  After a successful core-collapse supernova, a neutrino-driven wind develops
where it is possible to synthesize lighter heavy elements ($30<Z<45$). In the
early galaxy, the origin of these elements is associated to the r-process and
to an additional process. Here we assume the additional process corresponds to
the weak r-process or alpha-process taking place in neutrino-driven winds.
Based on a trajectory obtained from hydrodynamical simulations we study the
astrophysics and nuclear physics uncertainties with our main focus on the
$(\alpha,n)$ reactions. These are critical to redistribute the matter and allow
to further move it from light to heavy elements after nuclear statistical
equilibrium freezes out. In this first sensitivity study, we vary all
$(\alpha,n)$ reactions by given constant factors which are justified based on
the uncertainties of the statistical model and its nuclear physics input,
mainly alpha optical potentials under the conditions found in the wind. Our
results show that $(\alpha,n)$ reactions are indeed very important to predict
abundances. Therefore, further studies will follow to identify individual
critical reactions. Since the nucleosynthesis path is close to stability, these
reactions can be measured in the near future. This will uniquely allow to
reduce the nuclear physics uncertainties and thus to use observations to
constrain and understand the astrophysical conditions in the wind.
