Waste disposal for nuclear power plantsA technologically solved challenge

This brochure provides information about disposal of the residual materials and waste accumulating in German nuclear power plants.

The images, tables and graphics contained in the brochure may be used in preparing lectures concerning the disposal of nuclear power plants. For this purpose, the representations can be downloaded at: www.vgb.org/abfallmanagement.html.

Please make reference to the source when using the information.

Page

Foreword 4

1 Nuclear power plants and their corresponding disposal facilities in Germany 6

2 Radioactive materials from nuclear power plants 7

3 Classification of radioactive waste 8

4 Fuel assembly disposal 9 Reprocessing 10 Direct final disposal 11 Transport and interim storage of fuel assemblies 12 Conditioning and final disposal of spent fuel assemblies 14

5 Recyclable and non-recyclable radioactive materials 15 Residual materials and waste management concept 15 Release 16 Recycling of metals by melting 17 Radioactive waste 18 Annual operational waste volume from nuclear power plants in Germany 19 Optimised treatment methods for solid and liquid radioactive waste from nuclear power plants 19 Volume reduction of radioactive waste 19 Incineration facility for radioactive waste 20 High-pressure compaction of solid radioactive waste 21 In-drum drying for solidifying liquid radioactive waste 22 Examples of packaging of radioactive waste 23 Transport of radioactive materials 24 Interim storage 24

6 Decommissioning and dismantling of nuclear power plants 25

7 Quality assurance 27 Waste treatment with methods qualified by the BfS (Federal Office for Radiation Protection) 27 Waste package documentation 28 Waste Flow Tracking and Documentation System (AVK) 28

8 Final disposal 29 Responsible institutions in final disposal of radioactive waste in Germany 29 Structure of a repository for radioactive waste in a salt formation 31

9 Final disposal sites and pits 32 Development of final disposal 32 Asse 33 Morsleben 33 Konrad 34 Gorleben 35

Glossary 36 List of illustrations 40 Further websites 41

Imprint 43

Overview of topics

Renewables*

Oil and natural gas

100

90

80

70

60

50

40

30

20

10

0

Lignite

Shar

e of

ele

ctric

ity g

ener

atio

n in

%

Nuclear power

Old and newFederal StatesFormer West German States

*Hydro power, wind energy, biomass, photovoltaics, domestic waste and geothermics; practically only hydro power prior to 1990

Hard coal

1960 1970 1980 1990 2000 2010

Fig. 1 – Energy mix of Germany’s electricity supply between 1960 and 2010

For 40 years now, nuclear power has been making an important contribution to a safe, economical and environment-friendly power supply of the industrial nation of Germany. On occasions, the share of nuclear energy amounted to more than 30 %. During this period, radioactive waste have accumulated during operation of the nu-clear power plants, the disposal of which this brochure intends to describe.

Amendment of the German Atomic Energy Act1) in 2011 in the wake of the natural and reactor disaster in Japan has substantially transformed the situation of nuclear power in Germany: for eight plants, the authorisation for continued electricity production has been forced to immediatly expire. Restricted electricity generation quotas and concrete decommissioning dates have been assigned to the nine remaining nuclear power plants. Subsequently, the last three German nuclear power plants will be withdrawn from the grid at the end of 2022.

After assigning a modified use to nuclear power with these new framework conditions, it is to be expected in the future that the political endeavours for final disposal of radioactive waste as a duty of the German Federation will increase. These include the conver-sion and commissioning of the approved Konrad repository for non-heat-generating radioactive waste and the rapid further ex-ploration of the Gorleben salt dome so that a statement about the possible suitability for a repository for heat-generating radioactive waste can be made. Since some time will elapse until the repository is commissioned, the nuclear power plants have developed and are applying treatment methods for the waste. The aim is, in addition to manufacture repository-compatible and conditioned waste pack-ages, a reduction of the volumes of waste. Interim storage facilities exist and the transports are long-established practice.

The radioactive waste are disposed of according to the «polluter pays» principle: those who generate radioactive waste must bear all the disposal costs. This also applies to final disposal of the radio-active waste. Although the German Federation is responsible for this, the costs are nevertheless immediately passed on to the waste producers.

1)words printed in italics are explained in further detail in the glossary (from p. 36 onwards)

Foreword

Fig. 2 – Energy mix of Germany’s electricity supply from 2010

During the residual life spans of the nuclear power plants, further radioactive waste will accumulate. The same applies to decommis-sioning of the plants. Radioactive residual materials also arise how-ever during the use of radioactive materials in medicine, research and industry. During their disposal, i.e. in all stages of treatment, interim storage, transport and final disposal, protection of man and the environment takes utmost priority. Consequently, radioactive materials must be dealt with such that impermissible radionuclide concentrations in the biosphere are ruled out.

Tried and trusted methods, facilities and containers have been available for this purpose for many years now. To name a few examples:- Reprocessing of spent fuel was already developed almost

50 years ago and has been industrial practice in Europe since the 1980’s.

- Storage casks for spent fuel assemblies have been authorised and are in use since the early 1980’s.

- Central interim storage facilities for high-level waste (HLW) from reprocessing and spent fuel assemblies have existed since the early 1980’s; decentralised storage facilities at the power plant sites have been in operation since 2007 at the latest.

- Treatment methods for radioactive waste have existed since the

first nuclear power plants were commissioned; they have been continuously adapted to the changing requirements of interim storage and final disposal.

- The decommissioning of nuclear power plants has been com-mon practice for more than 20 years now; three plants have already been completely decommissioned.

- The Konrad repository for low and intermediate-level waste (LLW and ILW) is approved and is currently being extended.

- Solely implementation of the disposal stage, i.e. final disposal of heat-generating waste, has not yet been performed by the Ger-man Federation. Nevertheless, the necessary technologies have been available for many years.

In this brochure «Disposal of nuclear power plants in Germany: a technologically solved challenge», the methods for condition-ing, interim storage and final disposal of spent fuel assemblies and radioactive waste in addition to the political background and the legal framework are illustrated in pictorial and text form. It is intended to make a contribution to objective information and an open dialogue.

19 % 23 %

23 %

19 %

16 % Oil and natural gas

Nuclear power

Lignite

Hard coal

Hydro power and other renewables

5

Fig. 3 – Nuclear power plants and their corresponding disposal facilities in Germany

In Germany, 9 commercial nuclear power plants with a gross design rating of some 12,700 MW were in operation under load at 8 sites at the end of 2011, including 7 pressurised water reactors (PWR’s) and 2 boiling water reactors (BWR’s).

A total of 19 power and prototype reactors have now been shut down and are currently in different phases of decommissioning. The Niederaichbach nuclear power plant, the Kahl superheated steam reactor and the Kahl experimental nuclear power plant have been completely decommissioned; the former power plant sites have returned to «green meadows». With the resolution of the German Lower House on nuclear phase-out in summer 2011, the authorisa-tion for operation under load is expiring for eight plants.

Even before use of nuclear power for electricity generation was be-gun in 1962 with commissioning of the Kahl experimental nuclear power plant (VAK), key decisions concerning disposal of the radio-active materials accumulating during power plant operation were made:

Treatment of the operational waste is performed at the power plant sites or in central facilities. The waste treatment plants of the research centres in Karlsruhe and Jülich are also available for this purpose.

As early as between 1967 and 1978, radioactive waste were placed in storage in the Asse pit and between 1981 and 1998 in the Mors-leben repository. The Konrad pit is approved as a repository site and is currently being extended into a repository. The Gorleben salt dome is being explored at present. Until the repositories are com-missioned, radioactive waste are being stored at the power plant sites or in central interim storage facilities.

Until 2005, spent fuel assemblies were taken to France or Great Britain for reprocessing following a decay time in the fuel pool of the nuclear power plants. The reusable materials separated in the process are recycled in German nuclear power plants; the waste arising are returned to Germany according to contract and undergo interim storage until a suitable repository is available. The spent fuel assemblies undergo interim storage in decentralised storage facili-ties at the nuclear power plant sites.

1 Nuclear power plants and their corresponding disposal facilities in Germany

3

Fig. 4 – Differentiation of the radioactive residual materials

2 Radioactive residual materials from nuclear power plants

During operation and decommissioning of nuclear power plants, radioactive residual materi-als occur which, as stipulated by the legislator, are to be harmlessly recycled or disposed of in a controlled way, i.e. handed over to a Federal repository.

Materials, the activity inventory of which - following decontamination if necessary - may de-monstrably result in negligible radiation exposure of the population may be conventionally used, recycled or removed if the competent authority issues a corresponding release. They subsequently no longer fall under the term «radioactive materials» and are no longer sub-ject to monitoring under the German Atomic Energy Act.

