Safety of the facility
Radioactive waste contain hazardous substances that can irradiate anyone located nearby and, if released, contaminate human populations and the environment. The basic aim of Cigeo is to protect human and the environment from this waste over very long periods of time. Cigeo is designed to remain safe during its construction and operation and after closure. The approach is based on a large number of measures designed to avoid uncontrolled dispersion of radioactivity, ensuring that the quantity of radioactivity to which workers and local populations are exposed remains very low and does not pose a health risk. After closure of the repository, safety must be ensured passively and require no human intervention. Monitoring will nevertheless continue after closure, and actions will be implemented to create a perpetual reminder of the facility's existence.
Operational safety of Cigeo
When designing the repository, Andra identified all potential sources of hazards whose consequences could compromise the repository's safety functions and affect people and the environment. The defence-in-depth concept applies to Cigeo in the same way as to other nuclear facilities:
- For each identified hazard, Andra provides for design and operating measures to eliminate these hazards if possible, prevent them and reduce the probability of their occurrence.
- Inspection and monitoring action will be taken to detect any malfunction and return the facility to normal operating conditions.
- In spite of these measures, Andra assumes that potential accident situations could occur and provides for additional measures to control the situation and minimise its impact.
The safety of Cigeo after its closure must not depend on surveillance, for surveillance cannot be maintained with certainty beyond a period of a few hundred years. The long-term safety of Cigeo must therefore be ensured passively, i.e. without requiring any human intervention.
The Dossier 2005 prepared by Andra and evaluated by the ASN and the National Assessment Board showed that the impact of the repository after its closure would be slightly lower than that of natural radioactivity. This principle depends notably on the choice of geological medium and the repository design.
Safety rules set by the ASN
Cigeo will have to comply with the ASN's safety rules, both during its operation and after its closure. The measures taken and dimensioning criteria used to design Cigeo's facilities will be reviewed by the ASN before a licence to build it is issued. This licence is contingent on Andra's ability to demonstrate that it has all the risks under control.