In order to model fuse operation during circuit interruption, a detailed ma
ss and energy transport analysis is needed. In this paper, using a novel me
thod, the mass flow of the fuse element material, silver for this example,
is presented. By neutron activation of part of the element, we are able, af
ter interruption, to trace the distribution of the dispersed element materi
al. We show that there is a silver mass coming from the are ignition zone t
o the extremities, mainly in the direction of the anode.