Final Disposal of High-level Radioactive Waste in Germany

Full text

(1)

www.bmwi.de

Final Disposal of High-level Radioactive

Waste in Germany

– The Gorleben Repository Project

Energy

(2)

Publisher

Federal Ministry of Economics and Technology (BMWi) Public Relations/IA8 10115 Berlin www.bmwi.de Last Revised October 2008

The Federal Ministry of Economics and Technology has been awarded the berufundfamilie®audit certificate for its family-friendly HR policy. The certificate is granted by berufundfamilie gGmbH, an initiative of the Hertie Foundation. Editorial department

Federal Ministry of Economics and Technology (BMWi)

Design and production PRpetuum GmbH, Munich

Print

Silber Druck oHG, Niestetal

Photo credits BMWi

(3)

Final Disposal of High-level Radioactive

Waste in Germany

– The Gorleben Repository Project

(4)
(5)

Preface

Today, nuclear power stations play an important role in the stable and cost-effective supply of electricity in Germany. Regardless of the outcome of debates on the future of nuclear energy in Germany, existing and future radioactive waste has to be disposed of safely and securely for extended periods. On account of our responsibility towards present and future genera-tions, we need to take an objective approach based on scientific findings for the final disposal of radioactive waste.

In the opinion of the BMWi, finding a solution to the repository issue should not be treated as a politi-cal football by divergent politipoliti-cal interest groups. Supporters and opponents of nuclear energy alike should be equally committed to urgently addressing the issue of final radioactive waste disposal with a view to achieving prompt results. Our citizens rightly expect politicians and policymakers to exercise responsibility here. In this legislative term, the Federal Government made important decisions con-cerning the final disposal of low and medium-level waste, which account for approximately 90 percent of the waste volumes forecast. The “Konrad mine” reposi-tory is to go into operation in 2013 for this purpose.

A lot of controversy does, however, surround the further course of action to be taken for high-level radioactive waste. Exploration work has been under-way at the Gorleben salt dome since 1979 for this very purpose. A moratorium on exploration has been imposed since 2000 even though the results of the exploration have been positive up to now, and the questions which gave rise to the moratorium have been answered. The next steps to be taken in resolving the repository issue are a source of controversial political debate. Arguments against further exploration in Gorleben are the alleged unsuitability of the salt dome, as well as demands to look for new repository sites in alternative host rocks. These arguments often ignore the scientific findings and results of the exploration conducted at the Gorleben salt dome over the past number of decades.

In its capacity as the ministry responsible for fun-damentals-oriented research on repositories, the BMWi has summarised the findings on the Gorleben salt dome in this brochure. The conclusion reaffirms the ministry’s call to continue open exploration of the Gorleben salt dome. Only in this way a final statement on the suitability of Gorleben can be made, which will be the basis for further decisions on the final disposal of heat-generating high-level radioactive waste in Germany.

Federal Minister of Economics and Technology

(6)

4

I. Introduction . . . 8

II. Why should rock salt be used for the final disposal of high-level radioactive waste? . . . 12

III. Gorleben repository project . . . 15

1. How was the Gorleben salt dome chosen? . . . 16

2. How far has exploration work progressed at the Gorleben salt dome? . . . 21

3. Why does the exploration moratorium still apply? . . . 27

IV. State of research . . . 29

1. Alternatives to rock salt in Germany . . . 30

2. Basic research within the responsibility of the Federal Ministry of Economics and Technology . . . 32

3. Can Gorleben be compared to the Asse II mine? . . . 34

V. Would it make sense to look for new repository sites? . . . 35

VI. Roadmap to a repository for high-level heat-generating waste . . . 38

1. Continuing and completing exploration work at the Gorleben salt dome . . . 39

2. Safety assessment and international verification . . . 40

3. Putting the repository into operation . . . 41

VII. Summary . . . 42

VIII. Literature . . . 44

IX. Annexes . . . 47

Table of Contents

(7)

5

Table of Figures

Fig. 1: Geographical location of the Gorleben salt dome in Lower Saxony . . . 9

Fig. 2: Aerial photo of the Gorleben site . . . 10

Fig. 3: Properties of potential host rocks in Germany which are relevant for repository concepts . . . 14

Fig. 4: Location of the salt structures appraised by Richter-Bernburg & Hofrichter (1964) with regard to their suitability for the final disposal of radioactive waste . . . 16

Fig. 5: Distribution of the sites examined in greater detail with regard to their suitability as a radioactive waste management center as part of the Federal Government site selection process (KEWA study) . . . 17

Fig. 6: Location of the sites examined in greater detail with regard to their suitability as a radioactive waste management center as part of the site selection process conducted by the Land of Lower Saxony . . . 18

Fig. 7: Simplified geological section through the Gorleben salt dome . . . 21

Fig. 8: Section through the salt dome with excavations . . . 22

Fig. 9: Three-dimensional model of the outer shell of the Gorleben salt dome with the location of the mine workings . . . 23

Fig. 10: View of the gait road at the 840m level . . . 23

Fig. 11: Historical profile of exploration work at the Gorleben salt dome . . . 24

Fig. 12: Excavations with EB1 and areas still to be explored . . . 25

Fig. 13: Excavation work in a drift at the 840m level . . . 26

Fig. 14: Survey map of the regions with argillaceous rock deposits and salt domes in Germany which could be considered for the final disposal of high-level waste . . . 31

Fig. 15: Schematic illustration of a repository system in a deep geological formation . . . 32

Fig. 16: Demo experiments for direct final disposal . . . 33

Fig. 17: Comparison of the various repository concepts . . . 37

Fig. 18: Road headers at the Gorleben exploration mine . . . 39

Fig. 19: Diagram of the stages of development of the salt structures found in Germany . . . 48

(8)

6

List of Annexes

Annex 1: Rock salt: recommended as a host rock for the final disposal of high-level waste . . . 48

Annex 2: 1964 selection procedure implemented by the Federal Institute for Soil Research . . . 49

Annex 3: Selection process applied by the Federal Government for an WMC in the period between 1973 and 1976 (KEWA study) . . . 50

Annex 4: The four phases of the selection process applied by the Land of Lower Saxony in 1976/1977 . . . 51

Annex 5: Examples of how repository sites have been identified worldwide . . . 52

Annex 6: Additional results of exploration work conducted to date on the Gorleben salt dome . . . 55

Annex 7: Annex 4 on the agreement on June 14, 2000 . . . 56

Annex 8: Important points of the public debate in Wendland on the exploration of the Gorleben salt dome . . . . 57

Annex 9: Primary results of the BGR studies on crystalline rock, argillaceous rock and rock salt as host rocks . . . . 59

(9)

7

List of Abbreviations

AkEnd Committee on a Site Selection Procedure for Repository Sites BfS Federal Office for Radiation Protection

BGR Federal Institute for Geosciences and Natural Resources BMBF Federal Ministry of Education and Research

BMFT Federal Ministry for Research and Technology in legal succession BMwF Federal Ministry for Scientific Research

BMI Federal Ministry of the Interior

BMU Federal Ministry for the Environment, Nature Conservation and Nuclear Safety BMWi Federal Ministry of Economics and Technology

DoE Department of Energy (USA)

EB 1 Exploration area in Gorleben salt dome IAEA International Atomic Energy Agency IMAK Interministerial task force

HLW High-level waste

KEWA Nuclear fuel reprocessing company

NLfB State Office of Lower Saxony for Soil Research

NMU Ministry for the Environment and Climate Protection of Land Lower Saxony

OECD/NEA Organization for Economic Co-operation and Development/Nuclear Energy Agency PTB National Metrology Institute

PTKA-WTE Project Management Agency Forschungszentrum Karlsruhe Water Technology and Waste Management Division Project RSK Reactor Safety Commission

WMC Radioactive waste management center

(10)

8 I. Introduction

I.

