TRANSPORT OF RADIOACTIVE WASTE IN GERMANY - A SURVEY

U. ALTER

Ministry of Environment,

Nature Protection and Nuclear Safety, Bonn, Germany

Abstract

The transport of radioactive waste is centralized and coordinated by the German Railway Company (Deutsche Bahn AG, DB) in Germany. The conditioning of radio-active waste is now centralized and carried out by the Gesellschaft für Nuklear Service (GNS). The German Railway Company, DB, is totally and exclusively resposible for the transport, the GNS is totally and exclusively responsible for the conditioning of radioactive waste.

The German Railway transports all radioactive waste from nuclear power plants, con-ditioning facilities and the existing intermediate storage facilities in Germany. In 1992 nearly 177 shipments of radioactive waste were carried out, 1991 the total amount was 179 shipments.

A brief description of the transport procedures, the use of different waste packages for radioactive waste with negligible heat generation and the transport routes within Germany will be given. For this purpose the inspection authorities in Germany have used a new documentation system, a special computer program for waste flow trak-king and quality assurance and compliance assurance, developed by the electrical po-wer companies in Germany.

Final Repositories in Germany

The first final radioactive waste repository in Germany was the former salt mine "As-se" near Braunschweig/Wolfenbiittel. Disposal of radioactive waste was started in 1967 but only for 11 years up to 1978. During this time nearly 120 000 m³ of low- and me-dium-radioactive waste were disposed with an activity content of 1 250 TBq beta/gam-ma-activity and nearly 88 TBq o-activity.

In the former German Democratic Republic (GDR) a disused salt-mine was chosen for the disposal of low-radioactive waste III situated in Morsleben near to Helmstedt at the former German-German border. The final disposa/ started in 1978. Low level radioactive waste from the nuclear power plants in Greifswald and Rheinsberg, from the research and development facility in Rossendorf (Saxonia) and from different

users of low radioactive material in the former GDR were disposed in Morsleben from 1978 to 1991. Due to the decision of the court in Magdeburg the facility was clo-sed between February 1991 and the beginning of 1994. The Morsleben final waste disposal is back in operation since 13. January 1994. Low level radioactive waste from the shut-down nuclear power reactors in Greifswald and Rheinsberg are disposed in the facility now.

In the western part of Germany the disused iron ore mine Konrad near Braun-schweig/Salzgitter is planned to be the final disposal for radioactive waste with negligi-ble heat genaration. The capacity is scheduled to be up to 600 000 m³ of radioactive waste with a maximal beta/gamma-activity of nearly 5 000 000 TBq and an a-activity of maximal 150 000 TBq.

An other final repository-project exist in Lower-Saxonya, the Gorleben-project, a final repository for heat-generating radioactive waste. Today the Gorleben salt-dome is under examination.

General Situation

The electrical power generation from nuclear power plants has steadily increased in Germany since 1970, see table - 1 -. Due to the fact that the majority of the generated radioactive waste had to be stored in interim storage facilities a total amount of near-ly 55 000 m³ of waste with negligible heat generation exist, see table -2-.These values were given from the Radiation Protection Office in Salzgitter 121.

Tab. 1. KLI'XTRICITY CKNKRATION IN O K R M A N Y

Total electricity j»encratio» in !'>•>! : 45S.7 'l"\Vh

Nuclear 147,4 TWh Coal Power 149,4 TWh Lignite 84,0 TWh others 77,9 TWh

Total electricity generation in 1992 : 461,7 TWh

Nuclear IS8,8 TWh Coal 142,2 TWh Lignite 86,6 TWh others 74,1 TWh

Tnb. 2. Radioactive Waste with negligible heat generation in Germany during 1991 and 1990

Producer of Rad.

Waste

Reprocessing facility Nuclear Power Plants RID facilities other

4.

1990 m3

873 2 «82 ')

2 531 792

«878

1991 m3

799 1 846 ")

2 056 397 5098 ) final storage of 708 m in Morsleben

) final storage of 49 m in Morsleben

Structures of the nuclear energy industry in Germany

Since 1988 modification of the structures of important areas of the nuclear energy industry in Germany 131 has resulted in the following:

the conditioning of radioactive waste is now centralized and carried out by one firm belonging to the Gesellschaft für Nuclear Service (GNS)

the transport of radioactive material from nuclear power plants is centralized and coordinated by the German Railway Company (Deutsche Bahn AG, DB).

