METHOD FOR RECOVERING SERVICEABILITY OF NUCLEAR REACTOR FUEL ASSEMBLY SUBCHANNEL Russian patent published in 2007 - IPC G21C3/02 G21C17/00 

FIELD: nuclear engineering; retrofitting subchannels of high-power uranium-graphite tank reactor cores.

SUBSTANCE: proposed method for recovering serviceability of nuclear reactor fuel assembly subchannel includes reactor shutting down, dismounting of standard floor blocks from subchannel, and removal of fuel assembly. Process channel is checked for serviceability. Channel is visually inspected within reactor for integrity and channel inner diameter profile is measured. Then process channel pre-removal operations are made. Process channel is removed from subchannel and placed in storage. Construction clearance between process channel and graphite stacking is recovered by calibrating graphite column including finishing of central bore internal diameter to desired size and expansion device segment is installed between guard plate and top graphite block. Graphite column is checked for condition by inspecting inner surface of column. Telescopic joint height and inner diameter of graphite column central bore are measured. Then process channel removed earlier and found serviceable by its check results is reinstalled in fuel assembly subchannel. After that final mounting operations are conducted including welding of process channel to adjacent structures and formation of nuclear reactor subchannel.

EFFECT: ability of evaluating process channel life, reduced dose rate on attending personnel.

1 cl, 3 dwg