[en] An evaluation is made of the material flow to be expected up to the year 2000 to and from the various steps in the nuclear cycle. These include the reactors, reprocessing plants, enrichment plants, U mills, U conversion plants, and fuel fabrication plants. A somewhat more-detailed discussion is given of the safety engineering that goes into the design of containers and packages and the selection of the mode of transportation. The relationship of shipping to siting and transportation accidents is considered briefly

[en] One of the most uncertain elements in budget planning is estimating production costs of items that have heretofore only been produced in prototype configurations and quantities. This paper examines the design and development of a mathematical model which computes appropriate prices for new and unique products. The resulting model offers a producer a fair return on his investment and the consumer a fair purchase price

[en] The invention concerns a process for recovering energy in an isotope separation plant comprising a cascade line of compressors each followed by a separation stage crossed by the fluid to be enriched (UF₆). At the outlet of each separation stage there is a cooling system by heat exchange with a coolant, whereby the coolant undergoes a thermodynamic cycle during which it is expanded in a turbine directly coupled to a compressor

No abstract available

[en] A study has been made to predict the vibratory behaviour of the rotating machinery of a gaseous diffusion plant starting from the results obtained for a single machine. TRICASTIN gaseous diffusion plant uses several hundred of enrichment stages but only three different sizes of machine are used. Each individual machine is a vertical assembly of a compressor heat exchanger and diffusion barriers, this column is supported on four lugs on a concrete slab. This slab must accomodate thermal expansion and is placed on neoprene pads. Due to the compactness of the system the mass of concrete is relatively small. Typically the mass of a machine of the intermediate size is 84 T, the mass of associated concrete is 55 T. Furthermore this supporting slab is flexible, meaning that a dynamic analysis of the slab shows several frequencies below the compressor rotational speed. Extensive dynamic tests have been conducted on a machine supported on a rigid foundation. These tests have shown that the main source of mechanical excitation was caused at 50 Hz by the unbalance of the electrical motor rotor. Then the problem remained to predict the behaviour of a group of twenty machines in the plant itself. (orig.)

[en] Natural attenuation of TCE under aerobic conditions at the INEEL Test Area North site was demonstrated largely on the basis of preferential loss of TCE relative to conservative solutes (PCE and H-3) along groundwater flow paths. First order degradation half-lives were calculated from the rate of preferential TCE loss. We are utilizing the same approach at other DOE sites that have aerobic TCE plumes to determine if aerobic natural attenuation of TCE is rapid enough at these sites to be environmentally significant, i.e. if natural attenuation can reduce concentrations to acceptable levels before groundwater reaches potential receptors. The first step in this process was to identify TCE plumes at DOE sites that have the appropriate site conditions and data needed to perform this analysis. The site conditions include the presence of TCE in groundwater at appreciable concentrations in an aerobic aquifer, a co-mingled contaminant that can be used as a conservative tracer (e.g. PCE, H-3, Tc-99), a flow path that represents at least a decade of travel time, and several monitoring wells located along this flow path. Candidate sites were identified through interviews with knowledgeable individuals in the DOE system and by screening the U.S. Dept. of Energy Groundwater Database using the keywords ''TCE'' and ''groundwater''. The initial screening yielded 25 plumes for consideration. These sites had anywhere from one to 37 individual plumes containing TCE. Of the 25 sites, 13 sites were further evaluated because they met the screening criteria or were promising. After contacting DOE personnel from the respective sites, they were divided into three groups: (1) sites that meet all the project criteria, (2) sites that could potentially be used for the project, and (3) DOE sites that did not meet the criteria. The five sites with plumes that met the criteria were: Brookhaven National Laboratory, Lawrence Livermore National Laboratory, Paducah Gaseous Diffusion Plant, Rocky Flats Environmental Technology Site, and the Savannah River Site. Detailed characterization data from the promising plumes is being entered into our database as it is received. The next step is to calculate natural attenuation half-life values for all of these plumes. We will next identify the plumes in which natural attenuation via aerobic degradation of TCE is fast enough that it may be relevant as a component of a remedy. We will then select at least one of these sites and either modify an existing groundwater transport model or, if necessary, create a new model, for this plume. This model will initially include first order decay of TCE, and degradation will be parameterized using the half-live values determined from the field data. The models will be used to simulate the evolution of the TCE plume and to predict concentrations as a function of time at property lines or other artificial boundaries, and where potential receptors are located. Ultimately rate data from th e laboratory studies being performed at INEEL will be incorporated into this model, as well as the model of the TAN site to provide a realistic prediction of degradation rates and plume longevity. Although identifying suitable TCE plumes and obtaining characterization data has taken longer than expected, this process has successfully identified the plumes needed for the detailed modeling activity without adversely impacting the project budget

[en] Ontario Hydro has constructed a Tritium Removal Facility (DTRF) at its Darlington Nuclear Generating Station 'A' to extract tritium from the heavy water moderator systems of its CANDU nuclear reactors. This paper presents results of computer simulations of the DTRF process system to illustrate the major factors being considered in developing an optimum operating strategy

[en] An isotope separation plant comprises a succession of compressors. After each passage of the gaseous fluid through a separation wall, uranium hexafluoride needs to be cooled. This invention concerns the recovery of energy from the cooling fluid of the different compression circuits, the salient feature being that the cooling fluid is subjected to a thermodynamic cycle during which it is expanded in a turbine directly coupled to a compressor

[en] Gaseous diffusion plants that operate in the United States represent a unique combination of nuclear and chemical hazards. Assessing and controlling the health, safety and environmental risks associated with these plants require a unique methodology. Such a methodology has been developed for the diffusion plants and will soon be utilized to assess and control the risk of operating the plants. - The methodology provides an organized approach for identifying hazards and ranking the resulting risk to health, safety and the environment. The analysis is intended to be comprehensive, defendable and cost effective. To meet the goals of the US Department of Energy, a methodology was developed that required modification of existing analysis methods in order to address the unique hazards associated with gaseous diffusion plants. - Several state of the art risk based methods were modified and linked together to form a unique analysis approach that meets the specific safety goals of the gaseous diffusion plants. This approach will address the unique hazards that exist in diffusion plants as well as the unique consequences that can be caused by natural phenomena hazards. A three step approach is used to identify the risk involved in operating the plants. A brief description of each step and information on the transfer of analysis results from one step to the next are provided. - The specific results of the Accident Analysis allow the plants to develop the operating safety requirements, or limits of operation, which define the envelope of operations ensuring that the safety risk is maintained at an acceptable level. (author). 2 refs, 1 fig

[en] Short communication