A brief survey of decarboxylation reactions and carboxylation reactions that are known or presumed in biological systems will be presented. While a considerable number of amino acid decarboxylations are known, their mechanisms will not be included in the present discussion but will be reserved for a later paper in the symposium. The remaining decarboxylation reactions may be subdivided into oxidative and nonoxidative decarboxylations. In most cases, these reactions are practically irreversible except when coupled with suitable energy-yielding systems. The carboxylation reactions which are useful in the formation of carbon-carbon bonds in biological systems seem to fall into two or three groups: those which exhibit an apparent ATP requirement, and those which exhibit a reduced pyridine nucleotide requirement, and those which exhibit no apparent ATP requirement. Of the first group at least four cases, and possibly six or seven, are known, and one interpretation of them involves the preliminary formation of 'active' carbon dioxide, generally in the form of a carbonic acid-phosphoric acid anhydride. Those exhibiting no apparent ATP requirement seem to be susceptible to classifications as enol carboxylations in which the energy level of the substrate compound is high, rather than that of the carbon dioxide. There appear to be …

This report details activities of the Chemical Processing Department during the month of March 1958.

Uranium dioxide pellets sealed in Type 316 stainless steel containers with a helium gas were irradiated in helium and in C0/sub 2/ in thermal fluxes or the order of 1 x 10/sup 13/ n/(cm/sup 2/)(sec). Cladding-surface temperatures were reportedly between 1200 and about 1800 F. The hot-cell examination performed by BMI showed that there were no obvious effects of the irradiation on the specimen tested in helium. However, the specimen irradiated in the presence of C0/sub 2/ exhibited severe cladding-CO/sub 2/ reaction and possible central melting of the UO/sub 2/. Although comparisons between pre- and postirradiation data were difficult because of involved fabrication history of the specimens, the tests did further establish the fact that helium is a satisfactory coolant gas for stainless steel cladding material at a temperature of 1200 F. The data obtained from the specimen tested in the presence of C0/sub 2/ indicate that at temperatures in the range of 1600 to 1800 F Type 316 stainless steel is not compatible with C0/sub 2/. (auth)

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The He/sup 3/(n,p)T reaction can be utilized in a proportional counter for neutron-energy determination in the region 100 kev to 1 Mev. This has already been demonstrated and the reaction cross section in this energy region has been measured with a counter. For practical application of the counter as a spectrometer, such as in health physics work, it is desirable to increase the counter efficiency. A proportional counter utilizing an anticoincidence ring to reduce wall effect has been constructed for this purpose. Some preliminary tests of the proposed system are described. (auth)

In a recent report by J.R. Young means of circumventing the present bulk temperature limits are suggested. These have definite merit but do not present an overall picture of the problem. Therefore this bulk temperature limit is reviewed in order to place the problem in its full perspective. A program of action is suggested that should land to either: Revised operating conditions and process piping to obtain higher power levels at the same bulk outlet temperature, or the completion of production tests to permit higher bulk outlet temperatures with no significant changes in reactor piping.

The continuous plutonium concentration facilities proposed for the Purex Plant consist of a stripper-concentration unit in which the organic is removed and a portion of the required evaporation is accomplished, plutonium concentrator (No. 1 Pu Conc.) in which the final plutonium concentrate is produced, and a second concentrator which re-evaporates the totally condensed overhead from the No. 1 Pu Concentrator. In this report the Purex concentration ``package`` has been examined to determine whether the design is suitable for concentrating the various Redox 3BP solutions which may be produced (variable nitric acid to plutonium ratios) during operation at Redox Phase II processing rates. In Appendix {Lambda} a short-cut method is presented for the calculation of the operating conditions to be employed around the No. 1 and No. 2 Pu concentrators to produce a desired Pu-HNO{sub 3} product stream from a given feed solution. This method is considerably simpler than the trail-and-error solutions generally employed for such problems.

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This report addresses air-core strong focusing synchrotron.

This document details activities of the irradiation processing department during the month of March, 1959. A general summary is included at the start of the report, after which the report is divided into the following sections: Research and Engineering Operations; Production and Reactor Operations; Facilities Engineering Operation; Employee Relations Operation; and Financial Operation.

This document details activities of the irradiation processing department during the month of March, 1958. A general summary is included at the start of the report, after which the report is divided into the following sections: Research and Engineering Operations; Production and Reactor Operations; Facilities Engineering Operation; Employee Relations Operation; and Financial Operation.

The neocuproine colorimetric method was applied to the determination of copper in yttrium metal. From 5 to 80 - g of copper was determined in the presence of as much as 5OO mg of yttrium with a coefficient of variation of 2%. Copper was reduced to copper (I) with hydroxylamine and complexed with neocuproine (2,9-dimethyl-1,10-phenanthroline). The colored complex was extracted into chloroform and its absorbance measured, after dilution with ethanol, at 457 m - . (auth)

A method for the direct determination of uranium in a cyclohexane solution of tri-n-octylphosphine oxide (TOPO) is presented. The adduct, UO/sub 2/ Cl/sub 2/ x 2TOPO, that is formed when uranium(VI) is extracted from hydrochloric acid solutions by tri-n-octylphosphine oxide absorbs light in the ultraviolet region. This absorbance is measured at 230 m mu vs. a TOPO-cyclohexane solution that was contacted with hydrochloric acid of the same concentration as that in the test aliquot. The molar absorbance index is 5500. The method is not selective; of the elements that are extracted by TOPO from hydrochloric acid, iron(III), zirconium, molybdenum, tin and thorium, only thorium can be tolerated. (auth)

Eleven thorium-carbon alloys in the range 0.02 to 2.0% carbon were prepared by vacuum-arc melting. The hardness varied from 19 R/sub A/ for the 0.02% alloy to 108 R/sub B/ for the 2.0% alloy. The preparation of thorium- chromium alloy was hampered by a reaction with the zirconia molds, which results in porosity in the casting. The failure of aluminum-silicon bonded X-10 slugs after heat treatment for seven days at 400 deg C was traced to the failure to remove tin after the tin dip and the presence of a gas during heat treatment. Tensile tests were made on extruded thorium, and no correlation was found with extrusion variables. A composition effect was found, however, which showed a linear relationship between carbon content and tensile strength. Creep tests on thorium, uranium, and Inconel continue. The program of evaluating the variables in the fabrication of clad fuel elements, using MTR techniques was concerned mainly with the distribution of UO/sub 2/ in the core compact, the temperature of rolling, and the particle size of the metallic core powder. Progress is being made in the preparation of three-layer laminates without the use of a protective can during the hot-rolling operation but with the …

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