(11)

9

In the debate surrounding the use of nuclear power in Germany, the public and policymakers alike often argue that, while Germany uses nuclear power, the problem of the final safe disposal of the radioactive waste produced is not resolved. Is this argument justified? Is it really true to say that the final safe disposal of waste in Germany is not possible? Or can it be rightly claimed that the “repository issue in Germany is resolved”?

This brochure addresses these questions, provides answers, and forms an objective basis for discussions on the further course of action to be taken with regard to the final disposal of high-level heat-generating waste (HLW). The brochure explains how the Gorleben salt dome came to be a possible repository candidate, looks at the current international situation and the international policies that are in place, details the findings of exploration work to date, explains what results are available from 40 years of repository research, and examines the line of action to take going forward.

The current situation of final disposal in Germany The final disposal of radioactive waste is an important sociopolitical issue not only on account of the contro-versial debate surrounding the safe use of nuclear energy to generate electricity, but also particularly because the radioactive waste has to be disposed of safely for a very long time without causing any harm to humans or to the environment. A large quantity of the waste is already present today and is being stored safely aboveground at interim storage facilities. More waste will be added. This radioactive waste has to be disposed of in a repository. The Federal Government is responsible for the construction of such a permanent disposal facility.

Action is thus needed on the part of policymakers. Accordingly, the government parties agreed the following in their coalition agreement on November 11, 2005:

“The CDU, CSU and SPD acknowledge Germany’s responsibility for the safe final disposal of radioactive waste and will tackle this issue in a speedy and result-oriented manner. We intend to solve this question by the end of the current electoral period.”

(12)

10 I. Introduction

A solution has been found for the final disposal of non-heat-generating low and medium-level waste. In March 2007, the plan approval for the former Konrad iron ore mine near Salzgitter was finally endorsed by the Federal Administrative Court and cannot be appealed. The mine is now being converted into a repository, with plans to put it into operation in 2013.

Exploration work on the final disposal of high-level waste, in particular, has been underway at the Gorleben salt dome since 1979 (Fig. 1 and 2). The ex-ploration work has been interrupted since October 1, 2000 as a result of a moratorium imposed. This mora-torium was agreed between the Federal Government and the four main electric utility companies on June 14, 2000 as part of the plan to phase out nuclear power. The moratorium on exploration is still in place today due to the divergent positions of policymakers as to the further course of action to be taken.

Final disposal situation in other countries There is an international consensus that the final disposal of high-level waste in a purpose-built mine in deep geological formations is the best option and, from a technical perspective, can be implemented safely today. Consequently, many countries other than Germany – such as Finland, France, Sweden and the USA – are promoting repository projects in deep geological formations.

Responsibilit y under nuclear law for reposi-tories in Germany

According to the German Atomic Energy Act (§ 9a), the Federal Government is responsible for the final disposal of radioactive waste in Germany. Within the Federal Government itself, the Federal Fig. 2: Aerial photo of the Gorleben site

(13)

11

Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU) and the Federal Office for Radiation Protection (BfS), a subordinate authority, are responsible for the siting, planning, plant-related research and development, exploration, construction, operation and decommissioning of repositories for radioactive waste. The Federal Ministry of Economics and Technology (BMWi) is responsible for the nuclear energy industry and repository-related applied basic research. The Federal Institute for Geosciences and Natural Resources (BGR), a subordinate authority of the BMWi, deals with the primary geoscientific questions surrounding the final disposal of radioactive waste.

Up until 1986, the Federal Ministry of the Interior (BMI) was responsible for final disposal tasks which are now under the jurisdiction of the BMU. On the basis of discussions led since the 1960s, and following consultations with various teams of experts, the BMI drew up criteria for the final disposal of radioactive waste in 1983, and published these in the form of the “Safety Criteria for the Final Disposal of Radioactive Waste in a Mine” (BMI 1983). These criteria still apply today and were the basis for the Konrad mine being approved as a repository for low and medium-level waste.

Radioactive waste

Radioactive waste has different properties and is divided into two specific categories in Germany:

3

Low and medium-level waste:

This waste constitutes about 90 percent of forecast waste volumes (approximately 277,000 m3by 2040,

BfS 2007) but only contains approximately one per-cent of the radioactivity of the overall radioactive waste. This waste is primarily waste from nuclear power plants and from research and medicine. The radioactive decay of such waste does not result in any noteworthy production of heat. However, large quantities of gas are produced when the waste is stored. A small percentage of the medium-level waste can be assigned to heat-generating waste (e. g. fuel element hulls, reprocessing structural elements).

3

High-level waste:

This waste accounts for approximately ten percent of forecast waste volumes (approximately 22,000 m3by

2040, BfS 2007) and contains approximately 99 per-cent of the total radioactivity. Spent fuel elements from reactors and vitrified waste from reprocessing make up the vast majority of this waste. The radioac-tive decay of the radionuclides the waste contains causesconsiderable quantities of heat to be re-leased.The level of gas generated is far lower than in the case of low-level and medium-level waste. The different physicochemical properties of these two individual waste categories mean that different requirements have to be met to permanently dispose of these wastes in deep geological formations. For this reason, Germany follows the dual repository concept which involves the final disposal of the two types of waste in separate repositories in different host rock formations.

In contrast to other countries where low-level and intermediate-level radioactive waste is finally disposed of close to the surface, all radioactive waste in Germany should be finally disposed of in deep geological formations. The German concept for safe final disposal does not provide for waste retrieval once the repository has been sealed.

(14)

12 II. Why should rock salt be used for the final disposal of high-level radioactive waste?

II.

Why should rock salt be used

for the final disposal of high-level

radioactive waste?

(15)

13

The German disposal concept, which was developed using results from scientific research, is based on the following two principles for the final disposal of radioactive waste:

3

All radioactive waste generated should be finally disposed of in Germany in deep geological formations.

3

The geological barrier plays the most important role in isolating the waste, i. e. the rock salt encapsula-ting the radioactive waste in the case of Gorleben. Over 100 years’ experience in industrial salt-mining, and more than 40 years of intensive research, have given rise to an extensive knowledge base in Germany of the properties of rock salt which are relevant for the final disposal of radioactive waste, and of the numerous salt formations to be found in the country (Fig. 3 and Annex 1). This can be elaborated as follows:

3

Experience in mining in rock salt formations proves thatstable underground structurescan be constructed here. Thanks to the favorable mechanical properties of rock salt, cavities can be created

without any special supportand maintained for decades.

