2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/9632We have modified the standard code for primordial nucleosynthesis to include the effect of finite nucleon mass on the weak-interaction rates as calculated by Seckel \cite{seckel}. We find a small, systematic increase in the $^4$He yield, $ΔY \simeq 0.0057\,Y$, which is insensitive to the value of the baryon-to-photon ratio $η$ and slightly larger than Seckel's estimate. The fractional changes in the abundances of D, $^3$He, and $^7$Li range from 0.08\% to 3\% for $10^{-11}\le η\le 10^{-8}$.10 pages, 2 Figs available on request, FERMILAB-Pub-93/181-AAstrophysicsHigh Energy Physics - Phenomenologytext