J.P. Lempert
E. Biurrun
Deutsche Gesellschaft zum Bau und Betrieb
von Endlagern für Abfallstoffe mbH (DBE)
Peine, Germany

The German energy policy is currently based on an energy concept which includes nuclear power as a major option for future generations. The present lack of social consensus on nuclear energy has led to a virtual moratorium for construction of new facilities. In spite of this, remarkable progress has been quietly achieved in recent years in all aspects of waste management. After fully developing all necessary components to technical maturity and extensive testing in 1:1 scale, all major components of the high level waste (HLW) disposal system are now available. The operation of a deep geological repository at Morsleben provides hitherto unique experience in this activity. At the Gorleben site, the exploratory mine for the future German HLW repository is at a very advanced stage of construction. Near the repository site, the worldwide first spent fuel and HLW pilot encapsulation plant will be commissioned soon. In Konrad, the most novel repository technology is very close to come into service.

The perspectives of radioactive waste management in Germany should be seen in the context of the Federal energy policy. As typical for a country with very limited domestic energy resources this policy is primarily focused on guaranteeing energy supply in the long-term, while keeping costs within economically reasonable limits.

In recent times, global concern has arisen that greenhouse gas emissions can become a serious threat to the global climate. The German Federal Government committed very early to permanently reduce energy-related release of carbon dioxide (CO₂). Current energy policy thus concentrates in further developing and keeping open all technological options that significantly contribute to reduce energy-related pollution. In this regard, nuclear power is not an option between many, but in fact it is the one with the greatest CO₂ reduction potential. Therefore, the energy policy considers nuclear power as a substantial element of the country's energy supply mix also in the long-term.

In Germany, 19 nuclear power plants with 22 GW capacity cover 34% of the electricity demand, and avoid burning fossil fuels that will lead to emitting 160 million t of CO₂ per year. The use of nuclear power and of radioactive isotopes in medicine, research and industry, yield radioactive waste that must be properly treated and disposed of. Since the early sixties and up to present some 63,000 m³ of conditioned waste and 31,000 m³ of unconditioned waste have accumulated, as well as spent fuel with a heavy metal (HM) content totaling 6,700 t. Current forecasts of waste arising anticipates a total of approximately 395,000 m³ of low and intermediate level waste (LLW, ILW) as well as HLW and spent fuel with some 24,000 t of HM until the year 2080.

Upon a decision taken by the Government in the early sixties it is German policy to dispose of radioactive waste exclusively in deep geological repositories. In order to obtain the necessary knowledge and to develop repository technology, the Federal Government acquired in 1965 the Asse salt mine and established there the first European underground research laboratory. The Asse mine was also used until 1978 as experimental repository. In this large facility an extensive research and development program has been carried out for approximately 30 years, including a multiplicity of large scale tests. Research activities at the Asse have now practically come to an end, with the exception of a long-term heater test involving six spent fuel cask mock-ups with 65 t weight each and with a total heat output of 36 kW. The heaters, switched on in late 1990, will continue to run until fall 1998, data acquisition will cease next year.

Since the scientific knowledge and the technological basis for the German deep geological repositories are deemed basically available, research in the field has recently been reoriented. The work is now mainly addressing specific issues to be solved for confirming the suitability of the Gorleben site. Additionally, optimization of operational safety is given attention. Effort is also devoted to optimize performance assessment tools by using real life data obtained from the underground survey.

In Germany, the Atomic Energy Act and related ordinances provide the regulatory framework for radioactive waste management. Political basis of this activity is a basic agreement concluded between the Federal Government and the Federal States in 1979. Waste management originally anticipated on-site storage, interim storage in centralized facilities, spent fuel reprocessing, conditioning, and final disposal. Since 1994 spent fuel direct disposal is legally considered as an equivalent alternative to reprocessing.

Whereas final disposal is under the direct responsibility of the Federal Government, interim storage, reprocessing, conditioning, and transportation is left to the nuclear industry. As a matter of principle, all waste management costs are to be borne by the waste producer. The costs of developing and constructing disposal facilities are charged to producers as ruled by an ordinance on advanced payments. To cover uncertain future expenditures, as decommissioning and final disposal costs, waste producers must build reserve funds, which remain under their responsibility.

