Return of reprocessed radioactive waste

Until 2005, fuel elements from German nuclear power plants were transported for reprocessing to the United Kingdom and France. Most of the resulting high-level radioactive waste, which originated in Germany, have already been transported back to Germany. 25 casks with vitrified high-level radioactive waste are now ready to be returned to Germany. These casks will be stored in the Biblis, Brokdorf, Isar and Philippsburg interim storage facilities. The casks will later be taken from these facilities to a repository or to a nearby conditioning plant.

This high-level radioactive waste originates from German nuclear power plants. The nuclear power plant operators have had the fuel elements reprocessed abroad. Germany is committed to taking back this waste and returning it to the waste producers.

Reprocessing abroad was the usual disposal procedure prior to 2005 and up to 1994 was in fact mandatory.

The transport of German fuel elements for reprocessing in other countries has been prohibited by law since 2005. Nonetheless, reprocessing waste was still in storage abroad. Waste owners, i.e. the operators of nuclear power plants, are contractually required to accept the return of their radioactive waste to Germany. The Federal Republic of Germany is also bound under international law to take back this waste.

Reprocessing of fuel elements
Nuclear power plants run on radioactive materials, so-called “fuel elements”. These fuel elements are depleted after several years of operation and are replaced. In the past, the operators of German nuclear power plants transported their fuel elements to La Hague (France) and Sellafield (United Kingdom) for reprocessing. During reprocessing, spent fuel elements are reduced mechanically (decladding) and separated chemically into recycled nuclear fuel material and radioactive waste.

A new consensus: fair regional distribution

Up to 2011, 108 CASTOR® casks holding high-level radioactive waste from the reprocessing plant in La Hague were returned to the interim storage facility in Gorleben. Five containers with high-level radioactive waste from reprocessing in Karlsruhe are in interim storage in the Interim Storage Facility North near Greifswald. Another 25 CASTOR® casks will have to be returned to Germany in the next few years.

Concept for return

The relevant nuclear energy law stipulates that the remaining 25 casks can no longer be moved to the Gorleben interim storage facility but must in future be stored in on-site interim storage facilities. In 2015, the Federal Ministry for the Environment submitted a return shipment concept which provides for the fair distribution across the whole of Germany of waste from reprocessed German fuel elements which is still in storage abroad. A broad consensus was reached on the four sites to which radioactive waste will be returned: Biblis in Hesse, Brokdorf in Schleswig-Holstein, Isar in Bavaria and Philippsburg in Baden-Württemberg.

There is agreement on this between the Federal Government, all participating federal state governments and the nuclear power plant operators as waste producers who are and remain responsible for the return shipment of the waste generated by them. The previous operators of the interim storage facilities submitted applications for the four on-site interim storage facilities. BGZ has managed the applicable nuclear licensing procedures since 1 January 2019. It has now been decided which interim storage facilities will store high-level radioactive waste from German nuclear power plants until it is transferred to the repository. The interim storage facilities, in which high-level radioactive waste is already being stored in the form of irradiated fuel elements from each of the nuclear power plants, are technically equipped to store these casks.

In its “Overall concept for the return of vitrified radioactive waste from reprocessing” of 19 June 2015, the Federal Ministry for the Environment concluded that: “The prerequisites for returning casks of vitrified wastes from reprocessing to Germany have been fulfilled. The storage of these casks is technically feasible and legally possible. The instructions on the general requirements for technical and legal issues and procedures apply to […] all interim storage sites that are planned to be used.”

“The concept is intended as a guideline for nuclear plant operators on how they can fulfil their legal obligations of taking back and storing the radioactive waste in caskets from reprocessing plants abroad”,

explained the then Federal Minister, Dr. Barbara Hendricks.

Press release issued by the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety

Free State of Bavaria
The Bavarian State Government has recognised the return of radioactive waste as a national responsibility. The Federal Ministry for the Environment and the Bavarian State Government have published a joint statement on the return of nuclear waste.



Former Minister President Horst Seehofer gave his assurance in a press release that seven Castor casks would be stored at the Isar interim storage facility on the condition that the other potential sites in Schleswig-Holstein, Hesse and Baden-Württemberg also accept Castor casks.

