Nuclear material inventory verification techniques for large split-table type fast critical assemblies are being studied under this program. Emphasis has been given to techniques that minimize fuel handling in order to reduce facility down time and radiation exposure to the inventory team. The techniques studied include autoradiography, reactivity, and spectral index measurements.

PART 1: The effectiveness of a neutron well correlation counter (NWCC) and a random driver (RD) for plutonium-containing item assay and loss detection has been studied. The items were 4 in. x 2 in. x 1/4 in. stainless steel-clad metal plates and 6 in. x 3/8 in. stainless steel-clad oxide rods, each in two types of containment. PART 2: A neutron-counting/fuel-weighting system has been developed to provide the capability to assay the ZPR-6 and -9 plutonium fuel canisters rapidly and accurately. This system makes feasible the inline monitoring of fuel transfer from the storage vault to the fuel loading hoods and vice-versa. To exploit fully the system's potential, the equipment is intended to be used in conjunction with an on-line computer having a fuel and fuel-canister data base.

Nondestructive assay (NDA) methods, principally passive gamma measurements and active neutron interrogation, have been studied for their safeguards effectiveness and programmatic impact as tools for making inventories of highly enriched uranium fast critical assembly fuel plates. It was concluded that no NDA method is the sole answer to the safeguards problem, that each of those emphasized here has its place in an integrated safeguards system, and that each has minimum facility impact.

Annual report of the Argonne National Laboratory Radiological and Environmental Research Division regarding activities related to molecular physics and chemistry. This report discusses the Section's work on the physics and chemistry of atoms, ions, and molecules - especially their interactions with external agents such as photons and electrons.

Quarterly report of the Argonne National Laboratory Chemical Engineering Division regarding activities related to properties and handling of radioactive materials, operation of nuclear reactors, and other relevant research.

Quarterly report of the Argonne National Laboratory Chemical Engineering Division regarding activities related to properties and handling of radioactive materials, operation of nuclear reactors, and other relevant research.

Quarterly report on the activities of the Argonne National Laboratory Materials Science Division regarding studies on ceramic (refractory) and metallic materials presently being used or intended for use in coal-conversion processes. The program entails research in the fields of nondestructive testing and failure analysis, together with studies of erosive wear, corrosion, and refractory degradation.

Quarterly report on the activities of the Argonne National Laboratory Materials Science Division regarding economical conversion of coal into clean and usable alternate fuels will be advanced through the use of durable materials systems. This program is designed to provide part of the materials information necessary for successful operation of coal-conversion systems.

Post-test examinations were conducted to determine failure mechanisms, electrode morphologies, and in-cell corrosion of cell components, and to recommend appropriate design changes for improved cell performance and reliability. The reactive electrode materials required the design and construction of a special metallographic glovebox facility. Combinations of macro- and microscopic examinations determined that electrical short circuits were the predominant causes of cell failure. The major short circuit mechanism was extrusion of active material from one electrode and its subsequent contact with the opposing electrode (opposite polarity). Other mechanisms for short circuits included metallic deposits across separators, metallic deposits across the feed-through insulator (electrolyte leakage and corrosion), equipment malfunctions, cell assembly difficulties, etc. Post-test examinations confirmed that the short circuits were of mechanical origin; appropriate design changes were, therefore, recommended. Extensive microscopic examinations were conducted on both negative and positive electrodes to determine the morphology. Agglomeration of Li-Al was observed in the negative electrodes of most multi-plate cells. Examinations showed that the sulfides in the positive electrode remained as discrete particles in an electrolyte matrix. Also discussed are the results of post-test examinations to determine the following: lithium gradients in the negative electrodes, electrode expansion, materials distribution, copper deposition within electrode separators of …

The fuel-pin modeling code LIFE-GCFR has been developed to predict the thermal, mechanical, and fission-gas behavior of a Gas-Cooled Fast Reactor (GCFR) fuel rod under normal operating conditions. It consists of three major components: thermal, mechanical, and fission-gas analysis. The thermal analysis includes calculations of coolant, cladding, and fuel temperature; fuel densification; pore migration; fuel grain growth; and plenum pressure. Fuel mechanical analysis includes thermal expansion, elasticity, creep, fission-product swelling, hot pressing, cracking, and crack healing of fuel; and thermal expansion, elasticity, creep, and irradiation-induced swelling of cladding. Fission-gas analysis simultaneously treats all major mechanisms thought to influence fission-gas behavior, which include bubble nucleation, resolution, diffusion, migration, and coalescence; temperature and temperature gradients; and fission-gas interaction with structural defects.

