[en] The effects of alpha irradiation in the rare-earth silicate, Ca₂Nd₈(SiO₄)₆O₂, was investigated by x-ray diffraction, x-ray absorption near-edge spectroscopy (XANES), and extended x-ray fine structure (EXAFS) techniques. Irradiation with alpha particles emitted isotropically from a ²³⁸PuO₂ source to a cumulative dose of 2.25 times 10²¹ alphas/m² (0.36 dpa) produced measurable anisotropic lattice expansions, with no tendency toward the amorphization that was previously reported due to self-radiation damage in Cm-doped samples at similar displacement-damage (0.25 dpa) levels. The unit-cell volume expanded exponentially with dose to a value corresponding to 2.5% expansion at saturation. The fluorescence XANES data of irradiated surfaces indicate a rearrangement of the near-neighbor ions about Nd. The EXAFS results indicate an irradiation-induced increase in structural disorder that becomes readily apparent at distances of several coordination spheres away from Nd. 14 refs., 5 figs