3

Rock salt reacts to mechanical load with a slow, flowing movement that is known as “creeping”. This particular property of rock salt causes cavities in the rock to be “self sealed”. As a result, the necessary geo-logical barrier function is guaranteed in a natural way over very long periods of time once the emplace-ment process is complete.

3

Under natural stratification conditions, the permeability of the rock salttoward gases and liquids

is extremely low. The saline solutions found today in the Gorleben salt dome are just as old as the rock salt that formed the salt dome (solution trapped during sedimentation) – i. e. over 200 million years old. This is an indicator for the fact that rock salt can be regarded aspractically imperviousas a host rock.

3

Rock salt exhibits ahigh level of specific thermal conductivity. For this reason, rock salt is particularly well suited as a host rock for high-level waste since the heat can be dissipated to the surrounding rock far better than in the case of crystalline or argillaceous rock, for example.

Due to its specific properties, rock salt is particularly favorable as a host rock for the final disposal of high-level waste in Germany. Germany has the necessary scientific experience and extensive mining knowledge for final waste disposal in rock salt.

(16)

14 II. Why should rock salt be used for the final disposal of high-level radioactive waste?

Property Rock salt Clay/ Crystalline rock argillaceous rock (e. g. granite)

Thermal conductivity High Low Medium

Permeability Practically impermeable Very low to low Very low (unfractured) to permeable (fractured) Strength Deformation behavior Stability of cavities In-situ stress Dissolution behavior Sorption behavior Heat resistance

Medium Low to medium High

Visco-plastic (creep) Plastic to brittle Brittle

Self-supporting Artificial reinforcement required

High (unfractured) to low (highly fractured)

Isotropic Anisotropic Anisotropic

High Very low Very low

Very low Very high Medium to high

High Low High

Favorable property Average Unfavorable property

(17)

15

III.

Gorleben repositor y project

III. Gorleben repositor y project

(18)

16 1. How was the Gorleben salt dome chosen?

1. How was the Gorleben salt dome chosen?

In the debate surrounding the Gorleben salt dome, it is often claimed that the Gorleben site was purely selected for political reasons and that technical and scientific reasons did not play a role in the ultimate selection of the site. This is not true, however. If we take a look at the history of the selection procedure for the Gorleben salt dome, it is clear that the site was selected in a highly scientific and methodical process.

The selection procedure followed by the Federal Government

In the period between 1964 and 1976, the Federal Government initially embarked on a search for salt structures which would be suitable candidates for a repository, and later implemented a selection pro-cess for a repository site for radioactive waste when searching for a location for a radioactive waste management center (WMC – reprocessing, fuel element production, conditioning and final disposal should be concentrated at one site).

The sites identified in these processes (Annex 2 to 4) were chosen on the basis of the experience and results of numerous scientific searches, with predefined criteria for selection and exclusion, which were carried out from the middle of the 1960s to the start of the 1970s.

Initiated by recommendations and research work conducted by the American National Academy of Sciences, the then Federal Institute of Soil Research (Bundesanstalt für Bodenforschung) and the German Nuclear Energy Commission already voiced support for the final disposal of radioactive waste in salt de-posits deep underground at the start of the 1960s.

In 1963, the Federal Institute of Soil Research presented a report which underlined the particular suitability of salt formations as repositories, and contained an initial synopsis of the knowledge then available regarding salt structures in Germany [Martini 1963].

Following an order from the then Federal Ministry for Scientific Research (BMwF) issued on December 12, 1963, the Federal Institute of Soil Research named seven salt structures (Fig. 4), which were considered suitable sites to mine caverns for the final disposal of

radioactive waste, in a study it presented in 1964 [Richter-Bernburg & Hofrichter 1964]. Numerous criteria were applied for selecting the salt structures and for the comparative analysis of their suitability for the final disposal of radioactive waste (Annex 2). Since extensive knowledge of the outer shape and interior composition of the salt structures was not available in 1963/64, and additional studies were not carried out, the choice of the seven salt structures suggested cannot be put down to a systematic analy-sis of all the salt deposits available underground (Annex 2). Onsite work was terminated in 1966 on account of problems purchasing sites, and following the rejection of the projects in the regions affected.

Fig. 4: Location of the salt structures (red triangles) appraised by Richter-Bernburg & Hofrichter (1964) with regard to their suitability for the final dispo-sal of radioactive waste

1. Heide, 2. Geesthacht, 3. Harsefeld, 4. Bunde/Jemgum, 5. Krummendeich, 6. Leutesheim, 7. Bremen-Lesum; yellow circles – location of nuclear reactors

6 7 4 3 2

5 1

(19)

17

were considered in total. The selection process con-sisted of four specific phases (Annex 4).

In the fourth phase, the four remaining sites – the salt domes at Wahn, Lichtenhorst, Gorleben and Mariaglück/Höfer – were subject to further intensive technical investigations and discussion (Fig. 6). The results identified the Gorleben salt dome as the most favorable candidate. The Federal Government, how-ever, had reservations on account of Gorleben’s proxi-mity to the border with the GDR. In the cabinet bill for In 1973, the then Federal Ministry for Research

and Technology (BMFT) commissioned the nuclear fuel reprocessing company KEWA to identify sites for a radioactive waste management center. This search focused on finding a site that would guarantee the environmentally friendly operation of surface facili-ties for the reprocessing and conditioning of radio-active waste. The repository was merely an additional requirement here. Precisely this element was reflected in the site selection criteria which formed the basis for the dual phase selection process. Comprehensive selection criteria (Annex 3) were applied in Phase 1 (overview investigations) and Phase 2 (regional inves-tigations and interim site appraisals) of the Federal Government selection process known as the “KEWA study”. Taking geological expert reports into account, this study gave the sites at Ahlden (Lichtenhorst salt dome), Börger (Wahn salt dome) and Fassberg (Weesen-Lutterloh salt dome) the best rating (Fig. 5). Geological exploration work which the Federal Government commenced at these three sites in 1975 was suspended in August 1976 on account of local protests and not for technical or scientific reasons.

In the course of two multiphase selection processes, the Federal Government looked for salt structures for the purpose of final waste disposal and for a site for an WMC including a repository. Geological exploration work at the sites mentioned was suspended in 1966 and 1976 on account of protests from some of the local population.

