A definitive investigation of the boron-carbon equilibrium system is being made by x-ray diffraction, metallographic, and thermal analytical techniques. On the basis of metallogaphic and x-ray-diffraction studies it is concluded that boron carbide has a range of solubility from approximately 10 to 20 at.% carbon at 1500 to 2000 deg C. The melting point of the carbide-graphite eutectic was established as 2325 to 2350 deg C. No reversible allotropy of the beta -rhombohedral structure was observed. The solubility of carbon in boron is very small. The melting point of dilute carbon alloys is found to be essentially the same as that of pure boron (2040 to 2050 deg C). No metallogaphic evidence of a three-phase reaction of dilute alloys is observed. (auth)

The amount of Cf/sup 252/ and intermediate isotopes which could be made from Cm/sup 244/ in a reactor with high neutron flux was calculated. The variations of different isotopes formed in the bombardment as a function of time are described by a series of linear differential equations. The cross sections used were either weighed measured values or values estimated from the amounts of curium and californium isotopes formed in irradiations of heavy elements. The number of atoms of heavy curium isotopes per initial Cm/sup 244/ atom is given as a function of total flux intervals. The buildup of Bk/sup 249/ and the californium isotopes is also shown. (M.C.G.)

Summaries are given of the activities of the Nuclear Chemistry Division during 1960, in radioactivity and nuclear spectroscopy, fission, nuclear reactions, physical chemistry, instrumentation, and chemical engineering. Included are abstracts of graduate theses awarded during 196O for work conducted in the Division. (B.O.G.)

A condenser, suitable for use in the distillation of metals was designed. The temperature of the condensing surface was established by controlling the pressure over boiling NaK-78 contained within the condenser. Performance was evaluated in test units in which pure bismuth was distilled as the test metal. (auth)

Reduction of small charges of uranium tetrafluoride with magnesium proved to be successful. By hand-tamping of UF/sub 4/-- Mg blend, tap densities ranglng between3.1 and 3.4 g/cc were obtained. The reduction yields for these densities ranged from 72.79 to 93.71%. In the case of machinecompacted UF4-- Mg blend having tap densities from 3.58 to 3.68 g/cc, reduction yields were higher, ranging between 91.45 and 97.2%. Machine-compacted blends gave much more uniform temperature distribution curves during the preheating period, as a result of higher tap densities. The best yields were obtained by firing a machine- compacted blend containing 5% Mg excess at a furnace temperature of 650 deg C, giving an average crude metal yield of 96.3%. However, the high carbon content of 174 ppm in the crude uranium biscuits obtained by compacts reduction, as a result of hydrocarbon binder presence, appeared to be a disadvantage. Attempts were also made to demonstrate the initiation of the reduction reaction at temperatures lower than 500 deg C by taking x-ray-diffraction patterns of the samples of the UF4-- Mg charges heated up to various temperatures. (auth)

A test was made to obtain a record of radiation contamination levels during core I seed 1 refueling operations. The recorded survey data indicated generally lower radiation levels than had been expected. (J.R.D.)

The development of remote fabrication methods and equipment in which the cooling periods, chemical fission product separation, and complete decontamination of the fuel is not required is discussed. A process designed around precision casting in multiple, glass molds served as a basis for design of refabrication equipment. The injection casting process is used. Procedures and equipment were developed for the remote manufacture of right-cylindrical, uranium alloy fuel pins from the castings. Assembly, welding, and leak testing of the EBR-II fuel rods are described. Methods of sodium bonding and bond testing are described. (M.C.G.)

Revisions in the reactor system and operating procedures necessary for carrying out a proposed dry critical experiment in the EBR-II are described. The safety aspect of the program is considered. The critical experiment will be conducted in the EBR-II prior to filling the primary system with sodium. The facility, experimental program, operational and experimental procedures, and hazards and plant safety are described. (M.C.G.)