Radioactive residual materials that can not be released are to be regarded as radioactive waste and must be disposed of. Since the manner of disposal essentially depends on the physical, particularly radiological characteristics, spent fuel assemblies (irradiated fuel ele-ments) and intermediate and low-level radioactive operational or decommissioning waste are considered separately here.

Radioactive residual materialsfrom nuclear power plants

Waste For conventional use, recycling orremoval of released materials

Other radioactive materials - intermediate or low-level radioactive- non-heat-generating

Spent fuel assemblies- high-level radioactive- heat-generating

Operational waste

Other radioactive materials - intermediate or low-level radioactive- non-heat-generating

Decommissioning waste

7

Fig. 5 – Classification of radioactive waste

Radioactive waste are described according to international practice based on their radio-activity (measured in Bq per m3 of the waste) as low-level (LLW), intermediate-level (ILW) or high-level waste (HLW).

The radioactive inventory and the heat arising during radioactive decay are of significance for considerations relating to safety analysis regarding final disposal in Germany. Conse-quently, the radioactive waste submitted for final disposal are divided into those with negli-gible heat generation and into heat-generating waste:

- Waste with negligible heat generation involve above all waste from operation of the nuclear power plants and their decommissioning. They will be placed in storage in the future in the already approved Konrad repository.

- The heat-generating waste principally include the high-level radioactive fission products from reprocessing and spent fuel assemblies. A separate repository, e.g. in Gorleben (rock salt) is to be set up for the latter.

3 Classification of radioactive waste

Fission products from reprocessing

Conditionedfuel assemblies

Core components

Waste from reprocessing

Operational waste from nuclear power plants

Waste fromdecommissioning

Distribution of totalvolume of waste

Examples of waste Final disposalRadioactivity Waste designation

e.g. Gorleben repository

5 % of the volumeof waste with 99 % of the radioactivity

Konrad repository

95 % of the volumeof waste with 1 %of the radioactivity

Bq / m3

low-level

intermediate-level

high-levelheat-generatingwaste

waste with negligible heat generation

1014

1016

1012

1010

108

Fig. 6 – Ways of disposal for fuel assemblies in Germany

4 Fuel assembly disposal

Up to 1994, reprocessing of fuel assemblies was the politically de-sired and only permissible way of disposal. After the failure of Ger-man reprocessing, plants in France and Great Britain were used. The main stages are as follows:

- Decay storage of the fuel assemblies in the fuel pools of the nu-clear power plants

- Transport to France or Great Britain- Reprocessing of the fuel assemblies and recovery of the recycla-

ble uranium and plutonium- Repository-compatible conditioning, i.e. isolation and packing of

the fuel assemblies in disposal casks (POLLUX®) - Return of the conditioned waste to Germany for interim storage - Final disposal in deep geological formations- Manufacture of new uranium- or mixed-oxide fuel assemblies

On amendment of the German Atomic Energy Act in 1994, the way of disposal of direct final disposal was legally equated with reproc-essing. Since mid-2005, delivery of irradiated fuel assemblies to reprocessing plants has been impermissible according to the newly amended German Atomic Energy Act. Today, spent fuel elements are disposed of via the route of direct final disposal. The individual stages are as follows:

- Decay storage of the fuel assemblies in the fuel pools of the nu-clear power plants

- Packing in casks and storage containers- Dry interim storage in the central storage facilities in Gorleben

and Ahaus in addition to newly created storage facilities at the nuclear power plant sites

- Repository-compatible conditioning of the fuel assemblies- Final disposal in deep geological formations, for example in rock salt

9

Fig. 7 – Fuel assembly disposal: reprocessing / statistics for a PWR per year of operation

Reprocessing

Reprocessing of spent fuel assemblies was in the past the politi-cally desired and only permissible way of disposal. For this purpose, long-term contracts were concluded with the reprocessing plants in France and Great Britain. Under these contracts, 6,100 t of fuel assemblies are or will be reprocessed. As a result of the amend-ment of the German Atomic Energy Act, the incoming transport of fuel assemblies for reprocessing has no longer been permissible since mid-2005. Nuclear fuel introduced up to that time can also however be subsequently reprocessed. The complete recovery of the radioactive materials separated during the reprocessing in France and Great Britain for recycling or final disposal is agreed in the reprocessing contracts and is secured by state treaties.

For reprocessing, the fuel assemblies are initially mechanically crushed in shielded cells. The fuel contained in the fuel rods frag-ments is chemically dissolved. During several process stages, the recyclable fuel elements (uranium and plutonium) are separated from the waste (fission products and actinides) and cleaned.

Separated plutonium and uranium are recycled. The plutonium is processed together with depleted or natural uranium to form mixed-oxide fuel assemblies and is redeployed in the reactor. Around 86 % of the plutonium separated and remaining to be separated in the future has now already been recycled. The uranium is either enriched

again or mixed with already existing enriched material to form new fuel assemblies. The utilisation of both material flows is presented every year to the supervisory authorities of the Federal States.

The heat-generating liquid waste separated during the dissolution process are uniformly incorporated in a glass mass, cast in a stain-less steel canister and sealed with a lid. The remaining cladding and fuel assembly structural components are compacted and likewise packed in stainless steel canisters.

The stainless steel canisters for vitrified or compacted waste are of the same dimensions (gross volume 180 litres). Transport and interim storage are performed in casks, for example of the CASTOR® type. The reprocessing waste from a PWR operating year corre-spond to the volume of one to two of these casks and consist of approximately one third of HLW and approximately two thirds of ILW. The reprocessing waste packed transport and storage casks are repatriated to Germany where they remain in interim storage until final disposal.

Approximately 130 casks are required for the complete recovery of all vitrified HLW from reprocessing in France and Great Britain. Recovery from France has already been completed to a great extent and should be finished by around 2012. Completion of recovery of vitrified HLW from Great Britain could be accomplished around 2017. The interim storage capacities in the Gorleben and Ahaus

Fig. 8 – Fuel assembly disposal: direct final disposal; statistics for a PWR per year of operation

transport cask storage facilities suffice for recovery of all waste from reprocessing. This is presented before the supervisory authori-ties of the Federal States by the energy supply companies each year in proof of precautionary measures for disposal of radioactive waste according to the German Atomic Energy Act.

The return of the vitrified glass canisters to Germany is preceded by a multistage assent procedure in which the quality assurance organisation of the operator of the reprocessing plant, the compe-tent French and British state controlling bodies and the German authorities responsible for the interim storage and final disposal of radioactive materials are involved with their independent experts. The entire transport cycle is also predetermined in a master work sequence concept and is released at the behest of the competent authorities following appraisal by an independent expert.

Direct final disposal

Since mid-2005, the German Atomic Energy Act has stipulated direct final disposal as the only way of disposalfor the spent fuel assemblies. In this case, the spent fuel assemblies are treated after their use for electricity generation as waste and not, as during re-processing, as recyclable material.

The fuel assemblies remain as a rule in the fuel pool of the nuclear power plant for many years. The residual activity and temperature

of the fuel assemblies is reduced in this manner. They are sub-sequently transferred to transport and storage casks, e.g. of the CASTOR® type and conveyed to an interim storage facility at the nuclear power plant site.

Storage facilities have been set up and in operation at all nuclear power plant sites since 2007. During the 1990’s, a few fuel assembly casks were also transported to the central storage facility originally created for this purpose in Gorleben and Ahaus.

During interim storage, the fuel assemblies cool down such that they can subsequently be finally disposed of.

According to the current state of the art, fuel assemblies should be unloaded from the transport and storage casks after interim storage in a conditioning facility. The fuel rods are subsequently withdrawn from the fuel assemblies and packed in disposal casks, for example of the P OLLUX® type. In this form, they can finally be disposed of.

Other cask and repository concepts are under development as alter-natives. These among other aspects pursue the aim of being able to store reprocessing waste and spent fuel assemblies underground using the same technology.

11

Fig. 9 – Underwater loading of a CASTOR® cask

Transport and interim storage of fuel assemblies

Before their final disposal in deep geological formations, spent fuel assemblies must undergo interim storage for a number of years to allow the decay heat (heat generated by residual activity) to ad-equately subside. Consequently, special transport and storage casks have been developed for dry interim storage of the fuel assemblies.

The casks employed today, e.g. of the CASTOR® type, with a wall thickness of approx. 40 cm, weight up to 120 t and have a double lid system. They ensure shielding of the radiation of the fuel as-semblies with simultaneous outward heat dissipation. The double lid system consisting of a primary and secondary lid guarantees safe long-term inclusion and allows continuous monitoring of the tightness of the casks. Officially tested repair concepts exist in the unlikely event that leakage of one of the lids should occur.

