Objective
The specific aim of this study is to evaluate the consequences of gas generation from a radioactive waste repository. The evaluation will be carried out in terms of gas migration in the backfill and the host rock and in terms of mechanical effects.
The phenomenology of the physical process involved in gas transport will be reviewed; then some selected numerical codes taking into account two phase flow will be presented. The gas pressure build up will be simulated for different designs of repositories, different host rock characteristics using numerical two phase flow models such as reservoir simulators used in the oil industry. A sensitivity study will then be performed. The mechanical modelling using new theoretical developments for fracture initiation and propagation through the bifurcation theories will be carried out with the cooperation of the French Institute of Petroleum (IFP): the scientific adviser is Prof. Dragon from ENSMA in Poitiers (France).
The specific aim of this study is to evaluate the consequence of gas generation from a radioactive waste repository. The evaluation will be carried out in terms of gas migration in the backfill and the host rock and in terms of mechanical effects.
The gas produced from corrosion and radiolysis is mainly hydrogen. The gas flow rate is a dimensioning parameter for the ensuing pressure build up. The information availiable in the literature related to gas generation has been reviewed. It is concluded that the volume liberated may be 2 or 3 orders of magnitude greater than the repository volume. The first phenomenon expected is the dissolution of the gas into the surrounding water, the quantity dissolved depends on the solubility, pressure and temperature. The molecular diffusion is a possible phenomenon for gas migration but the quantity of gas evacuated by diffusion is expected to be low beacuase of the low diffusion coefficients. A simple 3-dimensional model has been run in order to test the physical validity of the data set and get some order of magnitude of the pressure response for hypothetical gas flow rates. The geometry consists in a clay host rock 200 m thick, whose top is at 600 m depth, separated by 2 permeable sandstone layers 100 m thick. The rock properties are assumed to be isotropic and homogeneous. The preliminary results indicate that the order of magnitude of the pressure build up is 6 MPa, for a constant gas flow rate over a period of time of 5000 years. The horizontal distance concerned by the gas migration is dependent on the clay effective (or kinematic) porosity: the horizontal distance is 100 meters for a kinematic porosity of 15% and 150 m for kinematic porosity of 3%. The vertical migration is of the same order of magnitude.
Those results are indicative and based on conservative and maybe non realistic assumptions: simplified geometry, no backfill materials, nonrepresentative gas flow rates, isotropic and homogeneous conditions.
Work programme:
1. Phenomenology review: inventory of two phase flow phenomenology applied to gas migration from a radioactive waste repository.
2. Laboratory experiments: limited number of investigations (threshold pressure, capillary pressure, relative permeability, etc.) on some representative host rock core samples.
3. Two phase flow modelling: suitability of existing reservoir codes, simulation of gas pressure build up (isothermal flow, and in thermal conditions), in porous and fissured medium.
4. Mechanical developments and modelling: theoretical works for the elaboration of a new criteria for fracture initiation and propagation.
5. Conclusions.
Fields of science (EuroSciVoc)
CORDIS classifies projects with EuroSciVoc, a multilingual taxonomy of fields of science, through a semi-automatic process based on NLP techniques. See: The European Science Vocabulary.
CORDIS classifies projects with EuroSciVoc, a multilingual taxonomy of fields of science, through a semi-automatic process based on NLP techniques. See: The European Science Vocabulary.
- engineering and technology other engineering and technologies nuclear engineering nuclear waste management
- engineering and technology environmental engineering energy and fuels fossil energy petroleum
- natural sciences mathematics pure mathematics geometry
- natural sciences chemical sciences nuclear chemistry radiation chemistry
You need to log in or register to use this function
Programme(s)
Multi-annual funding programmes that define the EU’s priorities for research and innovation.
Multi-annual funding programmes that define the EU’s priorities for research and innovation.
Topic(s)
Calls for proposals are divided into topics. A topic defines a specific subject or area for which applicants can submit proposals. The description of a topic comprises its specific scope and the expected impact of the funded project.
Calls for proposals are divided into topics. A topic defines a specific subject or area for which applicants can submit proposals. The description of a topic comprises its specific scope and the expected impact of the funded project.
Call for proposal
Procedure for inviting applicants to submit project proposals, with the aim of receiving EU funding.
Data not available
Procedure for inviting applicants to submit project proposals, with the aim of receiving EU funding.
Funding Scheme
Funding scheme (or “Type of Action”) inside a programme with common features. It specifies: the scope of what is funded; the reimbursement rate; specific evaluation criteria to qualify for funding; and the use of simplified forms of costs like lump sums.
Funding scheme (or “Type of Action”) inside a programme with common features. It specifies: the scope of what is funded; the reimbursement rate; specific evaluation criteria to qualify for funding; and the use of simplified forms of costs like lump sums.
Coordinator
92563 RUEIL MALMAISON
France
The total costs incurred by this organisation to participate in the project, including direct and indirect costs. This amount is a subset of the overall project budget.