[en] Systems of hypercomplex numbers, which had been studied and developed at the end of the last century, are nowadays quite unknown to the scientific community. It is believed that study of their applications ended just before one of the fundamental discoveries of our century, Einstein's equivalence between space and time. Owing to this equivalence, not-defined quadratic forms - which are in a quite strong relationship with hypercomplex numbers possessing divisors of the zero - have got concrete physical meaning. The aim of this work is to study these systems of numbers and to describe them in terms of a familiar mathematical tool, i.e. matrix algebra. Moreover, they will show how hypercomplex numbers possessing divisors of the zero candidate themselves to be the most proper mathematical language for treatment of propagative phenomena

[en] Estonia is among the countries who signed the Framework Convention on Climate Change (FCCC) at the UN Conference in Rio de Janeiro in June 1992. The FCCC calls on its parties to inventory national sources, to reduction in greenhouse gases and to development of projects responding to climate change. In 1994, an Estonian Country Study Project was initiated within the U.S. Country Studies Program. The Estonian Country Study Project is comprehensive, covering all sectors and directions of activity in Estonia that might impact climate change or be influenced by Global Climate Change. This book contains a collection of papers, covering the aims of the Estonian Country Study Project

[en] This report describes computer programs used to evaluate nuclear data of fission product (FP) nuclides stored in an evaluated nuclear data library JENDL, especially in the smooth part above the resonance region. Many programs were used for determination of nuclear model parameters, calculation of nuclear data, handling of experimental and/or calculated data, and so on. Among them, reported here are programs for determination of level density parameters (ENSDFRET, LVLPLOT, LEVDES), for making sets of JCL and input data for the theoretical calculation program CASTHY (JOBSETTER, INDES/CASTHY), and for conversion of format of CASTHY output files to the ENDF format (CTOB2). (author). 51 refs

[en] In a structural design using brittle materials such as graphite and/or ceramics it is necessary to evaluate the strength of component under complex stress condition. The strength of ceramic materials is said to be influenced by the stress distribution. However, in the structural design criteria simplified stress limits had been adopted without taking account of the strength change with the stress distribution. It is, therefore, important to evaluate the strength of component on the basis of the fracture model for brittle material. Consequently, the strength evaluation program, STEP, on a brittle fracture of ceramic materials based on the competing risk theory had been developed. Two different brittle fracture modes, a surface layer fracture mode dominated by surface flaws and an internal fracture mode by internal flaws, are treated in the STEP code in order to evaluate the strength of brittle fracture. The STEP code uses stress calculation results including complex shape of structures analyzed by the generalized FEM stress analysis code, ABAQUS, so as to be possible to evaluate the strength of brittle fracture for the structures having complicate shapes. This code is, therefore, useful to evaluate the structural integrity of arbitrary shapes of components such as core graphite components in the HTTR, heat exchanger components made of ceramics materials etc. This paper describes the basic equations applying to the STEP code, code system with a combination of the STEP and the ABAQUS codes and the result of the verification analysis. (author)

[en] Neutron sputtering yields have been measured for radioactive nuclide production reactions at a 14.9 MeV neutron energy. Materials investigated were F, Mg, Al, Sc, Ti, V, Cr, Fe, Co, Ni, Cu, Zr, Nb, Mo, Pd, Ag, Cd, In, Ta, Re, Pt, Au, Pb and SS316. The 14.9 MeV neutrons were produced by a D-T neutron generator at the Fusion Neutronics Source (FNS). The sputtered radioactive materials deposited on the collectors were investigated by the neutron activation analysis. In this work, all measurements were performed in air. Several different distances between the sample and the collector of the sputtered materials were chosen to be 0.2, 0.5, 1.0, 2.0, 3.0 and 5.0 mm to deduce the sputtering yield. The sputtering yields of fifty-seven reactions belonging to (n, 2n), (n, α), (n, p) and (n, np) have been measured. The systematics for reduced sputtering yield as a function of the atomic number (Z) have been derived for (n, 2n), (n, α), (n, p) and (n, np) reactions. A simple power function RS_n=aZ^b was very good to describe the systematics, where the parameters a and b were fitted according to the type of reactions. Most of the deviations between measured values and the systematic results are within a range of 25 %. Backward sputtering yields were lower by a factor of 1.5 to 180 than forward ones. The present results are discussed along with others experimental results and calculation results. (author). 57 refs

