1. X-ray and neutron diffraction studies were caried out on the crystal lattice of beryllium oxide annealed at 2000 degrees. 2. It was determined that neutron diffraction data confirms X-ray conclusions of the positions of beryllium atom positions in the crystal lattice of beryllium oxide. 3. From neutron diffraction data the values of the temperature fact B + 0.92 and the Debye characteristic temperature theta = 602 +- 13 degrees K were found.

The isotopes of lutecium were used to measure the neutron temperatures in two collimated beans of neutrons emerging from HIFAR>

A survey of the aqueous coordination chemistry of beryllium is given. The possible use of coordination chemistry in the separation of beryllium from fission products is discussed, outlining methods for separation processes.

Details are given of an apparatus used to dissolve irradiated ceramic, metallic, and carbide fuel specimens, to dilute the dissolver solutions accurate to a known volume, and to take aliquots with a specially adapted automatic burette. Procedures for its use are given.

The performance of a Schultz-type texture goniometer is shown to be adversely affected by a number of experimental errors all of which result in defocusing of the diffracted beam. Those errors result from the tilting of the specimen, from lack of precision in positioning it and from its absorption coefficient. An experimental procedure is outlined which minimized these errors and results in optimum performance of the instrument.

Methods are described for the determination of traces of Be, Th, and U in concentrated sulfuric-phosphoric acid mixtures. When the Be concentration is sufficiently high, the chrome azurol S spectrophotometric method may be applied directly, and a small correction made for phosphate interference. At lower concentrations Be should be first separated by an acetylacetone extraction. Th must be separated from sulfate and phosphate before the thoronol spectrophotometric method can be used. This is achieved by precipitating Th as the fluoride, using Y carrier. U may be determined spectrophotometrically with arsonazo after separating Be, Th, suIfate, phosphate, and other impurities by anion-exchange from hydrochloric acid solution. In an alternative procedure, U is reduced to the tetravalent state and precipitated with Th as the fluoride, again using Y carrier. The determination is then completed by a-c polarography.

A radioisotope method has been used to measure the flow in the light water circuit of HIFAR. A mean value of 756 pounds/sec was obtained which is in fair agreement with conventional Dall tube method. Attempts to measure the flow through individual cooling towers were not entirely successful, but some useful information was obtained.

An apparatus for differential thermal analysis of active or toxic materials is described. The technique is superior to thermogravimetric analysis. Analysis of the dehydration of beryllium sulphate shows that the process takes place in three stages. Some applications are given for a modified apparatus for quantitative work.

The reactor transfer function of HIFAR has been measured at low power and compared with the calculated response determine the prompt neutron lifetime. Lifetime values in the range 600 to 800 microseconds, depending on the position of absorbers withing the core and reflector , were obtained with an estimated error of less than 100 microseconds.

Stable solutions of basic beryllium nitrate can be formed with beryllium concentrations up to 9M, and an NO3/Be mole ratio as low as 1:1. The efficiency of basic beryllium nitrate as an agent for salting out uranium into a tributylphosphate/kerosene solvent has been compared with that of other salts. It appears possible to separate uranium and thorium from beryllium and fission products using a modified Thorex process in which beryllium nitrate replaces aluminum nitrate.

Measurements were made of the capacity of pre-treated Victorian brown coal for removing trace quantities of Sr2+ and Cs+ at pH 8.0 and 9.5 in the presence of various concentrations of Ca2+. At 20 p.p.m. Ca2+ breakthrough was immediate.

The concept of a dispersion fuel element is discussed with particular reference to irradiation damage. The application of this concept to the A.A.E.C. H.T.G.C. reactor system is outlined and the limitations imposed by irradiation damage considerations are discussed. The maximum desirable heavy metal - beryllium ratio (i.e. U+Th:Be) for the various systems under consideration should be about 1:55 for the system (U,Th)Be13 in Be, 1:13 for the system (U,Th)O2 in Be, and 1:8 for the system (U,Th)O2 in BeO. The disadvantages of keeping uranium and thorium in separate particles are discussed and it is suggested that to minimize irradiation damage effects, the fuel particles should consist of solid solutions of the uranium and thorium compounds.

A comparison of methods of capital cost estimation used for nuclear fuel reprocessing plants shows that, because of the special nature and complexity of such plants, cost estimation methods for conventional chemical plants involving the use of cost factors are not applicable and will give low estimates. Cost factors which are available from other countries where reprocessing plants are installed should be used with caution since those factors apply only for the particular design philosophy used and pertain to industrial conditions which are different in this county. Capital cost estimation methods involving direct take-offs from detailed design drawings are necessary to obtain reliable estimates. The methods of estimating operating costs for nuclear reprocessing and conventional chemical plants are similar.

