A strainer wall (1) to screen off a suction space (3) and a suction duct (5) connected to it in an emergency cooling system of a nuclear power plant includes at least one strainer wall element (2) which has an inlet side (12) and an outflow side (13), wherein the inlet side is essentially oriented perpendicular. The strainer wall element (2) is built up from a plurality of modular cassette units (11), which respectively contain a plurality of screen elements (17.1' 17.n.sup.m) open towards the inlet side (12) and connected to the outflow side (13).