First meeting of ASN’s Advisory Committee on Waste on the review of Andra’s license application to build a deep geological repository (Cigéo)

The ASN structured the review of the application submitted by Andra into three thematic groups: the basic data used for the Cigéo safety assessment, the operational safety of surface and underground facilities and the post-closure safety. Cross-cutting themes are also being reviewed, such as the adaptability of Cigéo and the industrial pilot phase.

ASN’s Advisory Committee on Waste (GPD), supported by members of the Advisory Committee on laboratories and plants (GPU) and the Advisory Committee on radiation protection (GPRP), reviewed the first thematic group on April 24 and 25, 2024.

The scoping the GPD review, as well as that of the IRSN, were subject to previous consultation with the public and other stakeholders.

At the end of this first meeting, the GPD reached the following conclusions:

1.    Knowledge of the Meuse/Haute-Marne site

The GPD considered the geotechnical and hydrogeological analyses conducted by Andra to be generally satisfactory. It noted Andra's commitment to further characterise the surface limestone in the area where the surface facilities will be located.

The GPD recommended that Andra define a research programme to address the remaining uncertainties about the structure of the host rock in the areas where the high-level waste disposal areas will be located. This programme should be completed before the excavation of the connecting galleries serving these disposal areas.

Finally, the GPD recommended Andra's approach to defining meteorological hazards to be supplemented to better take into account the impact of climate change on the Cigéo facilities.

2.   Properties and development of storage components

Generally speaking, the GPD noted that the definition of the planned testing program during the industrial pilot phase, which aims to enhance the knowledge of the performances of clay, cement and metallic components in the safety assessment, is at a preliminary stage.

The GPD specifically recommended:

• for the continuation of the review, that Andra specify its research program aimed at defining the formulation of the annular fill material (the material filling the space between the host rock and the steel liner of the high-level waste cells, shown in blue in Figure 1) of the high-level waste cells and provide the initial results obtained;

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• that a digging method minimizing rock damage, particularly at the future seals points, be defined before the excavation of access shafts.

The GPD also emphasised Andra's commitment to strengthening its demonstration, during the industrial pilot phase, of the non-fracturing of the rock due to the pressure associated with the release of hydrogen during the hydraulic-gas transition, as well as the performance achieved in terms of sealing tightness.

3.   Inventories of waste packages

The GPD considered that the waste inventories defined by Andra at the stage of the Cigéo license application are sufficient to pursue its development and examine its flexibility and adaptability. However, it noted that uncertainties related to the volume of primary packages whose packaging has not yet been determined remain.

The GPD also noted Andra's commitment to consolidate the inventory of chemical substances.

At this stage of the review, the GPD has not identified any factor challenging the adaptability of Cigéo in light of the reserve inventory as currently defined and the short-term developments planned in France (impact of extending the operation of reactors from 50 to 60 years and construction of six new EPR2 reactors).

However, the GPD stressed that the adaptation of the facility to other developments than those currently included in the reserve inventory, such as extending nuclear reactors operation beyond 60 years, constructing additional EPR2s, or a fleet of SMR and/or FNR, would have to be subsequently assessed based on future adaptability studies, once the associated scenarios are defined.

In conclusion to this first review meeting, the GPD concluded that Andra has acquired a solid knowledge base about the Meuse/Haute-Marne site, the components of the disposal system and the waste packages inventories. This knowledge is sufficient to assess the safety of Cigéo at the stage of the license application.

However, the GPD emphasized that the definition of the industrial pilot phase, both in terms of objectives and limitations, should be formalized by Andra during the review process in order to assess its adequacy.

The recommendations and positions of the GPD that will be formulated during the three review meetings of Cigéo license application will contribute to the ASN's opinion on this application in accordance with the provisions of Article L. 542-10-1. This opinion will be issued at the end of the entire technical review.

When appropriate, topics requiring additional information as part of the review process will be the subject to specific request for additional information by the ASN. Following the first meeting of the GPD on April 24 and 25, 2024, the ASN sent a follow-up letter to Andra requesting additional information regarding the topics of steel corrosion and the industrial pilot phase.

For further informations (in french):

See also:

Projet de centre de stockage en couche geologique profonde Cigéo

Après plusieurs décennies de recherche et développement, l’Andra a déposé, en janvier 2023, un dossier de demande d’autorisation de création pour une installation, nommée Cigéo, destinée au stockage des déchets de haute activité et moyenne activité à vie longue.