Abstract The vitrification of simulated HLW from the reprocessing of PHWR fuel was studied on a laboratory scale by the alternative method of powder glass sintering. The HLW was added in a proportion of 10 wt% to aluminoborosilicate glass powder. The powder mixture was treated using the procedure of cold pressing and subsequent sintering at about 1000 K. The microstructures of the sintered samples were analyzed by optical microscopy and SEM. Leaching tests were done in deionized water using the MCC-1 method (Ref. , D.M. Strachan, R.P. Turcotte and B.O. Barnes, Nucl. Technol. 56 (1982) 306) at 343 K between 7 and 300 days. The leaching rates were of the order of 10 −2 g m −2 d −1. Devitrification studies were conducted by heat-treating the samples at 950, 1000, 1050 and 1100 K for 3, 30, 300 and 3000 h. TIT type curves were obtained, showing that the maximum devitrification rate occurs at 1000 K. The samples present 53% of crystallinity after 3000 h at this temperature. Leaching rate measurements on devitrified samples did not show a significant change of this property in relation with the values for the as-sintered samples.