Study on the Viability of the Recycling by Electric Arc Melting of Zirconium Alloys Scraps Aiming the Scalability of the Process

2018 ◽  
Vol 930 ◽  
pp. 495-500
Author(s):  
Cristiano Stefano Mucsi ◽  
L.A.M. dos Reis ◽  
Maurilio Pereira Gomes ◽  
L.A.T. Pereira ◽  
Jesualdo Luiz Rossi
Keyword(s):  
Nuclear Reactor ◽  
Zirconium Alloys ◽  
Vacuum Arc ◽  
Pressurized Water Reactor ◽  
Pressurized Water ◽  
Vacuum Arc Remelting ◽  
Arc Melting ◽  
Vacuum Arc Furnace ◽  
Fuel Elements

Turning chips of zirconium alloys are produced in large quantities during the machining of alloy rods for the fabrication of the end plugs for the Pressurized Water Reactor (PWR) fuel elements parts of Angra II nuclear reactor (Brazil – Rio de Janeiro). This paper presents a study on the search for an efficient way for the cleaning, quality control and Vacuum Arc Remelting (VAR) of pressed zirconium alloys chips to produce a material viable to be used in the production of the fuel rod end plugs. The process starts with cutting oil clean out. The first step in this process consists in soaking a bunch of chips in clean water, to remove soluble cutting oils, followed by an alkaline degreasing bath and a wash with a high-pressure flow of water. Drying is performed by a flux of warm air. The oil free chips are then subjected to a magnet in order to detect and collect any magnetic material, essentially ferrous, that may be present in the original chips. Samples of the material are collected and then melted in a small non consumable electrode vacuum arc furnace for evaluation by Energy Dispersive X-ray Fluorescence Spectrometry (EDXRFS) in order to define the quality of the chips. The next step consists in the 15 ton hydraulic pressing the chips in a die with 40 mm square section and 500 mm long, producing an electrode with 20% of the Zircaloy bulk density. The electrode was finally melted in a laboratory scale modified VAR furnace located at the CCTM–IPEN, producing 0.8 kg ingots. The authors conclude that the samples obtained from the fuel element industry can be melting in a VAR furnace, modified to accommodate low density electrodes, allowing a reduction up to 40 times the original storage volume, however, it is necessary to remelt the ingots to correct their composition in order to recycle the original zirconium alloys chips. in a process to reduce volume and allow the reutilization of valuable Zircaloy scraps.

Production of Fe3Al-Based Intermetallic Alloys

1990 ◽  
Vol 213 ◽  
Author(s):  
Vinod K. Sikka
Keyword(s):  
Surface Finish ◽  
National Laboratory ◽  
Vacuum Arc ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Intermetallic Alloys ◽  
Vacuum Arc Remelting ◽  
Oak Ridge ◽  
Arc Melting

ABSTRACTThe melting of Fe3Al-based alloys at the Oak Ridge National Laboratory (ORNL) and commercial vendors is described. The melting processes evaluated include arc melting, air-induction melting (AIM), vacuum-induction melting (VIM), vacuum-arc remelting (VAR), and electroslag remelting (ESR). The quality of the ingots studied are based on internal soundness and the surface finish obtained. The ingots were analyzed for impurity levels observed in the alloys by various melting processes. Recommendations are made for viable processes for commercial melting of these alloys.

scholarly journals Hydrogen diffusion process in the oxides formed on zirconium alloys during corrosion in pressurized water reactor conditions

2017 ◽  
Vol 116 ◽  
pp. 1-13 ◽  
Author(s):  
Marc Tupin ◽  
Frantz Martin ◽  
Caroline Bisor ◽  
Romain Verlet ◽  
Philippe Bossis ◽  
...  
Keyword(s):  
Diffusion Process ◽  
Hydrogen Diffusion ◽  
Zirconium Alloys ◽  
Pressurized Water Reactor ◽  
Pressurized Water ◽  
Water Reactor

scholarly journals Research and Development of Novel Materials for Accident Tolerant Fuel Cladding of Nuclear Reactors

2020 ◽  
Keyword(s):  
Zirconium Alloys ◽  
Vacuum Arc ◽  
Temperature Oxidation ◽  
Main Research ◽  
Sic Ceramics ◽  
Protective Element ◽  
Loss Of Coolant ◽  
New Material ◽  
Water Reactors ◽  
Fuel Elements