The casks must undergo an extensive authorisation and licensing procedure under traffic law. They comply with the international regulations. Even a crash by a rapid flying military aircraft on a cask was simulated by a ballistic test. It was shown that even this highly unlikely event with extremely high stresses on the cask does not result in any failure of the sealed containment.

The fuel assemblies are loaded into the cask in the fuel pool of the nuclear power plant. The filled cask is drained, dried, tested for tightness and handled according to the requirements in terms of hazardous goods and storage regulations.

The central interim storage facilities in Ahaus and Gorleben were put into service in the early 1990’s as interim storage facilities for spent fuel assemblies and recovered waste from reprocessing. Pre-dominately casks containing vitrified HLW from reprocessing are stored in the Gorleben interim storage facility. The Ahaus interim storage facility is to primarily receive conditioned ILW likewise de-rived from reprocessing in the future.

Since discontinuation of the transports for reprocessing in 2005, additional storage capacities for spent fuel assemblies were re-quired in addition to the existing central storage facilities. Hence, on-site interim storage facilities were set up at all operational nu-clear power plants. The last of the 12 on-site interim storage facilities entered service in 2007. The operating licences of all interim storage facilities are limited to 40 years. It is therefore possible to dispense with transports of fuel assembly casks from the power plants to the central interim storage facilities until further notice.

Fig. 10 – Interim storage of CASTOR® casks

The following principles apply to storage of fuel assemblies in casks:

- The fuel assemblies are inside sealed and accident-proofed casks.

- The casks guarantee safe inclusion of the contents, radiation shielding, heat dissipation and criticality safety.

- In conjunction with the storage, the casks ensure compliance with all legal requirements concerning radiation protection of the environment (dose values according to the radiation protec-tion ordinance).

The interim storage facilities consist of reinforce concrete halls and in one case of two disposal tunnels in an adjacent former quarry. The capacities range between 80 and 192 cask storage locations.

In the loading area, the delivered casks are lifted off the transport vehicle using the hall crane and are transferred to the handling or maintenance area. In the latter, the pressure switch for cask moni-toring is installed, the protection plate is applied and radiological measurements and leakage tests are performed on the cask, if this has not already been done during handling after loading. The cask is set down at its storage location using the hall crane and is subse-quently connected to the monitoring system.

The heat emanating from the fuel assemblies is mainly dissipated with the hall air by natural convection.

13

Fig. 11 – Gorleben pilot conditioning facility (PKA); external view of the dismantling cell with manipulators

Conditioning and final disposal of the spent fuel assemblies

During the 1980’s and 1990’s, a reference concept for conditioning and final disposal of fuel assemblies was developed by the State and industry. This makes provision for the following stages:

A pilot conditioning facility (Pilot-Konditionierungsanlage, PKA) was created for conditioning spent fuel assemblies and put into service non-«radioactively». The individual working stages and working procedures were tested and demonstrated with inactive fuel as-semblies. In doing so, the fuel rods are mechanically withdrawn from the fuel assembly frame and placed «side by side» in disposal casks without any further treatment. The structural components of the fuel assemblies undergo high pressure compaction and are packed and disposed of in the cask as also used for other metallic waste from operation or decommissioning of the nuclear power plants. The compact packaging of the fuel rods and the high pres-sure compaction of the structural components reduce the volume to be disposed of.

The POLLUX® was developed as a disposal cask for the fuel rods from around 10 PWR or around 30 BWR fuel assemblies, to be stored horizontally in the tunnels of the repository. Handling of the cask in shaft and tunnel transport in addition to during emplace-ment was tested and demonstrated in above-ground trials in origi-nal sizes and dimensions.

In order to simplify handling in the repository, small containers were also developed which are suitable for vertical borehole em-placement – in conjunction with the vitrified HLW. In this case also, technical feasibility and reliability of the storage system has already been demonstrated in above-ground handling trials.

In the PKA waste from reprocessing can also be transferred from the interim storage casks to transfer casks for conveying to the r epository.

Fig. 12 – Gorleben pilot conditioning facility (PKA); internal view of the dismantling cell

5 Recyclable and non-recyclable radioactive materials

Residual materials and waste management concept

A series of framework conditions applies for dealing with radioac-tive residual materials, derived from legal regulations, operational action guidelines or the requirements of interim storage and final disposal:

Waste prevention: accumulation of radioactive waste should al-ready be avoided at the source. To this end, no unnecessary packag-ing materials should be introduced into the radiation-controlled area, films for masking or covering should be recycled and con-tamination of plant sections, tools or operating material should be prevented.

Release: the release of materials for conventional waste disposal or for recycling, either restricted, for example in nuclear facilities, or unrestricted for free use also serves to avoid radioactive waste.

Volume reduction: it serves above all for optimum utilisation of existing interim storage capacities and reduction in transports. For this purpose, the waste are conditioned, i.e. burnt or compressed for example.

Conditioning: its purpose is to transform the waste into a form com-patible with interim storage facilities and repositories by treatment and/or packing. The requirement of the repository is that the waste must be solidified (for example concreted), must not contain any free water to allow exclusion of decomposability and fermentability and be delivered in authorised packaging.

Interim storage: until transfer to a repository, the waste undergo in-terim storage at the nuclear power plant sites or in central facilities.

Final disposal: the waste are separated from the biosphere by final disposal in deep geological formations.

Waste tracking: the flow of the radioactive waste from their emer-gence to transfer to the repository is tracked. The Waste Flow Track-ing and Documentation System (AVK: Abfallfluss-Verfolgungs- und Produkt-Kontrollsystem) serves for this purpose. It documents all the necessary information concerning the quantity, whereabouts, processing status and packing of the waste.

15

Fig. 13 – Way of disposal for radioactive residual materials from radiation-controlled areas

Release

Release is performed by an administrative act of the competent authorities according to the radiation protection ordinance. Materi-als with a low level of radioactivity can be released if they may only result in an effective dose of up to 10 microsieverts per calendar year for individual members of the population. The authorities may consider this fulfilled if the release values stipulated in the radia-tion protection ordinance are complied with, i.e. 1/10 of the natural radiation exposure (ø 2.1 millisieverts per year in Germany) is not exceeded.

In individual cases, proof that the protection target is reached for a stipulated release path may be provided by a separate procedure.

Separate collection accordingto material type and

activity inventory

Radioactive residual materials accruing in the

radiation-controlled area

Direct reuse or recycling in the nuclear fi eld possible

and economically viable?

Release according to §29 StrlSchV (radiation protection ordinance)

possible, economically viable?

Radioaktiver Abfall Conditioning Interim storage and fi nal disposal

Reuse or recycling in the nuclear fi eld

Decay storage

Release

- Unrestricted release- Release for disposal- Release of scrap metal for recycling- Release of buildings for demolition- Release in the individual case procedure

Decontamination measures orbuffer storage are to be verifi ed and/or

implemented if necessary

NO

NO

YES

YES

Radioactive waste

Fig. 14 – Controlled recycling of metals

Recycling of metals by melting

During operation of nuclear facilities and their decommissioning, contaminated piping, valves, heat exchangers, containers and steel components of the most diverse types arise which if necessary following prior decontamination are melted down and reprocessed into products for nuclear facilities. Thus, disposal casks or shielding are manufactured from recy-cled material.

Up to 2009, contaminated plant components were processed in this way to make new prod-ucts (approx. 2000 cast components) with a total weight of 19,000 t in the form of cast iron containers, shielding components, crane weights etc. and redeployed in nuclear facilities.

Only the non-recyclable products arising from the melting process (e.g. slag, filters) are dis-posed of as radioactive waste, amounting to approx. 1% by weight of the material originally used.

17

Fig. 15 – Typical operational waste for a nuclear power plant with a PWR, by way of example annual raw waste of a 1300 MW plant and radioactivity spectrum

Radioactive waste

The annual amount of operational raw waste is around 200 m3 on average for a nuclear power plant with a PWR and around 280 m3 for a BWR. The difference lies in the fact that in a BWR, the primary steam directly drives the turbine and therefore contamination in larger plant sections is to be expected. The principal PWR waste flows include for example:

Ion exchange resins (bead resins): They are mainly used in the sys-tems such as coolant purification, fuel pool cleaning and coolant preparation. Their task is to chemically or physically bind dissolved fission products released by defect fuel rods in addition to corrosion products from the reactor circuit. The subsequent conditioning of the resins is based in principle on dehydration; they are ultimately stored as solid matter in the waste container.

Filter cartridge inserts: filter cartridge inserts used downstream from the ion exchangers serve to filter out solids such as abraded resin and radioactive corrosion products that are not retained on the ion exchange resins. The spent filter cartridge inserts undergo high pressure compaction and are packed in waste containers.