The main goal of restructuring is substantially to improve national safety measures by making one company in the private sector (GNS) totally and solely responsible for the conditioning of radioactive waste and one company (DB) totally and soleley responsi-ble for their transport.

The Federal Government is of the opinion that the combination of the two approa-ches - i. e. improvements to national regulations and structural change in the nuclear industry - is a particularly appropriate way of achieving their safety objectives avoiding certain disadvantages of free competition.

^ Shipments of radioactive waste in Germany 1991 and 1992 Konrad Transport Study Due to the fact that the inspection authorities in Germany could use a documentation

system, a computer program for waste flow tracking and quality assurance and com-pliance assurance, data from radioactive waste shipments are available.

Data for 1991 show a total amount of 179 shipments including shipments in January and February 1991 to the final repository Morsleben. In 1992 the total amount of shipments of radioactive waste were 177. This means only shipments of conditioning radioactive waste from nuclear power plants to waste-handling facilities or interim storage facilities. A short survey is given in figures - 1 - and - 2 -. Standardized contai-ners were used for those waste-shipments.

RadWaste Transport, 1992 Destination of Transport DU., 35 ——— GLB'47

MIT, 30

KFK, 30 Figure 1

RadWaste Transport, 1992 Mode of Transport

The "Gesellschaft für Anlagen- und Reaktorsicherheit, GRS" has finalized a safety analysis /4/ for the transports of non-heat-generating (low- to medium-level) radio-active waste to the planned final repository Konrad in 1991. The safety analysis has two main objectives:

Assessement of potential radiation exposures from normal (incident-free) portation, especially in the region of the final repository where all waste trans-ports converge.

Assessment of risks from transport accidents in the region of the final repository, i. e., the quantification of the frequency of accidents and of possibly resulting radiation exposures and contamination levels.

For the purpose of the study the anticipated waste transport volume and the waste properties were analysed in detail. This included information on the transport contai-ners, waste product properties, activity inventories and local dose rates of the waste packages being transported.

The relevant IAEA transport regulations /5/ contain the requirements to be met by the transport of shipping units carrying radioactive waste.

Radiation Exposure from Normal Transport

The total annual radiation dose received by an individual as a result of waste trans-ports passing by or sloping in this vicinity is derived from the dose rate at each loca-tion and the cumulative period of time spent by individuals at these localoca-tions during a period of one year. In this context, the study concentrated on exposure situations in which groups of persons are particularly exposed to the radiation field of the waste packages as a result of their living habits or their occupation. This corresponds to the normal procedure adopted in radiological protection in order to determine the poten-tial doses to "critical groups of individuals". For persons who do not belong to the

"critical group", the radiation exposure caused by the waste transport can generally be expected to be lower, and in most cases much lower, than for those in the critical group.

The doses determined for individuals of the critical group in the region of the final repository range approximately from 0,02 to 0,1 mSv/a.

To a large extent, doses are in the lower range of 0,02 mSv. This is either because on an average only short periods of time are spent in the immediate vicinity of the waste transports, since the vehicles generally pass by or stop only for a short time, or becau-se of the larger distances between the individual and the waste transports.

The highest exposure conditions were determined for residents of buildings closest to the track at the Braunschweig marshalling yard. The effective dose for this population group is between 0,1 and 0,2 mSv/a.

The potential radiation exposure of critical groups of persons in the population as a result of waste transports is well below the value of 1 mSv/a recommended by the IAEA transport regulations. The additional radiation exposure of the critical groups of persons as a result of the waste transports is equivalent at the most to a small fraction of natural radiation exposure. The radiation exposure of these groups of persons, and consequently even more significantly of those inhabitants of the region around the final repository who do not belong to the relatively few individuals of the critical groups, remains practically unchanged by the waste transports.

Considering the persons who are occupationally involved with waste transportation, that is employees of the Federal German Railways and Verkehrsbetriebe Peine-Salz-gitter, the dispatch and marshalling personnel at the Braunschweig marshalling yard and Beddingen interchange station, who are primarily involved in shunting and dispat-ching the waste wagons must be regarded as the critical occupationally exposed group of persons.

Depending on their functions, maximum doses of approximately 0,3 - 0,7 mSv/a are obtained for marshalling personnel and reception inspectors as a result of waste trans-port by rail. For the other transtrans-port personnel doses are significantly lower.

