Showing papers in "Nuclear Technology in 1982"
135 citations
TL;DR: In this article, the rates of migration, retardation factors, and distribution coefficients of radionuclides in the various horizons of three typical soils (podsol, ranker, and brown soil) were determined by employing batch procedures, column experiments, and evaluating the measured distribution of these radions in the field.
Abstract: Rates of migration, retardation factors, and distribution coefficients of /sup 137/Cs and /sup 90/Sr were determined in the various horizons of three typical soils (podsol, ranker, and brown soil) by employing batch procedures, column experiments, and evaluating the measured distribution of these radionuclides in the field as a result of their deposition from worldwide fallout. To obtain the distribution coefficients of the radionuclides for each soil horizon from the column experiments, the radionuclide distribution in the undisturbed soil monoliths (1 m long, 30-cm diam) was determined from the outside by a scanner technique after various times. The columns were irrigated with rainwater using the same quantities as observed at the site of sampling. Tritium labeled rainwater was used to obtain the hydrodynamic properties of the soil columns (pore water velocity, dispersion coefficient, and volumetric moisture content). Assuming that the fallout investigations yielded the most realistic results, the observations suggest that column experiments performed in the laboratory under approximately natural conditions can be used to obtain fairly realistic information about the migration of /sup 137/Cs and /sup 90/Sr in these soils. The use of distribution coefficients from batch methods for the prediction of radionuclide movement, on the other hand, can bemore » misleading, especially in soil horizons rich in organic matter.« less
124 citations
108 citations
Abstract: A bend test was developed to obtain ductility measurements on a large number of alloy variants being irradiated in the form of miniature disks. Experimental results were shown to be in agreement wi...
91 citations
TL;DR: The theory of the nuclear shell model has been studied extensively in the literature as discussed by the authors, with the focus on nuclear energy and its application in nuclear technology. pp. 406-406.
Abstract: (1982) Theory of the Nuclear Shell Model Nuclear Technology: Vol 56, No 2, pp 406-406
83 citations
TL;DR: In this article, cold-worked Zr-2.5 wt% Nb pressure tubes for Canada Deuterium Uranium Pressurized Heavy Water Reactors are made by hot extruding hollow billets into tubes that are cold worked to size and to develop their tensile strength.
Abstract: Cold-worked Zr-2.5 wt% Nb pressure tubes for Canada Deuterium Uranium Pressurized Heavy Water Reactors are made by hot extruding hollow billets into tubes that are cold-worked to size and to develop their tensile strength. All manufacturing steps are closely controlled, and the tubes meet very stringent specifications. To ensure that the tubes are free of unacceptable defects, the ingots, billets, and finished tubes are ultrasonically inspected. The strength and flaw tolerance of the tubes have been measured. Tubes removed from both research and operating power reactors have been examined to measure changes in each of these properties due to the effects of reactor operaton. All tests show that cold-worked Zr-2.5 wt% Nb pressure tubes have excellent tensile strength and resistance to failure.
72 citations
TL;DR: In this paper, the introduction to Metallurgical Thermodynamics (2nd ed.) is presented. But this paper is based on the same model as the one presented in this paper.
Abstract: (1982). Introduction to Metallurgical Thermodynamics (2nd ed.) Nuclear Technology: Vol. 56, No. 3, pp. 596-597.
70 citations
65 citations
65 citations
TL;DR: The main feature of an advanced pressurized water reactor (APWR) with improved fuel utilization is a plutonium-enriched tight lattice core integrated in an unchanged primary system of a common pres...
Abstract: The main feature of an advanced pressurized water reactor (APWR) with improved fuel utilization is a plutonium-enriched tight lattice core integrated in an unchanged primary system of a common pres...
63 citations
TL;DR: In this paper, a failure detection scheme consists of a set of five Kalman filters and a logical means for combining estimated state variables with instrument signals to produce decision functions, which identify faults, as they occur, in each of five instruments.
Abstract: A technique of functional redundancy (as opposed to hardware redundancy) for detecting incipient failures in process instruments is applied to a simulation of the loss-of-fluid test pressurizer. The failure detection scheme consists of a set of five Kalman filters and a logical means for combining estimated state variables with instrument signals to produce decision functions, which identify faults, as they occur, in each of five instruments. Test data from the simulated plant show that prompt detection of both bias faults and high noise faults is possible during small transient fluctuations in the pressurizer from its nominal operating state.
TL;DR: In this article, the generalized likelihood ratio (GLR) technique was used to detect failures in the sensors of a pressurized water reactor (PWR) pressurizer and identify bias in one of three level sensors.
Abstract: The generalized likelihood ratio (GLR) technique performs statistical tests on the innovations sequence of a Kalman filter state estimator. Using the results of these tests, failures in the sensors of a pressurized water reactor pressurizer are detected and identified. A third-order, linear model of the pressurizer dynamics, which is required by both the GLR and Kalman filter formulations, is developed from first principles. Using actual pressurizer data, the GLR method is employed to identify a bias in one of three level sensors.
TL;DR: In this paper, heat exchanger-thermal-hydraulic fundamentals and design are discussed. But the authors focus on the design of the Heat Exchanger-Thermal-Hydraulic Fundamentals.