Minister President Seehofer continued:

“Viable solutions to the great challenges of the day will only be found in consensus. Safe permanent and interim storage of the legacies of the nuclear age is a national task. Bavaria will not shy away from its shared responsibility.”

The press release issued by the Bavarian State Government



The present Bavarian State Government has reiterated this position. In its response to a question from a member of the State Parliament in the plenary session on 11 December 2018 the Bavarian State Ministry of the Environment and Consumer Protection, which is responsible for the supervision of nuclear power plants in Bavaria, clarified that:

“The on-site interim storage facilities meet all requirements. […] The Federal Government and the Free State of Bavaria agreed in 2015 that part of the returned radioactive waste would be placed in interim storage in Niederaichbach.”

Bavarian State Parliament, printed matter 18/45: Questions in the debating chamber, 18 December 2018, page 34

Schleswig-Holstein
Schleswig-Holstein has also declared its willingness to accept responsibility. The then minister for the energy transition, Dr. Robert Habeck, welcomed the concept presented by the Federal Ministry for the Environment as a fair distribution of burdens.
Baden-Württemberg

For Baden-Württemberg’s Minister of the Environment, Franz Untersteller, this decision means

“that there is now one less obstacle on the way to finding a repository”.

“The concept is intended as a guideline for nuclear plant operators on how they can fulfil their legal obligations of taking back and storing the radioactive waste in caskets from reprocessing plants abroad”,

explained the then Federal Minister, Dr. Barbara Hendricks.

Press release issued by the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety

Free State of Bavaria

The Bavarian State Government has recognised the return of radioactive waste as a national responsibility. The Federal Ministry for the Environment and the Bavarian State Government have published a joint statement on the return of nuclear waste.



Former Minister President Horst Seehofer gave his assurance in a press release that seven Castor casks would be stored at the Isar interim storage facility on the condition that the other potential sites in Schleswig-Holstein, Hesse and Baden-Württemberg also accept Castor casks.

Minister President Seehofer continued:

“Viable solutions to the great challenges of the day will only be found in consensus. Safe permanent and interim storage of the legacies of the nuclear age is a national task. Bavaria will not shy away from its shared responsibility.”

The press release issued by the Bavarian State Government

The present Bavarian State Government has reiterated this position. In its response to a question from a member of the State Parliament in the plenary session on 11 December 2018 the Bavarian State Ministry of the Environment and Consumer Protection, which is responsible for the supervision of nuclear power plants in Bavaria, clarified that:

“The on-site interim storage facilities meet all requirements. […] The Federal Government and the Free State of Bavaria agreed in 2015 that part of the returned radioactive waste would be placed in interim storage in Niederaichbach.”

Bavarian State Parliament, printed matter 18/45: Questions in the debating chamber, 18 December 2018, page 34

Schleswig-Holstein
Schleswig-Holstein has also declared its willingness to accept responsibility. The then minister for the energy transition, Dr. Robert Habeck, welcomed the concept presented by the Federal Ministry for the Environment as a fair distribution of burdens.
Baden-Württemberg

For Baden-Württemberg’s Minister of the Environment, Franz Untersteller, this decision means

“that there is now one less obstacle on the way to finding a repository”.

Legal basis of return shipments

Since 1 January 2014, section 9a(2a) Atomic Energy Act (AtG) requires energy utilities to ensure that radioactive waste is returned from reprocessing and stored in on-site interim storage facilities.

“The operator of installations for the fission of nuclear fuels for the commercial generation of electricity is required to ensure that solidified high-level fission product solutions derived from the reprocessing abroad of spent nuclear fuels are taken back and stored in on-site interim storage facilities […] until they are delivered to a repository for the disposal of radioactive waste.”

The term “on-site” refers to interim storage facilities at the locations of nuclear power plants.

The Atomic Energy Act (AtG)

Sources of quantities shipped abroad

Germany’s energy utilities have sent their spent fuel elements in containers for reprocessing from Germany to France (La Hague) and the United Kingdom (Sellafield).

