  The heating of the solar corona is one of the big questions in astrophysics.
Rapid pulses called nanoflares are among the best candidate mechanisms. The
analysis of the time variability of coronal X-ray emission is potentially a
very useful tool to detect impulsive events. We analyze the small-scale
variability of a solar active region in a high cadence Hinode/XRT observation.
The dataset allows us to detect very small deviations of emission fluctuations
from the distribution expected for a constant rate. We discuss the deviations
in the light of the pulsed-heating scenario.
