Indium Cadmium Research Articles

Analysis of Phébus FP experiments in Korea

In the Phébus FP program, the phenomenology of severe accidents in water cooled nuclear reactors have been studied, especially fuel rod degradation and the behavior of fission products released via the primary coolant circuit into the containment. This paper is focused on the analysis of Phébus FPT-1 and FPT-3 test results using the severe accident analysis code, MELCOR. Since FPT-1 was adopted as the OECD ISP-46 and FPT-3 as the SARNET2 WP8.3 benchmark problem, a variety of code-to-code and code-to-experiment comparisons are possible. The two tests, FPT-1 and FPT-3, were carried out under low system pressure and using fuel irradiated in a reactor to about 23GWd/tU, and in a steam-rich atmosphere for FPT-1 and in a steam-poor atmosphere for FPT-3. In FPT-3, the control rod was made of boron carbide (B4C) instead of silver–indium–cadmium (SIC) as in the previous test FPT-1. Intensive analysis of the FPT-1 and FPT-3 data highlighted major differences between them in the aspects of the fuel bundle degradation, material relocations, hydrogen production, and moreover fission product behavior, especially iodine behavior in the reactor coolant system and containment. The analysis results for two tests using MELCOR1For these analyses code version 1.8.5 was used.1, which is the main tool for assessment of Korean nuclear plants, were synthesized in this paper. Comparison between code estimates and experimental data demonstrated the code’s ability to simulate the whole sequence with reasonable accuracy, and assessed detailed models in the code. Also uncertainties, particularly regarding modeling of core degradation and fission product behavior, were identified showing that further model improvements are required in the code. In addition, MELCOR-RAIM, a coupled code, was used for simulation of the iodine behavior for both FPT-1 and FPT-3. The coupling was achieved by replacing the pool chemistry model of MELCOR with RAIM, which had been developed as a standalone model based on the IMOD code to analyze the behavior of iodine including organic iodide.

Material release from the bundle in Phébus FP

The experiments Phébus FP FPT-0 to FPT-3 tests conducted by IRSN have produced a large quantity of data on fission product, structural material and actinide release under prototypic nuclear reactor accident conditions that form a consistent set of data suitable for assessment of release models implemented in severe accident codes. Additionally, FPT4 provides valuable complementary data in a late phase debris bed geometry.Based on on-line and post-test measurements, the release of the main fission products could be assessed as well as their release kinetics in relation with bundle degradation progresses. Noble gases (Xe, Kr) are considered as very highly volatile; the other fission products can be classified as high-volatile (Cs, I, Te, Mo), semi-volatile (Rb) and low-volatile (Ru, Ba, La). Release of fission products is observed mainly in the oxidation phases, with the proportions depending on the elements concerned. Molten pool formation corresponds to a decrease of the release process. Post-test gamma-measurements show that deposition of fission products over the upper parts of the fuel rods is important with lower steam flow rates as given in FPT2 and FPT3.The fuel material fractional release (mainly U) is very low but could represent a significant fraction of the transported aerosol mass (FPT0 and FPT1).Release from the silver–indium–cadmium control rod is characterised by the initial Cd burst release on failure of the control rod, followed by a steady release of Ag, In and Cd from the molten absorber pool remaining in the stub. These elements are important as they can affect the physical and chemical forms of fission products such as iodine, hence their transmission to the containment. A large boron release, linked to an extended degradation of the boron carbide control rod, was observed during FPT3.The established link between bundle degradation and release mechanisms is clearly confirmed for both fuel and control rod materials, with the release being dependent on temperature, burnup, interactions between fuel and structural materials (mainly Zircaloy cladding, i.e. for Ba) and atmosphere (oxidising/reducing conditions, as can be noticed for Mo, Sn and Te), and mass flow rate.Comparison with the results of separate-effects test series (VERCORS, QUENCH) performed under similar temperature and atmosphere conditions will also be presented.