A total of around 5,393 tonnes of radioactive heavy metal (nuclear fuel) was shipped to La Hague in France and around 851 tonnes to Sellafield in the United Kingdom. The high-level radioactive waste brought back to Germany originates from the reprocessing of German fuel elements. These fuel elements are also from the nuclear power plants in Biblis, Brokdorf, Isar and Philippsburg.

The distribution of the casks to the four sites is based on a regional “polluter pays” principle and as such is fair and balanced. The high-level radioactive waste returned from reprocessing will be in interim storage in the five federal states from which nuclear power plants have sent most of the nuclear fuel abroad for reprocessing.

Share of nuclear fuel produced by nuclear power plants and shipped abroad for reprocessing per federal state (100 percent = 6,244 tonnes of heavy metal; source: BMU)

The largest volume of nuclear fuel sent abroad for reprocessing originates from nuclear power plants in Lower Saxony. 108 CASTOR® casks containing waste from reprocessed German spent fuel elements have been returned to Lower Saxony. Almost as much material has also been sent from nuclear power plants in Bavaria for reprocessing abroad. To date, however, not a single CASTOR® cask containing radioactive waste from Bavarian fuel elements has been returned to Bavaria.

Assignment to the four interim storage facilities

CASTOR® HAW28M casks with vitrified radioactive waste from reprocessing in the United Kingdom and France will be distributed to a total of four on-site interim storage facilities throughout Germany.

Five casks of vitrified intermediate-level radioactive waste from reprocessing in France will be stored in the on-site interim storage facility in Philippsburg. Six casks of vitrified high-level radioactive waste from reprocessing in the United Kingdom will be returned for on-site interim storage in Biblis and seven each to the on-site interim storage facilities in Brokdorf and Isar.

The diagram shows the example of Isar.

Casks for transport and storage

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CASTOR® HAW28M

Reprocessed radioactive waste is filled in a fluid state into stainless steel-coated containers (vitrified glass canisters) on location in La Hague and Sellafiled. The canisters are then welded and 28 of these vitrified glass canisters are packed securely in a CASTOR® HAW28M cask.

The casks are licensed for transport in Germany, France and the United Kingdom. They are also licensed for transport by sea from the United Kingdom to Germany. The current license only requires a primary lid for transport.

The 40 cm-thick walls of the cast metal container effectively shield the radiation emitted by the radioactive waste. The container’s lid system, which consists of solid steel lids, metal seals and screw fittings, safely and reliably encloses the radioactive waste when it is transported and stored and dissipates the heat produced by the waste by transferring it through the inner structures, the cask body and the cooling fins to the environment.

Technical data

Loading capacity

Max. 28 canisters with vitrified high-level radioactive material
Total thermal power: max. 56 kW
Total activity: max. 1.270 PBq

Dimensions and weight in the storage configuration

Overall height: approx. 6.1 m
Outer diameter: approx. 5.5 m
Cavity height: approx. 5.2 m
Cavity diameter: approx. 1.4 m
Cask weight, loaded: 115 t

Weight comparison CASTOR®HAW28M and aircraft

Cask safety

The CASTOR®casks withstand extreme accident conditions. Numerous tests conducted over the last four decades have demonstrated how safe the casks are. CASTOR® casks have undergone more safety tests than any other containers in the world.

Drop tests

Drop tests from different heights (7.5 m to 40 m) with varying impact conditions (horizontal, diagonal, vertical) compliant with IAEA (International Atomic Energy Agency) regulations. The cask manufacturers also conducted further tests in the early 1990s which went beyond the requirements of the licensing and approval authority. The cask remained sealed in all tests.

Fire tests

Thermal tests, such as fire tests and thermal load tests: These tests focus on cask temperatures. Computer simulations are now used to produce reliable drop and fire test predictions. The cask withstands temperatures without any damage.

Other tests

Tests which exceed official safety requirements. For example, explosion next to a CASTOR® cask of a fully-loaded liquid gas tanker. The test setup was heated up until the internal gas pressure caused the tanker to burst and the gas to explode. The cask penetrated the earth a few metres away from the test setup. The cask remained sealed.

