FE modelling of concrete biological shield exposed to neutron radiation

This paper presents development of a 3D nonlinear FE model of a concrete biological shield (CBS) in a nuclear power plant using WWER 440/213 nuclear reactor. Such structure is exposed to several nonmechanical effects, primarily the neutron radiation causing the radiation-induces volumetric expansion (RIVE). This causes internal stresses within the structure and years of operation lead to cumulation of this effect, finally developing into cracks. Crack propagation then disrupts the structure’s soundness and may lead to reduced shielding property. RIVE is introduced to the analysis as an isometric eigenstrain, varying along the height, depth and in circumference along the inner surface. The results focus on determining crack initiation and propagation. The primary vertical crack appears after approx. 6 years of operation and reaches width of 0.3 mm after approx. 12 years. After considered lifespan of 60 years, the primary crack reaches width of 4.6 mm.