| 摘要 |
1. Method of checking the dimensions and the position in a cross-sectional plane, i.e. a plane perpendicular to the axis of the vessel, of the elements of a nuclear reactor vessel conditioning the positioning of the internal structure of the reactor, after assembly of the vessel and machining of the elements, by comparing actual measured coordinates with the theoretical coordinates provided by the working drawing, characterized by the fact that : - the vessel (1) is kept in a horizontal position during checking operations, - a sighting instrument (18) mounted on a support (6), allowing displacement of the sighting instrument (18) with respect to the vessel in two directions perpendicular to the axis of the vessel (1) is displaced as far as a reference position defined by the sighting of a point (O) established in relation to the vessel, - a sighting mark (40) is disposed in relation to the element of the vessel (1) to be checked so as to make this sighting mark (40) coincide with the point whose coordinates are being checked, - the sighting instrument (18) is displaced from its reference position until accurate sighting of the sighting mark (40) is obtained, - the displacements in each of the directions of displacement of the sighting instrument (18) to bring it from the reference position to the position for sighting the sighting mark (40) are very accurately recorded to obtain the coordinates of the sighting point along each axis of displacement, - lastly, these coordinates are compared with the theoretical coordinates of the working drawing.
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