Determination of trace metals in nuclear-grade uranium dioxide by X-ray fluorescence spectrometry. A method is described for the simultaneous determination of low concentrations of Ca, Cr, Cu, Fe, Mn and Ni in nuclear-grade uranium dioxide by X-ray fluorescence spectrometry, without the use of chemical treatment. Samples are prepared in the form of double-layer pellets with boric acid as a binding agent. Standards are prepared in a U 3 O 8 matrix, which is more chemically stable than UO 2 and has similar matrix behaviour.
The correlation coefficients for calibration curves are better than 0. Erros range from 2. Standard test methods for chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade boron carbide. In a very high temperature reactor VHTR , graphite will be used not only for as a moderator and reflector but also as a major structural component due to its excellent neutronic, thermal and mechanical properties.
In the VHTR, wear of graphite components is inevitable due to a neutron irradiation-induced dimensional change, thermal gradient, relative motions of graphite components and a shock load such as an earthquake. Large wear particles accumulated at the bottom of a reactor can influence the cooling of the lower part and small wear particles accumulated on the primary circuit and heat exchanger tube can make it difficult to inspect the equipment, and also decrease the heat exchange rate.
In the present work, preliminary wear tests were performed at room temperature in ambient air environment to understand the basic wear characteristics of selected nuclear grade graphites for the VHTR. A model for predicting the lifetimes of Grade -2 titanium nuclear waste containers. Whiteshell Labs. The development of a model to predict the lifetimes of Grade -2 titanium containers for nuclear fuel waste is described.
This model assumes that the corrosion processes most likely to lead to container failure are crevice corrosion, hydrogen-induced cracking and general corrosion. Because of the expected evolution of waste vault conditions from initially warm Grades -2 and are presented. Also, the effects of impurities in the Grade -2 material are discussed.
Special attention is. Establishment of quality system program for the manufacture of nuclear grade steels. Recently, the pressure vessels employed in the fields of nuclear power generation, petroleum refining, and chemical industry tend to be large size and high performance, therefore thick steel plates and forgings of high quality are demanded, and the establishment and maintenance of strict quality assurance system for material production are required.
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A Quality System Certificate Material has been granted to Mizushima Works on March 11, , by the American Society of Mechanical Engineers for the manufacture of steel plates and forgings of nuclear grade. The quality system manual as the basis of quality assurance activities, the organization for quality assurance, its responsibility and authority, the discrimination of materials, the control of manufacturing processes, the qualification of workers in charge of nondestructive test, welding, heat treatment and others, the management of tests and inspections, the management of products with faults and repairing measures, and internal supervisory system are explained.
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The wide use of computers is novel in the field of quality system program. Kako, I. Nuclear heat-load limits for above- grade storage of solid transuranium wastes. Nuclear safety and heat load limits were established for above- grade storage of transuranium TRU wastes. Nuclear safety limits were obtained from a study by J.
Forstner and are summarized. Heat load limits are based on temperature calculations for TRU waste drums stored in concrete containers hats , and results are summarized.
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Waste already in storage is within these limits. The limiting factors for individual drum heat load limits were 1 avoidance of temperatures in excess of 0 F decomposition temperature of anion resin when anion resin is present in a concrete hat, and 2 avoidance of temperatures in excess of 0 F ignition temperature of paper at any point inside a waste drum. The limiting factor for concrete had heat load limits was avoidance of temperatures in excess of 0 F melt point of high density polyethylene at the drum liners.
A temperature profile for drums and hats filled to recommended limits is shown. Equations and assumptions used were conservative. Standard test methods for chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade uranium dioxide powders and pellets. Stereological estimation of nuclear volume in benign and malignant melanocytic lesions of the skin. Inter- and intraobserver variability of malignancy grading.
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The volume-weighted, mean nuclear volume nuclear vv may be estimated without any assumptions regarding nuclear shape using modern stereological techniques. As a part of an investigation concerning the prospects of nuclear vv for classification and malignancy grading of cutaneous melanocytic tum Performance evaluation of nuclear grade filters for the Trupact-I pressure equalization system. The performance of high-efficiency-particulate-air and ultra-low- penetration-air filters subjected to extreme environments of temperature, shock, pressure, and particulate loading was evaluated in a test program at the Sandia National Laboratories.
The test program was initiated to evaluate the feasibility of using commercially available nuclear-grade filters in the filtered pressure equalization system of a contact-handled transuranic waste transport system, called TRUPACT-I. The filtered pressure equalization system of TRUPACT-I assures containment of the activity within the limits permitted by federal regulations and simultaneously equalizes the pressure between the cavity of the packaging and the environment, and minimizes the buildup of radiolytically generated gases.
The filters were exposed to temperatures, pressures and stresses that exceed expected environments in normal and accident conditions of transport. The performance of the test filters was determined by measuring and quantifying filter efficiency and the Darcy constant. In addition, the integrity of the filter housing was evaluated using non-destructive helium leak testing. The details of the test program and results obtained from the tests are presented in this paper.