Structural and energetic assessment in cadmium–indium liquid alloys

The mixing behaviour of liquid cadmium–indium alloys has been analysed on the basis of quasi-chemical approximation by computing thermodynamic parameters, such as free energy of mixing (G M), entropy of mixing (S M), heat of mixing (H M) and chemical activities (a i) and structural functions, such as concentration fluctuation in the long wavelength limit (S cc(0)), the Warren–Cowley short-range order parameter (α 1) and the ratio of diffusion coefficients (D m/D id) of the alloys at 800 K. The analysis suggests that there is a tendency of like atom pairing (Cd–Cd, In–In) in Cd–In alloy over entire concentrations and ordering energy is found to be temperature dependent. Cd–In alloy at 800 K in the molten state is slightly segregating in nature.

Early phase fuel degradation in Phébus FP: Initiating phenomena of degradation in fuel bundle tests

The international Phébus Fission Product Programme investigated key phenomena occurring in light water reactor core meltdown accidents in a series of five in-pile experiments. Four of these tests focused on the degradation of fuel rod bundles, containing a central control rod, and on the resulting release of fission products, structural materials and actinides from the fuel rod bundle, their transport in the reactor coolant system (RCS) and their subsequent behaviour in the containment vessel. Various steam contents were used in the RCS, from highly oxidising conditions (in FPT0 and FPT1) to more reducing ones (in FPT2 and FPT3).The “early degradation phase” took place at the beginning of the Phébus driver core and fuel bundle heat-up phase, with a quasi-intact fuel bundle geometry. During this phase, the degradation of the control rod and the oxidation runaway due to the fast oxidation of the Zircaloy claddings of the fuel rods, were two major events which took place.The oxidation runaway locally increased the temperatures much above the temperatures resulting from the Phébus driver core heat transfer to the bundle and yielded a large hydrogen release, which amounted to 70–80% of the whole hydrogen production during the tests. The maximum hydrogen flow rates increased with increasing steam flow rates injected at the fuel bundle inlet.The failure mechanisms of silver–indium–cadmium (used in three tests) and boron carbide (used in one test) control rods involve eutectic interactions amongst the components of these control rods. Mechanical deformations of the control rod stainless steel cladding against the Zircaloy control rod guide tube are the main presumed mechanisms for the beginning of these eutectic formations. However, different post-failure scenarios can be postulated for the effect of control rod degradation on fuel bundle degradation for both types of control rods. The exothermic oxidation of the exposed boron carbide pellets led to the release of carbonaceous species (CO, CO2) as well as of additional hydrogen, but no significant methane release could be detected above the limits of detection.Overall, the results confirmed existing knowledge concerning early phase degradation phenomenology found in previous integral experiments such as CORA and QUENCH (Karlsruhe Institute of Technology) and Phébus SFD (IRSN Cadarache), and formed a sound basis for analysis of the late phase degradation subsequently observed. Quantitative analysis of boron carbide control rod degradation in FPT3 pointed to a need for improved modelling of chemical reactions involving this material, particularly its oxidation in steam; this has been studied in the BECARRE experiments conducted by IRSN in the International Source Term Programme, leading to better quantitative understanding and improved modelling in codes such as the European reference severe accident analysis code ASTEC.

Structural and optical properties of CdIn2S4:Cu thin film prepared by chemical spray pyrolysis

Cadmium indium sulfide (CdIn2S4) thin films were deposited by chemical spray pyrolysis technique on the glass substrate ,and doping by Cu= 1%,3%.5% . The films structure were analyzed by XRD . All the patterns of thin films prepared are polycrystalline .The optical properties are studied by UV-VIS spectrophotometer ,the absorption coefficient was calculated ,its value was more than 104 that supports the direct transition ,the energy gap found between 2.6 eV to 2.85 eV dependent on the ratio of Cu in the thin film. And finally the optical constants such as refractive index ,extinction coefficient, real and imaginary dielectrics were investigated.

