This report discusses the results of the environmental protection program at Argonne National Laboratory-East (ANL) for 1990. To evaluate the effects of ANL operations on the environment, samples of environmental media collected on the site, at the site boundary, and off the ANL site were analyzed and compared to applicable guidelines and standards.

By means of the unsteady-flow theory and a bilinear mathematical model, a theoretical study was conducted of the chaotic dynamics associated with the fluid-elastic instability of loosely supported tubes. Calculations were performed for the RMS of tube displacement, bifurcation diagram, phase portrait, power spectral density, and Poincare map. Analytical results show the existence of chaotic, quasi-periodic, and periodic regions when flow velocity exceeds a threshold value.

The COMMIX-1AR/P computer code is designed for analyzing the steady-state and transient aspects of single-phase fluid flow and heat transfer in three spatial dimensions. This version is an extension of the modeling in COMMIX-1A to include multiple fluids in physically separate regions of the computational domain, modeling descriptions for pumps, radiation heat transfer between surfaces of the solids which are embedded in or surround the fluid, a k-{var epsilon} model for fluid turbulence, and improved numerical techniques. The porous-medium formulation in COMMIX allows the code to be applied to a wide range of problems involving both simple and complex geometrical arrangements. The basic equations, underlying assumptions, and solution techniques are presented for the entire computer code, covering both old and new features.

Oxidation of copper and electronic transport in thermally grown large-grain poly-crystals of non-stoichiometric copper oxides were studied at elevated temperatures. Thermogravimetric copper oxidation was studied in air and oxygen at temperatures between 350 and 100 C. From the temperature-dependence of oxidation rates, three different processes can be identified for the oxidation of copper: bulk diffusion, grain-boundary diffusion, and surface control with whisker growth; these occur at high, intermediate, and low temperatures, respectively. Electrical conductivity measurements as a function of temperature (350 - 1134 C) and pO2 (10(sup⁻⁸-1.0 atm) indicated intrinsic electronic conduction in CuO over the entire range of conditions. Electronic behavior of non-stoichiometric Cu(sub 2)O indicates that the charge defects are doubly ionized oxygen interstitials and holes. The calculated enthalpy of formation of oxygen ((Delta)H(sub O(sub 2))) and the hole conduction energy (E(sub H)) at constant composition for non-stoichiometric Cu2O are 2.0 (plus minus) 0.2 eV and 0.82 (plus minus) 0.02 eV, respectively.

A set of experiments, based on the application of the Unsaturated Test method to the reaction of uranium dioxide with EJ-13 water, has been conducted over a period of 182.5 weeks. One half of the experiments have been terminated, while one half are still ongoing. Solutions that have dripped from uranium dioxide specimens have been analyzed for all experiments, while the reacted uranium dioxide surfaces have been examined for only the terminated experiments. A pulse of uranium release from the uranium dioxide solid, in conjunction with the formation of dehydrated schoepite on the surface of the uranium dioxide, was observed during the 39- to 96-week period. Thereafter, the uranium release decreased and a second set of secondary phases was observed. The latter phases incorporate cations from the EJ-13 water and include boltwoodite, uranophane, sklodowskite, compreignacite, and schoepite. The experiments are being continued to monitor for additional changes in solution composition and secondary phase formation, and have now reached the 319-week period.