Measurements available after incident in bore hole

In the process of the post-examinations, radiation protection officers of the Asse-GmbH detected about 10 litres of solution with high caesium activity levels. This was the result of measurements in a bore hole where contaminated debris had been detected in November 2013. The BfS had reported about the incident. The measurements concluded recently. The BfS informed the Asse-2 Monitoring Group about the measurement results on 7 March 2014. The solution and the radioactivity contained therein does not pose a risk to the workers and the environment and does not have any negative effects on the planning of retrieval.

Contaminated solutions must generally be expected in this area of the mine. Correspondingly, several times contaminated solution had been detected at other places. Operations on the 750-m level are therefore generally accompanied by radiation protection officers.

The point where the solution has been found is located near emplacement chamber 11. An activity of about 490 thousand becquerel per metre was measured. The contamination of the solution is thus clearly above the legal exemption limit. The BfS holds a licence for the handling of contaminated solutions. According to the licence, the exemption limit may be exceeded by a hundredfold. In this case, the value exceeded the 38-fold of the exemption limit. For security reasons, the bore hole has been sealed with Sorel concrete.

Measured was radioactive caesium-137. The radiation emitted by caesium-137 cannot penetrate the uppermost layers of the human skin. It is harmless as long as the substance does not get directly on the skin or into the body, for example via food. Furthermore there is no direct access to the area in front of emplacement chamber 11. It is a former gallery that was sealed following emplacement operations. From that gallery, no radioactivity can get into the environment.