A new simulation technique has been developed for the study of void swelling. Its salient characteristics include the use of fission‐fragment irradiation produced by doping with235U and irradiating in a thermal neutron flux; use of bulk specimens and the yield of continuous,insituswelling data. This technique has several unique advantages and, in conjunction with other conventional methods, it offers the possibility of detailed evaluation of void nucleation and growth theories. Preliminary results for low‐dose void swelling in Ni at 500°C are presented.