Method and apparatus for annulus spacer detection and repositioning in nuclear reactors

摘要

The present invention provides an apparatus for detecting and/or repositioning annulus spacers used to maintain the position of a pressure tube withm a calandria tube of a nuclear reactor. The method comprises the steps of: vibrationally isolating a section of the pressure tube; vibrating the wall of said pressure tube within said isolated section; detecting vibration of the wall at a minimum of two axial positions within said isolated sections; and detecting the reduction in vibration level of the wall at one or more of said axial positions in comparison to the remaining axial positions. The apparatus comprises a tool head to be inserted into the pressure tube, the tool head comprising a first end and a second and a clamping block m each of said ends. The clamping blocks are used to vibrationally isolate a section of the pressure tube located between said ends. The apparatus also comprises piezo-actuators operable to vibrate said pressure tube; and accelerometers used for measuring vibration of said pressure tube.

主权项

1. An apparatus for detecting and/or repositioning an annulus spacer, the annulus spacer having an inner cylindrical surface in contact with an inner tube and an outer cylindrical surface in contact with a generally coaxial outer tube, the apparatus comprising:
(a) a tool head sized for insertion within the inner tube, the tool head having a first end and a second end; (b) a first and a second clamping block assembly provided respectively at said first and second ends of said tool head, wherein each of the first and second clamping block assembly comprises at least one clamping member having a retracted position and an extended position in which the clamping member engages an inner surface of the inner tube, and wherein the first and second clamping block assemblies are provided at fixed positions relative to one another such that engagement with the inner surface of the inner tube maintains the section to be fixed in length to minimize effect of vibrations in a section of the inner tube between the first and second clamping block assemblies on remaining sections of the inner tube; (c) the tool head further comprises one or more piezo actuators, the one or more piezo actuators configured to be movable into contact with the inner surface of the inner tube and when in contact with the inner surface, configured to vibrate said inner tube; and (d) the tool head further comprising a plurality of accelerometers configured for measuring vibration of said inner tube at a minimum of two axial positions within the section of the inner tube between the first and second clamping block assemblies.