METHOD AND APPARATUS FOR DETECTING AND REPOSITIONING AN ANNULUS SPACER IN NUCLEAR REACTORS

摘要

The invention relates to a method and apparatus for detecting and positioning an annulus spacer used to maintain the position of a pressure tube within a calandria tube of a nuclear reactor. The claimed method comprises the steps of: vibrationally insulating a section of the pressure tube, vibrating the wall of said pressure tube within said insulated section, detecting the vibration of the wall at a minimum of two axial positions within said insulated section and detecting a lowering of the vibration level of the wall in one or more of the said axial positions in comparison with the remaining axial positions. The claimed apparatus has an inner cylindrical surface contacting an inner pressure tube (200) and an outer cylindrical surface contacting an outer calandria tube (400) and comprises: a working tool head (100) for instruments which is inserted into the pressure tube (200), the working head (100) having a first end and a second end, with clamping block (2) in each of the above mentioned heads, one or several actuators (6) which make the inner tube (200) vibrate and one or several accelerometers (8) for measuring the vibration of the inner tube (200).