The selection process of the Land of Lower Saxony

When the KEWA investigations and studies did not yield the desired result in 1976, Lower Saxony implemented a selection process for an WMC [see Tiggemann 2004]. The Land government of Lower Saxony deployed an interministerial task force (IMAK) for this purpose. In contrast to the procedure followed by the Federal Government, this process applied a far more extensive catalogue of criteria. The sites proposed in the KEWA studies were included. Despite initial strategic reservations, sites close to the border with the former GDR – such as the Gorleben salt dome – were no longer ruled out. 140 salt domes

Fig. 5: Areal distribution of the sites examined in greater detail with regard to their suitability as a radioactive waste management center as part of the Federal Government site selection process (KEWA study) (red triangles = sites)

1. Ahlden – Lichtenhorst salt dome, 2. Börger – Wahn salt dome, 3. Faßberg – Weesen-Lutterloh salt dome, 4. Friedrichskoog (Schleswig-Holstein, coastal location), 5. Karlsruhe (reproces-sing plant), 6. Lütau – Juliusburg salt dome, 7. Uchte (sparsely populated, near Loccum), 8. Mahlberg – tertiary potash depo-sits Oberrheintalgraben, 9. Sohlhöhe (Spessart), 10. Oberwesel (Southwestern Rhenish Massif);

(20)

18 1. How was the Gorleben salt dome chosen?

the Land government, no preference was initially made with regard to the two “best” sites at Gorleben and Lichtenhorst. The bill merely recommended that only one of the two sites be explored. In February 1977, the cabinet of Lower Saxony finally chose Gorleben since this site best met all the selection criteria. The political reservations of the Federal Government were not considered to be of a serious nature. The Federal Government accepted the Gorleben site as the pre-liminary choice for the radioactive waste manage-ment center (WMC) on July 5, 1977.

While the WMC project in Gorleben was the sub-ject of disputes and protests, which were primarily directed at the reprocessing plants, it also received continuous support with regard to the creation of jobs in the economically less developed border area. The Gorleben Commission was founded in 1977 as a discussion platform for the region. On the initiative of the Land government of Lower Saxony, a public symposium known as the “Gorleben hearing” was held between March 28 and April 3, 1979 and was attended by many international participants. In his policy state-ment on May 16, 1979, Minister-President Dr. Albrecht recommended not building the reprocessing plant as part of the WMC but did recommend all parties remain committed to the Gorleben repository project. Government leaders from the Federal Government and Länder established a State Secretaries Committee for Disposal on July 6, 1979. In their official decision on September 28, 1979, they welcomed “the willing-ness of the Land government of Lower Saxony to allow the construction of a repository in Gorleben as soon as the exploration work and mining-specific develop-ment of the salt dome find that this is a suitable site for a repository. For this reason, we will push ahead with exploration work and the mining-specific develop-ment of the Gorleben salt dome without delay” [BMI 1981].

1. Börger – Wahn salt dome 2. Ahlden – Lichtenhorst salt dome 3. Gorleben salt dome

4. Mariaglück mine – Höfer salt dome; Blue = salt structures found in North Germany

In line with the procedure at that time applied for the development of large-scale industrial projects, as soon as the site had been announced, the public was included in the processes and steps were taken, which also provided for hearings for the parties involved.

In retrospect, it can be said that the Gorleben project was revolutionary in terms of the steps it took when communicating with the public, particularly by establishing the Gorleben Commission in 1977 and holding the international Gorleben hearing in the spring of 1979.

Fig. 6: Location of the sites examined in greater detail with regard to their suitability as a radio-active waste management center as part of the site selection process conducted by the Land of Lower Saxony

(21)

19

Despite numerous and constantly voiced opinions, the decision reached in February 1977 to construct an WMC, including a repository, at the Gorleben site in the Land of Lower Saxony was systematically made on the basis of a selection process founded on objective technical and scientific criteria. There is no foundation to any accusations claim-ing the selection process was influenced by policy-makers which could have resulted in Gorleben being “preselected” as the site. There were public protests against the project but the project did have its supporters, particularly at a municipal level. It can also be said that the Gorleben reposi-tory project was revolutionary in terms of public participation, including the general population and participation at a municipal level.

Appraisal of the selection criteria applied at the time from today's perspective

It is often claimed that the criteria applied in those days would no longer be in line with criteria used today. This is not the case.

The Ministry for the Environment and Climate Protection of Land Lower Saxony (NMU) [NMU 2008] compared the selection criteria used by the then IMAK task force to catalogues of criteria subsequently created by various expert institutes [BGR 1977, EU 1980, RSK 1983, Kockel et al. 1995, AkEnd 2002, Hoth et al. 2007]. This comparison demonstrates that the criteria then applied still meet present-day standards. In light of the fact that an WMC was still being planned at that time, the Land paid particular attention in 1976 to sociodemographic, economic geographic and legal parameters, as well as to environmental factors

(Annex 4). There is no justification for criticism frequently voiced that “modern” criteria did not play a role at that time and were not taken into con-sideration. The then Land government made the internal and preliminary decision on the site follow-ing intensive consultation with expert authorities and departments on the basis of a contemporary catalogue of selection criteria. In the process, all the relevant areas were taken into consideration and the criteria set out were plausibly applied to the salt structures known in Lower Saxony. Even the most recent papers, some of which are still under discussion, e. g. IAEA 2007 (Safety Standards), or the planned amendment to the 1983 “Safety requirements for the final disposal of heat-generating radioactive waste” safety criteria specified by the BMU, do not contra-vene the procedure applied by the IMAK task force. Furthermore, elements of the requirement for a step-wise approach in choosing an exploration site, which is now accepted internationally, were even applied back then.

As is common practice today, the decision process at that time was also supervised intensively by con-sulting committees of the Federal Government, and the disposal concept was also found to be feasible from a safety and technical perspective. With regard to the concept of final disposal in salt domes, and particularly in the Gorleben salt dome, in October 1977 it was found that this constituted a “good solution from a safety perspective” and that “final confirma-tion will be possible following investigaconfirma-tion with exploration drilling and shaft and drift excavations” [RSK 1977].

The selection criteria applied in 1976/77 still meet current standards.

(22)

What procedure is applied internationally when identif ying repositor y sites?

Different final disposal solutions are already imple-mented in many countries for the large volumes of low and medium-level waste, and approved and licensed repositories are in operation. In identifying repository sites for high-level waste, the process that applies is similar to that used to select the Gorleben site. Several European countries, the USA and Japan have applied multiphase processes for selecting a repository site, some of which already began back in the 1970s. Apart from a few common elements, it is very difficult to otherwise compare the processes for selecting a site, however (Annex 5). There is no inter-nationally accepted standard for a selection process.

Each country has its own repository program because the country-specific geological conditions require specially tailored solutions with regard to safety. It is absolutely essential that all repository con-cepts constantly focus on maintaining strict safety requirements. Another decisive factor is that sites have been selected, or are to be selected, at an inter-national level in a step-by-step process with a “roll-back clause”, as in the case of Gorleben (Annex 5). The processes can be split into the following steps: 1. Identification of a large number of possible sites

for preselection (screening)

2. Open, unbiased surface exploration of one or more preselected sites, selection of one site 3. Open, unbiased underground exploration of the

selected site

4. Statement of suitability is obtained and approval process is initiated for the site, with particular importance being attached to the involvement of the local population and to the agreement of local authorities

5. Approval is granted with the possibility of a legal objection

The underground exploration phase is the most cost-intensive and time-cost-intensive step by far. The Gorleben repository project is currently in Phase 3 “open, unbiased underground exploration”.

20 1. How was the Gorleben salt dome chosen?

