Title: THE BREEDING RATIO OF A PLUTOMIUM LOADING IN EBR-I

The design and fabrication of Al-clad Pu folis and slugs, enriched and depleted U foils, and depleted U blanket slugs for breeding-gain studies with the plutonium core IV are described. The construction and dimensions of the irradiation baskets and thimbles are shown, and the special core fuel, blanket, and thermocouple rods are described. (D.C.W.)

Technical data are given concerning the fabrication of Zircaloy-clad U - 2 wt.% Zr alloy rod from extrusion billets. The development of high-yield extrusion billets for fabricating the enriched core and blanket rod is described. (auth)

The fabrication of the Mark-II fuel loading for EBR-I, consisting of a U- 2 wt.% Zr alloy, is described. Fuel slugs measuring 0.383 in. in diameter were centrifugally cast to size in massive Cu molds. The resulting microstructure was characterized by a fine grain size and a completely random grain orientation not easily obtained in wrought fissile material of comparable composition, even after heat treatment. Reproducibility of the desirable as-cast structure and physical properties of the fuel slugs was automatic. On thermal cycling in NaK in the temperature range from 50 to 550 deg C, the resulting fuel slugs exhibitedmore » negligible growth, even after 570 cycles. The gross weight of the 477 alloy fuel slugs produced in 31 productive melts was 67,199.6 g. The over-all process yield was 91.71%. These fuel slugs were loaded into 227 fuel rcds for shipment to EBR- I. (auth)« less