Facilities are licensed under the authority of the Federal State hosting the repository. Enforcement of the Atomic Energy Act by Federal States is supervised by the Federal Ministry for the Environment, Nature Conservation and Reactor Safety (BMU). Actual construction and operation of repositories is charged by an exclusive contract with the Federal Government to the German Company for the Construction and Operation of Final Repositories (DBE), a private company established in 1979.

In the recent past, the realization of the German waste management concept has been obstructed because of the deep controversy on energy policy in the country. Many Federal States are only willing to cooperate with the Federal Government in waste management under the condition of phasing out nuclear power. Therefore, licensing steps are greatly delayed and progress is often reached by court decisions or governmental directions.

In spite of all difficulties, construction of waste management facilities has achieved substantial progress. At present, all installations are either available or under construction. All Federal States have set up centers to collect for later disposal waste from non fuel cycle uses. Two HLW interim storage facilities for 1,500 t HM each are accepting spent fuel and vitrified reprocessing waste at Gorleben and Ahaus. There is sufficient centralized interim storage capacity for LLW and ILW at nuclear research centers and at commercial facilities. A pilot conditioning plant for demonstrating the encapsulation of spent fuel and vitrified HLW will be commissioned soon. All key equipment for handling and emplacement of HLW underground has been demonstrated in 1:1 scale and is now awaiting use in a future repository.

On behalf of the Federal Government, DBE currently operates facilities at three sites, the Morsleben underground repository, the exploratory mine at Gorleben, and the Konrad mine.

The Morsleben repository is located in Saxony-Anhalt, close to the border of this Federal State with Lower Saxony. At the site, potassium was mined until the early twenties, thereafter rock salt mining went on until 1969. Since minerals at Morsleben where extracted without backfilling, at the end of mining open cavities with an overall volume of approx. 10 million m³ remained available for other uses.

In 1970 the nuclear power plant operator of the former German Democratic Republic bought the mine from the potassium and salt industry in order to convert it into a repository for LLW and ILW. After extensive suitability investigations and conclusion of a licensing procedure waste disposal started in 1978. Rock cavities below the 500 m horizon were chosen for waste emplacement. In the course of German reunification the repository became a Federal Facility, and DBE was contracted to take over its operation.

The safety of the Morsleben repository was carefully reevaluated by order of the Federal Government in 1991. Comprehensive analyses confirmed that the site's safety is in compliance with the most stringent international standards. Operational safety is permanently optimized giving specific attention to protection of the personnel.

At Morsleben, the worldwide only existing deep geological repository, different categories of solid low level and intermediate level waste as well as sealed radiation sources are disposed of. Essentially, LLW packed in drums is stacked in chambers, remaining void space is backfilled with fly ash. Waste with higher activity content, delivered to the repository in shielding overpacks, is discharged through shielding lock systems into closed chambers located below an access drift. The packages are covered at some intervals with fly ash, full chambers are completely backfilled. Waste disposal is carried out on the basis of contractual arrangements between waste producers and the Federal Government. Ownership of the waste is passed over upon delivery, the producers pay a fee that settles for them all costs.

As of end of 1997, the radioactive waste disposed at Morsleben amounted to:

• 32,000 m³ radioactive waste and
• 6,600 sealed radiation sources.

Since the valid license does not cover repository decommissioning, which must be done in full agreement with the west German regulatory framework, a Plan Approval Procedure for this activity has been initiated in 1992.

After an extensive siting process, the salt dome near Gorleben was selected by the Government of Lower Saxony in 1979 as a possible site for a federal radioactive waste repository. Since then, a comprehensive exploration program is being carried out to confirm the dome's suitability to host a repository for all kinds of radioactive waste. The survey will provide all information about the geological and hydrogeological conditions in and around the salt dome needed for the future licensing procedure.

Surface survey using geophysical non penetrating methods as well as exploration boreholes yielded data on the cap rock, the salt dome flanks, and the surrounding strata. Four deep boreholes to an approx. depth of 2000 m as well as two further drillings at both shaft locations rendered first information on the dome's stratigraphy supporting the initial site suitability evaluation. A drilling program including 322 groundwater measuring points was conducted to investigate geological and hydrogeological conditions in the overburden. In order to examine the subrosion in the cap rock, several salt table boreholes were sunk.