Abstract: (1982). Heat Exchangers-Thermal-Hydraulic Fundamentals and Design. Nuclear Technology: Vol. 58, No. 3, pp. 556-556.
TL;DR: In this paper, it was shown that temperature is the major factor affecting the penetration rate of silicon carbide by palladium, and the effects of kernel composition, Pd concentration, other fission products, and SiC properties are secondary.
Abstract: Silicon carbide is the main barrier to fission product release from coated particle fuels. Consequently, degradation of the SiC must be minimized. Electron microprobe analysis has identified that palladium causes corrosion of the SiC in irradiated coated particles. Further ceramographic and electron microprobe examinations on irradiated particles with kernels ranging in composition from UO/sub 2/ to UC/sub 2/, including PuO/sub 2 -x/ and mixed (Th, Pu) oxides, and in enrichment from 0.7 to 93.0% /sup 235/U revealed that temperature is the major factor affecting the penetration rate of SiC by Pd. The effects of kernel composition, Pd concentration, other fission products, and SiC properties are secondary.
TL;DR: A Materials Characterization Center (MCC) has been established by the U.S. Department of Energy at the Pacific Northwest Laboratory (PNL) as discussed by the authors, where five standard leach tests and typical results usi...
Abstract: A Materials Characterization Center (MCC) has been established by the U.S. Department of Energy at the Pacific Northwest Laboratory (PNL). Five proposed standard leach tests and typical results usi...
TL;DR: Sorption experiments have been performed to determine the diffusion and sorption properties of cesium and strontium in crushed granite particles with one granite from Finnsjoen outside Forsmark on the east coast of Sweden as mentioned in this paper.
Abstract: Sorption experiments have been performed to determine the diffusion and sorption properties of cesium and strontium in crushed granite particles with one granite from Finnsjoen outside Forsmark on the east coast of Sweden, and one granite from the Stripa mine in central Sweden. Granite samples have been crushed and screened, and six different particle size fractions from 0.10 to 0.12 mm and 4 to 5 mm of each rock have been used in the experiments. The initial concentrations of inactive cesium and strontium were 10 to 15 ppm. A ''synthetic'' groundwater was used. The adsorption isotherm was found to be linear for strontium but nonlinear for cesium. One conclusion from this is that a prediction of cesium migration velocity from one single distribution coefficient is inappropriate. The experimental data indicate that the amount of sorption is dependent not only on the mass of granite particles but also to some extent on the size of the particles. A distinction has been made between sorption on external surfaces and inner surfaces. The amount of external surface adsorption was found to vary from 15 to 40% of the total adsorption capacity for the particle size fraction of 0.10 to 0.12 mm to amore » few percent or less for the largest particles used. Except for the largest particles, the experimentally determined diffusivities were found to lie in the interval expected from literature data on electric conductivities. The diffusivities were found to increase with increasing particle size.« less
TL;DR: In this paper, cold-worked Type 316 stainless steel was irradiated in the High Flux Isotope Reactor, which produces atomic displacement damage as well as helium through a two-step neutron absorption reaction with nickel.
Abstract: In a Tokamak reactor that operates in a cyclic mode, thermal stresses will result in fatigue in structural components, especially in the first wall and blanket. There has been limited work on fatigue in irradiated alloys, but none on irradiated materials containing irradiation-induced helium, which will be characteristic of fusion service. Specimens of 20% cold-worked Type 316 stainless steel were irradiated in the High Flux Isotope Reactor, which produces atomic displacement damage as well as helium through a two-step neutron absorption reaction with nickel. The specimens were irradiated at 430/sup 0/C to up to 15 dpa and 900 at. ppm helium. Following irradiation, specimens were tested in a vacuum at the irradiation temperature with total strain ranges from 0.30 to 2.0%. The irradiated specimens exhibited a reduction in fatigue life of a factor of 3 to 10 compared to unirradiated material. An endurance limit was observed at a total strain range of 0.3% for irradiated material.
TL;DR: In this paper, an integrated experimental approach to mechanistic studies of the leaching and dissolution of irradiated UO2 fuel is described, which includes an investigation of the solubility of the uO2 matrices.
Abstract: An integrated experimental approach to mechanistic studies of the leaching and dissolution of irradiated UO2fuel is described. The program includes an investigation of the solubility of the UO2 mat...
TL;DR: The role of suspended particles as carriers of dissolved nuclides from high-level radioactive waste repositories has been investigated in this article, depending on the concentrations of the suspended particles and their densities.
Abstract: The role of suspended particles as carriers of dissolved nuclides from high-level radioactive waste repositories has been investigated Depending on the concentrations of suspended particles and th
TL;DR: In this article, the degradation of polyethylene and polyvinyl chloride cable materials in the containment building of an operating nuclear reactor has been investigated, and it was determined that strong synergisms of radiation and elevated temperature, and also dose-rate effects, lead to surprisingly rapid degradation rates found with these materials.
