  Simulating complex astrophysical reacting flows is computationally expensive
-- reactions are stiff and typically require implicit integration methods. The
reaction update is often the most expensive part of a simulation, which
motivates the exploration of more economical methods. In this research note, we
investigate how the explicit Runge--Kutta--Chebyshev (RKC) method performs
compared to an implicit method when applied to astrophysical reactive flows.
These integrators are applied to simulations of X-ray bursts arising from
unstable thermonuclear burning of accreted fuel on the surface of neutron
stars. We show that the RKC method performs with similar accuracy to our
traditional implicit integrator, but is more computationally efficient when run
on CPUs.
