System for checking defects in an annular wall made of non-electrically conductive material and wherein a facilitated opening line is formed by means of a non-through notch along a circumference of said annular wall, the system comprising: - a plurality of first tools (6, 8) and a second tool (10; 20), made of electrically conductive material and configured to assume a work position wherein at least one of said first tools and the second tool are configured to be arranged inside and, respectively, outside the annular wall, at a first reciprocal distance so as the annular wall to be checked is interposed between said tools (6, 8; 10) said first tools each having an axis and said second tool (10; 20) being arranged to operate in the zone of said non-through notch; - control means for generating a potential difference between said tools in work position and for detecting the generation of an electric discharge between the tools determined by a defect of the annular wall, such as, for example, an excessive reduction or a lack of thickness; - movement means for taking said tools to the work position via a relative movement of the first tools with respect to the second tool, wherein said relative movement has at least one motion component in a direction that is transverse to said axis; the first tools each comprising a spindle (6, 8) that is rotatable around said axis and is insertible into the annular wall to drag the annular wall, the second tool comprising an electrode configured to face said spindles and situated outside the annular wall, the movement means being configured to insert the spindles (6, 8) in the annular wall and to move the spindles so as to rotate the annular wall facing said electrode such that the integrity check is conducted on a circumference of the annular wall, said movement means comprising a carousel that carries said spindles (6, 8) along a circular path; characterized in that said electrode (10; 20) comprises a circular sector coaxial with a rotation axis of said carousel and in that said electrode (10; 20) has a tip end intended to be in contact with or near the annular wall. - a plurality of first tools (6, 8) and a second tool (10; 20), made of electrically conductive material and configured to assume a work position wherein at least one of said first tools and the second tool are configured to be arranged inside and, respectively, outside the annular wall, at a first reciprocal distance so as the annular wall to be checked is interposed between said tools (6, 8; 10) said first tools each having an axis and said second tool (10; 20) being arranged to operate in the zone of said non-through notch; - control means for generating a potential difference between said tools in work position and for detecting the generation of an electric discharge between the tools determined by a defect of the annular wall, such as, for example, an excessive reduction or a lack of thickness; - movement means for taking said tools to the work position via a relative movement of the first tools with respect to the second tool, wherein said relative movement has at least one motion component in a direction that is transverse to said axis; the first tools each comprising a spindle (6, 8) that is rotatable around said axis and is insertible into the annular wall to drag the annular wall, the second tool comprising an electrode configured to face said spindles and situated outside the annular wall, the movement means being configured to insert the spindles (6, 8) in the annular wall and to move the spindles so as to rotate the annular wall facing said electrode such that the integrity check is conducted on a circumference of the annular wall, said movement means comprising a carousel that carries said spindles (6, 8) along a circular path;