The effects of irradiation conditions such as neutron flux, β and γ rays, and of heat flux on the corrosion behavior of Zircaloy-2 cladding tubes were studied by using an inreactor corrosion loop simulating BWR conditions. Platinum and hafnium rings were placed in the rigs as β and γ emitters, respectively, to evaluate local radiation effects on cladding corrosion. The tube materials included an early BWR 8 x 8RJ type and a new, more corrosionresistant BWR 9X9-type cladding. Both tubes contained UO₂ and Al₂O₃ pellets and were irradiated under the same conditions in two rigs in the same loop for about 180 days. Nodular corrosion appeared on the 8X8RJ-type tube, while the 9X9-type tube presented only uniform oxide layer. Metallographic and SEM observations revealed that the β and γ emitters enhanced the uniform oxide formation for the 9X9-type tube, while they increased the nodule density for the 8X8RJ type. Computer analyses on neutron flux and β- and γ-ray intensities were conducted for the 8X8RJ-type and 9X9-type test rods. Those results were utilized to comprehensively discuss and to understand the in-pile corrosion behavior.