Danger of a piece of rock falling in chamber on the 725-m level - waste will be covered with salt grit

Within the scope of an inspection of the Asse II repository on 27 April 2009, the Federal Office for Radiation Protection (BfS) found several locations with imbricated sluffing at the roof of emplacement chamber 7 on the 725-m level immediately above some emplaced drums. Chamber 7 is an emplacement chamber in the repository mine which is still open. There are a few drums in the chamber which have only partially been embedded in salt grit. That means that one must expect a larger piece of rock falling from the roof onto the uncovered drums. This could lead to a damaging of the stored drums and to salt dust and radioactive particles being dispersed. Since chamber 7 has not been sealed, released harmful substances could possibly get into the mine air and into other parts of the mine.

To prevent such a scenario, BfS will immediately cover the drums with salt grit in order to protect them from being destroyed by such a fall. Furthermore, the imbricated sluffing will be removed. The nuclear Repository Surveillance has already granted its approval to this danger prevention measure. The competent mining authority has been informed. The works will probably be completed next week.

There is no risk to the environment of the Asse II mine. Evidence-preserving measures are continuously carried out with which the mine air is monitored for radioactivity.