Real time solutions of Thermo-Hydro Mechanical problems with application to the design of Engineered Barriers via Reduced Order Methods
Authors: Moaven Arash , Massart Thierry J. , Zlotnik Sergio 
Published: March 2020

&lt;div&gt;&lt;strong&gt;Keywords:&lt;/strong&gt; Thermo Hydro-Mechanical (THM), Model Order Reduction (MOR), Parametric solutions, Real time simulations.&lt;/div&gt;&lt;div&gt;&amp;#160;&lt;/div&gt;&lt;div&gt;Radioactive waste is a by-product of nuclear power generation. It is hazardous to all forms of life and the&amp;#160;environment. Its radioactive activity naturally decays over time, so waste has to be isolated and confined&amp;#160;in&amp;#160;appropriate disposal facilities for a sufficient period until it no longer poses a threat. Deep geological&amp;#160;repositories constitute one of the most promising options for isolating this type of waste from human&amp;#160;and&amp;#160;environmental interactions. The analysis and prediction of the behaviour of such systems relies on&amp;#160;coupled&amp;#160;THM models [1]. The coupled nature of the problem is explained as follows [2]: i) a thermal&amp;#160;part including&amp;#160;the heat released by the wastes; ii) the mechanical behavior of the canister holding the&amp;#160;wastes, the isolation&amp;#160;system and the underground host rock; and, iii) the flow of natural water present in&amp;#160;any underground porous&amp;#160;media.&lt;/div&gt;&lt;div&gt;&lt;br&gt;A coupled THM problem depends on space, time, and on material parameters&amp;#160;(for instance, elastic modulus (E), heat conductivity (&amp;#954;) and hydraulic conductivity (K)) and&amp;#160;geometric&amp;#160;parameters (for instance, the distance between canisters). We seek for families of solutions depending on these parameters. We would like to provide a real time numerical simulation of the THM problem for any value of the parameters within a range. Real time here, means a solution provided in a few seconds (instead of several hours). Such a solution can be used within an inversion problem, to obtain an best fitting value of the parameters based on some observations, or even in a control situation, where the prediction of the simulation is used to take some decision in the field.&lt;/div&gt;&lt;div&gt;&amp;#160;&lt;/div&gt;&lt;div&gt;Reduced Order Methods (ROM) &amp;#160;are a family of numerical methods able to provide such a solutions. In this work we will present several parametric problems, and show how ROM &amp;#160;[3] can provide real time solution to (simple) THM problems.&lt;/div&gt;&lt;div&gt;&amp;#160;&lt;/div&gt;&lt;div&gt;
&lt;p&gt;&lt;strong&gt;REFERENCES:&lt;/strong&gt;&lt;/p&gt;
&lt;p&gt;[1] Toprak, E.; Mokni, N.; Olivella, S.; Pintado, X.: Thermo-Hydro-Mechanical Modelling of Buffer.&amp;#160;Synthesis Report. August 2013.&lt;/p&gt;
&lt;p&gt;[2] Selvadurai, A.P.S; Suvorov, A.P.: Thermo-Poroelasticity and Geomechanics.CAMBRIDGE UNIVERSITY&amp;#160;PRESS, 2017.&lt;/p&gt;
&lt;p&gt;[3] Diez, P.; Zlotnik, S.; Garcia-Gonzalez, A.; Huerta, A.: Encapsulated PGD algebraic toolbox operating&amp;#160;with high-dimensional data. Accepted In Archives of Computational Methods in Engineering,&amp;#160;2019.&lt;/p&gt;
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