Report issued by the Argonne National Laboratory covering the quarterly report from the Reactor Engineering Division. A summary of reactor programs, research, designs, development, and experiments are presented. This report includes tables, illustrations, and photographs.

The cup assembly of the Experimental Breeder Reactor (EBR) consists of blanket bricks, inner rings, and safety plug, all of natural uranium. The design of the finish machined brick is shown in Figure 1. These pie shaped bricks when stacked together, 12 bricks arranged in circular form and stacked seven rings high, comprise the cylindrical portion of the outer blanket, 17.875" I.D. x 30.875" O.D. after machining and canning. The inner ring, which is shown in Figure 2, fits inside the bottom layer of bricks. The circular opening in the center of the inner ring is closed by the safety plug shown in Figure 3.

The susceptibleness of certain "ceramic" substances to extreme radiation damage (such as that observed in graphite) as indicated by changes in dimensions and heat content is discussed in terms of the experimental evidence which is available.

The use of bromine trifluoride solution has been investigated for the preparation of purified uranium hexafluoride from ore concentrates. The best yields were obtained with the use of antimony pentafluoride solutions in bromine trifluoride, and less fluorine was consumed in the case of previously hydro fluorinated samples. This approach appears to be technologically sound and may prove economically superior to existing procedures in the case of newly constructed facilities.

This supplement includes reports on (1) transmission measurements with the fast chopper, (2) a search for Pu244, (3) crystallographic studies, (4) resonance flux in CP-[gamma], (5) multigroup methods for concentrated fast assemblies, (6) work on the ZPR-1 Reactor, and (7) work on the ZPR-II Reactor.