CdIn2S4 microsphere as an efficient visible-light-driven photocatalyst for bacterial inactivation: Synthesis, characterizations and photocatalytic inactivation mechanisms

New types of visible-light-driven photocatalysts with high activity for bacterial inactivation are needed to address the problems caused by outbreak of harmful microorganisms. In this study, cadmium indium sulfide (CdIn2S4) microsphere, which can be synthesized continuously by a facile ultrasonic spray pyrolysis method, was used as an efficient photocatalyst in inactivation of Escherichia coli K-12 under visible light (VL) irradiation for the first time. The as-prepared CdIn2S4 showed a micro-spherical morphology with diameter of 0.5–1.0μm. It had an energy band gap of 2.02eV and BET surface area of 34.8m2/g. It was found that bacterial cells could also be effectively inactivated inside a partition system without the direct contact with the photocatalyst, which was attributed to the diffusible photon-generated hydrogen peroxide (H2O2) rather than hydroxyl radicals (OH). Large amounts of H2O2 were produced from both conduction and valance bands with the involvement of superoxide (O2−). The used CdIn2S4 could be easily recycled by the partition system without loss of activity. The destruction process of bacterial cells was from the cell wall to the intracellular components as confirmed by TEM study. In addition, the O2− and OH radicals were also detected in the CdIn2S4-VL system by ESR spin-trap with DMPO trapping technology.

Sprayed CdIn 2O 4 thin films for liquefied petroleum gas (LPG) detection

Nanocrystalline cadmium indium oxide (CdIn 2O 4) thin films of different thicknesses were deposited by chemical spray pyrolysis technique and utilized as a liquefied petroleum gas (LPG) sensors. These CdIn 2O 4 films were characterized for their structural and morphological properties by means of X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. The dependence of the LPG response on the operating temperature, LPG concentration and CdIn 2O 4 film thickness were investigated. The results showed that the phase structure and the LPG sensing properties changes with the different thicknesses. The maximum LPG response of 46% at the operation temperature of 673 K was achieved for the CdIn 2O 4 film of thickness of 695 nm. The CdIn 2O 4 thin films exhibited good response and rapid response/recovery characteristics to LPG.

Photoelectrochemical performance of sprayed n-CdIn 2Se 4 photoanodes

Cadmium indium selenide thin films have been synthesized by spraying mixture of equimolar solution concentrations of cadmium chloride, indium trichloride and selenourea in aqueous media onto preheated FTO coated glass substrates at optimized substrate temperature and solution concentration. The photoelectrochemical cell configuration of n-CdIn 2Se 4/(1 M NaOH + 1 M Na 2S + 1 M S)/C has been used for investigate the current–voltage characteristics under dark and white light illumination, photovoltaic output, spectral response, photovoltaic rise and decay characteristics. It reveals the film of CdIn 2Se 4 exhibits n-type conductivity. The junction quality factor in dark ( n d ) and light ( n l ), series and shunt resistance ( R s and R sh ), fill factor (FF) and efficiency ( η) for the cell have been estimated. Gartner’s model was used to calculate minority carrier diffusion length and donor concentration ( n D ). The observed efficiency and FF of PEC solar cell is 1.95% and 0.37% respectively. Mott–Schottky plot shows the flat-band potential ( V fb ) of CdIn 2Se 4 films is −0.655 V/SCE.

(Photo) electrochemical investigations on spray deposited n-CdIn 2Se4 thin film/polysulphide/c photoelectrochemical solar cell1

Cadmium indium selenide (n-CdIn 2Se4) thin films have been synthesized by spraying the mixture of an equimolar solutions of cadmium chloride [CdCl2], indium trichloride [InCl3] and selenourea [(NH2)2CSe] in aqueous media onto preheated fluorine doped tin oxide (FTO) coated glass substrates at optimized parameters of substrate temperature and solution concentration. The photoelectrochemical (PEC) cell configuration of n-CdIn2Se/(l MNaOH + 1 MNa2S + 1 M S)/C has been used for investigating the current—voltage (I–V) characteristics under dark and white light illumination, photovoltaic output, spectral response, photovoltaic rise and decay characteristics. The PEC study reveals the thin film of CdIn2Se4 exhibits n-type conductivity. The junction quality factor in dark (nd) and light (nl), series and shunt resistance (Rs and Rsh), fill factor (FF) and efficiency (η) for the cell have been estimated. The observed efficiency and FF of PEC solar cell is found to be 1.95 and 0.37% respectively. Mott-Schottky plot shows the flat-band potential (V fb) of n-CdIn2Se4/(l M NaOH + 1 M Na2S + 1 M S)/C cell to be—0.655 V/SCE.

