Preliminary work for drilling into the first emplacement chamber

With the so-called cold trial, the Federal Office for Radiation Protection (BfS) commenced the preliminary underground work for drilling into the first emplacement chamber. This is to lay the foundations for a safe retrieval of the radioactive and chemo-toxic wastes from the Asse repository.

The term ‘cold trial’ refers to the drilling into the salt rock under realistic conditions at a location where neither radioactive nor chemo-toxic wastes are stored. When all authorities involved act in concert, i.e. in particular when all licences have been granted duly, the first emplacement chamber can be drilled into in this year already.

The cold trial will be conducted in a depth of 800 m. No radioactive waste was emplaced in this area. The objective of the cold trial is to test the drilling equipment with the drilling data recorder, the necessary safety installations (preventer) and the exploration devices (magnetic and radio probes). The preventer has the task of sealing the bore hole during the process of drilling into the chamber. Thus, it is ensured that no radioactive particles from the emplacement chambers can escape through the bore hole via gases, dusts or liquids. This must be guaranteed to protect the staff and the environment.

Retrieving the waste from the Asse mine is the best variant of how to further deal with the radioactive waste emplaced there. According to the current state of knowledge, this is the only way to establish the legally required safety for future generations (long-term safety) in the Asse mine. This has been the result of the comparison of options with the help of which the best possible variant for a safe decommissioning of the Asse repository has been determined. The results of this comparison were presented to the public in January this year. The trial phase that has commenced now serves to ensure the safety of the staff and the population in the planned phase of retrieving the radioactive waste.

In parallel, the BfS is developing criteria that are, in co-ordination with all parties involved in the closure procedure, to evaluate the results gained from the drilling into and later opening of emplacement chambers. This inquiry of facts will provide further information about the actual state of waste chambers, nuclear waste drums and waste packages which were emplaced in the Asse mine several decades ago.