A review on hydride precipitation in zirconium alloys

Bair, Jacob; Zaeem, Mohsen Asle; Tonks, Michael

doi:10.1016/j.jnucmat.2015.07.014

Cited by 124 publications

(50 citation statements)

References 110 publications

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“…Consequently, Zircaloy react with water, producing an oxide layer at the interface and hydrogen (H), of which a substantial fraction infiltrates into the cladding interior3. Due to the low solubility of H in α-Zr, which is the main component of claddings, hydrides precipitate in the cladding matrix456. Hydride formation can detrimentally affect the cladding integrity primarily in two ways.…”

mentioning

confidence: 99%

Anisotropic hydrogen diffusion in α-Zr and Zircaloy predicted by accelerated kinetic Monte Carlo simulations

Zhang

Jiang

Bai

2017

Sci Rep

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This report presents an accelerated kinetic Monte Carlo (KMC) method to compute the diffusivity of hydrogen in hcp metals and alloys, considering both thermally activated hopping and quantum tunneling. The acceleration is achieved by replacing regular KMC jumps in trapping energy basins formed by neighboring tetrahedral interstitial sites, with analytical solutions for basin exiting time and probability. Parameterized by density functional theory (DFT) calculations, the accelerated KMC method is shown to be capable of efficiently calculating hydrogen diffusivity in α-Zr and Zircaloy, without altering the kinetics of long-range diffusion. Above room temperature, hydrogen diffusion in α-Zr and Zircaloy is dominated by thermal hopping, with negligible contribution from quantum tunneling. The diffusivity predicted by this DFT + KMC approach agrees well with that from previous independent experiments and theories, without using any data fitting. The diffusivity along is found to be slightly higher than that along , with the anisotropy saturated at about 1.20 at high temperatures, resolving contradictory results in previous experiments. Demonstrated using hydrogen diffusion in α-Zr, the same method can be extended for on-lattice diffusion in hcp metals, or systems with similar trapping basins.The diffusion of hydrogen in hcp metals has attracted extensive research interests for both its scientific merit and technological importance. It is the rate-limiting step for solid hydrogen storage in Mg based alloys 1 and for mechanical property degradation in Ti 2 and Zr alloys 3 . For instance, Zr-based alloys such as Zircaloy2 and Zircaloy4 (denoted as Zircaloy) are widely used as the cladding of fuel rods in nuclear reactors for their excellent corrosion resistance and very low absorption cross-section of thermal neutrons. During their service time, these alloys operate in extremely harsh environments, combining high temperatures and corrosive coolants such as water. In light water reactors, Zircaloy claddings directly contact coolant water, with a local temperature at the interface of about 400 °C. Consequently, Zircaloy react with water, producing an oxide layer at the interface and hydrogen (H), of which a substantial fraction infiltrates into the cladding interior 3 . Due to the low solubility of H in α -Zr, which is the main component of claddings, hydrides precipitate in the cladding matrix 4-6 . Hydride formation can detrimentally affect the cladding integrity primarily in two ways. First, the formation of hydrides reduces the fracture toughness of the cladding matrix 7,8 , increasing the probability of fuel failure when fuel-cladding mechanical interaction (PCMI) occurs during fuel operation. Second, upon cyclic thermal and mechanical loadings, hydrides can dissolve and reorient. During used-fuel storage, fracture may propagate via the so-called delayed-hydride-cracking (DHC) mechanism, which is induced by the dissolving of matrix hydrides and their subsequent re-formation at crack tips 3,9 . To mitigate thes...

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mentioning

confidence: 99%

Anisotropic hydrogen diffusion in α-Zr and Zircaloy predicted by accelerated kinetic Monte Carlo simulations

Zhang

Jiang

Bai

2017

Sci Rep

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“…Kelongsong Zr-4 dengan kandungan hidrogen sebesar 225 ppm memiliki daktilitas yang lebih rendah dibandingkan dengaan yang hanya 60 ppm [4]. Penelitian lain menyebutkan bahwa pada saat kandungan hidrogen mencapai 600 ppm, kelongsong Zr-4 mulai kehilangan daktilitasnya bahkan pada kondisi yang ekstrim dengan kandungan hidrogen sekitar ~5000 ppm, kelongsong Zr-4 hanya memiliki regangan sebesar 1 % [5,6]. Salah satu teknik pengujian daktilitas adalah pengujian tarik transversal/ring yang telah banyak dilakukan oleh para peneliti [7][8][9][10].…”

Section: Pendahuluanunclassified

“…Keberadaan hidrogen dalam sampel Zr-4 dapat berada dalam bentuk larutan padat maupun presipitat hidrida yang terbentuk saat batas kelarutan tercapai [15]. Laju pendinginan rendah yang digunakan menyebabkan pembentukan fasa δ-hidrida dalam matriks α-Zr [16].…”