Influence of substrates on photoelectrochemical performance of sprayed n-CdIn2S4 electrodes

Cadmium indium sulphide (CdIn2S4) electrodes have been prepared onto the preheated fluorine doped tin oxide (FTO) coated glass and stainless steel (SS) substrates at optimized deposition conditions by using spray pyrolysis. Influence of substrates on the photoelectrochemical (PEC) performance has been carried out using cell configuration n-CdIn2S4/1 M (NaOH + Na2S + S)/C for studying the current–voltage (I–V), photovoltaic output, photovoltaic rise and decay, photo and spectral responses and capacitance–voltage (C–V) characteristics. The junction ideality factor in dark (nD) and light (nL), series and shunt resistances (Rs and Rsh), fill factor (FF) and efficiency (η) for the cell have been estimated. The measured fill factor (FF) and cell efficiency (η) of the cells are found to be 0.47%, 0.38%, and 1.06%, 0.38% for FTO and SS substrates respectively. The Energy band diagram of band bending has been constructed using the physical parameters estimated from Mott–Schottky plots. Mott–Schottky plots shows the flat-band potential (Vfb) of CdIn2S4 films to be −1.15 V/SCE and −0.90 V/SCE on FTO and SS substrates respectively.

Electrosynthesis and studies on Cadmium-Indium-Selenide thin films

Thin films of Cadmium Indium Selenide (CdIn2Se4) have been deposited on indium doped tin oxide coated conducting glass (ITO) substrates using potentiostatic cathodic electrodeposition technique. Cyclic voltammetry has been carried out in order to fix the deposition potential in the range between −1500 and +600 mV versus SCE. X-ray diffraction pattern shows that the deposited films exhibit tetragonal struc- ture with most prominent reflection along (200) plane. The dependency of microstructural parameters such as crystallite size, strain and dislocation density with deposition potential has been studied. Surface morphology and film composition have been analyzed using scanning electron microscopy and energy dispersive analysis by X-rays, respectively. EDX analysis reveals that films with well defined stoichiom- etry has been obtained at a deposition potential −950 mV versus SCE. The optical band gap, refractive index and extinction coefficient are evaluated from optical absorption measurements. The experimental observations are discussed in detail.

Aerosol behavior during SIC control rod failure in QUENCH-13 test

Abstract In a nuclear reactor severe accident, radioactive fission products as well as structural materials are released from the core by evaporation, and the released gases form particles by nucleation and condensation. In addition, aerosol particles may be generated by droplet formation and fragmentation of the core. In pressurized water reactors (PWR), a commonly used control rod material is silver–indium–cadmium (SIC) covered with stainless steel cladding. The control rod elements, Cd, In and Ag, have relatively low melting temperatures, and especially Cd has also a very low boiling point. Control rods are likely to fail early on in the accident due to melting of the stainless steel cladding which can be accelerated by eutectic interaction between stainless steel and the surrounding Zircaloy guide tube. The release of the control rod materials would follow the cladding failure thus affecting aerosol source term as well as fuel rod degradation. The QUENCH experimental program at Forschungszentrum Karlsruhe investigates phenomena associated with reflood of a degrading core under postulated severe accident conditions. QUENCH-13 test was the first in this program to include a silver–indium–cadmium control rod of prototypic PWR design. To characterize the extent of aerosol release during the control rod failure, aerosol particle size distribution and concentration measurements in the off-gas pipe of the QUENCH facility were carried out. For the first time, it was possible to determine on-line the aerosol concentration and size distribution released from the core. These results are of prime importance for model development for the proper calculation of the source term resulting from control rod failure. The on-line measurement showed that the main aerosol release started at the bundle temperature maximum of T ∼ 1570 K at hottest bundle elevation. A very large burst of aerosols was detected 660 s later at the bundle temperature maximum of T ∼ 1650 K, followed by a relatively steady aerosol release until core cooling by quench when the on-line measurements were stopped. Cd was released first from the control rod, followed by In, and finally, by Ag. The particle size distributions were bimodal indicating two aerosol formation mechanisms, evaporation followed by nucleation and condensation, as well as droplet and fragment generation. Generally, release is modelled as evaporation from molten regions of control rod materials. Clearly, results of this investigation give evidence of contribution by entrainment of droplets and fragmented material.