Metal components: these essentially involve high-level radioactive components, mostly from the core region (e.g. control rods).

Evaporator concentrates: these are the residues from the evapora-tion facility of the waste water treatment system. The concentrates are discontinuously drained with a solid content of approx. 15 to 20 % into concentrate containers where they are dehydrated and already packed as solids in waste containers.

Filter concentrates: the filter concentrates include the blow-downs from mechanical filters in the purification systems. They consist of the filtered-out materials and the filter media used. The subsequent drying of the filter concentrates allows interim storage as solids in waste containers.

Solid waste: solid waste arising from general nuclear power plant operation are composed of combustible waste, e.g. paper, clothing, plastics and non-combustible waste, such as scrap metal, rubble and mineral insulating material. The non-combustible waste under-go high pressure compaction in metal cartridges and are collected as in containers as compacted pellets.

Oils: lubricants and oils from the entire radiation-controlled areas are generally uncontaminated or only low contaminated. They can therefore often be released for conventional disposal.

Radioactivity

Bead resins

Bead resins

Filter cartridge inserts

Evaporator concentrates

Solid waste

Oils

Filter concentrates and sludges

Metal components

2 m3

2 m3

2 m3

2 m3

2 m3

18 m3

1 m3

170 m3

Bq / m3

1014

1012

1010

108

106

Fig. 16 – Optimised treatment methods for solid and liquid radioactive waste from nuclear power plants

Fig. 17 – Waste treatment methods for volume reduction

Annual operational waste volume from nuclear power plants in Germany

Approximately 3,900 m3 of raw waste per year currently accumulate in the German nuclear power plants. As a result of the treatment and conditioning methods applied today, the total volume of condi-tioned operational waste for final disposal is substantially reduced and amounts in total for all the efficient German nuclear power plants to a final disposal volume of only approx. 800 m3/year.

Optimised treatment methods for solid and liquid radioactive waste from nuclear power plants

It is endeavoured as a matter of principle to reduce the volume dur-ing waste conditioning. This aim is achieved through the condition-ing and packing methods available and under further development.

Volume reduction of radioactive waste

Example: combustible and compressible waste from nuclear power plants. Typical raw waste from a nuclear power plant include com-bustible and compressible waste. These waste are delivered in drums or containers in case of external conditioning. The raw waste are mainly sorted into combustible and non-combustible materials. Subsequent sorting is performed at the conditioner’s premises if necessary.

The volumes of ash from incineration amount in the most favour-able case to only approx. 1/50th of the raw waste volumes. They can be further reduced by a factor of 2 with the aid of a high-pressure compactor. The volume reduction results in a corresponding increase in the specific activity.

In the case of compressible raw waste, a volume reduction by a fac-tor of 2 to 5 can be achieved.

The high-pressure compacted waste must finally be packed in repository-compatible form. The transport and storage limit values for the dose rate are complied with through the selection of the cask shielding, e.g. steel or concrete container.

Solid waste

Metal com-ponents, rubble, etc.

Paper,plastics, fabrics, etc.

Metal com-ponents, insu-lation, etc.

Liquid waste

Sludges Filterconcentrate

Ionexchange resins

Oil Evaporator concentrate

Incineration

Compacting

Drying, dehydration, cementing

e.g. container

Salt block, granulate,powder, cement block

e.g. container, cast iron container

Solid waste Compacted pellet

Type of waste

Raw waste

Conditioning

Waste products

Repository cask

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Fig. 18 – Annual waste volume from operation of the German nuclear power plants – Last revised 2010

Incineration facility for radioactive waste

The aim of incineration is to substantially reduce the volume of the combustible waste such as plastics, fabrics, wood and paper, which are radioactively contaminated, in compliance with the emission control requirements.

The remaining mineral materials (ashes and filter dusts) are no longer decomposable and fermentable and can consequently be stored in the long term.

Fig. 19 – Loading an incineration furnace Fig. 20 – Flow diagram of an incineration facility for radioactive waste

The radioactivity contained in the raw waste is quantitatively trans-ferred to the incineration residues (ash and filter dusts) which are disposed of as radioactive waste. The volume reduction factor dur-ing incineration of the waste is approx. 50.

Fig. 21 – FAKIR hydraulic super compactor

Fig. 22 – Compacted pellet following high-pressure compaction

High-pressure compaction of solid radioactive waste

For high-pressure compaction, the waste are introduced into cartridges or pressing drums and are compacted with a pressing force of up to 2,000 t.

During this treatment, the waste are processed into dimensionally sta-ble compacted pellets. Compacted pellets are subsequently placed in 200-litre drums or repository containers.

Moist waste are dried in order to avoid free fluids > 1 % and gas forma-tion, e.g. as a result of corrosion.

21

Fig. 23 – PETRA mobile drying facility

In-drum drying for solidifying liquid radioactive waste

Drying processes are used for volume-reducing conditioning of liq-uid radioactive waste such as ion exchange resins, evaporator con-centrates or sludges. A possible method is in-drum drying. The final product of this process is a solid waste product (solid matter) which can undergo long-term storage in waste containers.

Depending on its design, a facility for in-drum drying can be oper-ated on a stationary or mobile basis.

The liquid waste stored in collecting tanks are drawn off using a pump and fed into the reservoir. The concentrate can be chemically treated in the reservoir.

The heat required for drying is supplied to the waste container by means of a heating system.

The steam (vapour) arising during evaporation is piped to the con-denser. The distillate accumulating is supplied to the waste water collection system. The system is operated at negative pressure in order to lower the boiling point.

Fig. 24 – MOSAIK® cask Fig. 25 – Repository container

Fig. 26 – 200-litre drum on activity measuring system

Examples of packaging of radioactive waste

The packaging guarantees safe handling of the waste during the necessary loading activities and transports in addition to during their interim storage and final disposal. Suitable types of packaging are available for the various waste types, customised in their design to the specific characteristics of the waste.

The cask spectrum ranges from 200-litre steel sheet drums to heavy cast iron containers for safe shielding from the radioactive radiation. All the packaging types used have undergone specific tests and licencing procedures both for transport and storage.

23

Fig. 27 – Loading of MOSAIK®-casks

Fig. 28 – Storage of concrete shielding for disposal

Transport of radioactive materials

Radioactive materials are considered as hazardous goods according to international and domestic legal regulations and are subject to the pertinent provisions under traffic law and the German Atomic Energy Act during transportation on public or publicly accessible highways. Suitable types of packaging are available for all radioac-tive materials for transportation.

The packaging depends on the characteristics, the activity inventory and the type of the radionuclides of the materials to be transported.

The hazardous materials ordinances stipulate the requirements that the packaging has to fulfil. The casks are equipped with a shock absorber for transport - if required.

Interim storage

In Germany and other countries, radioactive waste undergo interim storage above-ground following appropriate conditioning. This al-lows flexible organisation of disposal from emergence of the waste to their final disposal.

The following are available for this purpose for the nuclear power plant waste:- internal storage capacities at the nuclear power plant sites- external interim storage facilities: Gorleben, Mitterteich, Ahaus

They were essentially created at the instigation of the nuclear power plant-operating companies. These facilities are designed for storage of all types of radioactive waste from nuclear power plant operation and decommissioning.

Fig. 29 – Decommissioned nuclear power plants in Germany

Unlike industrial facilities, nuclear power plants are decommis-sioned at the end of their technical and economic lifespan, which implies that the plant has to be dismantled.

Already before commissioning of a nuclear power plant, the re-quirement existed in Germany to conceptually prove the latter’s ability to be dismantled and decommisssioned. Furthermore, the obligation exists under the German Atomic Energy Act to harm-lessly recycle radioactive waste or dispose of it in a controlled way. This indirectly induces among the operators the requirement under commercial law to make financial provision for the decommission-ing of their plants by forming provisions.

Consequently, the German nuclear power plant operators already dealt at an early stage with the question of decommissioing of their nuclear power plants in planning terms and developed a decommissioning concept with which both technical feasibility is proven and the costs are determined. The concept is updated at regular intervals in order to take account of modified framework conditions in addition to the state of the art and obtain current cost estimations for the formation of provisions.

Decommissioning can begin directly after granting of the decom-missioning licence. Alternatively, the plant can be transformed into a so-called «safe enclosure» for a limited period (e.g. 30 years) be-fore being subsequently dismantled.

In doing so, the section of the nuclear power plant containing the main radioactive components is transformed into a safe state free of fuel assemblies and other radioactive media. This area is subse-quently effectively sealed until decommissioning.

A large number of successfully implemented technologies are avail-able for dismantling itself, both for decontamination and disassem-bly and for the disposal of the materials accumulating.