Glass canisters

Vitrification does not mean that high-level radioactive waste is filled into glass containers. The high-level radioactive waste mass is bound by melting it with a special glass at a temperature of approximately 1,100° Celsius.

The melted glass mass is poured into a stainless steel-coated container (vitrified glass canister) while it is still fluid and then solidifies into a glass matrix. The glass canister is then sealed with a welded-on steel lid. The cylindrical glass canister has a diameter of 43 cm and a height of 134 cm. It is capable of encapsulating approximately 400 kilograms of glass mass. The high-level radioactive material is now encapsulated in the interior of the glass canister. The melting process is comparable to the colouring of glass bottles when an additive, such as iron oxide for green wine bottles or cobalt for blue vases, fuses with the glass and can no longer be separated from it, either by crushing or heating.

This ensures that the radioactive material is securely encapsulated by the glass matrix and the welded glass canisters. A further barrier is the CASTOR® cask’s double-lid sealing system. The cask also reliably shields the radiation produced by the radioactive inventory.

The approved repair concept

One of the main purposes of CASTOR® type casks is the ongoing safe confinement of high-level radioactive material. CASTOR® type casks are used for the transport and interim storage of high-level radioactive waste derived from the reprocessing of German fuel elements.

To date the lid system of the more than 1,200 CASTOR® casks stored in Germany has not changed. An approved monitoring and repair concept is in place for the unlikely event that the pressure changes in the lid system of a CASTOR® cask.


The casks, which weigh around 115 tonnes, are sealed during transport with a forged stainless steel lid. A metal seal is inserted between the cask and the lid. The CASTOR® is already sealed and ready for transport with this primary lid.

A secondary lid, or outer lid, is then placed on top. This outer lid is also fitted with a metal seal. The cavity between the lids is pressurized with helium. The pressure is permanently monitored by sensors during interim storage.

The repair concept agreed with the authorities is applied if there is any change in pressure between the two lids.

This has never yet occurred in any of the over 1,200 CASTOR® casks stored in Germany.

If the outer lid seal is the cause of the change in pressure, the repair concept provides for the outer lid to be removed in the interim storage facility and a new seal to be inserted. The CASTOR® cask remains closed by the inner lid throughout.

The repair concept is also designed to respond to the contingency of a change in pressure caused by the inner lid seal. The double-barrier system itself and the ability to monitor it can then be restored.

In this case, an additional “joining lid” is placed on top and welded with the cask.

The new cavity which is created between the outer lid and the joining lid welded on top of it is filled with helium and monitored.

The CASTOR® cask remains firmly sealed by the outer lid while the joining lid is being welded on top.


The monitored double barrier is then restored by the joining lid. The repair concept does not require a hot cell as the cask does not have to be opened at any time.

This procedure is the approved repair concept for all CASTOR®casks stored in Germany. There has never been any need to apply the concept in practice.

Step by step: the repair concept. Click here.


The casks, which weigh around 115 tonnes, are sealed during transport with a forged stainless steel lid. A metal seal is inserted between the cask and the lid. The CASTOR® is already sealed and ready for transport with this primary lid.

A secondary lid, or outer lid, is then placed on top. This outer lid is also fitted with a metal seal. The cavity between the lids is pressurized with helium. The pressure is permanently monitored by sensors during interim storage.

The repair concept agreed with the authorities is applied if there is any change in pressure between the two lids.

This has never yet occurred in any of the over 1,200 CASTOR® casks stored in Germany.

If the outer lid seal is the cause of the change in pressure, the repair concept provides for the outer lid to be removed in the interim storage facility and a new seal to be inserted. The CASTOR® cask remains closed by the inner lid throughout.

The repair concept is also designed to respond to the contingency of a change in pressure caused by the inner lid seal. The double-barrier system itself and the ability to monitor it can then be restored.

In this case, an additional “joining lid” is placed on top and welded with the cask.

The new cavity which is created between the outer lid and the joining lid welded on top of it is filled with helium and monitored.