The extent to which alternatives are taken into consideration in the selection process, and to what degree these alternatives are explored, differs from country to country. Surface exploration measures, and sometimes drilling, are carried out for the com-parative analysis of the safety of several sites. How-ever, no country considers underground exploration of more than one site. If several sites meet the suit-ability and safety requirements to the same extent, the choice is ultimately made from planning and sociological perspectives in particular.

There is an international consensus that a site can only be specified as a repository if it meets the strict safety requirements that apply. The extent to which alternative sites are included in the site selection process, and to what degree these sites are explored, differs from country to country. However, no country considers underground exploration of more than one site at a time.

(23)

21 2. How far has exploration work progressed at the Gorleben salt dome?

2. How far has exploration work progressed

at the Gorleben salt dome?

Results of exploration to date

The information gathered in the course of the surface and underground geological and geophysical explo-ration work, which has been underway since 1979, was summarized and assessed by the Federal Institute for Geosciences and Natural Resources (BGR) with regard to the final disposal of high-level waste [Bornemann et al. 2008] (Fig. 7 to 10). At the same time, the results of the exploration work performed on the overburden were published by the BGR in two addi-tional geological almanacs [Klinge et al. 2007 and Köthe et al. 2007]. The Gorleben salt dome is the world's best-explored and investigated site. Figure 11 provides an overview of the exploration program to date. To the present day, the waste producers have invested an estimated total of 1.5 billion euros in the repository project. The primary results of the explora-tion conducted to date can be summarized as follows:

3

The central section of the salt dome primarily consists of pure rock salt layers of the Hauptsalz (Staßfurt formation of the Zechstein, z2), which are largely solution-free and are particularly well suited for final disposal.

3

In exploration area 1 (EB1) of the Gorleben salt dome, the rock salt layers (z2) earmarked for the final disposal of radioactive waste extend further than orig-inally predicted on the basis of surface exploration.

3

An impermeable salt barrier, approximately 600 m thick, extends across the planned emplacement area to the overburden.

3

The assumption that rock salt can act as a barrier has been affirmed.

3

There are no hydraulic connections or flow paths between the rocks in the planned emplacement area and the aquifers in the overburden.

(24)

22

Fig. 8: Section through the salt dome with excavations

3

The creep rates (convergence rates) measured in the Hauptsalz mean that compact inclusion of the radioactive waste can be expected.

Additional findings of the exploration work are listed in Annex 6.

No analytical findings to date argue against the suitability of the Gorleben salt dome for the con-struction of a repository.

The results of explorations performed to date have been analyzed by the BGR and the majority have already been published. All the results con-firm the potential suitability (i. e. suitability sub-ject to the completion of the exploration work) of the Gorleben salt dome as a repository host rock. The Gorleben site is the best-explored and investi-gated potential repository site for high-level waste in the world.

(25)

23

Fig. 9: Three-dimensional model of the outer shell of the Gorleben salt dome with the location of the mine workings

(26)

24 2. How far has exploration work progressed at the Gorleben salt dome?

July 1977 The Federal Government accepts the preselection of the Gorleben salt dome as a potential repository site resulting from the site selection process conducted by the Land Lower Saxony. At the request of the Federal Government, the National Metrology Institute (PTB) initiates the planning approval procedure with the authorities of the Land of Lower Saxony.

November 1977 The Federal Institute for Geosciences and Natural Resources (BGR) presents a detailed examination program for the geological and geophysical exploration task.

June 1979 The Lüchow-Dannenberg district council approves the exploration program for the Gorleben salt structure.

Fall 1979 Surface exploration commences

The identification of sites for exploration drilling or seismic profiles was based on results for reflection seismic investigations conducted by the oil and gas industry in the 1930s and 1950s. The following were created in total over an area of approx. 300 km2:

34 deep boreholes

344 salt surface boreholes (1979 to 1985), 2 shaft pilot drills (1982)

3around 400 hydrogeological boreholes

Januar y 1980 to Four deep boreholes were sunk to a level of about 2000 m (the Lüchow-Dannenberg district

March 1981 council agrees in March 1980).

1983 The National Metrology Institute (PTB) publishes the findings of the surface exploration. The Federal Ministry of the Interior publishes the “Safety Criteria for the Final Disposal of Radioactive Waste in a Mine”

1983 Underground exploration commences

The Federal Government approves the underground geological and geotechnical exploration of the salt dome. The underground exploration work aims at increasing the knowledge base of the internal geological makeup of the salt structure, as well as knowledge of the petrographic, thermomechanical, rock dynamic and geohydraulic properties of the areas of the salt dome intended for the repository.

1984 Reflexion seismic measurements at 16 surface profiles running longitudinally and horizontally to the salt dome with a total length of 150 km, 549 deep soundings in boreholes and shallow seismic measurements over a total of 312 km for a more detailed exploration of the surface of the salt dome and the stratification conditions of the quaternary sediment.

1986 Work commences on sinking a shaft using ground freezing (Gorleben 1 shaft to 933 m, Gorleben 2 shaft to 840 m).

1986 Seismological monitoring of local earthquake activities commences.

1994 Completion of the inner shaft lining.

1996 Cut-through between the two shafts at the 840 m level.

1996–1998 Surface site exploration of the salt dome area to the north of the River Elbe (former GDR).

2000 Underground drift system approx. 7 km long. In addition to excavations, a total of 11 km of exploration boreholes and geotechnical wells were drilled to investigate the material and structural condition of the salt dome. Deformation and stress measurements are taken in the geotechnical wells.

October 1, 2000 Exploration moratorium commences, since then stand-by operation

July 25, 2005 “Statutory order to ban construction work in the area of the Gorleben salt dome with the aim to safe-guard exploration for a final repository”applicable for 10 yearsin accordance with the agreement of June 14, 2000

2008 BGR summarizes and publishes exploration findings to date, long-term measurements continued

(27)

Continuing exploration work on the salt dome would involve the following steps:

3

Completing exploration area EB1 and other exploration areas adjacent to the east with a system of cross-cuts and gait roads (Fig. 12 and 13).

3

Continuing the geological, geophysical and geotechnical exploration of the central section of the salt structure and its further progression starting at the 840 m exploration level.

3

Performing complementary investigations on the origin and presence of isolated hydrocarbons in the planned emplacement area.

25

What still has to be done?

As underground site exploration has been suspended since October 1, 2000, a final statement on the suit-ability of the Gorleben salt dome as a repository for high-level waste cannot be issued. While the majority of the exploration work in the salt dome has already been carried out, a final appraisal can only be made once the exploration phase, with the tasks listed below, has been completed and proof of suitability is provided in a site-specific long-term safety analysis. Approximately five years would be required for this [Thomauske 2004].

(28)

Afterwards, the drift network of the future repository has to be planned on the basis of the exploration results.

26 2. How far has exploration work progressed at the Gorleben salt dome?

Fig. 13: Excavation work in a drift at the 840 m level

A definitive statement on the suitability of the salt dome can only be issued once the exploration work has been completed. This would require around five more years once the moratorium has been lifted.

(29)

27 3. Why does the exploration moratorium still apply?

3. Why does the exploration moratorium still

apply?

