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

Published on 10/06/2024 at 16:10

Information notice

On January 16, 2023, Andra submitted a license application to build a deep geological repository named Cigéo to the French Ministry for Energy Transition. In March 2023, this Ministry requested the ASN to lead the technical review of Andra’s application. In June 2023, the ASN deemed the application admissible and referred the technical part of the application to the Institute for Radiological Protection and Nuclear Safety (IRSN) for a comprehensive review. The ASN also planned to call on its Advisory Committee on Waste (GPD) as part of this review.

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.

The industrial pilot phase

The industrial pilot phase was introduced in Article L. 542-10-1 of the French Environment Code, following the public debate on the Cigéo project held in 2013. This initial phase of the development of the Cigéo project aims to progressively test Cigéo's technical and operational functions under real conditions. It is intended to reinforce the reversible features of the facility and consolidate the demonstration of its safety, including through an in-situ testing program.

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.

  1. 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;

 

Schémas de face et en coupe d’une alvéole de déchets HA

Figure 1: Front and sectional diagrams of an HL waste cell

  • 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.

The hydraulic-gas transient

The hydraulic-gas transient is a period during which, over at least several tens of thousands of years, the plant's structures will become saturated with water. During this period, hydrogen will be released, mainly due to corrosion of the facility's metal components. Thus, the seals developed by Andra, in addition to their main function of preventing the circulation of water in the repository, must also allow the gas to flow, in order to avoid a rise in pressure in the facility.

  1. 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.

Adaptability

Adaptability is the ability of the Cigéo facility to evolve in order to accommodate waste related to changes in energy policy or uncertainties about waste management methods, as presented in the reserve inventory. This involves developing design studies to ensure the technical feasibility of disposing of this waste, and safety studies to check that these design changes, if implemented, do not compromise the safety of the facility.

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.

Find out more (French version)

Date of last update : 12/06/2024