  We improve Standard Big Bang Nucleosynthesis (SBBN) calculations taking into
account new nuclear physics analyses (Descouvemont et al. 2003). Using a
Monte-Carlo technique, we calculate the abundances of light nuclei versus the
baryon to photon ratio.The results concerning omegab are compared to relevant
astrophysical and cosmological observations. Consistency between WMAP, SBBN
results and D/H data strengthens the deduced baryon density and has interesting
consequences on cosmic chemical evolution. A significant discrepancy between
the calculated Li-7 deduced from WMAP and the Spite plateau is clearly
revealed. To explain this discrepancy three possibilities are invoked :
uncertainties on the Li abundance, surface alteration of Li in the course of
stellar evolution or poor knowledge of the reaction rates related to Be-7
destruction. In particular, the possible role of the up to now neglected
Be-7(d,p)2He-4 and Be-7(d,alpha)Li5 reactions is considered. The impressive
advances in CMB observations provide a strong motivation for more efforts in
experimental nuclear physics and high quality spectroscopy to keep BBN in pace.
