (PDF; 855 kB) . Oldenburg: EKN, 2010
  76. ↑ BfS: The safety of the population and employees comes first ( memento of November 29, 2010 in the Internet Archive ), accessed November 26, 2010
  77. ↑ Asse II: Again no increased radioactive pollution , BfS press release, accessed on September 21, 2018
  78. ↑ report. (PDF; 1.54 MB) Establishment of a 21st parliamentary committee of inquiry. Lower Saxony State Parliament, October 18, 2012, accessed on July 29, 2018 .

Coordinates: 52 ° 7 ′ 43 ″  N , 10 ° 40 ′ 15 ″  E