  The 18F(p,a)15O reaction is recognized as one of the most important reaction
for nova gamma-ray astronomy as it governs the early <= 511 keV emission.
However, its rate remains largely uncertain at nova temperatures due to unknown
low-energy resonance strengths. We report here on our last results concerning
the study of the D(18F,pa)15N reaction, as well as on the determination of the
18F(p,a)15O reaction rate using the R-matrix theory. Remaining uncertainties
are discussed.
