Probe for determination of ash in coal stockpiles

A portable low radioactivity probe was developed for the determination of ash in coal stockpiles. The probe employs two radioactive gamma-ray sources ¹³³Ba and ¹³⁷Cs of combined activity 1.5 MBq.     

Layout of an internally heated gas generator for the steam gasification of coal

Industrial-scale steam gasification of coal using heat from high temperature reactors requires research and development on allothermal gas generators. Bergbau-Forschung GmbH, Essen, does theoretical and experimental work in this field. The experiments deal with reaction kinetics, heat transfer and material tests. Their significance for the layout of a full-scale gas generator is shown. Including material specifications, the feasibility of a gasifier, characterized by a fluid bed volume of 318 m³ and a heat transferring area of 4000 m², results. The data, now available, are used to determine the gasification throughput from the heat balance, i.e. the equality of heat consumed and heat transferred. Throughputs of about 50 t/hr of coal are possible for a single gas generator, the helium outlet temperature of the HTR being 950°C. Bergbau-Forschung has commissioned a medium-scale pilot plant (200 kg/hr).     

Operation of a semi-technical pilot plant for nuclear aided steam gasification of coal

After intensive investigations on a small scale, the principle of the process has been tested in a semi-technical pilot plant. In its gasifier a fluidized bed of approx. 1 m² cross-section and of up to 4 m height is operated at 40 bar. Heat is supplied to the bed from an immersed heat exchanger with helium flowing through it, which is heated electrically. The plant was commissioned in 1976 and has been in hot operation for approx. 23 000 h, over 13 000 h whereof account for coal gasification. Roughly 1 600 t of coal have been put through. During recent years the processing of German caking long-flame gas coal and the marked improvement of the process by the use of catalysts have been demonstrated successfully.     

Ion beam induced damage in CaF2

The change in lattice parameter and the induced damage are studied in single crystal CaF₂ bombarded by a 15 MeV Cl ion beam. The lattice parameter change (strain) and the damage for increasing ion beam dose (5 × 10¹²/cm² to 7 × 10¹⁵/cm²) is observed via X-ray rocking curve analysis using a double-crystal diffractometer and X-ray reflection topography. The ion beam energy (range = ～ 4.5 μm in CaF₂) is such that both the electronic region and the nuclear cascade region of energy loss show up in the diffraction signal. By kinematical X-ray diffraction theory analysis, the progress of strain/damage depth profile with increasing beam dose is shown explicitly. The increase in strain is nonlinear with beam dose for the dose range studied. For increasing beam dose, the strain level in the electronic energy loss region is fixed, while that in the nuclear collision loss region increases effectively until that region becomes completely amorphous.     

Effect of Heating and Power Plants on the Environment

The OAO Gazprom has proposed that the consumption of natural gas by heating and power plants in Russia be decreased by 30 billion m³ per year and that this volume of gas be replaced by coal. Data on the environmental effects and effects on human health resulting from enterprises in the coal industry and heating and power plants burning coal and natural gas are analyzed. The volume of emissions of harmful substances into the atmosphere when 30 billion m³ of gas are replaced at heating and power plants by kansko-achinsk and hard kuznets coal is calculated (for three variants). The calculations show that decreasing the amount of gas burned by heating and power plants and increasing at the same time the consumption of coal results in a substantial increase in harmful emissions into the environment.     

Gasification of coal with steam using heat from HTRs

In existing coal gasification processes a substantial part of the coal is used to provide the heat for the reaction, for the generation and superheating of steam and for the production of oxygen. By using heat from HTRs to substitute this part, the coal is then completely used as raw material for gas production. This offers the following advantages compared with the existing processes: a saving of coal, less CO₂ emission and, in countries with high coal costs, lower gas production costs. A survey is given of the state of the project, discussing the first design of a commercial gasifier, the influence of the helium outlet temperature of the HTR, kinds of products, and the overall efficiency of the plant. The aim of the development is to demonstrate the use of heat from an HTR for full scale coal gasification, starting in 1985.     

