Direct disposal

The term direct disposal is understood to mean the disposal of spent fuel elements from nuclear power plants without the previous step of reprocessing . For this, the fuel will be after their discharge first few years to decades stored , until their radiation and heat output sufficiently decayed. The fuel elements must then be packaged (conditioned) in a way that is suitable for final disposal.

Since July 1, 2005, the transport of spent fuel elements from German nuclear power plants to reprocessing has been prohibited by the Atomic Energy Act. The only way of disposal that remains is what is known as direct final disposal. Switzerland also embarked on this path in 2006 in the form of a ten-year moratorium .

Reference concept

Various alternatives for the packaging were discussed and investigated. The current reference concept is the so-called POLLUX concept. The fuel elements are removed from the transport and storage casks ( CASTOR casks ) in a conditioning system . The fuel rods are then pulled out of the fuel assemblies in a “hot cell” and pushed into long, cylindrical cans. The cans are finally discharged POLLUX container, which then spent the repository and routes can be stored. The heat output of the fuel elements largely determines the time of storage.

Optimized concept

To optimize disposal, a new concept is currently being developed in which the fuel rods are no longer packed in cans and POLLUX containers , but in glass canisters . These are then to be disposed of in boreholes together with the high- and medium-level radioactive molds of the same diameter.

Pilot conditioning plant

A conditioning system is required for the packaging of spent fuel elements suitable for final disposal. A pilot plant, the so-called pilot conditioning plant (PKA) Gorleben, was built and approved. The capacity is 35 tons per year, about 450 tons per year would be technically possible. However, due to an agreement between the federal government and the energy supply companies, the use of the system is limited to the repair of damaged containers. This means that there is currently and for the foreseeable future no facility available in Germany for the packaging of spent fuel elements in containers suitable for disposal.

Concept of bearing bars

With this concept developed and generally recognized by the Öko-Institut , the separated, but not reprocessed plutonium , which poses a proliferation risk, is to be disposed of. First of all, so-called bearing rods are produced from the separated plutonium. These storage rods are then installed individually in normal spent fuel assemblies. This largely eliminates the risk of proliferation.

Web links

• Definition of direct disposal
• Conference on the topic of "direct disposal" - 1995
• Interview on the subject of "direct disposal" - 1989
• Information from the provider GNS Gesellschaft für Nuklear-Service mbH on the subject of final storage of radioactive waste

Individual evidence

1. ↑ Ch. Küppers et al .: The reprocessing of spent fuel elements from Swiss nuclear power plants , 1997