Catalyzes the conversion of monodehydroascorbate to ascorbate, oxidizing NADH in the process. H(+) + 2 monodehydro-L-ascorbate radical + NADH = 2 L-ascorbate + NAD(+) Optimum pH is 7.5-9.5. Expressed at relatively low levels in all tissues examined. Belongs to the FAD-dependent oxidoreductase family.