Effect of boron doping in the microwave surface resistance of neutron irradiated melt-textured Y1.6Ba2.3Cu3.3O7−x samples

► We investigate the microwave surface resistance of melt-textured YBCO samples. ► The samples are boron doped and irradiated by thermal neutrons. ► The main aim is to study of the effect of B2O3 addition on the fluxon dynamics. ► The results are discussed taking into account the d-wave nature of HTS. ► We found that the depinning frequency increases on increasing the B2O3 addition.