[en] GRESS is a FORTRAN precompiler and run time library which automatically processes computer models and adds derivative-taking capabilities to the normal calculated results. The GRESS system is under development at ORNL and work is proceeding in upgrading test versions of the precompiler to allow processing by GRESS of most of the ANSI X3.9-1978 FORTRAN syntax. Heretofore, a major limitation has been the inability of GRESS to process arrays with more than two dimensions. Consequently, a significant amount of human effort was required to convert three- and higher-dimensional arrays into two-dimensional arrays for processing with GRESS. This report describes the addition of ten operation codes to the GRESS precompiler and run time library to allow application to FORTRAN programs with three-dimensional arrays. The new operation codes were tested on a sample problem. A comparison of CPU time is made for sample problems run on a VAX 8600 computer with one-, two-, and three-dimensional arrays. It is recommended that GRESS be further modified to accommodate higher-dimensional arrays up to the ANSI X3.9-1978 limit of seven dimensions

[en] This report describes GETRANS, a two-dimensional neutron transport code based on the collision probability method. The code uses mixed rectangular (X-Y) and polar coordinates (R-theta); it is capable of representing some parts of a system in X-Y geometry and other parts of the same system in R-theta geometry. Thus cylindrical fuel channels and reactivity devices can be accurately modelled in square or rectangular cells. GETRANS calculates the collision probabilities numerically, solves the multi-group integral transport equation either for a single channel or for a relatively large reactor region containing several channels, and calculates few group cross sections. It is possible to treat fixed source or eigenvalue problems. Anisotropic scattering is accounted for approximately by using transport-corrected cross sections. The boundary conditions can be black, vacuum, reflective or any arbitrary input current distribution. Extensive comparisons with experiments have shown that very satisfactory results can be obtained within acceptable computation times. (author)

[en] In the presence of water, nuclear glasses undergo reactions that may be attributed, in part, to the nature of the chemical bonds set up within the glass structure, and - as regards other reactions - owing to the properties of the solute species. The main reactions involved include ion exchanges, these chiefly involving alkali metals, weakly bonded as these are to the glass network, silicon hydrolysis-condensation reactions, resulting in the formation of a porous hydrated layer, gradually taking on a passivating role, along with the precipitation of crystallized secondary phases. At the temperatures of interest in the disposal context (25 - 90 C degrees), such secondary phases mainly involve clay minerals. Fundamental research studies, conducted to gain an understanding of the mechanisms involved, have highlighted the existence of a strong coupling, at the mesoscopic scale, between the aforementioned chemical reactions, and solute transport, the hydrated layer having the ability to take on a passivating role, as its porosity closes. A new model named GRAAL (for Glass Reactivity with Allowance for the Alteration Layer), includes an explicit description of the four chief alteration mechanisms acting on glass: formation of the passivating layer by glass hydration, diffusion of water across that layer, dissolution of that layer over its outside surface, and precipitation of crystallized secondary phases. The equations may either be solved analytically, for simple cases, or be integrated into a geochemical code, to cater for chemistry-transport couplings, and simulate complex systems

[en] A general method for the extension of GAUSSIAN70, an ab initio molecular orbital computer code, to any number of atomic orbitals is presented. Changes needed to redimension the code are shown. (U.S.)

No abstract available

[en] Environmental qualification (EQ) of equipment important to safety in nuclear power plants ensures its capability to perform designated safety function on demand under postulated service conditions, including harsh accident environment (e. g. LOCA, HELB). The computer code GOTHIC was used to calculate pressure and temperature profiles inside NPP Krsko containment during limiting LOCA and MSLB accidents. The results of the new best-estimate containment code are compared to the older CONTEMPT code using the same input data and assumptions. The predictions obtained by both codes are very similar. As a result of the calculation the envelopes of the LOCA and MSLB pressures and temperatures, as used in FSAR/USAR Chapter 6, can be used in EQ project. (author)

[en] The software of the NAIRI-2 computer plotter has been described. The GRAFIC subprogram system composed in the NAIRI-2 language, enables graphic presentation of information, obtained from the ''NAIRI-2'' computer, as well as from the basic computers (BESM-6, CDC-6500) through the information processing system. Graphic dependency can be shown in the selected scale as a continuous line with program linear interpolation between the points or as seperate points with the construction of X,Y coordinate axes for any given direction. The autocode with some new operators, put in the NAIRI-2 computer translator, is used to operate subprogram system. To illustrate this two programs are given, which can read the tables of five different variables from a magnetic tape and can construct graphic dependence

No abstract available

[en] We present a status update of a full simulation package using GISMO. This package is a functioning tool producing simulation data for the two standard LCD detector designs, in a framework allowing easy changes to the detector designs. The simulation engine, GISMO, is separated from the application code, GISMOAPPS, to allow for a future upgrade to GEANT4 within the same framework

No abstract available