The effect of sealing of the NSC enclosing perimeter on the surface contamination of the external surfaces of the Shelter object roof and assessment of the possibility of their deactivation - L. I. Pavlovskyi; D. V. Horodetskyi; Ye. A. Menshenin; O. O. Odintsov; L. A. Palamar; O. P. Solonenko (Nuclear power and the environment, 2022)