Abstract: This system is able to intervene on the inner pane (2) of a "high activity` cell whilst ensuring the biological and radiological protection of operators.It includes means able to extract the shielding window (5) of the orifice and a protective screen (7) mounted moving with respect to a fixed structure (20, 21) and intended to block up the orifice of the cell when the shielding window (5) is extracted. It includes handling means, such as pliers (32), for intervening on the pane (2) with equipment able to be passed through the shield (7) by means of a spring barrel (36).Application for cleaning of the sealing pane (2) on "high activity" screened cells.