Instable isotope of caesium, physical half-life ca. 30.2 years.

CASTOR is an abbreviation of the name "Cask for Storage and Transport of Radioactive Material" and comprises several types of containers, constructed in Germany, that are designed for the transport and interim storage of spent fuel elements from nuclear power plants and high-level radioactive waste resulting from the reprocessing of fuel elements in Germany.

Most people are aware of clay as a material for the ceramic industry. It occurs frequently as a sedimentary rock underground in Germany. Claystone mainly consists of a large number of minerals (e.g. montmorillonite, illite and smectite). However, the composition of the mineral is not only relevant for classifying the claystone, but its grain size (< 0.002 mm) and its solidification too. Claystone deposits that are relevant for nuclear disposal (claystone formations) have developed at various periods during the last few million years. The claystone must meet various criteria to be considered as a host rock for disposing of high-level radioactive waste; they are specified in the Disposal Safety Requirements Order and the Site Selection Act.

Compagnie Generale des Matieres Nucleaires, today AREVA NC, French group of companies for nuclear fuel supply and waste management, operates among others the reprocessing plant in La Hague.

Conditioning is the treatment and packaging of radioactive waste suitable for interim storage and/or disposal. The most important sections of conditioning are the solidification of liquid waste and packaging suitable for handling, taking into account the necessary radiation protection for the personnel in the interim storage facilities and repositories who have to handle the waste later on.

Pollution of work spaces, devices, rooms, water, air etc. due to radioactive substances. Surface contamination: Pollution of a surface with radioactive substances, comprising non-adhesive, adhesive activity and that having entered via the surface. Surface contamination is specified in terms of activity per unit area, the unit is Becquerel per square centimetre. Surface contamination, non-adhesive: Pollution of a surface with radioactive substances, where a further distribution of the radioactive substances cannot be excluded.

Areas where persons can receive an effective dose per calendar year above 6 mSv or organ doses above 15 mSv for the eye lens or 150 mSv for the skin, hands, forearms, feet, and ankles.

The state of a nuclear reactor in which a self-sustaining chain reaction takes place. Subcriticality is the state in which no chain reaction can be sustained.

The state of a nuclear reactor in which a self-sustaining chain reaction takes place. Subcriticality is the state in which no chain reaction can be sustained.

The state of a nuclear reactor where a self-perpetuating chain reaction is taking place. Undercriticality is the state where no chain reaction can be sustained.

Crystalline rock is used as a building material, among other things. It is often found in the bedrock in Germany and consists of a variety of minerals. Crystalline rock is also described as metamorphic or magmatic rock. Magmatic rock is formed when magma cools and crystallises. Metamorphic rock is formed from older rock by a process of transformation under high pressure or in high temperatures.

The crystalline rock must meet various criteria to be considered as a host rock for disposing of high-level radioactive waste; they are specified in the Disposal Safety Requirements Order or the Site Selection Act.