The studies were primarily directed toward selection of the optimum loading for Core lA and a prediction of its properties. Included are analyses of some relevant experiments on Core 1, and prelimlnary modifications of Core 1 to Core lA. The factors which must be considered for the optimum loading determination are discussed. Four different loading pattenrs were investigated, which were considered to span the numerous possibilitles. Adequate cold shutdown was found to be almost unobtainable without the use of boric acid. For this reason, and because the heat transfer and stability limitations are severe, greater weight was given to heat transfer as opposed to control requirements. The use of boron-stainless steel poison strips fastened to the sides of the spike elements is considered insofar as in improving the loading from either the heat transfer or control standpoint. The relatlve advantages and disadvantages of the use of stainless steel fuel followers as opposed to Zircaloy followers are discussed. (B.O.G.)

None

The results of an investigation into the effect of irradiation on the quality and integrity of several commercial siliocnized-silicon carbide (Si-- SiC) coatings for graphite are summarized. Si-- SiC-- coated graphites were oxidationtested at 1000 deg C in air both before and after irradiation. Data show that base graphites for coating must be fairly isotropic and must be stable toward high temperature radiation damage if the coating is to survive in-reactcr conditions. (auth)

None

Six examples are given of the application of analog computers in the fields of reactor engineering, heat transfer, and dynamics: deceleration of a reactor control rod by dashpot, pressure variations through a packed bed, reactor kinetics over many decades with thermal feedback (simulation of a TREAT transient), vibrating system with two degrees of freedom, temperature distribution in a radiating fin, and temperature distribution in an irfinite slab with variable thermal properties. (D.L.C.)

Tables of the energy, pressure, and chemical composition for a stellar mixture, originally a pure Fe/sup 56/, are presented as functions of temperature and density. They cover a range of conditions pertinent to the evolution of supernovae, involving the deconiposition of iron into helium plus neutrons, and the later stage of decomposition of helium into neutrons and protons. Relativistic degeneracy of electrons is included in these calculations. (auth)

The Juggernaut is a light-water-cooled and moderated, graphite- reflected, heterogeneous thermal reactor designed to provide experimental facilities for conducting basic research in the neutron flux range to 4 x l0 n/cm/ sec at an operating power level of 250 kw(t). Pertinent design and operating characteristics are tabulated. Evaluations are made for potential hazards posed by certain hypothetical major accidents during the operation, and the adequacy of the safeguards provided to insure that the health and safety of personnel, within and beyond the site boundary, are not unduly endangered. The results indicate that in the event of any conceivable reactivity increase, auxiliary and inherent safety features pecuIiar to the Juggernaut will operate to insure automatic shutdown through a nondestructive BORAX-type process. (B.O.G.)

Two groups of plutonium bars, one group containing 165 ppm iron and the other 678 ppm iron were end-quenched from the beta, gamma, delta, delta-prime, and epsilon phases. In general, cooling rate was found to have three striking effects on microstructure. The alpha grain size was found to decrease with increasing cooling rate during cooling from all phases. Upon cooling high-iron plutonium from the epsilon phase, the size of the Pu--Pu6/sub 6/Fe eutectic network decreased with increasing cooling rate. Cooling high-iron plutonium from temperatures between 413 and 460 deg C produced a wide variety of Pu --Pu/sub 6/ Fe configurations in the microstructure. Finally, the size of an unidentified spheroidal inclusion, soluble in the delta and higher temperature phases, decreased as cooling rate increased across the delta to gamma transformation. These effects of cooling rate can be used to indicate the cooling rate or thermal history that a particular plutonium specimen has encountered. A linear relationship between the alpha grain size and the Pu--Pu/sub 6/Fe eutectic network size was observed. The network size was roughly two times larger than the alpha grain size. Hardness traverses on each of the bars indlcated no apparent effect of coollng rate during quenchlng on …

Results of the examinations of corrosion specimens exposed in the HRT are presented. Specimens examined include core screen samples, core specimen array No. 1, blanket specimen array No. 2, core solution line specimen arrays No. 103 and 103A, and blanket solution line specimen array No. 203. These data include corrosion rates, computed from specimen weight-changes, and results of chemical analyses of scales removed from the specimens or specimen holders. A summary is included of the HRT operating schedule during exposure of the specimens and of the status of examinations for the specimens removed from the reactor prior to run 20. (auth)

Recent work on isotopic x ray sources is reportcd. The research was directed toward optimization of high-level isotopic sources and evaluation of their use in typical scientific and technical applications. The resulting experi- mental data are used in obtaining an approximate mathematical formulation of x- ray output as a function of beta energy, target mnaterial, and source configuration. (J.R.D.)