“The primary result of the investigation is an illustration of both the possibilities and the limita-tions of a generic comparison of host rocks, and answers to the twelve open issues. According to the results, no host rock exists that always guarantees maximum repository safety. Tailored and specially engineered repository concepts can be developed for all the rele-vant host rocks in Germany.” The BfS continued that “it is only possible to compare various options if speci-fic sites and repository concepts are compared. This results in the need for a site comparison”.

However, according to the majority of the reposi-tory experts who attended the workshop “from a geoscientific perspective, the results of the expert report do not provide any basis for the need for a site comparison”. In an official statement [BGR 2007], the BGR also made it clear that “the results indicated in the individual expert reports do not contradict the positive appraisal of the geological findings at the Gorleben site”. Furthermore, the BGR stressed that “none of the geological findings to date argues against the suitability of the Gorleben salt dome for the final disposal of radioactive waste.” The BMWi is also of the opinion that consideration of the open issues did not yield any negative points regarding the Gorleben salt dome. There is also just as little evidence of the need for a site comparison.

The open issues concern final disposal in general. They have been addressed in extensive studies and discussed with national and international experts. They have been answered, and no ques-tions remain open. The results are positive: no facts were presented that may prevent the resump-tion of the exploraresump-tion work at the Gorleben salt dome. There are no factual reasons to keep the moratorium imposed.

The exploration moratorium

The agreement between the Federal Government and the electric utility companies that regulates nuclear power phase-out (initiated on June 14, 2000 and signed on July 11, 2001) also defines the further course of action to be taken as regards the Gorleben salt dome repository project (Annex 7).

In line with this agreement, exploration work was discontinued on October 1, 2000, and a moratorium was imposed for “a minimum of three years and a maximum of ten years” to clarify open issues. This moratorium still applies today. Annual costs to keep the project open total around 20 million euros which have to be borne by the waste generators (electric utility companies and research institutes).

The agreed maximum duration of the exploration moratorium is ten years, i. e. it will last until September 30, 2010 at the very latest.

Open issues to be clarified during the mora-torium and resolution of same

In compliance with the agreement, the BMU formulated a number of questions (Annex 7) which concern the final disposal of radioactive waste in general, and which should take international information and findings, in particular, into account. These questions are known as the “open issues”. After much delay, the BfS, as the body responsible for coordinating investigations regarding these open issues, did not receive the results of the studies conducted for this purpose until mid 2005.

In September 2005, the BfS organized a workshop to discuss the results of the research projects with a “pluralistic team of experts”. On November 5, 2005, the BfS published both the individual studies and the results of the workshop in a consolidated report enti-tled “Comparative Analysis of Host Rocks”. The BfS sum-marized the results of the research projects on the open issues, and the results of the discussions with repository experts, in the consolidated report published on November 5, 2005 as follows [BfS 2005]:

(30)

28 3. Why does the exploration moratorium still apply?

Local communit y calls for exploration work to continue

Large-scale technical projects have always been, and remain, a source of controversy and debate among the general public in the Federal Republic of Germany. Be it the western runway at Frankfurt airport or plans to build new roads – such projects are always contro-versial and disputed. Plants to dispose of radioactive waste are no exception. Thus, it is absolutely essential to include the residents of a possible site for the dis-posal of nuclear waste if plans to explore the area, and possibly build a repository, are to go ahead. For this reason, the government already started encouraging dialogue with the region in 1977 when “Gorleben” was officially announced as the chosen site.

Time and again, the municipal parliaments and the citizens of the district of Lüchow-Dannenberg have intensely debated decisions concerning Gorleben (Annex 8). For decades, local politicians from both political parties (CDU and SPD), in particular, have spoken in favor of performing or resuming exploration work at the site. There is still majority support in the councils of the district of Gorleben, and in the Gartow association of communes, for the continuation of the exploration work. They demand an end to the politi-cal gridlock and want clarity on the future of the site.

On the other hand, there is a strong protest movement against Gorleben, which is not only sup-ported by some local citizens but is also driven, in particular, by opponents of nuclear power from all over Germany. This protest movement was and is motivated by a general anti-nuclear power senti-ment, rejection of the Gorleben salt dome repository project and the periodic transfer of radioactive mate-rial to the Gorleben interim storage facility.

Ever since the project began, a strong protest movement has been active in Gorleben which was not only triggered by the repository project. However, in the municipal area in particular, an intensive debate between supporters and oppo-nents of the Gorleben exploratory mine has taken place. The district councils of Gorleben and the Gartow association of communes take a positive view of the Gorleben repository project and demand the rapid, continuation of the explora-tion work open with regard to results (Annex 8).

(31)

29

IV.

State of research

IV. State of research

(32)

30

1. Alternatives to rock salt in Germany

30 1. Alternatives to rock salt in Germany

Since the start of the 1960s, research has been con-ducted in Germany on the final disposal of radioactive waste in various host rocks. In addition to announcing the Gorleben salt dome as a possible repository candi-date, at the request of the EU the BGR also created a catalogue of potential host rock formations in Germany in 1977 [Kockel & Roland 1977]. On behalf of the BMU and the Federal Ministry of Education and Research (BMBF), the BGR published two studies in 1995 contain-ing a selection and appraisal of possible sites in rock salt and crystalline rocks (granite, gneis) [Bräuer et al. 1994 and Kockel & Krull 1995]. These studies observed all rock deposits following criteria for exclusion and consideration that are still valid today.

In 2003, the BMWi commissioned the BGR to con-duct a supplementary study on the distribution of argillaceous rock in Germany [Hoth et al. 2007] and summarize the results of existing studies in a survey map [BGR 2007]. Internationally recognized criteria for exclusion and consideration, as well as the criteria for exclusion and minimum requirements [AkEnd 2002] drawn up in 2002 by the Committee on a Selection Procedure for Repository Sites (AkEnd), formed the basis for these investigations. In addition to the Gorleben salt dome and the salt domes already identified by the BGR in 1995 as backup options, argillaceous rock deposits from the early Cretaceous period in North Germany and from the Jurassic period

in North and South Germany were identified and the results documented in a survey map (Fig. 14). Due to its unfavorable properties in comparison with rock salt and argillaceous rock, information on crystalline rock was not recorded. All the data available from maps, archives and existing boreholes (over 24,000) formed the basis for the investigation. Since then, there is clarity on the host rocks available in Germany that could be possible candidates for the final disposal of high-level waste (Fig. 14). The BGR consolidated report entitled “Investigation and Evaluation of Regions with Potentially Suitable Host Rock Formations” summarizes the results of research on rock salt, crystalline rock and argillaceous rock as host rocks in Germany [BGR 2007]. The results found that for Germany, rock salt exhibits considerable advantages as a host rock for the final disposal of high-level waste compared to argillaceous and crystalline host rocks (Annex 9).

As a result of the work carried out by the BGR, there is clarity on the host rocks which are avail-able in Germany and generally suitavail-able for the final disposal of high-level waste, as well as on the geographical distribution of such rocks. On the basis of the evaluation criteria applied, rock salt is found to be the most suitable host rock in Germany.

