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.

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.

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.

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.

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.

A set of simultaneous differential equations is established to describe the temperature distribution for coolant flow in three concentric channels separated by walls of finite thermal conductivity and surrounding a cylindrical heat source. The solution of this set of differential equations is dependent on the heat source function Q(z) which must be known or specified. An assumed function Q(z) constant is taken as being a representative case and the resultant solutions are applied to several geometric arrangements. The system of three channel flow reduces to two channel flow when there is zero heat flow across the outer intermediate wall. This condition may arise if the wall is a perfect insulator, or if the flow in the third channel is zero. For the former case the temperature in the third channel is constant over its length, and in the second the stationary coolant assumes the temperature of the coolant in the middle channel. From the set of differential equations established for two channel flow, treatment similar to that used for three channel flow is adopted and the resultant solutions are applied to several geometric arrangements. Brief mention is made of single channel flow. By assuming that the heat sources is zero …

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 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.

Concentric tubular reactor fuel element geometries to give equal coolant outlet temperatures are presented. Oscillations from tube to tube in thickness and temperatures generally occur but it is possible to eliminate them by choice of the centre element. This may be a fuel rod or a non-heat—producing rod with or without a surrounding annulus of fuel. The geometries and temperatures are dependent on the voidage and on a non-dimensional parameter equivalent to a Biot number based on the channel equivalent diameter.

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.

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.

Fast neutron irradiation affects the properties of beryllium oxide by causing displacements and by causing nuclear transmutations. This report outlines the overall aims of a programmer to investigate this problem, reviews the information from overseas laboratories, and describes the results obtained to date at Lucas Heights. Results are given of measurements of properties of beryllium oxide fabricated by various methods and irradiated to doses of up to 7 x 10(20) avt (fission neutrons) at temperatures of 75 - 700 degrees C. The properties include macroexamination, dimensions, porosity, lattice parameter and line broadening, mechanical properties, thermal conductivity, metallography, and long wavelength neutron scattering. It is shown that an anisotropic lattice growth occurs which results in crumbling of the material at high doses. Fine-grained (<3 mu) materials withstands crumbling up to much higher doses than coase-grained material. The relationship between macroscopic growth, latttice growth, and the cracking and powdering is discussed in some detail and the results used to show the reasons for apparent discrepancies in data from overseas laboratories. Information relating to the defect structure is discussed and it is suggested that interstitial clusters in the basal planes are probably the cause of the marked anisotropy in the lattice growth. The …

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.

A programme is described for determining the neutron enhancement due to the (n,2n) reaction in a reactor moderated by beryllium. For moderation by pure beryllium the enhancement has been found to be 9.7 per cent.

The 25% Cr, 20% Ni type stainless steel has been proposed for use in the Australian High Temperature Gas Cooled Reactor in core structures, and in hot gas ducting. Thus a knowledge of the compatibility of this steel with high pressure carbon dioxide was required. Rates and mechanisms of corrosion were investigated for machined, vapour blasted, and etched pretreated samples of this steel, exposed to carbon dioxide up to 3,000 hours in the temperature range 650 degrees C at gas pressures from 3 p.s.i.g. to 280 p.s.i.g. Oxide film flaking as apparent at all temperatures investigated but was only severe for pre-ground samples at 710 degrees C and above, and for pre-vapour blasted samples at 760 degrees C and above. However, severe intergranular penetration was observed in pre-etched samples on exposure to carbon dioxide at 650 degrees C and above. Pressure of the gas appeared to have no systematic effect on the corrosion rate, at least in the temperature range investigated. The maximum useful temperature for which the steel could be used would be limited by the amount of oxide flaking permissible. In reactor gas circuits where a small amount of scale flaking could be tolerated, the steel is satisfactory …

As part of a general study of the co-ordination chemistry of beryllium, the beryllium salicylate complexes have been investigated by ion exchange procedures. The evidence indicates that a neutral 1 : 1 and an anionic 1 : 2 chelate exist in solution under appropriate conditions, and their stability constants have been determined by ion-exchange methos. The values of the stability constants were found to be [beta]1 = 4.97 x 10 (12), and [beta]2 = 2.63 x 10(22).

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.

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 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.

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.

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.

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.

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.