A one-dimensional electrokinetic model has been developed to simulate the transport of cesium and strontium ions through a concrete disk. The model predicts the variation of the ion concentrations in the anolyte and catholyte. The sensitivity of the ion concentration in the anolyte and catholyte to the overall mass transfer coefficient and ion diffusion coefficient is investigated. Using reasonable values for the diffusion coefficient and the overall mass transfer coefficient, good agreement is obtained between the experimental and computed variations in the anolyte concentrations. The results for the catholyte concentrations are in qualitative agreement with the experimental observations. The variation in the pH in the anolyte and catholyte, and the voltage drop across the disk, are predicted by the model. (C) 1997 Elsevier Science B.V.