The results of the transport accident risk analysis will be summarized in the paper

"Safety Analysis of the Transportation of Radioactive Waste to the Konrad Waste Disposal Site, IAEA-SR-189/27" (Mr. F. Lange).

Morsleben Transport Study

A transport safety analysis study has been conducted for shipments of low to medium level radioative waste materials suitable for underground disposal at the Morsleben final repository /6/. The objective of the study - refered to as Morsleben Transport Study - is the anaylsis of transport operations and the assessment of the radioalogical risks from normal transportation and potential accidents. The annual volume of waste shipments assumed for the study is 865 shipping units corresponding to a waste volu-me of approximately 5 000 m³. These values are consistent with courrent estimates of the disposal capacity of the Morsleben final repository for one-shift operation.

A shipping unit generally represents a standard 20'-freight container used as overpack for transporting the varius reusable and non-reusable waste packages types. The pak-kages accepted for disposal are assumed to be primarily 200 1-drums, cylindrical con-crete containers, and cubical sheet steel containers.

The requirements concerning the package activity content, the characteristics of the waste packages and other relevant paramenters result from:

the current waste acceptance criteria based on safety considerations for the Mors-leben repository

regulations for transporting hazardous materials.

The information required to describe the type, quantity and propertiers of the various waste materials suitable for disposal at the Morsleben final repository are based on a survey at major waste producers. Consistent with the preliminary waste acceptance criteria only low specific a-activity waste materials (< 40 MBq/m³) are included in the study.

Rail transport ist the preferred shipping mode nationally. But the Morsleben final repository has no rail accès. This is the reason why in the repository region, however, i. e. the 40 - 50 km region around the disposal site, waste transportation have to be primarily by road from the marshalling yard Magdeburg-Sudenburg to the location of the final repository.

The assessment of the potential radiation exposure from normal transportation to the transport personnel and the public is based on an analysis of the transport and hand-ling operations, the dose rate of the waste packages, and the potential exposure con-ditions along the transport route.

Only critical group of individuals, i. e. person exposed to radiation from the waste packages, are considered in the study. The dose estimates for members of the public are generally less than 0,08 mSv/a and the transport personnel are generally less than 1.1 mSv/a, respectively, except for truck transport personnel where doses can be as high as 5 mSv/a or even above depending on the driving schedule of the individual truck drivers.

The accident analysis relies to a large extent on probabilistic safety assessment techni-ques taking into account the broad range of values of model parameters which deter-mine the radiological consequences of transport accidents and the estimated frequency of occurrence.

The expected frequency of road transport accidents resulting in minor radioactive releases in the region surrounding the repository has been estimated to be on the order of 1 in 60 per year. The doses and environmental consequences of such dental events are very low and are limited to the site of the accident. Transport acci-dents and the associated relesases resulting in doses at the accident site exceeding 2 mSv/a is approximately 1 in 250 for an assumed operating period of 20 years.

An effective lifetime-dose of 50 mSv will not be exceeded under any circumstances at the site of the road transport accident that can be reasonably assumed for dose as-sessment.

From the results of the study it can be concluded that the overall transport risk from shipments of radioactive waste materials to the Morsleben final repository is very small.

REFERENCES

III GESELLSCHAFT FÜR REAKTORSICHERHEIT (GRS), Safety Analysis of the Morsleben Waste Disposal Site, GRS-79, Cologne (1991)

121 BRENNECKE, P., HOLLMANN, A. Amount of Radioactive Wastes arising in the Federal Republic of Germany, BfS-ET-17/93, Salzgitter (1993) /3/ ALTER, U., COLLIN, F. W., FASTEN, C, Transport of Radioactive

Mate-rials in the F.R.G. since 03. October 1990 - a Survey, PATRAM'92, Packaging and Transportation of Radioactive Materials (Proc. Int. Symp, Yokohama, 1992)

/4/ LANGE, F. et al, Konrad Transport Study: Safety Analysis of the Transporta-tion of Radioactive Waste to the Konrad Waste Disposal Site, GRS-91, Cologne (1991)

151 INTERNATIONAL ATOMIC ENERGY AGENCY, Regulations for the Safe Transport of Radioactive Material, 1985 Edition (As Amended 1990), Safety Series No. 6, IAEA, Vienna (1990)

/6/ LANGE, F. et al, Transport of Radioactive Waste to the Morsleben Waste Disposal Site, to be published, Cologne (1994)

TRANSPORT OF RADIOACTIVE WASTE IN