Excursion to the Asse visitor mine

Dirk Merten

Including taking off underwear...putting on new clothes...and going!

On August 7, 2019, students of the module "Radio- and chemotoxic elements in the environment" went in search of clues at the Asse mine. A guided tour provided interesting insights into the ongoing safeguarding of the mine.

In the former salt mine in Lower Saxony, potash salt was mined from 1909 to 1925 and rock salt from 1916 to 1964.

From 1967 to 1978, the storage of radioactive waste was tested on a large scale and 47,000 cubic meters of low and medium level radioactive waste were stored at levels 511 m, 725 m and 750 m below sea level. De facto, the mine, which was approved as a research mine, served as of 1971 for the final disposal of the entire low and intermediate level radioactive waste of the Federal Republic of Germany. The stored casks were partially stowed away in order to minimize the storage costs and the radiological disposition of the personnel. It can be deduced from this that retrieval was not an objective.

The numerous cavities from the time of salt mining, 131 mining chambers were created in the southern flank alone, were filled with overburden material but lead to stability problems today. Between 1995 and 2004, the cavities continued to be backfilled, but without satisfactory results, so that the stability of the mine is acutely endangered.

In addition, groundwater has been seeping into the mine since 1988. It is saturated with rock salt and thus does not lead to dissolution of the salt in the mine, but it must be feared that radioactive inventory could be discharged via the water path in the future.

At the turn of the year 2008/2009, the plant was placed under nuclear law and treated as a repository. Subsequently, three scenarios were examined by the then responsible Federal Office for Radiation Protection:

  1. Complete retrieval of the radioactive inventory
  2. Relocation within the mine to stable areas
  3. Complete filling of all cavities with concrete

Since 2013, the retrieval of the waste has been driven forward by the Federal Company for Final Disposal, since the long-term safety of the other scenarios cannot be guaranteed. The public is fully involved in this process.

Today, the highest exposure comes from temperatures of up to 40°C, and the level of radioactive radiation in the Asse is well below the average level above ground.

A visit to the interesting information center, which provides multimedia insights into the history of the mine, is also possible for private persons, as is a tour of the mine, although due to the low capacity, registration should be made several months in advance.
in advance due to the low capacity.