Particulate agglomeration and separation at high temperatures and pressures are examined, with particular emphasis on the unique features of the direct-cycle application of fluidized-bed combustion. The basic long-range mechanisms of aerosol separation are examined, and the effects of high temperature and high pressure on usable collection techniques are assessed. Primary emphasis is placed on those avenues that are not currently attracting widespread research. The high-temperature, particulate-collection problem is surveyed, together with the peculiar requirements associated with operation of turbines with particulate-bearing gas streams.

Annual report of the Argonne National Laboratory Radiological and Environmental Research Division regarding activities related to molecular physics and chemistry. This report discusses a study on the physical properties and the chemical reactions of atmospheric constituents, with emphasis on the role of pollutants arising from the use of fossil fuels. Special effort is being placed on understanding nucleation phenomena through the study of the molecular properties of gas phase clusters.

A nondestructive autoradiographic technique is described which can provide a verification of the piece count and the plutonium content of plutonium-containing fuel elements. This technique uses the spontaneously emitted gamma rays from plutonium to form images of fuel elements on photographic film. Autoradiography has the advantage of providing an inventory verification without the opening of containers or the handling of fuel elements. Missing fuel elements, substitution of nonradioactive material, and substitution of elements of different size are detectable. Results are presented for fuel elements in various storage configurations and for fuel elements contained in a fast critical assembly.

Quarterly progress report discussing projects by Argonne National Laboratories and subcontractors related to high-temperature batteries.

Plane-strain stress intensity factors for a pressurized hexagonal subassembly duct with a crack in a corner or midflat are presented in convenient graphical form for representative LMFBR hexcan dimensions. Corner-crack calibrations based on several different models of the round hexcan corner are determined first in order to bound the stress intensity factor. A subsequent finite-element analysis of a uniformly pressurized hexcan with a corner crack gives accurate data for the stress intensity factor from which a weight function for this geometry may be constructed. The effects of different numbers of cracks, different locations for cracks, and different loading modes are discussed briefly, and some comments are made on the application of linear elastic fracture mechanics to cracked hexagonal ducts that have suffered a high degree of irradiation embrittlement.

The finite difference methods of Lax, Lax-Wendroff (two-step), donor cell type and finite-element method using Galerkin procedure with B-splines as approximating functions are compared with the method of characteristics for the solution of water-hammer transients as typified by valve closure problems. From the point of view of accuracy, the two-step Lax-Wendroff method and the method of characteristics are comparable and produce the best results. The Lax methods fair worst. The donor cell type and the Galerkin procedure with quadratic B-spline basis as approximating functions display roughly the same accuracy. From the comparison presented, it appears that Galerkin technique offers no substantial advantage over the other finite-difference methods except that of ease in handling boundary conditions as compared to finite-difference methods.

A simple representation for the crack-face displacement is employed to compute a weight function solely from stress intensity factors for a reference loading configuration. Crack face displacements given by the representation are shown to be in good agreement with analytical results for cracked tensile strips, and stress intensity factors computed from the weight function agree well with those for edge cracks in half planes, radial cracks from circular holes, and radially cracked rings. The technique involves only simple quadrature and its efficacy is demonstrated by the example computations. The weight function for a corner crack in an LMFBR hexagonal sub-assembly duct is constructed from stress-intensity-factor results for the uniformly over-pressurized case, and it is shown how this may be used to determine the stress intensity factors.

In view of the practical importance of the drift-flux model for two-phase flow analysis in general and in the analysis of nuclear-reactor transients and accidents in particular, the kinematic constitutive equation for the drift velocity has been studied for various two-phase flow regimes. The constitutive equation that specifies the relative motion between phases in the drift-flux model has been derived by taking into account the interfacial geometry, the body-force field, shear stresses, and the interfacial momentum transfer, since these macroscopic effects govern the relative velocity between phases. A comparison of the model with various experimental data over various flow regimes and a wide range of flow parameters shows a satisfactory agreement.