Abstract

The Konrad mine near Salzgitter, Germany, is currently in the process of being rebuilt as a repository for radioactive waste with negligible heat generation. Due to the operating constraints the lining of the drifts and rooms is to be carried out in a way to guarantee a period of use of approx. 40 years without maintenance. The mine openings will be excavated in a complex geology, which is shaped partly by squeezing rock mass conditions and numerous planes of weakness, and in a depth of approx. 850 m. The lining concept provides a double shell lining. The measurements of the lining's deformations are to be compared to the results of the numerical calculations for the final state in order to detect critical regions in the shell before damage occurs. The example of the Konrad mine shows, that the phases of planning and execution are crucial for a long time of maintenance free usage of underground structures.

Introduction

The Konrad mine is a former iron ore mine near Salzgitter in Germany. The mine workings extend over six floors with a depth between 800 m and 1300 m. Early considerations for the conversion of the mine into a repository for low and intermediate radioactive waste range back to the mid-1970s. The mine was taken over by the Federal Republic of Germany after the fundamental suitability was determined in the early 1980s and a planning approval process was initiated. In this planning approval process, the basic conditions for the construction and operation of the repository were defined. The planning approval decision was made in 2002 (Niedersächsisches Umweltministerium 2002). The Konrad repository is the first repository in Germany with an approval based on the nuclear law. The Konrad mine has been rebuilt into a repository for low and intermediate radioactive waste since 2007, after the planning approval decision was confirmed by the responsible courts.

The essential basic conditions for the construction of the repository result from the planning approval decision based on the development during the 1990s. This refers not only to the waste to be placed, but also to the bearing and geometry of certain mine workings. This ensures the usage of vehicle technology and machine technology needed for the storage without any restrictions. Additionally, the controlled area of the repository has to be maintenance-free and fit for purpose for at least 40 years.

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