FIELD: nuclear reactors. SUBSTANCE: nuclear fuel assembly packing provided with tubular zirconium alloy sleeves has cylindrical casing and block sliding within casing and incorporating bushing and thin rod-extracting strip locked in position in spaced relation relative to bushing by means of supporting tubes which pass control rods. Supporting tubes are routed through bushing and spring shell loaded towards annular boss of casing by means of helical pressure springs concentrically mounted on supporting tubes in drillings made in bushing and in spring shell. Tool guide tube arranged in center has spring-loaded plunger that juts through spring shell and sets height of rod control group below upper end of casing irrespective of extension or compression of packing with tubular sleeve length varying relative to other inner parts of reactor. Upper packing is joined for its disconnection to fuel assembly by means of tubular inserts attached to tubular sleeves and provided with compressing pins thickening outside and abutting against loose end. When compressing pins are inserted into strip holes for extracting the rods, shutoff tubes are inserted into supporting tubes to set apart compressing pins of inserts and to bring them in mesh with annular slots in holes. In this way, provision is made for removable attachment of upper packing to fuel assembly and for using zirconium alloy to manufacture guides. EFFECT: improved design of upper packing. 7 cl, 11 dwg
