METHOD FOR PRODUCING NUCLEAR REACTOR FUEL-ELEMENT REFERENCE SPECIMEN Russian patent published in 2008 - IPC G21C3/00 

FIELD: nuclear power engineering; production of fuel rod for nuclear power stations whose sealing involves welding operations.

SUBSTANCE: one of claddings of fuel-element production lot manufactured from one molten-metal lot is trimmed to size not to exceed distance between welder clamps which hold butt-end of reference specimen cladding to prevent its axial displacement in the course of welding. Reference specimen cladding is faced in addition at side of joint under check; prior to do so, cladding is connected through split joint to extension piece carrying expanding devices on its ends to obtain total length equal to that of fuel element cladding; then reference specimen is marked. Prior to inserting butt-end of reference specimen cladding into welder, this butt end is checked for condition and geometry, and for compliance with specified requirements, whereupon specimen cladding is welded and joint obtained is checked for condition. Remaining length of cladding with first plug welded thereto is trimmed on side of checked-up welded joint by length of cladding section deformed in expanding chuck-electrode of welder and used for manufacturing next reference specimen for new production lot of same material lot melt; cladding of production lot of fuel elements being manufactured is cut into different lengths of which one is tubular extension piece and remaining ones whose quantity equals minimum that of fuel elements in production lot and formed from one molten metal lot. Each cladding of reference specimen produced in the process is marked and then additionally faced at side of joint under check; prior to do so, claddings are connected through split joint to extension piece carrying expanding device on its ends to obtain total length equal to that of fuel element. Then butt-end of reference specimen cladding is joined with tubular extension piece by means of solid-section adapter that functions at the same time as auxiliary plug and has expanding devices at ends; then at least one butt-end of adapter joined with reference specimen cladding end is placed in welder. Reference specimen cladding is held in position in the course of welding by clamping the cladding within welding zone with aid of expanding chuck electrode and by additional compression of extension piece with clamp disposed in front of expanding chuck electrode. Welding is conducted upon checking end of reference specimen blank for condition, geometry, and for compliance with specified requirements prior to charging reference specimen into welder.

EFFECT: enhanced radiation safety, reduced material input, enhanced quality of welded joints.

3 cl 7 dwg