device for abstuetzen and center of the brennstoffkanaelen brennelementeinsaetzen in a nuclear reactor

摘要

953,475. Nuclear fuel elements. UNITED KINGDOM ATOMIC ENERGY AUTHORITY. Feb. 14, 1963 [Feb. 20, 1962], No. 6502/62. Heading G6C. A spacer ring 5, e.g. of alumina, interposed between the oblique faces of two tubular fuel elements 3, 4 comprises two similar semi-circular parts 5a, 5b engaging by lug and groove connections 6 and having projections 7a-7d extending in both axial directions. The projections are part spherical in contour where they abut the wall of the surrounding coolant channel 2. The grooves of the connections 6 are formed oversize to provide clearances 6a in order to accommodate expansion of the ring 5 in operation, whilst the faces 6b closely engage each other. The projections 7a, 7b on the upper part 5a of the ring 5 extend radially to the channel wall and downwardly so as to overlap the edge of the lower fuel tube 4 while the projections 7c, 7d on the lower part 5b similarly extend to the channel wall but also upwardly to overlap the edge of the upper fuel tube 3. The peripheral portion of the ring 5 between the projections 7c, 7d subtends an angle at the channel axis whose bisector lies along the line of the radial component of the axial force to which the fuel tubes are subjected set up by virtue of the inclined planes of contact between the fuel tubes 3, 4 and the ring 5. This radial component serves to hold the fuel tubes 3, 4 steadily in a central position within the channel 2. Dimensional changes in the fuel tubes 3, 4 and the ring 5 can be accommodated under operating conditions by sliding in the inclined planes of contact between them.