The initial and long-term nuclear characteristics of two internally cooled heteroingeneous graphite-moderated two-region molten-salt reactors were studied. The reactors have doubling times of 22.5 and 27.5 years. Methods of decreasing the doubling times by removing the Pa/sup 233/ from the core and by increasing the specific power of the reactor are described. (auth)

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S>The oxidation resistance of thin sheets of Fe - 28 wt. % Cr - 2.67 to 10.0 wt. % Al alloys, nominally 0.004, 0.006, 0.008, 0.012, and 0.016 in. thick, was determined by exposure in static air for 100 hr at 2100 and 2300 deg F. A minimum of 3.67 and 9.37 wt.% Al was necessary to prevent excessive oxidation of 0.004-in. thick sheet material at 2100 and 2300 deg F, respectively. Specimens of lower Al content and greater thickness withstood oxidation attack. Oxidation of Fe - Cr - Al alloys apperars to be related to the diffusion of Al to surfaces of the sheet to form an adherent protective layer of Al/sub 2/ O/sub 3/.(auth)

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This constitutes a review of the path of carbon in photosynthesis as it has been elaborated through the summer of 1952, with particular attention focused on those aspects of carbon metabolism and i t s variation which have led to some direct information regarding the primary quantum conversion act. An introduction to the arguments which have been adduced in support of the idea that chlorophyll i s a physical sensitizer handing i t s excitation on to thioctic acid, a compound containing a strained 1, 2 -dithiolcyclopentane ring, i s given.

A method is described for the preparation of PuF/sub 3/ by means of a solid phase-gas reaction between Pu(IV) oxatate or Pu(III) oxalate and Freon-type compounds such as CC1/sub 2/F/sib 2/. (auth)

Modified Zirflex process flowsheets were developed for recovering uranium from the newer power reactor fuel alloys after discharge from the reactor. The STR (1% U97% Zr-2% Sn) and EBWR Core-1 (93.5% U-5% Zr-1.5% Nb clad in Zircaloy-2) fuels are used as examples of low- and high-uranium fuels, respectively. A dissolvent of 6 M NH/sub 4/F yields a solution of zirconium and a precipitate of ammonium uranous fluoride. In one process, ammonium hydroxide is added to produce insoluble hydrous oxides of uranium, zirconium and niobium. The NH/sub 4/F-NH/sub 4/OH supernatant is removed by filtration, partially evaporated, and recycled as dissolvent. The uranium and zirconium oxides are dissolved in nitric acid to yield a solvent extraction feed solution of low fluoride content. In an alternative process nitric acid and aluminum nitrate are added to the ammonium fluoride fuel solution to oxidize U(IV) to soluble V(VI) and prepare a stable solution suitable for solvent extraction. Chromic acid is also added in the case of the STR fuel. In a variation of this flowsheet for the EBWR fuel, only- enough 6 M NH/sub 4/F is added to dissolve the cladding. Nitric acid and aluminum nitrite are then added io dissolve the core. Insoluble niobic …

Experiments are described that have been designed to measure separately annihilation and reaction cross sections for antiprotons of approximately 450 MeV on oxygen, copper, silver, and lead. A new and more luminous spectrograph has been built for this experiment. The antiproton cross sections a r e compared with total proton cross sections, and are found to be larger by a factor varying from 1.74 for oxygen to 1.39 for silver. Calculations based on the optical model give a reasonable connection between these cross sections and the 6-p and 6-n cross sections. Finally, the information available on antiproton production cross sections is collected. There are indications that a free nucleon is several times as effective as a bound one for producing antiprotons.

A discussion is presented of the macrostructure of the chloroplast insofar as it is known and knowable by means of microscopy (visible, ultraviolet and electron). This leads to a number of principles of structure to be found in the granum universally distributed throughout the plant kingdom. A chemical analysis of the constitution of these lamellar structures leads to a deduction of structural principles for such molecules as are found therein. The application of these structural principles to the visible structure of the lamella leads to a microstructure on a molecular level of these lamellae which, in turn, leads to a theory of their function.

Samples containing 5 to 10 mg of uranium were extracted with hexone (methyl isobutyl ketone) and titrated coulometrically in sulfate media. Relative standard deviations of 0.43% for samples containing 5 mg and 0.56% for 10 mg were determined by precision studies. (auth)

A previous investigation concerned with liquid-core fuel elements and the materials from which they could be constructed revealed tht an alloy of U--5 wt. % Nb had considerable promise as container material. Results are given from a further investigation of this alloy, as well as another containing 10 wt. % Nb, to determine the time and temperature limits within which tbe oxide layer remains protective, the factors which hasten or delay the breakdown of the film, and the mechanism whereby the film deteriorites, (auth)

Two methods for extrusion cladding were investigated and evaluated. In the coaxial method, the component parts of the extrusion assembly are concentric, and the fuel plate moves in the same direction as the hydraulicpress ram. In the right-angle method, the fuel-plate metion is perpendicular to that of the ram. Ribbed sheaths of aluminum were extruded satisfactorily on 3-in.-wide uranium plates in lengths up to about 10 ft. Lowest extrusion pressures were achieved with the most streamlined designs of mandrel tips, using flatfacod shear dies. Good results were obtained with billet and die temperatures of about 1050 deg F, at extrusion speeds up to 60 ipm. Extrusion pressures were 25,000 to 60,000 psi. End-cladding procedures were developed which involvod attaching end plates machined from aluminum powder-metallurgy products (12 to l8 wt. % Al/sub 2/O/sub 3/) to the core by means of T-shapod joints, and cladding the entire assembly with aluminum. Excellent bonds were achieved, on uranium as well as on the end plugs. The median values obtained by stud weld tests were 26,000 psi for uranium, and 12,000 psi for the end plugs. The importance of proper tool alignment and avoidance of imbalance of forces caused by pressure differentials within the …

Report on methods for making spherical uranium particles.

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