  The chemical composition of the ultra-high-energy (UHE) cosmic rays serves as
an important clue for their origin. Recent measurements of the elongation rates
by the Pierre Auger Observatory hint at the possible presence of heavy or
intermediate mass nuclei in the UHE cosmic rays. Gamma-ray bursts (GRBs) and
hypernovae have been suggested as possible sources of the UHE cosmic rays. Here
we derive the constraints on the physical conditions under which UHE heavy
nuclei, if they are accelerated in these sources, can survive in their intense
photon fields. We find that in the GRB external shock and in the hypernova
scenarios, UHE nuclei can easily survive photo-disintegration. In the GRB
internal shock scenario, UHE nuclei can also survive, provided the dissipation
radius and/or the bulk Lorentz factor of the relativistic outflow are
relatively large, or if the low-energy self-absorption break in the photon
spectrum of the prompt emission occurs above several KeV. In internal shocks
and in the other scenarios, intermediate-mass UHE nuclei have a higher
probability of survival against photo-disintegration than UHE heavy nuclei such
as Fe.
