ANDRA wishes to improve its numerical simulation capacities in relation to the following subject: transfer of two-phase and multi-constituent tritium in the surface storage structures of the Aube Center. The objective of this framework agreement is the development of efficient modeling of these phenomena and to identify a field of operation. The code recommended by ANDRA for this type of modeling is TOUGH2-MP. The candidates invited to tender must imperatively consider this code to constitute their basic offer. Other codes may be offered, but only as a variant accompanying their basic offer. The framework agreement put in place will allow ANDRA to enter into all subsequent contracts that ANDRA deems necessary and in relation to the subject and objectives of the framework agreement, within the limit of the allocated budget.

Main location: premises of the holder / Total duration: 24 months.

ANDRA wishes to improve its numerical simulation capacities in relation to the following subject: transfer of two-phase and multi-constituent tritium in the surface storage structures of the Aube Center. The objective of this framework agreement is to arrive at an efficient modeling of these phenomena and to identify a field of operation. The code recommended by ANDRA for this type of modeling is Tough2-MP. The candidates invited to tender must imperatively consider this code to constitute their basic offer. Other codes may be offered, but only as a variant accompanying their basic offer. Subsequent contracts that may be awarded under this framework agreement may include the following tasks:

1) analysis of data from three pressure and temperature sensors (located outside and inside the structures) and validation of the Tough2-MP EOS allowing transfer simulations to be carried out. The developments necessary to adapt the calculation code will be implemented, tested and validated;

2) physical and digital conceptualization of simulations (representation of atmospheric boundary conditions, aquifer, engineered components such as RSGE, resin for waterproofing structures, etc.);

3) carrying out simulations for the two categories of structures in the Center de l'Aube;

4) sensitivity analysis of the model to simulation parameters and assumptions, estimation of the operating range, for example:

- task 4.1: sensitivity to the water state of the components of the structures,

- task 4.2: sensitivity to the position of the source term in the work,

- task 4.3: sensitivity to the parameters assigned to the sealing resin,

- task 4.4: sensitivity to thermal and barometric variations (intraday variations).

The framework agreement put in place will allow ANDRA to enter into all subsequent contracts that ANDRA deems related to the subject and objectives of the framework agreement, provided that an agreement is reached with the holder. and within the limit of the allocated budget.

Place: the required services will be performed at the holder's premises. Follow-up meetings, in which the incumbent must participate, will be organized on a regular basis. The duration of the framework agreement is set at 24 months maximum, knowing that the completion of the main subsequent contracts should be contained within the limit of the first 18 months.