The paper describes the challenges and worldwide scientific studies aimed for the manufacturing of the fuel elements claddings tolerant to a loss of coolant accidents (Fukushima NPP, March 2011, Japan) for water-cooled reactors. The main research results obtained at NSC KIPT on the development of materials for fuel element claddings, tolerant to accidents with loss of coolant, are given. The structure and properties of the developed vacuum-arc chromium coatings were investigated. It is shown, that these coatings can be used as protective element for existing fuel claddings, made of zirconium alloys, in light-water reactors of the PWR and BWR types. Alloyed SiC-based ceramic was developed to replace zirconium-based fuel claddings. It has been established that doping of 0.5 wt% Cr into SiC leads to an increase in the ability to resist the formation of cracks (crack resistance) by 25 – 30%. The effect of Cr alloying on the corrosion resistance of SiC ceramics under conditions, simulating the medium of the first circuit of the VVER-1000 reactor, is analyzed. It was established that doping of even a small amount of Cr leads to a slowdown in corrosion processes in SiC ceramics. In order to create new material for fuel elements claddings Fe-Cr-Al-based alloys with the doping of alloying elements (Y, Zr and Mo) were also developed and studied. Obtained alloys showed high mechanical properties and resistance to high-temperature oxidation.

Depletion Calculation for a Nodal Reactor Physics Code

2010 ◽  
Author(s):  
Antonio Carlos Marques Alvim ◽  
Fernando Carvalho da Silva ◽  
Aquilino Senra Martinez
Keyword(s):  
Diffusion Equation ◽  
Nuclear Reactor ◽  
Reactor Core ◽  
Expansion Method ◽  
Design System ◽  
Pressurized Water Reactor ◽  
Reactor Physics ◽  
Pressurized Water ◽  
Nodal Method ◽  
Orthogonal Polynomial Expansion

This paper deals with an alternative numerical method for calculating depletion and production chains of the main isotopes found in a pressurized water reactor. It is based on the use of the exponentiation procedure coupled to orthogonal polynomial expansion to compute the transition matrix associated with the solution of the differential equations describing isotope concentrations in the nuclear reactor. Actually, the method was implemented in an automated nuclear reactor core design system that uses a quick and accurate 3D nodal method, the Nodal Expansion Method (NEM), aiming at solving the diffusion equation describing the spatial neutron distribution in the reactor. This computational system, besides solving the diffusion equation, also solves the depletion equations governing the gradual changes in material compositions of the core due to fuel depletion. The depletion calculation is the most time-consuming aspect of the nuclear reactor design code, and has to be done in a very precise way in order to obtain a correct evaluation of the economic performance of the nuclear reactor. In this sense, the proposed method was applied to estimate the critical boron concentration at the end of the cycle. Results were compared to measured values and confirm the effectiveness of the method for practical purposes.

scholarly journals A Parametric Study of the Vacuum Arc Remelting (VAR) Process: Effects of Arc Radius, Side-Arcing, and Gas Cooling

2019 ◽  
Vol 51 (1) ◽  
pp. 222-235 ◽  
Author(s):  
E. Karimi-Sibaki ◽  
A. Kharicha ◽  
M. Wu ◽  
A. Ludwig ◽  
J. Bohacek
Keyword(s):  
Molten Pool ◽  
Vacuum Arc ◽  
Internal Quality ◽  
Solidification Behavior ◽  
Vacuum Arc Remelting ◽  
Thermal Fields ◽  
Vacuum Plasma ◽  
Process Effects ◽  
Gas Cooling

Abstract Main modeling challenges for vacuum arc remelting (VAR) are briefly highlighted concerning various involving phenomena during the process such as formation and movement of cathode spots on the surface of electrode, the vacuum plasma, side-arcing, the thermal radiation in the vacuum region, magnetohydrodynamics (MHD) in the molten pool, melting of the electrode, and solidification of the ingot. A numerical model is proposed to investigate the influence of several decisive parameters such as arc mode (diffusive or constricted), amount of side-arcing, and gas cooling of shrinkage gap at mold–ingot interface on the solidification behavior of a Titanium-based (Ti-6Al-4V) VAR ingot. The electromagnetic and thermal fields are solved in the entire system including the electrode, vacuum plasma, ingot, and mold. The flow field in the molten pool and the solidification pool profile are computed. The depth of molten pool decreases as the radius of arc increases. With the decreasing amount of side-arcing, the depth of the molten pool increases. Furthermore, gas cooling fairly improves the internal quality of ingot (shallow pool depth) without affecting hydrodynamics in the molten pool. Modeling results are validated against an experiment.

