Abstract: An improved filling for emergency cooling towers of nuclear power plants, of the type made of a grid of tubular rods in plastic material, such as PVC, has an anchoring system by which it can withstand atmospheric depressions or overpressures up to 700 Kg/m.sup.2, as required. The tubes of plastics, arranged in pairs of staggered, spaced parallel rows, are inserted to pass through two opposite walls of at least one elongated square section, perpendicular thereto and preferably of the same plastic material. The distance between the two rows is slightly less than the diameter of an auxiliary stiffering tube which is inserted between said two section walls and the two rows of tubes, transversely thereto. For each layer of filling, a particular system of fixing said square sections to the concrete structure of the tower is described to meet also the aseismatic requirements.