Simulation of a Fukushima - Type Event in Spent Fuel Pools from Cernavoda NPP

To test the strength capability of the concrete Cernavoda NPP (Nuclear Power Plant) ST (Spent Fuel) Pools for long time period (4 weeks) after a loss of cooling accident following an projectbased earthquake with loss of the liners tightness the behaviour of two concrete types was analyzed, namely: C25/30, for the Spent Fuel Pools infrastructure and C18/22.5 for the separating wall. Samples were prepared in compliance with the existing regulations and then were kept in Pools with water for 1 year. Test were performed on: series of samples from both concrete types for mechanical strength and permeability considering the conditions of 25 days treatment in water at 50℃ and 100℃, respectively, and 25 days treatment in dry air at 50℃. Each series of samples contained cement paste samples used the microstructural characterization. After the treatment of the cement samples, determinations of mechanical strength and permeability were performed a relative dynamic modulus of elasticity was calculated. For the cement paste samples the mineralogical composition by XRD and the morphology by electron microscopy were determined. Interpretation of results describing the behaviour of macroscopic properties of concrete, the strength, the permeability and the modulus was performed taking into account the microstructural analysis. The results shown an appropriate behaviour of the Spent Fuel Pools infrastructure concrete and for the separating walls, under the assumptions imposed. Changes evidenced are insignificant, and follow the normal process of concrete evolution. (author).