Apparatus and method for customizing replacement upper core plate inserts of a nuclear reactor.

摘要

The apparatus comprises a circular gauge plate (51) which has: (a) a diameter corresponding substantially to the diameter of the upper core plate of the reactor to be gauged; (b) U-shaped peripheral gauging slots (55) of known size for receiving, with clearance, the guide pins (33) for the lower internals of the reactor; (c) means (57) for positioning the gauge plate within the core barrel (11) at the normal elevation of the upper-core-plate inserts and the guide pins; (d) means (59, 63) for positioning the gauge plate relative to the reactor baffle-plate arrangement (25); and, (e) means (63) for determining the actual positior of the gauge plate relative to the baffle plates (27). Utilizing the means (c) and (d) above, the gauge plate is accurately positioned in a core barrel (without the upper internals therein) such that it rests upon the upper ends of the baffle plates and the guide pins extend into the respective gauging slots, whereupon the clearances between the gauge plate and the core barrel, and between the sides of each gauging slot and the adjacent sides of the guide pin therein, are measured (85, 87, 89) and the actual position of the gauge plate relative to the baffle plates is determined (means e), the measurements and actual-position data being made available for use in customizing the replacement upper-core-plate inserts.