Abstract: "The half-life of polonium has been measured by a calorimetric method using samples several thousand times larger than have been previously available. The value is found to be 138.3 +/- 0.1% days."

The following report summarizes the data taken from a series of measurements on the combustion and ignition properties of hexone. The experiments were taken at the Bureau of Mines Central Experiment Station by their personnel, and the samples were given to them by KAPL and Hanford.

Report discussing progress made by the National Research Corporation in developing preparation of ductile zirconium for the month of August, 1949.

The geometry of the magnetic pole structure in the cloverleaf cyclotron suggests the use of three dees excited by three phase rf placed in the valleys out of the way of the beam. Experience with the model machines indicates that it is desirable to be able to vary the phase angles between the three dee voltages through 30 or 40 degrees and to be able to maintain them at any given value within plus or minus one degree. It is desirable, also, to be able to vary the phase angle independently of the amplitude of the dee voltages. There are several possible ways of meeting these requirements. The one which was chosen appears to be the most flexible and to best meet the problems presented by the center geometry of the machine.

One of the oldest properties of electrons is their emission of x-rays (discrete and continuous spectra) when impinging on matter. Cloud-chamber tracks show light ionization, and considerable multiple scattering, except for fast electrons. Tracks are long and range indefinite.

From Introduction: "The self-shielding characteristics of a number of absorbers and of U-235 and U-238 have been investigated in PPA-20 (66°). Most of the measurements have been made in Ring 3 at the core mid-plane. The foil doubling technique was employed. Particular attention was given to 'thin' foil regions for the purpose of extrapolating the data to zero thickness."

Abstract: Radiochemical and carrier techniques have been applied to the determination of minute amounts of Fe, Cr, Ni, and Co which appear as corrosion products of Inconel. The results are as follows: Fe, 0.061 per cent; Cr, 0.15 per cent; Ni, 0.037 per cent; and Co, .0005 per cent.

Very little information and data are available on the various physical properties of Zircaloy tubing, especially the high temperature- high pressure failure aspects. As greater use is being made of the low cross-sectional properties of this material in the design and development of reactor components, it was considered desirable to determine the type of failure that would be experienced under conditions of a localized over-heating. This hot-spot could be caused by "cocked" or warped fuel elements coming in direct contact with the process tube, thereby preventing adequate cooling media at the particular location.

100% recovery of uranium from pyrolytic carbon-coated spheroids of uranium dicarbide has been accomplished by an aqueous electrolytic process at the small scale laboratory level. This result was obtained in a system which circulated 1 molar nitric acid through a thin bed of the spheres. The bed was supported between a glass frit and the anode, with which the bed was in contact. The anode was a spiral of platinum wire; the cathode was a grid of titanium wire. Current density was about 0.2 amp/cm2 based on geometric surface area calculated from the average particle size of 150 microns. Initial flow rate was about 1.3 ml/cm2/sec. Reaction temperature was 72-82°C; time was 15 hours. At 1/5 the above current density and at the same temperature recovery was smaller and was independent of concentration of nitric acid over the range 1-4 molar; also recovery in 1 molar ammonium nitrate was about the same as in 1 molar HNO3. About a 100-fold increase in recovery was obtained by going from a convection stirred cell at 90°C to the pumped type of cell at 54°C using ammonium nitrate as the electrolyte.