>The mechanical and physical properties of Zircaloy-2 were determined as a function of five test variables: temperature, grain size, direction to rolling, hydrgen content, and the presence or absence of a notch. The investigation included studies of the coefficient of thermal expansion, elastic moduius, tensile properties, creep properties, and low-cycle fatigue properties. Approximately 470 specimens from a single ingot were tested in the course of the investigation. (auth)

The preferred orientation and anisotropy of strain behavior of Zircaloy- 2 were studied as functions of fabrication variables. An inverse-pole-figure technique was used for the preferred orientation determinations. Evaluation of the effects of the fabrication variables on the anisotropy of strain behavior was accomplished by a contractile strainaxial strain analysis. An analysis of strain behavior in the normal direction was developed on the basis of theory of plastic flow of anisotropic metals. A simple intuitively derivable relation was found to exist between the strainstrain analysis and the preferred orientation data. Correlations of the strain-strain data with true-stress-truestrain diagrams and mechanical properties were attempted. The preferred orientation of Zircaloy-2 produced by the Oak Ridge National Laboratory-Homogeneous Reactor Project (ORNL- HRP) metallurgy fabrication schedule (ingot breakdown at 1500 to 1900 deg F, major reduction at 1800 to 1900 deg F or 1350 to 1450 deg F, a heat treatment of 30 min at 1800 at 1550 deg F followed by a water quench or rapid air cool to below 1200 deg F, a final reduction of 25 to 40% at 1000 deg F. and a 3O-min anneal at 1400 to 1425 deg F) was weak compared to that of most of the …

The energy loss spectra for gamma rays in NaI and CsI crystals were calculated by the Monte Carlo method. The calculations were carried out for point sources, broad and collimated parallel beams, and disc sources of monoenergetic gamma rays varying in energy from 0.142 to 14.0 Mev. The crystals considered were right circular cylinders. varying from small crystals of height and diameter of 0.5 inch to large crystals of height 12 inches and diameter 9 inches, and a sphere of 1-inch radius. Also calculated simultaneously with the energy loss spectra were the efficiencies and total absorption fractions. (auth)

The program was written for the Philco-2000 computer to provide a nuclear design computing tool equivalent to the IBM-704 computer program MUFT-4 and to provide a set of routines for a future spatial multigroup program, P/sub 3/ MG-1. In addition to the features of its 704 predecessor, MUFT-5 provides a more complete isotopic edit, an optional blackness coefficient edit, and the use of a complete P/sub i/->i>s library. The resultant program is found to be easier to use because of the simplicity of running several problems, more valuable because of the many additional results that are edited, and more economical because of the changes made in programming. (auth)

The nuclear characteristics of the initial core loading for the Yankee Atomic Electric Company power plant are described. These characteristics include core reactivity, control rod and boron worths, and reactivity coefficients. In addition to operating characteristics, parameters for the cold and hot zero power cores are obtained for comparison with startup experiment data. Calculations to determine these characteristics are based on mechanical design specifications. (auth)

The oxidation of uranium(IV) by oxygen and nitrous acid was studied in both 30% TBP-""Ultrasene"" and in aqueous solutions. Emphasis was placed on reactions between uranium(IV) and nitrous acid. Distribution coefficients were measured for uranium(IV) and uranium(VI) in the nitric acid-30% TBP system. The use of uranium(IV) as a reductant for plutonium in the Purex process is discussed. (auth)