Quarterly report on the activities of the Argonne National Laboratory Materials Science Division regarding an examination of cores taken from the slag-refractory interface of seven refractories.

MINPACK-1 is a pack of FORTRAN subprograms for the numerical solution of nonlinear equations and nonlinear least-squares problems. This report provides an overview of the algorithms and software in the package, and includes the documentation and program listings.

A technique for incorporating automatic transformations into processes such as the application of inference rules, subsumption, and demodulation provides a mechanism for improving search strategies for theorem proving problems arising from the field of program verification. The incorporation of automatic transformations into the inference process can alter the search space for a given problem, and is particularly useful for problems having broad rather than deep proofs. The technique can also be used to permit the generation of inferences that might otherwise be blocked and to build some commutativity or associativity into the unification process. Appropriate choice of transformations, and new literal clashing and unification algorithms for applying them, showed significant improvement on several real problems according to several distinct criteria.

The results of an international comparison calculation of a large (1250 MWe) LMFBR benchmark model are presented and discussed. Eight reactor configurations were calculated. Parameters included with the comparison were: eigenvalue, k/sub infinity/, neutron balance data, breeding reaction rate ratios, reactivity worths, central control rod worth, regional sodium void reactivity, core Doppler and effective delayed neutron fraction. Ten countries participated in the comparison, and sixteen solutions were contributed. The discussion focuses on the variation in parameter values, the degree of consistency among the various parameters and solutions, and the identification of unexpected results. The results are displayed and discussed both by individual participants and by groupings of participants (e.g., results from adjusted data sets versus non-adjusted data sets).

A computational method is described for improving the accuracy of a given eigenvalue and its associated eigenvector, arrived at through a computation in a lower precision. The method to be described will increase the accuracy of the pair and do so at a relatively low cost. The technique used is similar to iterative refinement for the solution of a linear system; that is, through the factorization from the low-precision computation, an iterative algorithm is applied to increase the accuracy of the eigenpair. Extended precision arithmetic is used at critical points in the algorithm. The iterative algorithm requires O(n²) operations for each iteration.

Three types of metallic thermal insulation were investigated analytically and experimentally: multilayer reflective plates, multilayer honeycomb composite, and multilayer screens. Each type was subjected to evacuated and non-evacuated conditions, where thermal measurements were made to determine thermal-physical characteristics. A variation of the separation distance between adjacent reflective plates of multilayer reflective plates and multilayer screen insulation was also experimentally studied to reveal its significance. One configuration of the multilayer screen insulation was further selected to be examined in sodium and sodium oxide environments. The emissivity of Type 304 stainless steel used in comprising the insulation was measured by employing infrared technology. A comprehensive model was developed to describe the different proposed types of thermal insulation. Various modes of heat transfer inherent in each type of insulation were addressed and their relative importance compared. Provision was also made in the model to allow accurate simulation of possible sodium and sodium oxide contamination of the insulation. The thermal-radiation contribution to heat transfer in the temperature range of interest for LMFBR's was found to be moderate, and the suppression of natural convection within the insulation was vital in preserving its insulating properties. Experimental data were compared with the model and other published results. …

The program and 24 abstracts are given. The abstracts are divided into the following categories: structure and elastic properties, transport and electronic properties, magnetism and superconductivity, and phonons. The engineering of novel materials using sophisticated preparation techniques has received considerable attention in recent years. This interest has been mainly stimulated by recent developments in preparation techniques such as Molecular Beam Epitaxy, Thermal Vapor Deposition and Sputtering. These advances in deposition technology allow for the first time the preparation of layered materials with well defined layer thicknesses approaching interatomic spacing and opens up new avenues for the production and stabilization of materials that do not occur in nature. In addition to the extensive experimental work on artificial semiconductor superlattices there has been a parallel, almost independent, development relating to artificial metallic superlattices. Although the experimental sophistication of the field is considerable the development of major related theoretical ideas has not kept pace. In view of the large body of experimental work, a pressing need exists for the development of conceptual ideas relating to the novel physics that is created by artificially adding a new periodicity to the lattice. Because of this the Office of Naval Research is sponsoring the first "Workshop …

