Results are presented from atomistic computer modeling of hydrocalumite (cement AFm-phase) with Cl- and I- anions in the interlayer space as a potential adsorbent of radionuclides Cl-36, I-129, Cs-137. Properties of the crystals themselves and the interaction between aqueous solutions of CsCl and CsI and surfaces of crystalline phases are studied. It is shown the adsorption of Cl- is stronger than that of I- on surfaces of hydrocalumite, which can be explained by the difference in ionic radii of hydrated anions.