Hidden fracture patterns could speed toxic contamination deeper into rock
Scientists discovered that subtle variations inside underground fractures can dramatically accelerate how contaminants move through rock—arriving 3-5 times faster than current safety models predict. The finding matters for nuclear waste storage, water utilities, and mining companies that rely on fractured rock barriers to contain hazardous materials.
Originaltitel: Enhanced transport with early arrivals and reduced attenuation in ensemble realisations of discrete fracture networks with internal fracture heterogeneity: [Transport amélioré avec percées précoces et atténuation réduite dans les réalisations d’ensemble de fractures discrètes en réseau avec hétérogénéité interne des fractures] [Transporte optimizado mediante tiempos de arribos tempranos y atenuación reducida en conjuntos de redes de fracturas discretas con heterogeneidad interna] [存在内部裂隙非均质性的离散裂隙网络集合实现中的传输增强、提前到达与衰减减弱] [Transporte aprimorado com chegadas precoces e redução da atenuação em realizações de conjunto de redes de fratura discretas com heterogeneidade interna de fratura]
<p>Multiple realisations of a 100 × 100 × 100 m<sup>3</sup> rock volume with stochastically generated fractures based on statistics collected from the Forsmark site in Sweden are studied using different texture representations of internal fracture heterogeneity. Solute transport by particle tracking is investigated with reference to a smooth fracture plane representation, corresponding to an assumption of effectively homogenous fractures. A Lagrangian transport formulation is adopted where the two key transport variables, travel time <em>τ</em> and transport resistance <em>β</em>, are evaluated. Results indicate that fracture heterogeneity textures with strong internal correlation lead to an increased number of particles with short arrival times and weak transport resistance. This combined effect can lead to a reduction in contaminant attenuation for solute transport in discrete fracture networks when compared to homogeneous fracture property assumptions. A need for the quantification of internal fracture heterogeneity of natural fractures is thereby identified in order to further evaluate implications for real-world applications.</p>