Macro-phenomenological approach

If we use the macro-phenomenological approach, we do not include the intrinsic properties, which represent the movement at a molecular-level. In this sense it is a difficult procedure to establish a correct system of governing and constitutive equations. For example, if we consider the experimental results for a micro-inhomogeneous material, we frequently observe differences if the specimen size is changed. The experimental results are only intrinsically true for the size range of that experiment. In this sense, the macro-phenomenological scheme is interpolation-based. 

The high-level radioactive wastes (HLW s) produced at nuclear power plants must be isolated from the population for an extremely long time, i.e., more than 10,000 years. There are plans to construct HLW disposal facilities in deep underground repositories. Thus, the safety of the barrier system must be evaluated for time scales in excess of 10,000 years this is beyond the scope of any conventional scientific experiment-based approach. We need to use an alternative method that is based on a macro-phenomenological approach. 

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