In Germany, 19 nuclear power plants and prototype plants of the first construction generation, mainly those with a small and moder-ate output, had already been dismantled by the end of 2010. Among these, three - the Niederaichbach nuclear power plant, the Kahl su-perheated steam reactor and the Kahl experimental nuclear power plant - have now been completely dismantled. With the resolution of the German Lower House on nuclear phase-out in summer 2011, the authorisation for operation under load is expiring for a further eight plants.

6 Decommissioning and dismantling of nuclear power plants

25

Fig. 30 – Distribution of the accrued masses during decommissioning of the radiation-controlled area of a PWR (indications in t)

During dismantling of the nuclear section (radiation-controlled area) of a large nuclear power plant with a PWR, around 143,000 t of concrete structures accumulate with reference to the total mass of 156,500 t, which can be almost completely conventionally recycled following removal of any surface contamination. Only approximate-ly 600 t of the concrete requires final disposal as radioactive waste.

The mechanical installations - essentially piping and components - including the entire steel construction (e.g. platforms and mount-ings) form a mass of around 13,500 t in the radiation-controlled area of a PWR. Among these materials, only around 3,000 t require transfer to a repository as radioactive primary waste and around 500 t as radioactive secondary waste (incl. from decontamination). The remaining 9,800 t can likewise be directly released or recycled after decontamination or melting down. Clearance is given for con-ventional disposal for approx. 700 t.

Hence, with reference to the total mass of the radiation-controlled area, only a good 2 % need to be conveyed to a repository as radioac-tive waste.

The repository container volume from the decommissioning of all energy supply company nuclear power plants (both, those already in decommissioning and those currently in operation) is expected to amount to approx. 115,000 m3, i.e. all the dismantling waste to be disposed of would fit into a cube 50 m square.

Since the waste accumulating during decommissioning of the nu-clear power plants are similar to the radioactive waste arising dur-ing nuclear power plant operation, the same conditioning methods are by an large used during their treatment.

Fig. 31 – Transport of a steam generator out of the Stade nuclear power plant for recycling

Total mass of the radiation-controlled area(PWR reference power plant)

156,500

For freerecycling

For fi nal disposalConcrete and reinforcement

Plant components

Radioactive waste(concrete/reinforcement)

Radioactive waste(plant components)

Radioactive waste(secondary waste, e.g. from decontamination)

Material for harmlessrecycling

Waste for conventional disposal

For harmless9,800143,000

13,500

700

3,000

500

600

For dumping

recycling

For fi nal disposal

For fi nal disposal

Fig. 32 – Treatment of radioactive waste with work sequence plans concerning interim storage and final disposal

Quality assurance acquires particular importance during condition-ing of radioactive waste from nuclear power plants. The measures involved are based in this case on the following main tenets:

- Waste treatment with methods qualified by the Federal Office for Radiation Protection (BfS)

- Waste package documentation- Waste Flow Tracking and Documentation System (AVK)

Waste treatment with methods qualified by the BfS

A provision of the radiation protection ordinance is that condition-ing of radioactive waste for the purpose of final disposal be per-formed using methods qualified by the BfS. Full account was taken of this requirement with introduction of work sequence plans and likewise in individual cases by campaign-independent procedure qualifications.

For product control with work sequence plans, all relevant working and testing stages are listed that must be followed up to interim storage and final disposal of the waste.

Before the conditioning work may begin, the work sequence plans are studied and assessed by independent experts. The BfS and the competent supervisory authority approve the work sequence plans based on these studies.

The waste conditioning is performed according to established treatment stages, with an accompanying control - generally by the experts of the respective conditioning facility commissioned by the supervisory authorities - being performed. All waste and treatment data are documented during the conditioning work.

7 Quality assurance

Work sequence plansapplication to

Work sequence plans release

Accompanying control

Documentation

Release

Interim storage facility

Supervisory authority

Repository

BfS BfS (Federal Offi ce

for Radiation Pro-

tection)

Conditioning

Responsibility

Waste producer

Waste producer

BfS/supervisoryauthority

BfS/supervisoryauthority

RepresentativeExpert

RepresentativeExpert

RepresentativeExpert

Interim storage/fi nal disposal

Interim storage/fi nal disposal

Preparationfor conditioning

Preliminary testingProcedure qualifi cation

Test report

27

Fig. 33 – Waste Flow Tracking and Documentation System (AVK: Abfallfluss-Verfolgungs- und Produkt-Kontrollsystem) collage

Waste package documentation

The data collected during conditioning are included in the waste package documentation. These data are supplemented with analysis data. Following an internal quality control, the package documentation is verified and audited by independent experts. The verified documentation forms the basis for the delivery to the interim storage facility or repository. The Waste Flow Tracking and Documentation System forms an important basis.

Waste Flow Tracking and Documentation System, AVK

The regulatory guideline on the control of residual radioactive ma-terial and radioactive waste (waste control guideline) of the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU)requires that the quantity, whereabouts, processing status and packaging of the waste can be traceably determined with regard to safe interim storage and final disposal by documen-tation of all disposal stages (conditioning, transportation and in-terim storage). The radiation protection ordinance prescribes that an electronic system accepted by the BfS be used for this purpose.

In order to fulfil this requirement, the German nuclear power plant operators, the conditioning facilities and the external interim stor-age facilities have been implementing the AVK in a data network since mid-1991. The AVK system provides its users among other

aspects an overview of the flow of the nuclear power plant waste with information about the container type, activity inventory and transport data.

The waste producers are organised in the so-called AVK association and use a central system administration and user support in addi-tion to a central body which performs with its own software the function of superordinate data control, archiving and analysis in the sense of self-monitoring by the operators.

Since 1995, the suitability of the AVK system has been regularly ap-praised with regard to the official requirements by an independent expert. In the form of this system, the waste producers (energy sup-ply companies), conditioners and operators of interim storage facili-ties have at their disposal a practice-proven electronic documenta-tion system for radioactive waste recognised by the authorities which allows uninterrupted tracking of the waste from their origin to their transfer to a Federal repository.

Fig. 34 – Responsible institutions in final disposal of radioactive waste in Germany

Responsible institutions in final disposal of radioactive waste in Germany

According to the German Atomic Energy Act, it is the German Federa-tion’s responsibility to set up facilities for securing and final disposal of radioactive waste. The Federal Office for Radiation Protection (BfS) is responsible for planning, constructing, operating and decommis-sion the facilities. It is subject with regard to nuclear safety and ra-diation protection to the technical directions of the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU), which is advised among other by the Disposal Commission (ESK), the Reactor Safety Commission (RSK) and the Radiation Protection Com-mission (SSK).

For practical fulfilment of its duties, the BfS generally commissions as a third part the Deutsche Gesellschaft zum Bau und Betrieb von Endlagern für Abfallstoffe mbH (DBE).

The geoscientific expertise is contributed by the Federal Institute for Geosciences and Natural Resources (BGR). Research and development concerning final disposal has been or is conducted by the Helmholtz Centre in Munich, the Karlsruhe Institute of Technology and the Jülich research centre in addition to various universities and other institutes. This work is financed and organised by the Federal Ministry of Economics and Technology (BMWi), formerly also by the Federal Ministry of Educa-tion and Research (BMBF) and insofar as site-specific, by the BfS.

Construction and operation of a repository require planning approv-al. The supreme Federal State authorities appointed by the Federal State government involved are responsible for this. In the case of the planning approval procedure for the Konrad repository, this was the Ministry for the Environment, Energy and Climate Protection of Lower Saxony (NMU).

Anyone who possesses radioactive waste is obliged according to the German Atomic Energy Act to hand these over to a German Federal facility. For as long as no repository is available, the waste must undergo interim storage. This is either the task of the operator of nu-clear facilities or of the Federal States for deliverers from medicine, industry and research (Federal State collection facilities).

Financing of the necessary expenditure for exploration, approval procedures and construction of the repository is provided by the waste producers according to the «Ordinance on Advance Payments for the Establishment of Federal Facilities for Safe Custody and Final Storage for Radioactive Waste». The current costs of repository op-eration and repository decommissioning are likewise borne by the waste producers.

8 Final disposal

BergämterPlanning approvals

Federal State authoritiesplanning approval

RSK/SSK/ESKconsultancy

BGR

BMUAdministrative and technical

supervision

BMWiAdministrative and technical

supervision

Necessary expenditureOrdinance on Advance Payments for the Establishment of FederalFacilities for Safe Custody and Final Storage for Radioactive Waste

BMUFederal Ministry for the Environment,Nature Conservation and Nuclear Safety

RSKReactor safety commission

SSKRadiation protection commission

ESKDisposal commission

BMWiFederal Ministry of Economics and Technology

BfSFederal Offi ce for Radiation Protection

BGRFederal Institute for Geosciences and Natural Resources

DBEDeutsche Gesellschaft zum Bauund Betrieb von Endlagernfür Abfallstoffe mbH

BfSResponsible for construction

and operation, applicant

DBEConstructor and operator

Gorleben project

Waste producer

Konrad repository

29

Fig. 35 – Responsibilities for disposal of radioactive waste

Technical specifications for the radioactive waste to be disposed of (repository conditions) are stipulated for each repository. Compliance with these specifications must be proven and documented for each waste package. Together with the geological barriers of the repository, protection of man and the environment from harm by ionising radia-tion from the radionuclides contained in the waste is thereby guaran-teed in the long term.

