QUARTERLY REPORT FOR OCTOBER, NOVEMBER, AND DECEMBER 1957

3 9 8 4 3 3 3 6 9 6 5 5 have been started on possible urania-ceramic fuels with magnesia, alumina, zirconia, magnesia-- zirconia and calcia--zirconia. Mixtures of 45 magnesia--45 zirconia and 9 magnesia--81 zirconia by weight appeared to give good preliminary promise. Work on ThO/sub 2/--10 wt.% UO/sub 2/ has centered about improvement in density of pellets and elimination of cracking and open porosity. Efforts to increase the percentage of urania in thoria--urania have met with considerable success up to 70 wt.% urania in air-firing tests. Some attempts have been made to prepare UC by reaction of UO/sub 2/ with carbon, but so far an incomplete reaction has resulted. As to metal fuels, a sample of U--3 wt.% Ti--1.5 wt.% Nb has shown good corrosion resistance in 245 deg C water, slightly better than the EBWR fuel alloy. Fast Power Breeder Program. An improvement of the average yield of EBR- IItype fuel pin injection castings has been attained, reaching over 90% as compared with yields of 50 to 60% in the recent past. The uranium-plutonium- fissium alloys proposed for the fuel of EBR-II are being given further examination. The thermal conductivity of U-- 20 wt.% Pu--10 wt.% Fs alloy was determined at 0.053 (cal/seccm- deg C) at 600 deg C and thermal expansion at about 16.7 10/sup -6/ per deg C in the range 20 to 510 deg C. Reactor Systems Research and Development. A calibration test of the ultrasonic inspection technique was made on known defect Croloy tubing to check its effectiveness in the examination of fuel jacketing material. Development is continuing on a beta ray method for measuring clad thickness and on the scintillation counting method of measuring uranium content of fuel plates. An improved design of probe coil for eddy current measurement of cladding thickness has made possible the use of pulse signals instead of the sinusoidal type. Dynamic tests in a new loop are being employed to check the hypothesis that cathodic ions from the loop construction materlal have been responsible for unusual effects of velocity in the corrosion of alunninum. Corrosion inhibition of magnesium by fluorides is being studied. Specimens of graphite--1 wt.% U/sub 3/O/sub 8/ fired at 950 deg C have been made for density and porosity measurements. The bulk density was determined at 1.53 g/cc for a sample with porositv of 21.2 vol.%. Argonne Low Power Reactor. An ultrasonic evaluation of the bond quality of 197 ffuel elements for ALPR showed only 8 free of defects. A common dcfect was edge bond separation. Production, Treatment, anid Properties of Materials. Dilatation curves have been obtained for single crystals of uranium in two crystallographic directions, STA001! and STA010!. Compressive tests have been made at 600 C on an uranium single crystal. An analysis made from x-ray backreflection diagrams shows the slip planes to be STA021! and the slip direction to be quite close to the STA112!. Since the STA112! planes have denser packing directions, the reason for the STA112! is not clear. The densest direction STA100!, being perpendicular to the direction of compression, was inoperative in this test. Results of the investigation of recrystallization of he; vily cold rolled alpha uranium sheet have shown that three recrystallized preferred orientations can be obtained, depending on the annealing temperature, whether it is (1) below 360 deg C, (2) 400 deg --600 deg C, or (3) near 650 deg C. The beta-gamma transformation in high purity uranium has been determined at 774.8 plus or minus 1.6 deg C. A higher than expected transformation temperature for an uraniumcarbon alloy containing 325 ppm C has been sittributed to the very low rate of precipitation of small amounts of UC iron gamma uranium. Phase diagram work continues on uranium systems with individual fissium elements: Ruthenium, rhodium, ruthenium- molybdenum