Start of drilling into first chamber by end of this year

Test phase increases safety for retrieving the Asse waste

Date: 07/05/2010

The Federal Office for Radiation Protection (BfS) wants to start drilling into the first waste-containing chamber in the Asse mine by the end of this year. This will be the first step of the test phase (finding of facts). In a second step the emplacement chambers will be opened, in a third step the waste will be recovered for test purposes. This is to help answer essential questions relating to a guarantee of safety when retrieving the radioactive and chemo-toxic wastes.

By the end of the year first results about the state of the waste in the emplacement chambers should be available. The BfS is on schedule with the finding of facts. Following the comparison of options, the BfS announced in January that the complete retrieval of the radioactive waste was the best solution for decommissioning the Asse mine.

With the three steps of the test phase the experts want to answer three questions:

What radiation levels will the staff be exposed to while recovering the waste?
How long will it take to retrieve the around 126,000 drums containing radioactive and chemo-toxic wastes?
How much of the waste can be recovered with remote-controlled machines?

The firms DMT and TÜV Nord Sys Tec are currently preparing on behalf of the BfS the drilling into chamber 7 on the 750-m level. Subsequently they intend to drill into chamber 12. The investigation concept this is based on will be available as download (only in german). In chamber 7 more than 4,300 packages containing radioactive waste were dumped or stacked between 1977 and 1978. The objective of the drilling is to find out about the atmosphere and air contamination in the chamber, in what state the chamber and the packages are and whether there are saline solutions in the chamber. Samples will be taken through the borehole. Thus it can be determined if toxic or explosive gas mixtures have developed in the emplacement chambers. Also equipment like cameras, magnetic and radio probes will be inserted via the borehole. For the first time, the concrete conditions will thus be determined in a chamber where drums have been located in a sealed and inaccessible condition for more than 30 years. More findings are to be obtained about the state of the roofs and walls in order to gain information about the packages and occupational health and safety in the emplacement chambers.

By applying a graded safety concept it will be ensured that no contaminated substances can escape from the boreholes into the mine or the environment uncontrollably. This requires the installation of locks and filters to prevent a possible dispersion of the chemo-toxic and radioactive substances. These safety measures are also required for the retrieval of the waste.

The schedule for the first step of the finding of facts can only be realised when all parties involved act in concert during the necessary planning work, the purchasing of equipment, the licensing procedures and the actual drilling and measuring works.