A New Model to Predict the Oxidation Kinetics of Zirconium Alloys in a Pressurized Water Reactor

2008 ◽  
Vol 5 (5) ◽  
pp. 101312 ◽  
Author(s):  
V. Bouineau ◽  
A. Ambard ◽  
G. Bénier ◽  
D. Pe^cheur ◽  
J. Godlewski ◽  
...  
Keyword(s):  
Oxidation Kinetics ◽  
Zirconium Alloys ◽  
Pressurized Water Reactor ◽  
Pressurized Water ◽  
Water Reactor ◽  
New Model ◽  
Kinetics Of

Consolidation of Compacted Zircaloy Chips via Vacuum Arc Melting - Analysis of the Electric Arc

2005 ◽  
Vol 498-499 ◽  
pp. 258-263 ◽  
Author(s):  
C.S. Mucsi ◽  
Rubens Nunes de Faria Jr. ◽  
E. Galego ◽  
J.L. Rossi
Keyword(s):  
Fourier Transforms ◽  
Electric Arc ◽  
Vacuum Arc ◽  
Vacuum Arc Remelting ◽  
Electrical Arc ◽  
Arc Melting ◽  
Vacuum Arc Melting ◽  
Linear Behaviour ◽  
Melting Analysis ◽  
Electric Signals

The main objective of this work is to present the preliminary results on the analysis of the signals arising from the electrical arc, during the vacuum arc remelting of Zircaloy electrodes, aiming the automation of the fusion process. Zircaloy electrodes were made from compacted chips resultant of the machining of Zircaloy rods. The melts were performed in a prototype (vacuum arc remelting) VAR furnace under low pressure of argon and the arc was fed by a constant DC power source. Both filtered and unfiltered signals were recorded by means of a data acquisition system. The fast Fourier transforms FFT and autocorrelation integral were used as tools for data analysis. The result showed that the events occurring within the electric arc have a strong influence on the electric signals. The analysis allowed inferring that the VAR electric arc system has mainly a chaotic behaviour and sporadic periods of linear behaviour. The conclusion of this work is that a control system may be developed, based on the modelling of the non-linear behaviour of the arc, mainly chaotic. This may allow the achievement of an automatic control for the process and yield better quality products.

Preliminary Benchmark Validation of a Lattice Physics Code COSLATC

2016 ◽  
Author(s):  
Tongrui Yang ◽  
Zhanquan Liu ◽  
Yuhang Yan ◽  
Shuo Li ◽  
Hui Yu ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Engineering Application ◽  
Pressurized Water Reactor ◽  
Lattice Calculation ◽  
Pressurized Water ◽  
Preliminary Validation ◽  
Development Center ◽  
Validation Strategy ◽  
Calculation Code

COre and System INtegrated Engine for design and analysis (COSINE) is developed by State Nuclear Power Software Development Center (SNPSDC), which is an integrated nuclear engineering code package. A lattice physics code named COSLATC is an essential part included in COSINE. COSLATC is a multi-group two-dimensional transport code. Pin cells and assemblies of Pressurized Water Reactor (PWR) can be calculated by COSLATC. It is used to calculate few group constants and nuclei densities for core simulator. In order to make sure the quality of the COSLATC, a strategy of verification & validation (V&V) are discussed and applied to the COSLATC. Firstly a V&V requirement analysis is performed. A test matrix considering the variety of fuel enrichments, materials, geometric and working conditions is generated. Then the corresponding benchmark is collected and classified. Finally, the numerical results of COSLATC and the reference values are compared and analyzed. According to the validation strategy discussed above, the preliminary validation is carried out. The benchmark provides consistent and comprehensive tests for high burnup (approx. 70GWd/t) fuels of PWR. By comparison with k-infinity and isotopic composition in the UO2 and MOX fuels pin cell problems or assembly problems benchmark, the result shows that the calculated results from COSLATC code agree well with reference results. COSLATC will be an important lattice calculation code in the scientific calculation and engineering application.

scholarly journals Industrial applications of modelling tools to simulate the PAMCHR casting and VAR process for Ti64

2020 ◽  
Vol 321 ◽  
pp. 10011
Author(s):  
Emiliane Doridot ◽  
Stéphane Hans ◽  
Alain Jardy ◽  
Jean-Pierre Bellot
Keyword(s):  
Joint Venture ◽  
Metal Flow ◽  
Sensitivity Study ◽  
Industrial Applications ◽  
Liquid Pool ◽  
Vacuum Arc ◽  
Operating Parameters ◽  
Vacuum Arc Remelting ◽  
Arc Melting ◽  
Ingot Quality

The PAMCHR (Plasma Arc Melting Cold Hearth Refining) process followed by a VAR (Vacuum Arc Remelting) melting is used to recycle Ti64 scrap for aeronautical applications. The produced ingot quality is linked to the quality of charging materials and to numerous operating parameters. Ecotitanium (a company created by UKAD, a joint-venture between Aubert & Duval and UKTMP, ADEME and Crédit Agricole Centre France) launched a program with the Institut Jean Lamour dedicated to the development of specific modelling tools in order to get a better understanding of operating parameters effect on the final ingot quality. A model of the PAMCHR casting was developed and used to describe the heat transfer, liquid metal flow and alloying elements behavior during mixing in the liquid pool followed by segregation during solidification. The effect of PAMCHR electrode composition on the final VAR ingot composition is also studied using the SOLAR VAR model. Model validation by comparison with industrial ingots is presented with some examples of operating parameters sensitivity study.

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