The tensile deformation behavior of nuclear-grade isotropic graphite posterior to hydrostatic loading. The effects of prehydrostatic loading on microstructural changes and tensile deformation behavior of nuclear-grade isotropic graphite have been examined. Scanning electron micrographs show that formation of microcracks associated with delamination between basal planes occurs under hydrostatic loading.
Hydrostatic loading on specimens results in the decrease in tensile strength and increase in residual strain generated by the applied tensile stress at various levels, indicating that the graphite material is weakened by hydrostatic loading. The effects of prehydrostatic loading on the tensile stress-strain behavior of the graphite were examined in more detail.
The ratio of stress after hydrostatic loading to that before hydrostatic loading on the stress-strain relationship remains almost unchanged irrespective of strain. Availability analysis of safety grade multiple redundant controller used in advanced nuclear safety systems. The voting logics for redundant architectures are based on the forwarding error detection.
It means that the receivers perform the voting logics based on the status information of transmitters. To analyze the availability of SPLC, we construct the Markov model and simplify the model adopting the system unavailability rate. Acoustic emission during tensile deformation and fracture of nuclear grade AISI type stainless steel specimens with notches.
Acoustic emission generated during tensile deformation and fracture of nuclear grade AISI type stainless steel specimens with notches has been studied. The extent of acoustic activity generated depends on notch tip severity, notch tip blunting and tearing of the notches. Acoustic emission technique can be used to estimate the size of an unknown notch. Investigating the effects of stress on the pore structures of nuclear grade graphites. Taylor, Joshua E.
Graphite is used as a moderating material and as a structural component in a number of current generation nuclear reactors. During reactor operation stresses develop in the graphite components, causing them to deform. It is important to understand how the microstructure of graphite affects the material's response to these stresses.
A series of experiments were performed to investigate how the pore structures of Pile Grade A and Gilsocarbon graphites respond to loading stresses. A compression rig was used to simulate the build-up of operational stresses in graphite components, and a confocal laser microscope was used to study variation of a number of important pore properties.
Values of elastic modulus and Poisson's ratio were calculated and compared to existing literature to confirm the validity of the experimental techniques. Mean pore areas were observed to decrease linearly with increasing applied load, mean pore eccentricity increased linearly, and a small amount of clockwise pore rotation was observed.
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The response to build-up of stresses was dependent on the orientation of the pores and basal planes and the shapes of the pores with respect to the loading axis. It was proposed that pore closure and pore reorientation were competing processes. Grading nuclear , cortical and posterior subcapsular cataracts using an objective scatter index measured with a double-pass system.
To evaluate objectively intraocular scattering in eyes with nuclear , cortical and posterior subcapsular cataracts by means of an objective scatter index OSI obtained from double-pass images. To compare the results with those obtained using clinical conventional procedures. In this prospective, observational, cross-sectional, non-consecutive case series study, eyes with cataracts of patients were analysed eyes had nuclear , 41 eyes had cortical and 24 eyes had posterior subcapsular cataracts. The control group consisted of eyes of 68 healthy patients. The results of the study showed that OSI is a useful parameter for evaluating large amounts of intraocular scattering that can be used, in combination with other conventional procedures, as a valuable tool in clinical practice to grade cataracts objectively.
The present paper deals with evaluation of organic base nuclear grade anion exchange resins Amberlite IRN and Purolite NRW by application of radioactive tracer isotopes I and 82 Br. The evaluation was made on the basis of their performance in iodide and bromide ion-isotopic exchange reactions carried out under different experimental conditions like temperature and ionic concentration. It was observed that during iodide ion-isotopic exchange reaction at a constant temperature of Also at a constant temperature of The identical trend was observed for the two resins during bromide ion-isotopic exchange reaction.
The results of present investigation also indicate that during the two ion-isotopic exchange reactions, for both the resins, there exists a strong positive linear correlation between amount of ions exchanged and concentration of ionic solution; and strong negative correlation between amount of ions exchanged and temperature of exchanging medium.
The overall results indicate that under identical experimental conditions, Amberlite IRN resins show superior performance over Purolite NRW resins. Oxidation of PCEA nuclear graphite by low water concentrations in helium. Contescu, Cristian I. Accelerated oxidation tests were performed to determine kinetic parameters of the chronic oxidation reaction i.
Since that H - graphite is now unavailable, it is urgently needed to characterize chronic oxidation behavior of new graphite grades that are being considered for use in gas-cooled reactors. The Langmuir—Hinshelwood mechanism of carbon oxidation by water results in a non-linear reaction rate expression, with at least six different parameters. Data analysis employed a statistical method based on multiple likelihood estimation of parameters and simultaneous fitting of non-linear equations.
The results show significant material-specific differences between graphite grades PCEA and H - which were attributed to microstructural dissimilarity between the two materials. It is concluded that kinetic data cannot be transferred from one graphite grade to another.