Abstract: The deterioration of polyethylene and polyvinyl chloride cable materials in the containment building of an operating nuclear reactor has been investigated. Since the maximum dose experienced by the cable materials was only 2.5 Mrad during about 12 yr of operating life, the extent of material degradation was surprising. Laboratory aging experiments on the two materials established that the cause of the material deterioration in the plant was radiation-induced oxidation. The degradation rate was correlated with local levels of radiation intensity. It was determined that strong synergisms of radiation and elevated temperature, and also dose-rate effects, lead to the surprisingly rapid degradation rates found with these materials. It is concluded that in the design of laboratory methods for aging and qualification testing of organic materials for use in a nuclear plant environment, the possible occurrence of dose-rate effects and synergisms needs to be taken into account.
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TL;DR: In this paper, the authors proposed a complementary cumulative distribution function (CCDF) with appropriately chosen parametric form, which takes into account several different aspects of risk, including overall or average risk, accidents posing high relative risks, the rate at which accident probability decreases with increasing accident consequences, and the impact of high frequency, low consequence accidents.
Abstract: Approaches to the regulation of risk from technological systems, such as nuclear power plants or chemical process plants, in which potential accidents may result in a broad range of adverse consequences must take into account several different aspects of risk. These include overall or average risk, accidents posing high relative risks, the rate at which accident probability decreases with increasing accident consequences, and the impact of high frequency, low consequence accidents. A hypothetical complementary cumulative distribution function (CCDF), with appropriately chosen parametric form, meets all these requirements. The Farmer limit line, by contrast, places limits on the risks due to individual accident sequences, and cannot adequately account for overall risk. This reduces its usefulness as a regulatory tool. In practice, the CCDF is used in the Canadian nuclear licensing process, while the Farmer limit line approach, supplemented by separate qualitative limits on overall risk, is employed in the United Kingdom.
TL;DR: The most actively pursued ULSI separation methods work with uranium vapor, organic uranium compounds, or uranium hexafluoride (UHF) as discussed by the authors, and the atomic vapor process has reached the highe...
Abstract: Today, the most actively pursued uranium laser isotope separation methods work with uranium vapor, organic uranium compounds, or uranium hexafluoride. The atomic vapor process has reached the highe...
TL;DR: In this paper, the authors present the experimental and theoretical foundation for this performance, with particular emphasis on the geometrical response function and the statistical limits of fuel-motion resolution.
Abstract: Fuel-motion surveillance using the fast-neutron hodoscope in TREAT experiments has advanced from an initial role of providing time/location/velocity data to that of offering quantitative mass results. The material and radiation surroundings of tha test section contribute to intrinsic and instrumental effects upon hodoscope detectors that require detailed corrections. Depending upon the experiment, count rate compensation is usually required for deadtime, power level, nonlinear response, efficiency, background, and detector calibration. Depending on their magnitude and amenability to analytical and empirical treatment, systematic corrections may be needed for self-shielding, self-multiplication, self-attenuation, flux depression, and other effects. Current verified hodoscope response (for 1- to 7-pin fuel bundles) may be paramatrically characterized under optimum conditions by 1-ms time resolution; 0.25-mm lateral and 5-mm axial-motion displacement resolution; and 50-mg single-pin mass resolution. The experimental and theoretical foundation for this performance is given, with particular emphasis on the geometrical response function and the statistical limits of fuel-motion resolution. Comparisons are made with alternative diagnostic systems.
TL;DR: A nationally coordinated materials development program for fast breeder reactors is being conducted to improve the economy and reliability of replaceable core components as discussed by the authors, which is comprised of three phases: component development, core component selection, and component assembly.
Abstract: A nationally coordinated materials development program for fast breeder reactors is being conducted to improve the economy and reliability of replaceable core components. The program is comprised o...
TL;DR: A preferential dissolution by a factor of 1.1 to 10 of the radiogenic nuclides 234U, 230Th, and 228Th relative to their corresponding structurally incorporated isotopes 238U and 232Th has been investigated in this paper.
Abstract: A preferential dissolution by a factor of 1.1 to ~10 of the radiogenic nuclides 234U, 230Th, and 228Th relative to their corresponding structurally incorporated isotopes 238U and 232Th has been obs...
TL;DR: In this article, the sorption of four radionuclides, /sup 90/Sr, /sup 137/Cs, /Sup 144/Ce, and /sup 237/Pu, on drill core material from two rock formations in the Canadian Shield has been studied as part of the Canadian Nuclear Fuel Waste Management Program.
Abstract: The sorption of four radionuclides, /sup 90/Sr, /sup 137/Cs, /sup 144/Ce, and /sup 237/Pu, on drill core material from two rock formations in the Canadian Shield has been studied as part of the Canadian Nuclear Fuel Waste Management Program. For all four radionuclides, sorption increased with increased mafic mineral content of the rock. Autoradiographic investigations showed enhanced sorption on dark, or mafic, minerals and high sorption on chlorite infilling material in a closed fracture. Desorption was less complete than sorption after the same equilibration time, indicating a degree of irreversible sorption, or slower desorption kinetics. The effect of surface roughness (measured by mercury porosimetry) on sorption was not as great as that of the chemical and mineral composition of the rock.