摘要:
The invention relates to an economic method for sintering spherical sol-gel material. Spherical hexavalent oxidic uranium material, such as A.D.U. or UO3-hydrate, is converted into nuclear fuel of high density by means of a sinter stage, which consists in heating-up and cooling at a rate of 10* - 65* C/min. The sinter stage may be preceded by a preheating stage. Whereas the starting material may contain finely divided carbon. Previously only spherical sol-gel material of tetravalent uranium and pressed compacts of ceramic uranium dioxide powder where sintered with the above heating rates. Tetravalent uranium material has disadvantages with respect to hexavalent uranium material.
摘要:
A plate spring for use in a spacer grid for holding a rod-like element against lateral displacement, by exerting a pressure force on the element in a direction normal to the plane of the plate spring, said plate spring having a longitudinal dimension and a transverse dimension within said plane and when in the relaxed state having a bow-shaped bend in one direction in its major middle part for engagement with the rod-like element said spring further having between said bow-shaped bend and each end of the spring an arch extending in the same direction as said bend, at least one end of the spring being formed in at least two longitudinally extending branched parts which are transversely spaced apart.
摘要:
A method for spot welding Zircalloy straps in open air to form a heat-exchange grid for holding a plurality of rod-like elements against lateral displacement. Contiguous areas of the straps are clamped between spot-welding electrodes and immediately thereafter the clamped areas are sprayed with a non-viscous volatile liquid, preferably a pure organic compound free of sulfur, fluorine, chlorine and iodine, such as acetone or ethanol. Heated by the welding current, the liquid volatilizes to expell air, thus preventing weakening of the weld by absorbed nitrogen or oxygen.
摘要:
A spacer grid for holding against lateral displacement a plurality of nuclear reactor fuel rods of heat exchange tubes includes means defining a plurality of side-by-side parallel compartments, each compartment being provided with a specially shaped arched spring plate which engages the fuel element or heat exchanger tube. The spring plates are so contoured and apertured as to provide passages for the flow of heat exchange fluid to thereby avoid stagnation of the fluid.