Section: Gambar 2 Mikrostrukurunclassified

Pengaruh Hidrogen Terhadap Kekuatan Tarik Kelongsong Bahan Bakar Nuklir Berbasis Paduan Zirkonium

Sigit

Afghani

Setiawan

et al. 2017

urania

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ABSTRAK PENGARUH HIDROGEN TERHADAP KEKUATAN TARIK KELONGSONG BAHAN BAKAR NUKLIR BERBASIS PADUAN ZIRKONIUM.Selama operasi reaktor nuklir, zircaloy-4 (Zr-4) sebagai kelongsong bahan bakar nuklir berada pada lingkungan yang berpotensi menimbulkan kegagalan mekanik, terutama akibat interaksinya dengan hidrogen. Hidrogen berdifusi ke dalam kelongsong dan pada saat melewati batas kelarutan akan terpresipitasi menjadi hidrida rapuh yang menyebabkan degradasi sifat mekanik. Teknik pengujian tarik ring digunakan dalam penelitian ini untuk mengetahui pengaruh keberadaan hidrida terhadap kekuatan tarik kelongsong Zr-4. Kelongsong Zr-4 dipanaskan pada temperatur 500 °C dan 600 °C dalam kondisi vakum selama satu jam yang diikuti dengan proses hidrogenasi bertahap hingga mencapai tekanan 1000 mbar dan ditahan selama tiga jam sebelum didinginkan secara normal di dalam tungku. Dengan menggunakan persamaan gas ideal diperoleh kandungan hidrogen yang terserap oleh kelongsong Zr-4 berturut-turut sebesar 674 ppm dan 1215 ppm pada temperatur hidrogenasi 500 °C dan 600 °C. Proses hidrogenasi pada temperatur 500 °C menyebabkan peningkatan kekerasan mikro hingga 36 % dan pada temperatur 600 °C dapat meningkatkan kekerasan mikro hingga 49 % jika dibandingkan dengan kelongsong Zr-4 tanpa perlakuan. Sementara itu, analisis mikrotruktur menunjukkan presipitat hidrida lebih banyak menempati batas butir. Presipitat hidrida lebih panjang dan tebal pada temperatur hidrogenasi yang lebih tinggi. Kenaikan jumlah hidrogen menghasilkan kenaikan nilai tegangan sebesar 4,4 %, penurunan nilai regangan sebesar 2,1 % dan kenaikan level kekerasan mikro Vickers sebesar 13 %. Hal ini menunjukkan bahwa keberadaan presipitat hidrida dalam kelongsong meningkatkan kekuatan tarik dan menurunkan daktilitasnya.. Kata kunci:Hidrogen, kekuatan tarik, kelongsong, uji tarik ring, daktilitas.

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“…Some research papers have been found on numerical modelling of hydrogen and hydrides distribution in zirconium alloy [8], numerical modelling of hydrides growth [9] and hydrides shape and orientation [10] in zirconium alloy in the presence of hydrogen using the finite element method. More papers can be found on fracture modelling of zirconium alloy with hydrides [11][12][13], etc.…”

Section: Introductionmentioning

confidence: 99%

Numerical prediction of mechanical properties of zirconium alloy with hydrides using finite element method

Janulionis¹,

Dundulis²,

Kriūkienė³

et al. 2018

energetika

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During nuclear power plant (NPP) operation, degradation effects like ageing, corrosion, fatigue, and others may significantly impact component integrity. One of the degradation mechanisms is hydrogen absorption. High levels of hydrogen in zirconium alloys can lead to the formation of zirconium hydrides and that can influence material properties. Therefore, determination of material properties under different levels of hydrogen concentration in zirconium alloys is important. It is not always possible to conduct an experimental testing. Therefore, there is a need for alternative methods for determination of material properties. This article presents the numerical prediction of material properties of zirconium 2.5% niobium alloy with hydrides.According to the objective of the work, numerical prediction was performed using the finite element (FE) method. This was done by creating a finite element model of zirconium hydride embedded in zirconium alloy. The geometry and size of hydride were measured from a real specimen. The size of zirconium alloy surrounding the hydride was selected in such a way that hydride volume part in the model would match experimental measurements. The prognosis results were compared with the experimental data.

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A review on hydride precipitation in zirconium alloys

Cited by 124 publications

References 110 publications

Anisotropic hydrogen diffusion in α-Zr and Zircaloy predicted by accelerated kinetic Monte Carlo simulations

Anisotropic hydrogen diffusion in α-Zr and Zircaloy predicted by accelerated kinetic Monte Carlo simulations

Pengaruh Hidrogen Terhadap Kekuatan Tarik Kelongsong Bahan Bakar Nuklir Berbasis Paduan Zirkonium

Numerical prediction of mechanical properties of zirconium alloy with hydrides using finite element method

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