  We discuss a small-scale experiment, called $\nu$-cleus, for the first
detection of coherent neutrino-nucleus scattering by probing nuclear-recoil
energies down to the 10 eV-regime. The detector consists of low-threshold
CaWO$_4$ and Al$_2$O$_3$ calorimeter arrays with a total mass of about 10 g and
several cryogenic veto detectors operated at millikelvin temperatures.
Realizing a fiducial volume and a multi-element target, the detector enables
active discrimination of $\gamma$, neutron and surface backgrounds. A first
prototype Al$_2$O$_3$ device, operated above ground in a setup without
shielding, has achieved an energy threshold of ${\sim20}$ eV and further
improvements are in reach. A sensitivity study for the detection of coherent
neutrino scattering at nuclear power plants shows a unique discovery potential
(5$\sigma$) within a measuring time of ${\lesssim2}$ weeks. Furthermore, a site
at a thermal research reactor and the use of a radioactive neutrino source are
investigated. With this technology, real-time monitoring of nuclear power
plants is feasible.
