Isothermal decomposition of sodium bromate at temperatures: 613, 633 and 653 K occurs through (i) initial gas evolution, (ii) short induction period, (iii) acceleratory and (iv) decay stages. Irradiation as well as doping shorten the induction period; I, facilitate the rate of reaction in the last two periods, without affecting the initial puff of gas. The combined effect of these treatments eliminate the induction period and increase the extent of decomposition remarkably. The data are best fitted to Prout-Tompkins mechanism exploring that nucleation occurs in a chain-branching manner, the nature of which remains unaltered by these treatments.