PREPARATION OF CdIn2Se4n-TYPE SEMICONDUCTOR USED AS THERMOELECTRIC MATERIAL BY SOL–GEL METHOD

The objective of this research was to study the effect of various parameters such as temperature and pH to the formation of cadmium indium selenide ( CdIn2 Se 4 ) thin films, which were fabricated by sol–gel dip-coating method. This n-type semiconductor compound is suitable for application as thermoelectric materials. Cadmium, indium, selenium precursors were separately dissolved by solvents: ethanol, hydrochloric acid, and acetic acid to form metal alkoxides. The precursor solutions were then mixed together in N 2 atmosphere. These metal alkoxides were hydrolyzed by adding water and then polycondensed by adding ethylene glycol to become gels. These gels were adjusted to various acid-base values by adding diethylnolamine. Glass substrates were dipped into the gels to form thin films. These thin films were annealed at various temperatures in N 2 atmosphere and characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and fourier transfrom infrared spectroscopy (FTIR) techniques. The results indicated that CdIn2 Se 4 compound occurred by the reaction at room temperature with pH 4 and annealed at 450°C in N 2 atmosphere.

Understanding the behaviour of absorber elements in silver–indium–cadmium control rods during PWR severe accident sequences

In the case of a hypothetical severe accident in a Pressurized Water Reactor (PWR), Silver–Indium–Cadmium (SIC) control rod failure occurs early during the sequence. Release of absorber melt could induce early fuel rod degradation by interaction of molten SIC alloy with fuel rod cladding, and the absorber materials could interact with the fission products, affecting significantly their speciation and transport in the primary circuit as well as their behaviour in the containment. This paper summarises the experimental and modelling progress made on this topic within SARNET over the whole project. Following a review of the status of knowledge, including the modelling in the main severe accident codes (ATHLET-CD, MAAP4, SCDAP, MELCOR, ASTEC), detailed calculations of the specific EMAIC and integral PHEBUS FPT2 experiments were performed. Accurate calculation of vapour pressure of the molten absorber elements is needed, requiring reliable values of the activity coefficients. The importance of accurate reproduction of the control rod degradation was shown, with the behaviour of absorber elements at rupture being critical as well as the thermodynamic data and speciation of the system Ag–In–Cd–Zr–H–O. The QUENCH-13 bundle experiment (FZK), conducted with a realistic integral geometry composed of 20 electrical heated rod simulators and one central SIC absorber rod, has helped to characterize the behaviour of absorber elements at the time of rod rupture, with measurements of the SIC release, using impactors (AEKI) and electrical low-pressure impactor and Berner low-pressure impactors (PSI). Coordinated pre and post-test calculations using SCDAP/RELAP5 based codes (PSI), MAAP4 (EDF), ATHLET-CD (GRS), ASTEC (IRSN) helped in defining the test and in its interpretation. Before this experiment, five tests were performed on small-scale SIC control rod samples using different designs and conditions. They helped in defining the conditions for the QUENCH-13 experiment. Five additional tests on similar small-scale samples are foreseen to help interpretation of the QUENCH-13 results. In QUENCH-13 the on-line aerosol measurements with electrical low-pressure impactors indicated control rod failure in the range 1550–1600 K; the test was terminated later at 1813 K by water reflood. Analysis of aerosols measured at sample points in the off-gas line showed significant Cd and In transport after rod failure with a smaller amount of transported Ag. Relocated SIC melt in the form of rivulets was detected in the lower part of the bundle. Investigation of SIC material properties (solidus, liquidus) by further analysis of data from QUENCH-13 is also presented. In parallel, an exhaustive review of activity coefficients of the elements in the SIC melt, including the effect of Zr was began (IRSN with the CNRS Marseille).

Helium-Plasma-Prepared (111)A HgCdTe and (211)B InSb

Brief low-energy helium plasma exposure of mercury cadmium telluride and indium antimonide results in oxide- and elemental-component-free, nearly stoichiometric surfaces. In these initial experiments, the only remaining residue is a topmost trace layer of carbon similar to that present on wet etched and reduced surfaces. The nature of these surfaces was determined by in situ Auger electron spectroscopy, monochromatic X-ray photoelectron, and ion scattering spectroscopy, and compared with established wet chemical and hydrogen argon plasma preparations.

