Decommissioning planning

Date

21/10/2011

According to the present state of knowledge, the best variant of how to further deal with the radioactive waste emplaced in the Asse II mine is retrieving all the waste. The legally required long-term safety can only be ensured for the Asse site after all the waste has been retrieved.

When the waste is retrieved, the radioactive waste will be recovered from the Asse mine and taken above ground (retrieved). For this purpose the drums need to be recovered from the chambers and placed into overpacks for the transport above ground. The waste is transported via the shaft.

Once it has been taken above ground, the waste is initially taken into a buffer facility and subsequently post-treated (post-qualified) in a conditioning plant, packed for future disposal and then stored in an interim storage facility. Until it will be taken to a repository the waste will remain in the interim storage facility.

Current works

Current works relating to retrieval are divided into two areas:

• Fact finding
• Planning works relating to retrieval

The trial phase (fact finding) is the first step of the overall task “retrieval of the radioactive waste”. This would typically be followed by planning works for retrieval. Both parts need to be pursued in parallel, however. Due to the state of the mine (inflow of saline solution, deformation) this procedure is mandatory for decommissioning the Asse mine. A special challenge of this approach consists in the fact that initial planning works need already start although essential planning basics can only be determined in the scope of fact finding.

Status of planning works

Current plans in terms of retrieval comprise

• Planning the interim storage facility,
• Renewal of the hoisting plant,
• Plans for sinking a new shaft.

In order for retrieval being successful, even under the unfavourable site conditions and/or the design-exceeding inflow of water that cannot be ruled out, precautions and the establishment of an emergency response need to be prepared and implemented, in case an uncontrollable inflow of water should occur. These works are also carried out parallel to the fact finding and planning of retrieval.

Status of trial phase

One result of the comparison of options was that there are sill considerable uncertainties relating to retrieval of the waste. These uncertainties are to be resolved with the help of an in-depth fact-finding process (trial phase). In a first step two emplacement chambers will be drilled into, in a second step the chambers will be opened and, in a third step, the first waste stored in the chambers will be recovered by way of trial.