Recycling of Zircaloy Machining Chips by VAR Remelting and Powder Metallurgy Techniques

Takiishi, Hidetoshi; Duvaizen, J.H.; Sato, I.M.; Rossi, Jesualdo Luiz; Pereira, Luíz Miguel; Martinez, L.G.

doi:10.4028/www.scientific.net/msf.727-728.356

Cited by 11 publications

(6 citation statements)

References 7 publications

(8 reference statements)

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“…The Zircaloys [8] Zircaloy-2 and Zircaloy-4 have appropriate chemical compositions. In comparison to Zircaloy-2, Zircaloy-4, which was introduced later, is a Ni free material and has better performance related chiefly to its lower hydrogen absorption under water corrosion [9].…”

Section: Introductionmentioning

confidence: 99%

Long-Term Corrosion Testing of Zy-4 in a LiOH Solution under High Pressure and Temperature Conditions

et al. 2021

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The fuel cladding is one of the most important structural components for maintaining the integrity of a fuel channel and for safely exploitation of a nuclear power plant. The corrosion behavior of a fuel cladding material, Zy-4, under high pressure and temperatures conditions, was analyzed in a static isothermal autoclave under simulated primary water conditions—a LiOH solution at 310 °C and 10 MPa for up to 3024 h. After this, the oxides grown on the Zy-4 sample surface were characterized using electrochemical measurements, gravimetric analysis, metallographic analysis, SEM and XPS. The maximum oxide thicknesses evaluated by gravimetric and SEM measurements were in good agreement; both values were around 1.2 µm. The optical light microscopy (OLM) investigations identified the presence of small hydrides uniformly distributed horizontally across the alloy. EIS impedance spectra showed an increase in the oxide impedance for the samples oxidized for a long time. EIS plots has the best fit with an equivalent circuit which illustrated an oxide model that has two oxide layers: an inner oxide layer and outer layer. The EIS results showed that the inner layer was a barrier layer, and the outer layer was a porous layer. Potentiodynamic polarization results demonstrated superior corrosion resistance of the samples tested for longer periods of time. By XPS measurements we identified all five oxidation states of zirconium: Zr0 located at 178.5 eV; Zr4+ at 182.8 eV; and the three suboxides, Zr+, Zr2+ and Zr3+ at 179.7, 180.8 and 181.8 eV, respectively. The determination of Vickers microhardness completed the investigation.

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Section: Introductionmentioning

confidence: 99%

Long-Term Corrosion Testing of Zy-4 in a LiOH Solution under High Pressure and Temperature Conditions

et al. 2021

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“…The test rodlet used as a sample was an axial section of a Pressurized Water Reactor (PWR) pin (fuel radius of 4.1 mm with a cladding thickness of 0.500 mm). The pin section was is inserted in a test rig having two concentric cylinders, a heater cylinder made in Zircaloy® (Zirc-2 [19]), and a pressure cylinder made of stainless steel, both of them with a thickness of about 3 mm. A third cylinder was also present during the irradiation test, but removed in the measurement phase.…”

Section: A Instrumental Setupmentioning

confidence: 99%

A Computational Methodology for Estimating the Detected Energy Spectra of the Gamma-Ray Flux From Irradiated Nuclear Fuel

Senis

Elter

Rathore

et al. 2022

IEEE Trans. Nucl. Sci.

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Gamma-ray spectrometry using collimated detectors is a well-established examination method for irradiated nuclear fuel. However, the feasibility of examining a particular nuclide of interest is subject to constraints; the peak must be statistically determinable with the desired precision and the total spectrum count rate in the detector should not cause throughput issues.Methods were assembled for gamma spectrum prediction to optimize instruments for gamma emission tomography and to enable a priori feasibility evaluation of determination of single peaks of irradiated nuclear fuel. The aim was to find reliable results (~10% accuracy) regarding total spectrum and peak count rates with faster computation time than a full-Monte Carlo approach. For this purpose, the method is based on depletion calculations with SERPENT2, a point-source kernel method for the collimator response, a rig response matrix and a detector response matrix, both computed with MCNP6. The computational methodology uses as input the fuel properties (dimensions, materials, power history, and cooling time), and the instrumental setup (collimator and detector dimensions and materials).The prediction method was validated using measured data from a high-burnup, short-cooled test fuel rodlet from the Halden reactor. Absolute count rates and ratios of characteristic peaks were compared between predicted and measured spectra, showing a total count rate overestimation of 7% and discrepancies between 2-20% for the single peaks (same order of magnitude of the uncertainty). This level of agreement is deemed sufficient for measurement campaigns planning, and the optimization of spectroscopic instruments for use in gamma scanning and tomography of nuclear fuel.

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“…A Zircaloy-4 tube alloy (see alloy composition in Table 1) was used as a substrate, as this material is used in fuel cladding tubes [34]. The Zircaloy-4 tube with an outer diame ter of 13 mm and a wall thickness of 0.45 mm was cut into 20 mm sections and then halved lengthwise.…”

Section: Coating Materialsmentioning

confidence: 99%

Corrosion Behavior of Chromium Coated Zy-4 Cladding under CANDU Primary Circuit Conditions

et al. 2021

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The manuscript is focused on corrosion behavior of a Cr coating under CANada Deuterium Uranium(CANDU) primary circuit conditions. The Cr coating is obtained via the thermionic vacuum arc procedure on Zircaloy -4 cladding. The surface coating characterization was performed using metallographic analysis and scanning electron microscopy (SEM) with an energy dispersive spectra detector (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) investigations. The thickness of the Cr coating determined from SEM images is around 500 nm layers After the autoclaving period, the thickness of the samples increased in time slowly. The kinetic of oxidation established a logarithmic oxidation law. The corrosion tests for various autoclaving periods of time include electrochemical impedance spectroscopy (EIS) and potentiodynamic tests, permitting computing porosity and efficiency of protection. All surface investigations sustain electrochemical results and promote the Cr coating on Zircaloy-4 alloy autoclaved for 3024 h as the best corrosion resistance based on decrease in corrosion current density values simultaneously with the increase of the time spent in autoclave. A slow increase of Vickers micro hardness was observed as a function of the autoclaved period as well. The value reached for 3024 h being 219 Kgf/mm2 compared with 210 Kgf/mm2 value before autoclaving.

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Recycling of Zircaloy Machining Chips by VAR Remelting and Powder Metallurgy Techniques

Cited by 11 publications

References 7 publications

Long-Term Corrosion Testing of Zy-4 in a LiOH Solution under High Pressure and Temperature Conditions

Long-Term Corrosion Testing of Zy-4 in a LiOH Solution under High Pressure and Temperature Conditions

A Computational Methodology for Estimating the Detected Energy Spectra of the Gamma-Ray Flux From Irradiated Nuclear Fuel

Corrosion Behavior of Chromium Coated Zy-4 Cladding under CANDU Primary Circuit Conditions

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