  The temperature of hot accretion flows around black holes is sufficiently
high for the ignition of nuclear reactions. This is potentially an important
nucleosynthesis mechanism in the universe. As the first step in studying this
problem, we need to measure physical quantities such as density and temperature
of the accretion flow. In usual studies of the hot accretion flow, viscous
dissipation is considered to be the only heating mechanism, while the heating
caused by nuclear reactions is not considered. In this paper, we investigate
whether the energy generation rate of nuclear reaction is important compared to
the viscous heating. Our calculation indicates that the former is at most one
percent of the latter and thus is not important. The dynamics of accretion flow
can be therefore calculated in the usual way, without the need to consider
heating due to nuclear reactions.