Fig. 36 – Tunnel section in Gorleben, roadheading machine

Duty to surrender

Final disposal

- Exploration- Construction- Operation- Decommissioning

Nuclear power plant operator

German Federation

Development, operation and decommissioningof the power plants

Development of suitable methods for treatingwaste and fuel assemblies

Performing reprocessing/conditioningInterim storage

Financing of fi nal disposal

Fig. 37 – Structure of a repository for radioactive waste in a salt formation

Structure of a repository for radioactive waste in a salt formation

According to international practice, HLW and heat-generating waste are to be stored separately from the LLW with negligible heat generation. In this case, final disposal of radioactive waste in deep geological formations is currently considered the safest method of separating them from the biosphere.

Salt formations for example are suitable for HLW, i.e. heat-gen-erating waste. These readily dissipate the heat resulting from the radioactive decay and firmly enclose the waste through their convergence. Fundamentally speaking, clay rock or granite can also be used for a repository. Non-heat-generating waste place more limited requirements on the geological formation. Consequently, a large number of such repositories in different types of rock are in operation throughout the world.

Various different technical and natural barriers prevent a return of radionuclides into the biosphere and harm to man and the envi-ronment. In the case of the example of HLW and heat-generating waste from reprocessing, these may for instance include:- Waste product

Glass block; in this case the heat-generating fission products are included at high temperature in a liquid glass melt which sub-sequently solidifies to form a glass block.

- Packaging Stainless steel casing (canister), which surrounds the glass block

- Backfill Backfilling of the cavities between the waste packages

- Seal systems Bore hole seals

- Repository formation Salt dome; the plasticity of the salt results in complete inclusion of the waste within a short period and the good thermal con-ductivity reduces thermal stresses

31

Fig. 38 – Asse II pit

Development of final disposal

Already in the early 1960’s in Germany, it was decided that all radioactive waste would be disposed of in deep geological formations in order to permanently separate them from the biosphere. This not only includes HLW, but also LLW and ILW with negligible heat generation.

For LLW or those with negligible heat generation, the Konrad pit has received legally binding approval in Germany and is currently being extended into a repository. A whole series of such repositories already exist outside Germany, for example in Sweden and Finland in gran-ite at a depth of up to 100 m. Such waste are also stored near the surface of the ground in France, Great Britain, Spain, the Czech Republic, Hungary, Japan and in the USA. Hence, final disposal of waste with negligible heat generation is common practice throughout the world.

The technologies are also already developed however for final disposal of HLW and heat-generating waste, even though only two sites are implemented in practical terms for this purpose, i.e. Östhammar in Sweden and Olkiluoto in Finland. The corresponding technologies have been developed and demonstrated in own underground laboratories.

9 Final disposal sites and pits

Fig. 39 – Morsleben repository in service until 1998

Asse

From the end of the 1960’s until 1978, LLW was stored in the Asse pit as a German Federal research facility. Within this context, the German Federation had extensive research, development and demonstration work carried out in a former salt mine. The repository technologies for heat-generating waste ultimately occupied a forefront position in this case. More particularly, the heat input into the surrounding salt rock was studied.

As a result of the former mining operation, the stability of the mine workings of the Asse pit cannot be guaranteed in the long term. Consequently, various different decommissioning options are being discussed: backfilling of the pit, recovery of the waste and relocation of the waste within the Asse. Whether recovery from the Asse is even possible at all and offers safety advantages over backfilling is still be-ing studied at the time of the brochure’s going to press.

Morsleben

Until 1998, around 6,000 sealed radioactive sources and around 37,000 m3 of waste were stored in the Morsleben waste repository (Endlager für radioaktive Abfälle Morsleben, ERAM), including ap-prox. 14,000 m3 from the nuclear power plants of the former West German States. The salt mine under decommissioning entered serv-ice in 1981. In 1986, it received a permanent operation permit which was valid until 30th June 2000 following an assessment of safety according to the Unification Treaty. The continued operation of the ERAM (as a Federal repository) for LLW and ILW from the former West German States and new Federal States was begun in 1993.

On 25th September 1998, emplacement was initially halted based on a court decision. The Federal Government at that time sub-sequently decided not to resume emplacement operation of the ERAM. A planning approval process for decommissioning has been initiated.

33

Fig. 40 – Konrad mine, shaft 1

Konrad

In 1975 the former Gesellschaft für Strahlen- und Umweltforschung (GSF) began at the instigation of the German Federation studies of the suitability of the Konrad pit, a former iron ore mine, as a repository for LLW. A crucial aspect for the choice was the extraor-dinary dryness of the mine. The pit proved itself suitable and the Physikalisch-Technische Bundesanstalt (PTB) as the competent Federal authority at that time (the predecessor of the Federal Office for Radiation Protection, BfS) applied for institution of the planning approval procedure in 1982. The Konrad repository was to accommo-date some 650,000 m3 LLW and ILW at a depth of 800 m to 1,300 m.

In May 2002, the planning approval decision for receiving a waste volume of 303,000 m3 was made by the Environment Ministry of Lower Saxony (NMU). The background for the reduced volume of waste was the requirement up to 2080 forecasted by the BfS in 2001 based on the statutory regulations. After fending off all the lawsuits filed against the repository, legal certainty has existed since 2007. Directly thereafter, the work for conversion of the mine into a repository began. In this connection, new chambers are being excavated for emplacement of the waste. Since 2011, final disposal conditions have existed based on which repository-compatible packaging of the radioactive waste can be started.

Fig. 41 – Gorleben site under exploration

Gorleben

In 1973/74, the Federal Government at that time planned a «Nuclear Disposal Centre». The concept involved constructing all the neces-sary facilities for closing the nuclear fuel circuit, i.e. reprocessing, waste treatment and final disposal at a single site. During an inten-sive search for locations, 140 salt domes were initially considered, among which 4 were assessed in greater detail. The Gorleben site was ultimately chosen and was nominated by the Federal Govern-ment in 1977 for concrete suitability studies.

The above-ground exploration work began in 1979 and the first deep drillings in 1980. The surface exploration was successfully completed in 1983. Owing to the positive results, the Federal Gov-ernment approved the underground exploration. The «Gorleben Hearing» was held in 1979 for the decision on the location with broad and active participation of science and the public. The results of the subsequent site investigations were discussed in several pub-lic workshops in the late 1970’s and in the 1980’s. Two shafts were sunk down to a depth of around 900 m and the infrastructure was set up underground. Until 2000, the studies were performed in so-called exploration area 1.

From October 2000 onwards, the exploration work was interrupted for a maximum of 10 years («moratorium») in order to clarify gener-al safety and conceptual issues concerning final disposal submitted by the Federal Government. These matters were successfully dealt with by the end of 2005. In summary the BfS concludes that salt is basically suitable as a host rock for a repository. Doubts about the suitability of the Gorleben salt dome cannot be derived from the reports. Other possible repository formations, such as clay or crystal-line rocks do not impose themselves.

In October 2010, the Federal Government ended the moratorium and resumed the exploration work open-endedly. It is accompanied by a provisional safety analysis for the Gorleben site based on the experience gained up to 2010. This will subsequently be submitted to an international peer review. The aim is to create clarity about the suitability of the Gorleben salt dome by 2017. Alongside the provisional safety analysis, the Environment Ministry launched a dialogue and participation procedure for supporting further ex-ploration of Gorleben. The actual approval procedure with public participation would follow once positive results are available. In the event of a positive planning approval decision, commissioning as a repository would be conceivable in the year 2035.

35

Glossary

Abfallfluss-Verfolgungs- und Produkt-Kon-trollsystem, AVK s.a. «Waste Flow Tracking and Documentation System»

Activity Number of atomic nuclei decaying per sec-ond in a radioactive substance. The unit of measurement is the Becquerel, Bq = [1/sec.].

Atomic Energy Act, AtG (Atomgesetz) The legal basis for use of nuclear energy in Germany. Original intended purpose: promo-tion of use of nuclear energy for peaceful purposes and protection of life, health and material goods against the harmful effect of ionising radiation. The 2002 amendment involved deletion of promotion and orderly phasing out of use of nuclear energy.

