Safety analyses for the Konrad mine
- Comprehensive safety considerations have been made for the Konrad repository in the scope of the plan-approval procedure.
- They determine requirements for the technical systems and components, operational procedures and the waste packages to be disposed of, and they are binding in order to guarantee safe operation and to minimise possible effects.
- Before the Konrad mine will be taken into operation as a repository for low-level and intermediate-level radioactive wastes, the safety standard of the facility will be verified once again according to the state of the art of science and technology.
The protection of man and environment is of highest priority. For this reason, comprehensive safety considerations have been made in the scope of the plan-approval procedure for the Konrad repository.
These safety analyses determine requirements to the technical systems and components, the operating procedures and the waste packages to be disposed of. They are binding in order to guarantee safe operation and to minimise possible consequences. Furthermore, it was investigated in long-term safety analyses how the repository could develop after it has been sealed and possible consequences were derived.
Examination of the analyses by experts
By means of model calculations, the most different operating conditions and possible consequences were run through and evaluated. All safety analyses were examined by experts on behalf of the Lower Saxon Environment Ministry. Compliance with specifications is controlled by the Repository Surveillance unit, the Lower Saxon Environment Ministry and the responsible state mining authority.
Analysis of possible incidents
In addition to the safety analysis of normal operation, accidents were analysed. That means, events in the planned operating procedures which might lead to a release of radioactive substances into the environment were identified and evaluated. Technical or human failure and rock-mechanical causes can be the reason for such accidents. In that context, the Lower Saxon Environment Ministry stated that the Konrad repository was designed in a manner that is balanced from the safety point of view. Precaution required according to the state of the art of science and technology has been taken against damage.
Long-term safety analysis
The objective of disposal is to safely and permanently enclose the radioactive waste in deep geological formations. To furnish evidence that this objective will be achieved, the long-term development of the Konrad repository was forecast with the help of geo-scientific methods. In model calculations, the dispersion of radionuclides from the repository up into the groundwater near the surface was examined and evaluated.
Contamination of groundwater in 300,000 years at the earliest
The model calculations show that it would take radionuclides at least 300,000 years to get into the groundwater near the surface. The transport of long-lived radionuclides with a higher retention level in the geosphere takes a lot longer. For these, the model calculations show relevant concentrations only after several million years.
Exposure far below limit values
The calculated maximum radionuclide concentrations that may occur in the groundwater near the surface have been taken as a basis for the determination of the radiation exposure in the biosphere. For an infant, the effective dose calculated according to the provisions set out in the Radiation Protection Ordinance is max. 0.26 millisieverts per year; for an adult it is max. 0.06 millisieverts per year. It is thus lower than the value of 0.3 millisieverts per year, this value having been applied for evaluation by the licensing authority.
No risk for man and environment
Altogether, the possible impact on the near-surface groundwater through the release of radionuclides and other pollutants from the repository is so low that no adverse effects to man and environment need to be feared.
New safety check prior to taking the repository into operation
Before the Konrad mine will be taken into operation as a repository for low-level and intermediate-level radioactive wastes, the safety standard of the facility will, however, be verified once again according to the state of the art of science and technology.
This is congruent with the identity and values of the Federal Office for Radiation Protection (BfS), for which safety comes first regarding the construction of the Konrad repository. Furthermore, it is legally required to check on a regular basis whether the repository meets all safety requirements in the way it has been designed and to see the further development of the state of the art of science and technology. Preparations for the safety check in the BfS started already in 2014 and will probably continue for several years.
State of 2015.08.12