Postprint version. Published in Astroparticle Physics, Volume 35, Issue 12, July 1, 2012, pages 839-849.
The definitive version is available at https://doi.org/10.1016/j.astropartphys.2012.02.008.
The CUORE Crystal Validation Runs (CCVRs) have been carried out since the end of 2008 at the Gran Sasso National Laboratories, in order to test the performance and the radiopurity of the TeO2 crystals produced at SICCAS (Shanghai Institute of Ceramics, Chinese Academy of Sciences) for the CUORE experiment. In this work the results of the first 5 validation runs are presented. Results have been obtained for bulk contaminations and surface contaminations from several nuclides. An extrapolation to the CUORE background has been performed.