Becquerel, Bq Unit of measure for activity, correspond-ing to the decay of one atomic nucleus per second. The former conventional unit of activity was the Curie [Ci]. 1 Ci corresponds to 37,000,000,000 Bq.

Bead resins Spherical ion exchangers which serve for example for coolant purification (another type of ion exchanger includes for example powder resins).

Biosphere Sphere of life of all the earth’s organisms in-cluding the air (several kilometres), the earth (a few metres deep) and water.

Boiling Water Reactor, BWR A power reactor in which water serves both as a coolant and moderator and boils in the reactor core. The resulting steam is generally directly used for driving a turbine. Six plants of this type are currently in operation in Ger-many.

CASTOR® cask A cask for interim storage and transport of high-level radioactive materials such as for example fuel assemblies or radioactive waste products («glass canisters» from reprocess-ing).

Clearance Procedure on which the release of formerly radioactive materials is based. The cleared materials can be used or conveyed as waste to conventional dumps.

Conditioning Transformation of radioactive waste into a form compatible with interim storage facilities and repositories. This includes for example solidification, compaction, incinera-tion and dehydration. Repository-compatible conditioning of fuel assemblies involves for example isolation and packing of the fuel as-semblies in the disposal cask (POLLUX®).

Convergence The characteristic of rock salt formations of closing artificially created or naturally occur-ring cavities plastically and seamlessly. Intro-duced heat accelerates this process.

Criticality safety Safety against impermissible occurrence of critical or supercritical configurations or states. The criticality describes the state of the ongoing chain reaction.

Decay heat Heat continues to be generated after reactor shut-down as a result of decay of fission prod-ucts. This heat is known as the decay heat.

Decay time The reason for the initially high radiation in-tensity and heat generation is the short-lived fission and decay products resulting from nuclear fission contained in the fuel. The time

in which a major portion of the short-lived radionuclides decreases such that the fuel as-semblies can be transported with an accept-able radiation intensity level is known as the decay time.

Decommissioning In the technical sense, all activities geared to direct or subsequent removal of a nuclear facility.

Decontamination Chemical or physical process for removal or reducing an undesirable contamination by radioactive materials.

Deep geological formations Site solely used in Germany for final disposal of radioactive waste. Depth around 500 to 1,200 m.

Depleted uranium Uranium with a smaller percentage of 235ura-nium than the 0.7205 % occurring in natural uranium.

Deutsche Gesellschaft zum Bau und Betrieb von Endlagern für Abfallstoffe mbH, DBE, Peine According to the Atomic Energy Act of the Federal Republic of Germany, represented by the Federal Office for Radiation Protec-tion (BfS), DBE was commissioned as a third party to plan and construct facilities for final disposal of radioactive waste of the German Federation. In particular, it conducts opera-tions in the Konrad repository and in the Morsleben decommissioning project in addi-tion to the exploration work in Gorleben. The DBE shareholds include both industry and the Federal Republic of Germany.

Dismantling The disassembly and removal of any struc-ture, system or component during decom-missioning. Dismantling may be performed immediately after permanent retirement of a nuclear facility or it may be deferred.

Disposal Commission, (Entsorgungs-kommission, ESK), Bonn Advises the Federal Ministry for Environment, Nature Conservation and Nuclear Safety in matters of nuclear disposal. The latter comprises the aspects of conditioning, in-terim storage and transports of radioactive materials and waste and furthermore the decommissioning and dismantling of nuclear facilities in addition to final disposal in deep geological formations.

Dose, effective Effective dose is a measurement of human radiation exposure. In determining the ef-fective dose, the differential efficacy of the various types of radiation (α-, β-, γ-radiation, X-rays and neutron radiation) in addition to the varying degrees of sensitivity of the organs to radiation is assessed. Unit of meas-ure: Sievert [Sv].

Dose rate Dose per time unit, unit of measure: Sieverts per hour [Sv/h].

Energy supply company Energy supply companies or electricity supply companies are enterprises that feed electrical power into the public grid and/or ensure sup-ply by natural gas or district heating.

Federal Institute for Geosciences and Natural Resources (Bundesanstalt für Geowissen-schaften und Rohstoffe, BGR), Hanover Specialised authorities of the Federal Ministry of the Economy and Technology, the central scientific and technical institution for con-

sultancy of the Federal Government in all geo-relevant matters and therefore also re-sponsible for final disposal in deep geological formations.

Federal Office for Radiation Protection (Bun-desamt für Strahlenschutz, BfS), Salzgitter Competent authority for radiation protection, subordinate to the Federal Ministry for Envi-ronment, Nature Conservation and Nuclear Safety and responsible for the final disposal of radioactive waste. The predecessor organi-sation until 1989 was the PTB (Physikalisch-Technische Bundesanstalt).

Federal Ministry of Education and Research (Bundesministerium für Bildung und Forschung, BMBF), Berlin/Bonn Responsible among other aspects for loca-tion-independent basic research into disposal of radioactive waste, now jointly with the Federal Ministry of the Economy and Tech-nology.

Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (Bundes-ministerium für Umwelt, Naturschutz und Reaktorsicherheit, BMU), Berlin/Bonn Founded in 1986 from the Federal Ministry of the Interior. The subordinate Federal Office for Radiation Protection is responsible among other aspects for final disposal and radiation protection. Furthermore, the Ministry is ad-vised by several independent committees of experts: ESK, RSK and SSK.

Federal Ministry of Economics and Technol-ogy (Bundesministerium für Wirtschaft und Technologie, BMWi), Berlin/Bonn Responsible among other aspects for energy policy, including nuclear energy, particularly for nuclear research and international organi-sations.

Fuel assembly Arrangement consisting of a large number of fuel rods for utilisation of nuclear fuel in a nuclear reactor. In a BWR, some 70 fuel rods form a fuel assembly and in a PWR up to 300.

Fuel pool A pool filled with water in the radiation-controlled area in which fuel assemblies are stored after use in reactors until their activity and heat generation have subsided to a de-sired value.

Fuel rod, fuel (nuclear) Tubes filled with fuel for nuclear fission in nuclear reactors. The fuel consists of uranium dioxide or a mixed oxide of uranium dioxide and plutonium dioxide in tablet form (pel-lets), occasionally also as an alloy.

Fission products Nuclides resulting during fission of a nucleus, e.g. 235U.

Half-life Period after which 50 % of a specific number of atomic nuclei are decayed.

Handling license Regulates handling of radioactive materials within the context of the radiation protection ordinance.

Helmholtz Centre Munich German research centre of health and the environment, Neuherberg near Munich. Its predecessor was the Gesellschaft für Strahl-en- und Umweltforschung (GSF), the former owner of the Asse research mine and respon-sible for basic research into final disposal of radioactive waste.

High-level waste, HLW Waste with levels of activity concentration high enough to generate significant quanta-

37

Glossary

ties of heat by the radioactive decay process or waste with large amounts of long-lived ra-dionuclides that need to be considered in the design of a disposal facility for such waste.

Interim storage Timeframe of storage of radioactive materi-als until transfer to a repository.

Intermediate-level waste, ILW Waste that because of its content, particu-larly of long-lived radionuclides, requires a greater degree of containment and isolation than that provided by near-surface disposal. However, ILW needs no provision, or only limited provision, for heat dissipation dur-ing its storage and disposal. ILW may con-tain long-lived radionuclides, in particular, alpha-emittung radionuclides that will not decay to a level of activity concentration ac-ceptable for near-surface disposal at greater depths, of the order of tens of metres to a few hundred metres.

Ion exchange resins Resins which, owing to their chemical struc-ture, are capable of ion exchange and are used for purifying waters, e.g. cooling water, of radioactive materials.

Low-level waste, LLW Waste that is above clearance levels, but with limited amounts of long-lived radio-nuclides. Such waste requires robust isolation and containment for periods of up to a few hundred years and is suitable for disposal in engineering near-surface facilities. This class covers a very broad range of waste. LLW may include short-lived radionuclides at higher levels of activity concentration and also long-lived radionuclides, but only at relatively low level of activity concentration.

Ministry for the Environment, Energy and Climate Protection (Niedersächsisches Mini-sterium für Umwelt, Energie und Klima-schutz, NMU), Hanover The authority of the Federal State of Lower Saxony for the environment, energy and climate protection. The ministry has for ex-ample technical supervision over the Federal Office for Mining, Energy and Geology, the area of activity of which extends over min-ing law in conjunction with facilities for stor-age and treatment of radioactive materials.

Mixed-oxide fuel assemblies, MOX MOX fuel assemblies consisting of a mix-ture of uranium and plutonium oxide, less frequently thorium oxide.

