METHOD AND DEVICE FOR SEALING INNER SPACE OF PRESSURE-TUBE GRAPHITE MODERATED WATER COOLED REACTOR Russian patent published in 2005 - IPC

FIELD: nuclear power engineering; sealing inner space of pressure-tube reactors, especially when decommissioning them and placing in long-time storage.

SUBSTANCE: proposed method for sealing inner space of pressure-tube graphite moderated water cooled reactor, that is, risers and upper plate, includes installation of means for executing auxiliary operations above work zone, mechanical surface cleaning facilities in zone being sealed for removing fouling layer, plugs, and their fastenings. For sealing risers, metal disk brush is inserted in rod chuck and moved down to riser hollow through desired depth, set in rotary motion, and inner surface section in the form of belt is cleaned while combining effective vertical, longitudinal, and transversal motions of brush; cleaned surface is coated with preserving material by means of preservative feeder installed in chuck while sequentially setting rod in joined longitudinal and transversal motions. Plug is caught by means of gripping tool and installed in riser hollow at desired depth directly within location of riser surface prepared for treatment, and riser top is coated with additional safety layer of preservative material. Then holes in reactor upper plate are sealed; to this end, upper plate surface is cleaned over alignment contour of cover plug and upper-plate hole by means of butt-end rotating metal brush, whereupon built-up metal on upper-plate hole edge, if any, is scraped by means of revolving grinding wheel, and cleaned surface of upper plate is coated with preservative layer with aid of preservative feeder mounted in chuck. Then cover plate is installed on hole by means of gripping tool inserted in rod chuck aligning in the process its contour with that of cleaned surface of upper plate; then partitions are placed on upper plate along cover contour and clearance formed in the process is filled with additional safety layer of preservative.

EFFECT: enhanced reliability of sealing reactor inner space in narrow and hard-to-get-at work zone at high radiation background; reduced labor consumption and dose impact on personnel.

2 cl, 8 dwg