A urea reactor tray having a base plate; and a number or quantity of hollow cup-shaped members, which project vertically from the base plate along respective substantially parallel axes perpendicular to the base plate, and have respective substantially concave inner cavities communicating with respective openings formed in the base plate; the tray having a number or quantity of first cup-shaped members, each of which extends axially between an open top end having the opening, and a closed bottom end, and has a lateral wall with through holes substantially crosswise to the axis, and a bottom wall which closes the closed bottom end and has no holes.