The European X-ray free-electron laser facility in Hamburg

Activities on free-electron laser (FEL) X-ray sources, based on linear accelerators, to produce spatially coherent, ultra-short (∼100 fs) pulses with very high peak brilliance (10²⁸-10³² photons/s/mm²/mrad²/0.1% BW) are summarized, with special emphasis on the European XFEL project in Hamburg. The scientific case includes time-resolved studies of dynamics on sub-ps scales, structural studies by imaging of non-periodic systems, and investigation of high energy-density phenomena such as non-linear X-ray optics and the production of warm dense matter. Examples are presented, with reference to the experience gained on the presently operational facilities, FLASH at DESY, Hamburg and LCLS in Stanford, California.     

Modification of Ti6Al4V Corrosion Property by Nitrogen Ion Implantation

In this project the effect of nitrogen ion implantation on the corrosion resistance of Ti6Al4V alloy is studied. Nitrogen ions are implanted with four fluences from 8 × 10¹⁷ to 5 × 10¹⁸ ions/cm² in the Ti6Al4V substrates. The effect of ion implantation on surface morphology and roughness is investigated with Atomic Force Microscopy. X-ray diffraction is used for phase analysis of the samples and as a result Ti₂N(105) in the fluence of 1 × 10¹⁸ ions/cm² and TiN in fluence of 2 × 10¹⁸ ions/cm² are observed. For corrosion resistance analysis in one molar sulfuric acid a potansiostate device is used and the best corrosion resistance is obtained for the fluence 2 × 10¹⁸ ions/cm². Moreover corrosion resistance variation is explained by microstructure considerations.     

Peak identification of L X-ray spectra of elemental Np and U

The L X-ray photons emitted by transuranic (TRU) elements are expected to be useful for developing nondestructive TRU monitors. Energy spectra of L X-rays emitted by ²⁴¹Am, ²³⁸Pu and ²³⁹Pu sources were measured by a transition edge sensor (TES) microcalorimeter, which allowed precise peak identification with high energy resolution. In the measurements using the TES microcalorimeter, the full width at half-maximum energy resolution was 62.6 eV at 17.222 keV for ²³⁹Pu source, 62.5 eV at 17.222 keV for ²³⁸Pu source and 60.9 eV at 17.751 keV for ²⁴¹Am source. This study demonstrates the separation of ²⁴¹Am and plutonium isotopes by L X-ray spectroscopy using a TES microcalorimeter.     

Effect of swift heavy ion irradiation on hydrothermally synthesized hydroxyapatite ceramics

The effect of swift heavy ion irradiation on hydroxyapatite (HAp) ceramic - a bone mineral was investigated. The irradiation experiment was conducted using oxygen ions at energy of 100 MeV with three different fluences of 10¹², 10¹³, 10¹⁴ ions/cm². The irradiated samples were characterized by glancing angle X-ray diffraction (GXRD), atomic force microscopy (AFM), dynamic light scattering (DLS), photoluminescence spectroscopy (PL), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX). GXRD confirmed incomplete amorphisation of HAp with increase in fluence. There was considerable reduction in particle size on irradiation leading to nanosized HAp (upto 53 nm). PL studies showed emission in the visible wavelength region. The irradiated samples exhibited better bioactivity than the pristine HAp.     

Effect of irradiation by 140 Mev Ag ions on the optical and electrical properties of polypropylene/TiO2 composite

Changes in the optical, structural, dielectric properties and surface morphology of a polypropylene/TiO₂ composite due to swift heavy ion irradiation were studied by means of UV–visible spectroscopy, X-ray diffraction, impedance gain phase analyzer and atomic force microscopy. Samples were irradiated with 140 MeV Ag¹¹⁺ ions at fluences of 1 × 10¹¹ and 5 × 10¹² ions/cm². UV–visible absorption analysis reveals a decrease in optical direct band gap from 2.62 to 2.42 eV after a fluence of 5 × 10¹² ions/cm². X-ray diffractograms show an increase in crystallinity of the composite due to irradiation. The dielectric constants obey the Universal law given by ε α f ⁿ⁻¹, where n varies from 0.38 to 0.91. The dielectric constant and loss are observed to change significantly due to irradiation. Cole–cole diagrams have shown the frequency dependence of the complex impedance at different fluences. The average surface roughness of the composite decreases upon irradiation.     