The surface exploration confirmed in principle the suitability of the salt dome to host a repository. Thereafter, preparatory work for underground exploration started in 1982. This exploration will provide definitive information on the dome's geological structure and on the space required to dispose of the mentioned waste volumes. Obviously, such information cannot be obtained by survey from the surface.

Construction of the exploratory mine commenced by sinking two shafts with an inner diameter of 7.5 m, and continued with the excavation of the mine underground infrastructure, which is currently being equipped. The rock volume excavated hitherto amounts to approx. 180,000 m³. Among other activities, refurbishment of shaft 1 is being carried out by installing the hoisting machine that will be in service in the future repository. Drifts and crosscuts are being driven to start in the very near future to explore the prospective waste disposal areas. The dome will be examined by these exploration drifts and crosscuts and by boreholes drilled from the drifts. Direct geological mapping of the strata crossed and evaluation of drilling cores will be complemented by non destructive methods as, e.g., seismic profiles, borehole radar scanning, geoelectric, geomagnetic, and gravimetric survey.

If the underground exploration yields positive results the exploratory mine can be turned into a final repository. The future licensing and operation of the repository is highly dependent on consensus between the main waste producers and the Government.

The former Konrad iron ore mine is situated in Lower Saxony. Mining started at Konrad in the sixties and was phased out for economical reasons in 1976. In the same year, the Konrad site was selected for further investigation as a possible repository because of the great depth of the ore horizon, the fact that the mine is extraordinarily dry, and the complete isolation from shallow groundwater by clayish overlying rock.

Results of the extensive survey and evaluation program carried out by order of the Federal Ministry for Education, Science, Research and Technology led in 1982 to a positive statement regarding the suitability of the site for constructing a radioactive waste repository. The Konrad site is characterized by favorable petrophysical properties in the ore horizon as host rock, a high barrier effect of the overburden, and a favorable geological long term prognosis.

DBE has been entrusted with developing the repository technology, carrying out the licensing procedure in cooperation with the Government, and later transforming the mine into a repository and operating it.

The repository layout will consist of 6 emplacement fields at different levels in depths of 800 m, 850 m, 1,100 m and 1,300 m. Until end of waste disposal drifts with a total length of about 50 km will be driven into the rock, including 35 km for waste disposal and about 15 km for other purposes.

Drifts and galleries in the Konrad repository will have a cross-section of 25 m². For waste packages disposal, chambers with a cross-section of approximately 40 m² and up to 1,200 m length will be excavated into the iron ore deposit. All in all, a net disposal capacity of approximately 650,000 m³ of waste packages will be available.

The license for Konrad is expected very soon. Transformation into a repository will begin thereafter, involving construction of completely new surface facilities around the upcast shaft Konrad 2, which will serve for hoisting waste to the underground. Conversion of the mine itself will cover excavation and equipping of necessary infrastructure areas, disposal chambers, and access drifts and will require approx. four years.

As mentioned, one essential of German energy policy is to use nuclear power in an energy mix together with fossil fuels and renewable energies. Technical solutions for managing and disposing radioactive waste are available since many years. All relevant facilities are either in an advanced stage of construction or already in operation. Ongoing research ensures a continuous improvement and optimization of the required technology.

Considering the substantial progress achieved in repository engineering and project realization at Konrad, Gorleben, and Morsleben, the Government is now of the opinion that a complete governmental responsibility is no longer necessary. Further construction as well as later repository operation could well rest in the hands of industry, with the authorities concentrating on licensing and supervision. A corresponding amendment to the Atomic Energy Act is on the way.

With regard to the German nuclear program enough repository space will be available in the near future. Due to waste volume reduction, and possibly no further nuclear power installations in our country, a perspective for storing surplus waste might be seen in the future.

A recently published study has analyzed waste volumes in European countries with limited nuclear power. It is obvious that by economical considerations alone repositories for HLW in these countries will be very costly. The mentioned study proposed a regional repository which could accept waste from several countries.

A safe solution for radioactive waste disposal is in principle available in Germany. Its complete realization is highly dependent on society's ability to achieve consensus.