The CASTOR® cask remains firmly sealed by the outer lid while the joining lid is being welded on top.


The monitored double barrier is then restored by the joining lid. The repair concept does not require a hot cell as the cask does not have to be opened at any time.

This procedure is the approved repair concept for all CASTOR®casks stored in Germany. There has never been any need to apply the concept in practice.

All casks can be transported to a repository

CASTOR® casks which are sealed with an inner and outer lid are prepared for transport by removing the outer lid. However, CASTOR® casks which have a joining lid welded on top of them can also be transported to a repository. In this case, the joining lid is removed before transport while the cask remains sealed by the outer lid.

The current license only permits the CASTOR® HAW28M to be transported with the inner lid. The cask manufacturers have informed the approval authority about the concept for removal and transport of casks from an interim storage facility within the current licensing procedure for the four sites referred to above. This concept includes extending the transport license to the outer lid. There are no known technical grounds for calling this concept into question. In the unlikely event of CASTOR® casks having undergone repair, BGZ has already tasked the cask manufacturer with obtaining an extension of the transport license for the CASTOR® HAW28M.

No hot cell is required at the site either as, in this concept, the CASTOR® HAW28M remains sealed by the outer lid even if there is a change of pressure in the lid system.

This ensures that all CASTOR® casks can be placed and kept safely in interim storage and subsequently taken from the interim storage facility to the repository.

There will also be a receiving storage facility with a conditioning plant at the repository site where the high-level radioactive waste will be prepared for storage in the repository.

The interim storage facility will remain an interim storage facility.

CASTOR® HAW28M: Successful test run in the Biblis interim storage facility

Safety through to final disposal

In August 2015, the Cabinet of the Federal Government of Germany adopted the National Waste Management Programme for the responsible and safe disposal of radioactive waste in Germany.

The public was extensively involved prior to this in the framework of a strategic environmental assessment. The public consultation process enabled public authorities and ordinary citizens to give their responses to the draft programme. The strategy for the management of nuclear waste in the National Waste Management Programme for Germany was drawn up with the participation of the public and the federal states. As well as low-level and intermediate-level radioactive waste of all kinds and high-level radioactive waste from nuclear power plants, the strategy also covers waste from reprocessing. This waste will be stored in the interim storage facilities pending final disposal.

The Site Selection Act requires that a repository site is found for high-level radioactive waste by 2031. The repository will then be licensed and built. The repository is scheduled for commissioning around the year 2050.

The National Waste Management Programme provides for a receiving storage facility to be built at the repository site. This receiving storage facility should be licensed when the first partial license for the repository is granted – i.e. in the early 2040s. This will enable work to begin on clearing the interim storage facilities before the repository is commissioned.

The National Waste Management Programme

Dialogue and transparency

BGZ, the Federal Ministry for the Environment and the energy utilities provided information at all four sites at an early stage. This participative dialogue with the people in the region will continue: The last dialogue took place in the Hotel Sell in Brokdorf on 8 May 2019. BGZ organised another information event in the Aichbachhalle in Niederaichbach on 16 May 2019. The dates for Biblis and Philippsburg will also be published on this website.

Isar
Around 500 ordinary citizens accepted the BGZ's invitation. BGZ has continued the dialogue with citizens living near the Isar interim storage facility on the return of radioactive waste from the reprocessing of German fuel elements abroad.

As the approval authority, the Federal Office for the Safety of Nuclear Waste Management issued a statement on the representations made by the Municipality of Niederaichbach on the storage of vitrified high-level radioactive waste from reprocessing in the United Kingdom.

Responsibilities for return shipments

GNS Gesellschaft für Nuklear-Service
(on behalf of the waste producers)

BGZ Gesellschaft für Zwischenlagerung

  • Acceptance and inspection of loaded casks
  • Storage of casks in interim facilities
  • Safe interim storage of casks
  • Transfer to the repository

BGE Bundesgesellschaft für Endlagerung

  • Acceptance and inspection of casks
  • Operation of the receiving storage facility at the repository site in compliance with the Site Selection Act
  • Storage in the repository