The 11B(p,α0)8Be nuclear reaction and 11B(p,p)11B backscattering cross sections for analytical purposes

The ¹¹B(p,α₀)⁸Be nuclear reaction and the ¹¹B(p,p)¹¹B backscattering cross sections were measured at a laboratory scattering angle of 165° in the energy range from 1700 to 2700 keV with an absolute accuracy of about 7%. The cross section values were derived by using the simultaneously measured RBS spectra of the protons backscattered from a thin gold layer. The measured cross section values are compared with X-ray photoelectron spectroscopy (XPS) and heavy ion elastic recoil detection analysis (HERDA) results of amorphous hydrogenated boron/carbon (a-B:C:H) layers. The cross section data are presented in graphical and tabular form.     

Coating of Titanium Nitride on Stainless Steel Targets by a 4?kJ Plasma Focus Device

Titanium nitride thin films were deposited on stainless steel (SS316L) targets by using a 4?kJ plasma focus device. The corresponding energy flux delivered to SS316L surface is estimated to be 2.69?×?10¹³?kev?cm^?3?ns^?1. X-ray diffraction analysis reveals the formation of a nanocrystalline titanium nitride coating on the surface of targets. Thickness of the elements found on the surface of treated samples which are obtained by Rutherford backscattering spectrometry analysis (RBS) were (×10¹⁵ at/cm²) .45% Ti, 50% N and 5% Fe. Scanning electron microscopy was used to indicate changes in surface morphology. Existence of grains in different size confirms the formation of TiN crystals on the surface of targets.     

Seasonal variations in the concentrations of selected heavy metals and radionuclides in Sava River sediments upstream and downstream of NPP Krsko

In order to estimate the influence of a nuclear power plant and other industrial and agricultural anthropogenic sources on the quality of Sava River sediments, samples taken from seven locations (one upstream and six downstream of the Krsko NPP) were characterized. Seasonal variations in the sediment composition were determined on the basis of four samplings taken during the year 2004 (in February, May, October and December). Total concentrations of the elements Cr, Mn, Fe, Cu, Zn, Co and Pb in the sediment fractions less than 0.5 mm have been measured by source excited energy dispersive X-ray fluorescence (EDXRF), while ⁴⁰K, ¹³⁷Cs, ¹³¹I, ⁷Be, ²²⁸Th, Th(²²⁸Ra), U(²³⁴Th), ²²⁶Ra and ²¹⁰Pb were determined by gamma spectrometry. Mineralogical examinations of the samples were performed using the X-ray diffraction (XRD) method.     

Recharging processes, radiation induced strain and changes of OH bands under H ion implantation in Ti doped lithium niobate

A systematic analysis of variations in structural and optical characteristics of Z-cut plates of titanium doped congruent lithium niobate single crystals implanted with 120 keV proton beam at various fluences of 10¹⁵, 10¹⁶ and 10¹⁷ protons/cm² is presented. Through, high resolution X-ray diffraction, atomic force microscopy, Fourier transform infrared and UV-visible-NIR analysis of congruent lithium niobate, the correlation of properties before and after implantation are discussed. HRXRD (0 0 6) reflection by Triple Crystal Mode shows that both tensile and compressive strain peak are produced by the high fluence implantation. A distinct tensile peak was observed from implanted region for a fluence of 10¹⁶ protons/cm². AFM micrographs indicate mountain ridges, bumps and protrusions on target surface on implantation. UV-visible-NIR spectra reveal an increase in charge transfer between Ti³⁺/Ti⁴⁺ and ligand oxygen for implantation with 10¹⁵ protons/cm², while spectra for higher fluence implanted samples show complex absorption band in the region from 380-1100 nm. Variations of OH⁻ stretching vibration mode were observed for cLN Pure, cLNT2% virgin, and implanted samples with FTIR spectra. The concentration of OH⁻ ion before and after implantation was calculated from integral absorption intensity. The effect of 120 keV proton implantation induced structural, surface and optical studies were correlated.     