MOSAIK® The «mobile collection container in the nu-clear power plant» (Mobile Sammelbehälter im Kernkraftwerk) describes both a trans-port and interim storage facility cask made of ductile cast iron, particularly for interme-diate-level radioactive waste such as for ex-ample crushed core components, dried ion exchange resins or evaporator concentrates. The cask is likewise suitable for transport of sources and other radioactive waste.

Natural barriers A part of the repository concept, oppos-ing return of the radioactive waste finally disposed to the biosphere. It includes host rock, reducing conditions (no free oxygen), concentrated salt solutions in the deep geological subsurface and different barrier effects of superimposed formations (e.g. in the overburden) with different water per-meabilities.

Natural convection Dissipation of heat owing to the different densities of the air and the ensuing air movement.

Natural uranium Naturally occurring uranium consists 99.275 % of 238U, 0.72 % of 235U fissionable and 0.005 % of 234U.

Nuclide A type of atom, defined by the number of protons and neutrons in addition to the en-ergetic status. More than 3,700 radioactive nuclides are currently known.

OECD Organisation for Economic Cooperation and Development, which offers a platform for governments for exchange of experience and identification of «Good Practice» in addition to coordination of international political collaboration.

On-site interim storage facility On-site interim storage facilities exist at all German nuclear power plant sites. They mainly serve for storage of spent fuel as-semblies.

Package Conditioned and packed radioactive waste, i.e. the waste product including the sur-rounding cask.

Planning approval decision A planning approval decision develops and implements spatially relevant projects. The planning approval decision completes this process in which a decision is made on per-missibility.

POLLUX® cask It was developed for final disposal of irradi-ated fuel assemblies, but is also suitable for interim storage and transport. The POLLUX® cask is capable of receiving up to 10 PWR or up to 30 BWR fuel assemblies.

Pressure switch The pressure switch is a part of the cask surveillance system and controls the pres-sure applied for monitoring tightness of the cask between the primary and secondary lid of the double barrier system of an interim storage cask.

Pressurised Water Reactor, PWR A power reactor in which the heat from the reactor core is dissipated by water main-tained under high pressure to ensure that a high temperature is achieved and boiling in the reactor core is prevented. The cooling water gives off its heat to a secondary circuit in a steam generator. Eleven plants of this type are currently in operation in Germany.

Protection target The protection targets for nuclear facili-ties are among other aspects defined and anchored in the German Atomic Energy Act. They comprise protection of the population against the hazards of nuclear energy and the harmful effect of ionising radiation.

Radiation-controlled area An area in nuclear facilities in which indi-viduals may receive an effective dose of more than six millisieverts per year and to which access is regulated.

Radiation Protection Commission, (Strahlen-schutzkommission, SSK), Bonn Advises the Federal Ministry for Environment, Nature Conservation and Nuclear Safety in all matters of protection against ionising and non-ionising radiation.

Radiation Protection Ordinance, StrlSchV An ordinance within the German Atomic En-ergy Act relating to protection against dam-age caused by ionising radiation.

Radioactivity The property of specific substances of transforming themselves without externs influence, thereby emitting a characteristic (ionising) radiation.

Radionuclide An unstable nuclide which spontaneously decays without external influences with emission of radiation.

Reactor Safety Commission (Reaktor-Sicher-heitskommission, RSK), Bonn Advises the Federal Ministry for Environ-ment, Nature Conservation and Nuclear Safe-ty in matters of safety of nuclear facilities.

Reference power plant A nuclear power plant (PWR or BWR) repre-sentatively selected for a reference study in Germany. Based on the study conducted by the operators, which is continually adapted to the current background events, both technical feasibility and progress in addition to the costs for the decommissioning of nu-clear facilities can be determined.

Release An administrative act which brings about the discharge of radioactive materials in addition to objects, buildings, ground areas, plants or plant sections which are activated or contaminated with radioactive materials for utilisation, recycling, elimination or pos-session or for their transfer to a third party as non-radioactive materials.

Repository Storage site for safe, indefinite and main-tenance-free final disposal of harmful materials, in deep geological formations in Germany.

Sorption Binding of radioactive substances in the ef-fective containment zone of a repository.

Ton, t Measurement of weight, 1 t is equivalent in the international unit system to 1,000 kilo-grams (kg) or 1 megagram (Mg).

Waste Control Guideline A guideline for control of radioactive re-sidual materials and radioactive waste of the Federal Ministry for Environment, Nature Conservation and Nuclear Safety, which as a supplement to the radiation protec-tion ordinance governs the monitoring of radioactive residual materials and waste. The guideline requires determination of the quantity, whereabouts, processing status and packaging of radioactive waste with regard to safe interim storage and final disposal by means of documentation of all treatment and disposal stages.

Waste Flow Tracking and Documenta-tion System (Abfallfluss-Verfolgungs- und Produkt-Kontrollsystem, AVK) A system introduced for compliance with the Waste Control Guideline, guaranteeing documentation of the status, packaging and whereabouts of a specific existing quantity of waste at any given time.

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Fig. 1 Energy mix of Germany’s electricity supply between 1960 and 2010 4Fig. 2 Energy mix of Germany’s electricity supply from 2010 5 Fig. 3 Nuclear power plants and their corresponding disposal facilities in Germany 6Fig. 4 Differentiation of the radioactive residual materials 7Fig. 5 Classification of radioactive wastes 8Fig. 6 Way of disposal for fuel assemblies in Germany 9Fig. 7 Fuel assembly disposal: reprocessing 10Fig. 8 Fuel assembly disposal: direct final disposal 11Fig. 9 Underwater loading of a CASTOR® cask 12Fig. 10 Interim storage of CASTOR® casks 13Fig. 11 Gorleben pilot conditioning facility; external view of the dismantling cell with manipulators 14Fig. 12 Gorleben pilot conditioning facility; internal view of the dismantling cell 14Fig. 13 Way of disposal for the materials from radiation-controlled areas 16Fig. 14 Controlled recycling of metals 17Fig. 15 Typical operational waste for a nuclear power plant with a PWR 18Fig. 16 Optimised treatment methods for solid and liquid radioactive waste from nuclear power plants 19Fig. 17 Waste treatment methods for volume reduction 19Fig. 18 Annual waste volume from operation of the German nuclear power plants – Last revised 2010 20Fig. 19 Loading an incineration furnace 20Fig. 20 Flow diagram of an incineration facility for radioactive waste 20Fig. 21 FAKIR high pressure hydraulic compactor 21Fig. 22 Compacted pellet following high-pressure compaction 21Fig. 23 PETRA drying facility 22Fig. 24 MOSAIK® cask 23Fig. 25 Repository container 23Fig. 26 200-litre drum on activity measuring system 23Fig. 27 Loading of MOSAIK®-type waste containers 24Fig. 28 Storage of lost concrete shielding (LCS) 24Fig. 29 Decommissioned nuclear power plants in Germany 25Fig. 30 Distribution of the accrued masses during decommissioning of the radiation-controlled area of a PWR 26Fig. 31 Transport of a steam generator out of the Stade nuclear power plant for recycling 26Fig. 32 Treatment of radioactive waste with work sequence plansconcerning interim storage and final disposal 27Fig. 33 Waste Flow Tracking and Documentation System (AVK) collage 28Fig. 34 Responsible institutions in final disposal of radioactive waste 29Fig. 35 Responsibilities for disposal of radioactive waste 30Fig. 36 Tunnel section in Gorleben, roadheading machine 30Fig. 37 Structure of a repository for radioactive waste in a salt formation 31Fig. 38 Asse II pit 32Fig. 39 Morsleben repository in service until 1998 33Fig. 40 Konrad mine, shaft 1 34Fig. 41 Gorleben site under exploration 35

List of illustrations

Further websites

Final disposal in Germany – authorities and executing facilities www.bmu.de www.bmwi.de www.bfs.de www.endlager-asse.de www.endlager-konrad.de www.bgr.bund.de www.dbe.de

Foreign websites on storage and final disposal of radioactive waste www.nagra.ch www.skb.se www.posiva.fi www.nirond.be www.oecd-nea.org www.andra.fr www.surao.cz www.enresa.es corwm.decc.gov.uk

Further links www.entsorgungsforschung.de www.endlagerung.de www.kernenergie.de

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Publisher and copyright

«Working Panel Waste management» of VGB PowerTech e.V. Klinkestrasse 27-31, 45136 Essen, Germany ©2012 ISBN 978-3-86875-400-1 Telephone: + 49 201 81 28 - 0 (switchboard) Telefax: + 49 201 81 28 - 350 Email: info@vgb.org Internet: www.vgb.org Cover illustration: nuclear power plants at the Gundremmingen site Layout and realisation: together concept Werbeagentur GmbH, Essen

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