A method is given for constructing the complete neutron spectrum for a well-moderated thermal reactor such a HIFAR, from the total effective flux, the temperature of the Maxwellian, the epithermal spectral index and the total integrated fission flux. A sample calculation is also included.

Some preliminary measurements have been made of the rate of dissolution of beryllium when refluxed with ammonium fluoride solution. The rate of dissolution exhibits pseudo first order dependence on the "free" fluoride concentration defined as the concentration of total fluoride less that assumed to be present as BeF4. The solubility of uranium metal in ammonium fluoride - beryllium fluoride solutions increases with free fluoride concentration, where the uranium is present in solutions as U(1V). Thorium metal is attacked only slightly under similar conditions. Beryllium may be selectively leached from UBe13 by ammonium fluoride solutions if the fine A-/Be mole ratio is greater than 4:1. The solubility of uranium under these conditions suggests that this is not a satisfactory solvent for mixtures of these alloys with Be when the U/Be ratio is small, but that it could be used successfully as a decladding agent for an oxide fuel clad in beryllium meta.

A method for comparison and evaluation of thermoelastic stresses is given for a range of fuel element shapes based on parameters available from the initial study of a reactor system. The shapes studied, in descending order of stress level are circular rods, concentric tubes, flat plates, and a matrix of circular holes.

The dissolution of dense beryllia was studied in a variety of reagents. The dissolution rates were too slow to be of practical importance except those for hydrofluoric acid, sulfuric acid, and mixtures of sulfuric and phosphoric acids. The reaction with hydrofluoric acid was studied in more detail in an attempt to throw some light on the dissolution process. The initial dissolution rate appeared to be proportional to the square of the acid concentration between 0 and 20M. An apparent activation energy of 12 Kcal/mole BeO was obtained from the temperature coefficient of the dissolution.

The second partial differentials of the production cost equation are derived in a generalized and non-dimensional form in order to determine the effect on production cost of electricity from a gas-cooled nuclear power plant of departure from optimum operating conditions. Fuel element surface temperatures up to 650 degrees C, production costs up to 1d. (A)/kwh and reactor coolant temperature rises up to half the maximum surface temperature are included. The most significant parameter is the ratio of the reactor coolant temperature rise to maximum surface temperature which causes a maximum increase in production cost of 0.5 per cent, for a +- 5.0 percent change in its value.

Details are given of a monitor for the continuous determination of deuterium in helium. Excess oxygen is added to the gas stream and the oxygen concentration determined before and after passage of the gas through a deuterium-oxygen recombination unit. Oxygen concentrations are measured with galvanic cells. The accuracy is better and +- 10 percent in the range 200 - 5000 v.p.m. deuterium. operating instructions for the Lucas Heights equipment are given.

Empirical methods are given for calculating reactivity changes in HIFAR with changes in fuel loading, poison concentration, and temperature variations. The procedures are derived from the analysis of typical operating programs, reinforced by analogue computer analysis of variation of the important fission product poisons Xenon 135 and Samarium 149.

A description is given of a method used to determine the co-ordinates of successive collision points in a problem associated with the diffusion of neutrons through a hexagonal lattice of circular rods. The basic geometrical relations and a computer flow charge are includes.

The high flux research reactor HIFAR contains ten tons of heavy water which acts as moderator and primary coolant. Over an eighteen months period regular microbiological examinations have been carried out on samples of heavy water taken from various parts of the circuit. The heavy water circuit provides an interesting opportunity for the study of microorganisms because of the high isotopic purity (greater than 99.6 per cent.), and the high chemical purity of the heavy water in the reactor. Furthermore, during its passage through the reactor core the water and suspended bacteria are subjected to intense irradiation, the neutron flux being approximately 10 14 neutrons cm-2 sec-1. The presence of bacteria in the heavy water circuit has been demonstrated and experimental results and methods used are discussed. Some evidence is presented to show that the ion—exchange resin bed contributes nutrients to support bacterial growth.

A description is given of a method suitable for the automatic solution of certain optimum design problems on a digital computer for cases where the number of constraints imposed on the design is not greater than the number of design variables. The problem is transformed to one requiring the minimization or maximization of an unconstrained function, for which a gradient method is used.

Breakaway corrosion of Be in moist CO2 can be avoided if the Be is fabricated using preoxidized powder. The powder is preoxidized by heating in dry O/sub 2/. Preoxidation of Be powder was measured as a function of temperature and time of heating in O/sub 2/. The subsequent reactions of the preoxidized powder in moist CO/sub 2/ at 700 deg C were studied and the effect of increasing amounts of added oxide was measured. A model is proposed to explain the inhibition of corrosion by added oxide. (auth)