This working note is intended to help a person install and test LINPACK. The instructions are designed for a person whose responsibility is the maintenance of a mathematical software library. It is assumed that the reader has a working knowledge of the system job control language and some experience with numerical calculations. The installation process involves reading a magnetic tape, creating a library from the Fortran source, then running and examining the output of the test aids.

A modified Newton method for unconstrained minimization is presented and analyzed. The modification is based upon the model trust region approach. This report contains a thorough analysis of the locally constrained quadratic minimizations that arise as sub-problems in the modified Newton iteration. Several promising alternatives are presented for solving these sub-problems in ways that overcome certain theoretical difficulties exposed by this analysis. Very strong convergence results are presented concerning the minimization algorithm. In particular, the explicit use of second-order information is justified by demonstrating that the iterates converge to a point that satisfies the second-order necessary conditions for minimization. With the exception of very pathological cases this convergence occurs whenever the algorithm is applied to problems with continuous second partial derivatives.

This report describes the implementation of an algorithm of Stoer and Schittkowski for solving linearly constrained linear least-squares problems. These problems arise in many areas, particularly in data fitting where a model is provided and parameters in the model are selected to be a best least-squares fit to known experimental observations. By adding constraints to the least-squares fit, one can force user-specified properties on the parameters selected. The algorithm used applies a numerically stable implementation of the Gram-Schmidt orthogonalization procedure to deal with a factorization approach for solving the constrained least-squares problem. The software developed allows for either a user-supplied feasible starting point or the automatic generation of a feasible starting point, re-decomposition after solving the problem to improve numerical accuracy, and diagnostic printout to follow the computations in the algorithm. In addition to a description of the actual method used to solve the problem, a description of the software structure and the user interfaces is provided, along with a numerical example.

Nuclear materials inventory-verification techniques for large split-table fast critical assemblies are being studied in this program. Emphasis has been given to techniques that minimize fuel handling in order to reduce facility downtime and radiation exposure to the inventory team. The techniques studied include drawer seals, autoradiography, and spectral index measurements. Two-drawer sealing techniques have been studied, and the relative strengths and weaknesses are pointed out. The rod-type locking mechanism would not disrupt the reactor cooling air flow or interfere with autoradiography but is more expensive to implement. Passive autoradiography was used in a ZPPR inventory to verify to a 93% confidence level that less than 8-kg plutonium was missing. The inventory was completed in four days by a five-member team with radiation exposures well within acceptable limits. Two autoradiographic film packages were developed to distinguish HEU from a DU matrix. The 30-mil pack requires an exposure between 4 and 16 hours and fits into most of the drawers. The 40-mil pack requires only a two-hour exposure but fits into less than half the drawers.

This report presents results from an investigation on the low-frequency fatigue-crack growth behavior of Type 304 stainless steel at 482 and 593 C. Included were continuous-cycling tests with a triangular loading waveform, waveshape-effects tests employing slow-fast, fast-slow and square waveforms, creep-crack growth rate tests, and a block-loading test. The results are compared with similar test data from the literature, and the block-loading test results are compared with results predicted by integrating the relations for da/dN obtained under constant conditions.

This report describes the design of a facility capable of the simultaneous testing of up to 50 high-temperature (400 to 500 C) lithium alloy/iron sulfide cells; this facility is located in the Chemical Engineering Division of Argonne National Laboratory (ANL). The emphasis will be on the lifetime testing of cells fabricated by ANL and industrial contractors to acquire statistical data on the performance of cells of various designs. A computer-based data-acquisition system processes the cell performance data generated from the cells on test. The terminals and part of the data-acquisition equipment are housed in an air-conditioned enclosure adjacent to the testing facility; the computer is located remotely.

Report documenting the creation of a computer program (written in FORTRAN and MACRO) to assist researchers in writing technical documents that include formulas and graphics. It includes operating instructions for using the program and example documents.