[en] It is generally considered that an unsaturated zone is generated in the vicinity of a drift after excavation. In such a zone, invasion of air containing oxygen possibly changes geochemical environment (redox condition) of the rock mass. However, no measurement technique for quantitative understanding of this unsaturated zone is currently available. This study has been started to develop the measuring method in the several years. This year, fundamental information has been obtained through analysis, laboratory experiments using homogeneous rock samples and field measurement described below. (1) experiments on the mechanism of undersaturation in rock. (2) experiments on the measuring method of the extend of unsaturated zone. (author)

[en] Electroplating experiments on uranium foil have been conducted in order to develop low-enriched uranium composite targets suitable for the production of ⁹⁹Mo. Preparation of the foil surface prior to plating was found to play a key role in the quality of the resultant coating. A surface preparation procedure was developed that produces both zinc and nickel coatings with the desired level of coating adherence and coverage. Modifications of the existing plating processes now need investigation to improve to uniformity of the plating thickness, especially at the foil perimeter

[en] Argonne National Laboratory-West (ANL-W) has approximately 680,000 liters of raw sodium stored in facilities on site. As mandated by the State of Idaho and the US Department of Energy (DOE), this sodium must be transformed into a stable condition for land disposal. To comply with this mandate, ANL-W designed and built the Sodium Process Facility (SPF) for the processing of this sodium into a dry, sodium carbonate powder. The major portion of the sodium stored at ANL-W is radioactively contaminated. The sodium will be processed in three separate and distinct campaigns: the 290,000 liters of Fermi-1 primary sodium, the 50,000 liters of the Experimental Breeder Reactor-II (EBR-II) secondary sodium, and the 330,000 liters of the EBR-II primary sodium. The Fermi-1 and the EBR-II secondary sodium contain only low-level of radiation, while the EBR-II primary sodium has radiation levels up to 0.5 mSv (50 mrem) per hour at 1 meter. The EBR-II primary sodium will be processed last, allowing the operating experience to be gained with the less radioactive sodium prior to reacting the most radioactive sodium. The sodium carbonate will be disposed of in 270 liter barrels, four to a pallet. These barrels are square in cross-section, allowing for maximum utilization of the space on a pallet, minimizing the required landfill space required for disposal

[en] The Spallation Neutron Source (SNS) is an accelerator-based short-pulse neutron scattering facility designed to meet the needs of the neutron scattering community in the US well into the next century. SNS is a US Department of Energy (DOE) construction project that is planned to be completed at Oak Ridge National Laboratory late in 2005. SNS is being designed and will be constructed by a 5-laboratory collaboration including Argonne National Laboratory, Brookhaven National Laboratory, Lawrence Berkeley National Laboratory, Los Alamos National Laboratory and Oak Ridge National Laboratory. The functional requirements for the SNS have been set by the scientific community and DOE. SNS will initially operate at 1 MW with one target station operating at 60 Hz and having 18 beam ports for neutron scattering experiments. The first 10 neutron scattering instruments are provided as part of the SNS construction project, and will be selected to span the types of science anticipated to be most important for this facility on the basis of input from the user community. This paper describes the process of selection and design of these first 10 instruments. The extensive R and D program to support the design and construction of these instruments and to help pave the way for future instruments will also be discussed. A set of 10 reference instruments has been developed to help establish the layout of the experiment hall and the interface between the instruments and the target station. This layout and some of the associated interface issues will be described. Examples of the design and performance of some of these reference instruments will also be discussed as an indication of the types of instrumentation involved and the new scientific capabilities that should be available when the SNS becomes operational

[en] The electric transport of high-temperature superconductors, such as YBa₂Cu₃O_7-x (YBCO), can be strongly restricted by the presence of high-angle grain boundaries (GB). This weak-link behavior is governed by the macroscopic GB geometry and the microscopic grain boundary structure and composition at the atomic level. Whereas grain boundaries present a considerable impediment to high current applications of high T_c materials, there is considerable commercial interest in exploiting the weak-link-nature of grain boundaries for the design of microelectronic devices, such as superconducting quantum interference devices (SQUIDs). The Josephson junctions which form the basis of this technology can also be formed by introducing artificial barriers into the superconductor. The authors have examined both types of Josephson junctions by EM techniques in an effort to understand the connection between microstructure/chemistry and electrical transport properties. This knowledge is a valuable resource for the design and production of improved devices