Elemental and proximate analysis of coal by x-ray fluorescence assisted laser-induced breakdown spectroscopy

Although laser-induced breakdown spectroscopy (LIBS), as a fast on-line analysis technology, has great potential and competitiveness in the analysis of chemical composition and proximate analysis results of coal in thermal power plants, the measurement repeatability of LIBS needs to be further improved due to the difficulty in controlling the stability of the generated plasmas at present. In this paper, we propose a novel x-ray fluorescence (XRF) assisted LIBS method for high repeatability analysis of coal quality, which not only inherits the ability of LIBS to directly analyze organic elements such as C and H in coal, but also uses XRF to make up for the lack of stability of LIBS in determining other inorganic ash-forming elements. With the combination of elemental lines in LIBS and XRF spectra, the principal component analysis and the partial least squares are used to establish the prediction model and perform multi-elemental and proximate analysis of coal. Quantitative analysis results show that the relative standard deviation (RSD) of C is 0.15%, the RSDs of other elements are less than 4%, and the standard deviations of calorific value, ash content, sulfur content and volatile matter are 0.11 MJ kg−1, 0.17%, 0.79% and 0.41% respectively, indicating that the method has good repeatability in determination of coal quality. This work is helpful to accelerate the development of LIBS in the field of rapid measurement of coal entering the power plant and on-line monitoring of coal entering the furnace.     

Crud Behaviors in High Temperature Water, (II)

Sample specimens of type 304 stainless steel and Zircaloy-2 were exposed to the OWL-1 loop water at 280°C for 23d. After the exposure, a number of crystallites are distributed either separately or sometimes in agglomerate on the surfaces. The X-ray diffraction analysis and XMA analysis of the type 304 stainless steel surface revealed that more than 95% of the crystallites have a M₂O₃-type of structure, and some are enriched in Cr. In the sub-sequent radiochemical analysis of the fractions detached by the various cleaning processes (ultrasonic, electrostripping and electropolishing), it is noticed that the ⁶⁰Co/Co ratio decreases with the depth of the corrosion layer from the value close to that of insoluble crud in the water (crud-P) to that of soluble crud (crud-F).     

Efficiency of formation of radiation defects in silicon upon implantation of silicon and phosphorus ions

Accumulation and annealing of radiation defects in silicon and in the heavily phosphorus doped silicon layers implanted with Si⁺ or P⁺ ions have been studied by the X-ray diffraction method. The observed differences in the introduction rates of stable radiation defects are due to the differences between the intensities of annihilation processes determined by charge states of defects.     

Microstructure of ion-implanted region in TiNi alloy

TiNi alloy samples implanted with various fluences of 3 MeV Cu²⁺ ions were characterized by transmission electron microscope (TEM) and X-ray diffractometer. Cross-sectional TEM images of the samples showed that amorphous region was seen at the fluence of 10¹⁴ ions cm^?2 in case of ion implantation at 300 K of the substrate temperature, but in case of ion implantation at 100 K it did not appear even at 10¹⁵ ions cm^?2. These results were also confirmed by X-ray diffraction profiles of the same samples. Consequently, the extent of microstructure change of TiNi alloy by ion implantation was different depending on the substrate temperature.     

Residence Time of Crud on Surfaces of Channel Box in JPDR

Characterization of crud on surfaces of the channel box in JPDR has been carried out by means of chemical, radiochemical, X-ray diffraction and infrared spectrum analyses. The main cations in the crud are Fe and Ni: The sum of their weights amounts to more than 90% of the total weight of the cations found. The results of X-ray diffraction and infrared spectrum analyses revealed that the crud consisted of Ni_0.65Fe_2.35O₄, NiO and γ-FeOOH.

Based on the neutron flux calculated from the burn-up of ²³⁵U and ²³⁸U in the spent fuel, the apparent residence time of elements on the surface of the channel box was calculated to be 230 d for Co, 260 d for Ni and 70 d for Fe. The value for Fe should be taken as a minimum value, because of the presence of γ-FeOOH in the crud, which has been formed during the storage in a pond.

The present data are discussed in correlation with the one in the reactor water.