METHOD FOR REPLACING PROCESS CHANNELS OF WATER- GRAPHITE REACTORS Russian patent published in 1999 - IPC

FIELD: major repairs of water-graphite reactors involving replacement of process channels. SUBSTANCE: nuclear fuel is removed from process channels of one half of reactor and conveyed to cooling pond. Channels of this half of reactor are dried out and removed from reactor, graphite stacking cells are calibrated, new channels are installed and fixed in position within this half of reactor and filled with circulating-loop coolant. Then new channels of first half of reactor are refueled from second half and fuel elements of first half are dried out and removed from reactor. Upon calibration of graphite stacking in second half of reactor, new channels are installed in it and fixed in position, nuclear fuel extracted earlier from first half of reactor is removed from cooling pond and placed in new process channels of second half. Process channels of first half are removed in row-by-row manner starting from peripheral ones towards center and refueling of first channel from second one is conducted in sector-by-sector manner starting from that adjacent to first half towards sector of first half adjacent to second half; second-half channels are charged with fuel in row-by- row manner from reactor center to periphery. EFFECT: facilitated procedure. 5 dwg