  We propose an experimental setup to measure the work performed in a
normal-metal/insulator/superconducting (NIS) junction, subjected to a voltage
change and in contact with a thermal bath. We compute the performed work and
argue that the associated heat release can be measured experimentally. Our
results are based on an equivalence between the dynamics of the NIS junction
and that of an assembly of two-level systems subjected to a circularly
polarised field, for which we can determine the work-characteristic function
exactly. The average work dissipated by the NIS junction, as well as its
fluctuations, are determined. From the work characteristic function, we also
compute the work probability-distribution and show that it does not have a
Gaussian character. Our results allow for a direct experimental test of the
Crooks-Tasaki fluctuation relation.