(33)

31

Rock salt/argillaceous

host rock formations in

Germany worth investigating

April 2007

Argillaceous rock formations (Cretaceous/Jurassic) Thickness > 100 m

Depth > 300 m and < 1000m below ground level Salt domes worth examining (according to BGR study 1995) Gorleben exploration site

0 50 100km

Federal Institute for Geosciences and Natural Resources Saarbrücken Munich Stuttgart Mainz Wiesbaden Düsseldorf Erfurt Dresden Magdeburg Potsdam Berlin Hanover Bremen Hamburg Kiel Schwerin Wahn Zwischenahn Waddekath Gorleben Gülze-Sumte

Fig. 14: Survey map of the regions with argillaceous rock deposits and salt domes in Germany which could be considered for the final disposal of high-level waste

(34)

32 2. Basic research within the responsibilit y of the Federal Ministr y of Economics and Technology

2. Basic research within the responsibility of the

Federal Ministr y of Economics and Technology

Various institutes conduct research on the final disposal of radioactive waste, whereby a distinction must be made between application-oriented fundamental research and site-specific research. R&D activities that are related to HLW disposal are basically the respon-sibility of three specific departments: the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU), the Federal Ministry of Economics and Technology (BMWi) and the Federal Ministry of Education and Research (BMBF). Application-oriented fundamental research, comprising generic and site-independent research, is the technical respon-sibility of the Ministry of Economics and Technology. This includes the national research centers, which, however, receive their basic financing from the Ministry of Education and Research. Fundamental research is financed by the federal budget. In contrast, site-specific research is refinanced by the waste gener-ators (electric utility companies and public-sector research institutes) following the “polluter pays principle” (§ 21b of the Atomic Energy Act).

The Federal Government supports the production and development of scientific and technical know-how for the final disposal of radioactive waste. Since 1998, the BMWi has been responsible for application-oriented fundamental research for final waste dis-posal. The BMWi has assigned the Project Management Agency Forschungszentrum Karlsruhe, Water Techno-logy and Waste Management Division Project (PTKA-WTE), responsibility for implementing this funding and support task. PTKA-WTE manages and supports about 70 concurrent multiannual research projects on average every year. The “focus of future R&D in the final disposal of radioactive waste (2007 – 2010)” BMWi research concept forms the framework for the research and development activities receiving some ten million euros in funding every year [BMWi 2007].

The results from over 40 years of research and development and from more than 500 research pro-jects carried out in this period provide a strong basis for implementing a repository project in Germany,

(35)

33

ticularly with rock salt as the host rock. All scientific and technical findings to date confirm that it is possi-ble to safely implement a repository for high-level waste in rock salt from a technical perspective.

The German repository concept for the direct final disposal of spent fuel elements in rock salt acting as a host rock (Fig. 15 and 16) has been developed and elaborated, and its feasibility verified, in the course of several years of research and development. As part of this concept, spent fuel elements in large self-shielding POLLUX casks are emplaced in drifts. Canisters with vitrified waste from reprocessing ope-rations are to be permanently disposed of in boreholes. The main technical components of the concept have been tested in large-scale demonstration experiments. Furthermore, extensive research projects have been

carried out to develop concepts for backfilling and sealing drifts and shafts (“geotechnical barriers”). In addition, different disposal concepts have been examined and analyzed in safety assessment studies (Fig. 16).

The aim of the research was and is to facilitate the implementation of a repository for high-level waste and to further optimize the German repository concept.

40 years of repository research and over 500 suc-cessful research projects provide the basis for implementing a safe and secure repository for high-level waste in rock salt as a host rock.

(36)

34 3. Can Gorleben be compared to the Asse II mine?

3. Can Gorleben be compared to the Asse II

mine?

From 1965 to 1995, research and development work for the final disposal of radioactive waste in salt for-mations was carried out at the Asse II mine, a former salt mine. Against this backdrop, low- and medium-level waste was also deposited until 1978. The focus of the various research projects included investigating the interaction between radioactive waste and the salt formation as well as various emplacement tech-nologies.

Around 55 years of intensive salt mining shaped the Asse mine before it came to be used as a research mine. During this time (1909 to 1964), an extensive system of cavities was created which is not separated from the overburden by a sufficiently thick rock salt barrier at the southwest flank of the salt structure. The cavity system proved to be mechanically unstable on the long term. The underlying processes caused damage to the rock salt layer at the southwest flank of the digging operations.

The damage of the rock salt barrier by intensive salt mining is identified as the reason for the brine intrusion witnessed today. Currently, research work is focusing on developing a safe sealing concept for the Asse II mine.

In contrast, the Gorleben salt dome is untouched, i. e. salt was never mined here at any stage. Up to now, only cavities especially needed for exploration work have been excavated in the salt dome. Due to the safety criteria for final disposal, the new cavities to be created will be surrounded on all sides by a sufficiently thick layer of rock salt. As a result, this rules out the “Asse problems” right from the start.

The conditions at the Asse II mine cannot be ap-plied to a potential repository site at the Gorleben salt dome. The Gorleben salt dome never housed a salt mine. On the contrary, a new mine is being excavated here to explore the site's suitability to host a repository. Thus, the German repository concept in rock salt is not called into question.

(37)

35

V.

Would it make sense to look for

new repositor y sites?

(38)

36 V. Would it make sense to look for new repositor y sites?

All international procedures already implemented, or currently ongoing, for determining a repository site feature a high degree of national characteristics and conceptual differences on account of the specific host rock (see Chapter III.1). A standardized international procedure cannot be derived from these approaches. Ever since 1976, the German Atomic Energy Act has demanded that repository sites meet strict safety requirements in such a way that a hazard for humans and the environment can be definitively ruled out. The aim is to find an appropriate, suitable location for the repository.

The Gorleben salt dome was identified in 1977 in a complex selection process involving over 140 salt domes (see Chapter III.1). Surface and underground exploration work has been in progress since 1979. The results of all the exploration work to date argue in favor of the suitability of the salt dome to host a repos-itory. The Federal Government also drew attention to this fact in the agreement on June 14, 2000, which forms the basis for nuclear energy phase-out.

As explained in detail in Chapter IV. 1, over the past number of years the BGR has identified all the potentially suitable regions in Germany with rock salt, argillaceous rock which could serve as potential host rocks. BGR investigations show that rock salt is the best host rock in Germany for the final disposal of high-level waste [BGR 2007]. When comparing the various re-pository concepts for rock salt, crystalline rock and argillaceous rock, the particular advantages associated with rock salt are also arguments in favor of using this rock as the host rock (Fig. 17).

On the basis of the exploration results acquired to date for the Gorleben salt dome and comprehensive studies conducted by the BGR, there is no need for an often-demanded new selection process for repository sites in Germany. There are no statutory provisions for this in the Atomic Energy Act. On the one hand,

the Atomic Energy Act does not make a distinction between “suitable” and “more suitable” repository sites but demands across-the-board compliance with the strictest safety requirements. On the other hand, in the course of the planning approval procedure for the Konrad repository for low- and medium-level waste with negligible heat generation, a court ruling deemed a comparative selection procedure unnecessary. Furthermore, it is practically impossible to identify a “most suitable” site on the basis of comparative site analysis since different repository systems would have to be compared due to the variability of the geological conditions (e. g. different host rocks). On account of their complexity, a clear ranking system for the various repository systems could not be created. Thus, a reliable and plausible decision for one specific site would not be possible. Ultimately, sociopolitical criteria without any relevance to safety (e. g. local willingness to participate in the project), and not safety-specific factors, would play a pivotal role in the final outcome.