Studies on gas sensing performance of CuO-modified CdIn2O4 thick film resistors

Abstract Cadmium indium oxide powder was derived from calcination of cadmium indium sulphide prepared by a flux method. The material was confirmed by XRD. Thick films of this powder were prepared on glass substrates using screen-printing technique. CuO-modified CdIn 2 O 4 thick films were obtained by dipping technique in which Cu 2+ was incorporated as an additive into the CdIn 2 O 4 base material. The films were fired at 500 °C for 2 h. The films were characterized by SEM and EDAX. The electrical conductivity of the films was determined. The gas sensing performance of pure and modified CdIn 2 O 4 films were investigated for various gases. The films showed best response to chlorine gas. Modified films were found to be more sensitive than pure CdIn 2 O 4 to chlorine gas. The quick response (∼6 s) and fast recovery (∼22 s) are the main features of the modified sensor.

Electrochemically deposited photoactive CdIn 2Se 4 thin films: Structural and optical studies

Electrochemical synthesis of photoactive cadmium–indium–selenide (CdIn 2Se 4) thin films at ambient temperature was reported. The nanocrystalline nature and 1:2:4 elemental chemical stoichiometric ratio for Cd, In and Se were obtained from the X-ray diffraction and energy dispersive X-ray analysis, respectively. Irregular shaped islands of about 400–500 nm in sizes composed of large number of small (∼30–40 nm) spherical grains were confirmed from the atomic force microscopy and the scanning electron microscopy images. The photoelectrochemical measurement of CdIn 2Se 4 film electrode in presence of 1 M polysulphide electrolyte revealed 0.42% photoelectrochemical device conversion efficiency, under the light illumination intensity of 80 mW/cm 2.

Studies on CdIn2O4 derived from CdIn2S4 prepared by flux method

Stoichiometric and nonstoichiometric powders of cadmium indium oxide were derived from calcination of cadmium indium sulphide prepared by flux method. The materials were confirmed by XRD. Thick films of above prepared powders were prepared on glass substrates using screen printing technique. The thick films were characterized by SEM and EDAX. The electrical conductivity of CdIn2O4 thick films was calculated. The gas sensing performance of stoichiometric thick films of CdIn2O4 was tested for various gases. The films showed good response to LPG.

Determination of CdIn 2S 4 semiconductor parameters by (photo)electrochemical technique

Semiconducting n-CdIn 2S 4 thin films have been deposited on amorphous and fluorine-doped tin oxide (FTO) coated glass substrates by using a well-known spray pyrolysis technique. With the objective of finding the optimum conditions for the deposition of CdIn 2S 4 thin films, the influence of substrate temperature on properties of the films have been studied. Photoelectrochemical (PEC) technique has been employed to optimize substrate temperature. The films are characterized by the techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive analysis by X-rays (EDAX) and PEC studies. The SEM studies reveal the compact morphology with large number of grains. EDAX studies show that the material formed at optimized substrate temperature is nearly stoichiometric. Measured values of efficiency ( η) and fill factor (FF) for the PEC cell are 1.06% and 0.47, respectively. Various physical parameters of cadmium indium sulphide (CdIn 2S 4) film are estimated. Energy band diagrams for CdIn 2S 4 and polysulphide electrolyte, before and after making junction have been constructed.

Properties of transparent conducting oxides formed from CdO alloyed with In 2O 3

The structure, optical and electrical properties of transparent conducting oxide films depend greatly on the methods of preparation, heat treatment, type and level of dopant. Thin films of (CdO) 1− x (In 2O 3) x have been grown by electron beam evaporation technique for different concentrations of In 2O 3 ( x = 0, 0.05, 0.1, 0.15 and 0.2). Increase of doping led to increased carrier concentration as derived from optical data and hence to increased electrical conductivity, which degraded the transparency of the films. An improvement of the electrical and optical properties of Cadmium indium oxide (CdIn 2O 4) has been achieved by post-deposition annealing. A resistivity value of 7 × 10 − 5 Ω cm and transmittance of 92% in the near infrared region and 82% in the visible region have been obtained after annealing at 300 °C for 90 min in air.