Notwithstanding all the points listed above, ini-tiating a new search for repository sites in Germany would not only considerably delay the process of finding a solution to the high-level waste repository issue, but would also result in additional costs am-ounting to billions of euros to be borne by electricity consumers.

According to the Atomic Energy Act a new selection process for repository sites in Germany would be justified scientifically and legally only, if the Gor-leben site were found to be definitely unsuitable as a repository on completion of the exploration open with regard to results. There are no indica-tions of this being the case at present. Nor is there any justification for introducing a new selection process at present when comparing the German process with processes used in other countries.

(39)

37

Components Rock salt Clay/argillaceous rock Crystalline rock

Emplacement depth Approx. 900 m Approx. 500 m 500 – 1200 m

Storage technique* Drifts and deep boreholes

Drifts and/or short boreholes

Boreholes or drifts Storage temperature

Backfill*

Interim storage period (fuel rods and HLW canisters)

Drift reinforcement

Container concept

Mining experience

Max. 200° C Max. 100° C Max. 100° C

(bentonite backfill)

Crushed salt Bentonite Bentonite

Min. 15 years Min. 30 – 40 years Min. 30 – 40 years

Not necessary Necessary and potentially very complex

Necessary in severely fractured zones

Established New development

required for Germany

New development required for Germany Very extensive

(salt-mining) Hardly any

Extensive (iron ore mining)

Favorable property Average Unfavorable property

* Is adapted to the host rock in question.

(40)

38 VI. Roadmap to a repositor y for high-level heat-generating waste

VI.

Roadmap to a repositor y for

(41)

39

Surface and underground exploration has been in progress at the Gorleben salt dome since 1979. Results of the exploration work to date confirm Gorleben’s potential suitability as a repository. However, a final appraisal of the suitability of the Gorleben salt dome can only be drawn up once all the salt dome areas earmarked for the final disposal project have been explored. Only about five more years would be needed for this work. For this reason, the moratorium should

be lifted promptly and exploration work open with regard to results should be resumed.

Should it result that the Gorleben salt dome is not suitable as a repository for high-level waste, a new repository site with rock salt as the host rock would have to be determined on the basis of the existing BGR studies.

1. Continuing and completing exploration work

at the Gorleben salt dome

1. Continuing and completing exploration work at the Gorleben salt dome

(42)

40

In addition to continuing exploration work on the Gorleben salt dome, the results of the exploration have to be assessed. Furthermore, a site-specific safety case has to be prepared which will act as the central document in the subsequent approval process.

It is common international practice that national projects to implement a repository for high-level waste be evaluated by an independent international organization. Switzerland, France and Sweden, for example, commissioned the Organization for Economic Cooperation and Development/Nuclear

Energy Agency (OECD/NEA) to evaluate their safety assessments and concepts implemented as part of the national repository programs. This quality assurance measure, which is generally practiced and accepted internationally, would also be appropriate for Germany. It would result in an independent appraisal of the suitability of the Gorleben site and the concept. The verification process could improve transparency and lead to greater objectivity in public debates on the final disposal issue. A period of approximately two years would be required for a process like that. 2. Safet y assessment and international verification

2. Safet y assessment and international

verification

(43)

41

The following steps have to be carried out before a repository at the Gorleben site can be put into operation: 1. Lifting of the exploration moratorium,

comple-tion of exploracomple-tion work and appraisal of the exploration results. At the same time, the safety case has to be prepared and the project has to be verified internationally.

2. Carrying out the approval process with all the necessary plans, participation from the public and ultimate granting of plan approval. 3. Construction of the repository.

In line with earlier plans of the BfS, a period of about five years is estimated for every step – extended delays in the approval process aside [Thomauske 2004]. Presuming the moratorium on the exploration will

3. Putting the repositor y into operation

3. Putting the repositor y into operation

last for a maximum of 10 years until the end of September 2010, and presuming underground exploration can continue on October 1, 2010, with a timeframe of about five years for each of the three steps listed above it should be possible to put the re-pository at the Gorleben salt dome into operation around 2025. Up until then, costs of at least 1.1 billion euros still have to be borne by the waste generators.

A final statement on the suitability of the Gorleben salt dome can only be issued if exploration work is completed and a safety case is prepared. At the same time, the repository project should be as-sessed internationally. Once exploration work is resumed, at least 15 more years are needed to put the Gorleben repository into operation.

(44)

42 VII. Summar y

VII.

(45)

40 years of repository research and over 500 success-ful research projects have provided the scientific basis for ensuring that a safe repository for high-level waste can be implemented in Germany. It has also been found that, in Germany, rock salt is best suited to act as a host rock. Furthermore, thanks to the work conducted by the BGR, there is clarity on the distribution and location of host rocks which would be suitable for the final disposal of high-level waste in Germany.

The Gorleben salt dome is the world’s most inten-sively examined and explored site for a possible reposi-tory. The decision taken in February 1977 to focus on the Gorleben site was based on an objective and criteria-driven selection process. The selection criteria applied then still meet today's standards. There are no scientific grounds, or grounds under atomic energy law, for a new selection process for repository sites in Germany. Nor is there any justification for introducing a new site selection process at present when we compare the Ger-man process with processes used in other countries. The open issues that gave rise to the exploration mora-torium have been dealt with in extensive studies and discussed with national and international experts. These issues have been addressed and no issue remains open. No negative aspects that speak against the Gorleben salt dome were identified.

Continuing the moratorium on exploration work at the Gorleben salt dome results in a stalemate in the quest to find an appropriate solution to the repository question, and impedes any progress on the path towards

addressing this issue quickly, and finding a solution in this legislative period, as set out in the German govern-ments coalition agreement.

The moratorium needs to be lifted and the with regard to results open, unbiased exploration of the Gorleben salt dome has to be continued and completed. Only in this way can a final statement be made on the suitability of the site to host a repository. Up to now, all the results of the exploration work carried out argue in favor of the Gorleben salt dome as a suitable candidate for the safe final disposal of high-level waste. As long as new exploration results do not reveal evidence to the contrary, it would not make any sense to embark on a new search for repository sites in a new selection pro-cess. Legal regulations up to now have stipulated that the waste generators (electric utility companies and public bodies) are obliged to finance the Konrad mine and Gorleben salt dome repository projects. Costs for the simultaneous exploration of other possible reposi-tories would have to be borne solely by the Federal Government.

In summary, it can be said that the repository prob-lem in Germany has been technically resolved. Policy-makers now have to reach a decision to end the grid-lock on the constructive solution to the issue of the final disposal of high-level waste.

Frequently asked questions on the Gorleben repository project are listed and answered in Annex 10.

Figure

Updating...

References

Updating...