Hydrogen in Zircaloy: Mechanism and its impacts

Suman, Siddharth; Khan, Mohd. Kaleem; Pathak, Manabendra; Singh, R.N.; Chakravartty, J.K.

doi:10.1016/j.ijhydene.2015.03.049

Cited by 98 publications

(31 citation statements)

References 98 publications

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“…There is neither agreed hydrogen diffusion mechanism through the oxide layer nor known data about the hydrogen diffusion coefficient within the oxide [49]. A presence of oxygen may affect hydrogen migration barriers on an atomic scale.…”

Section: Oxides and Hydrogen Entrymentioning

confidence: 99%

Hydrogen degradation of pre-oxidized zirconium alloys

Szoka

Gajowiec

Zieliński

et al. 2017

Advances in Materials Science

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The presence of the oxide layers on Zr alloys may retard or enhance the hydrogen entry and material degradation, depending on the layer features. This research has been aimed to determine the effects of preoxidation of the Zircaloy-2 alloy at a different temperature on hydrogen degradation. The specimens were oxidised in laboratory air at 350ºC, 700ºC, and 900ºC. After, some samples were tensed at 10-5 strain rate and simultaneously charged with hydrogen under constant direct voltage in 1 N sulfuric acid at room temperature. Other specimens were charged without any tension, then annealed at 400ºC for 4 h and finally tensed at above strain rate. The SEM examinations were performed on the cross-sections and fracture faces of specimens. The obtained results demonstrate the effects of the oxide layer on the cathodic current and hydrogen entry, mechanical properties and the appearance of hydrides and fracture behaviour.

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Section: Oxides and Hydrogen Entrymentioning

confidence: 99%

Hydrogen degradation of pre-oxidized zirconium alloys

Szoka

Gajowiec

Zieliński

et al. 2017

Advances in Materials Science

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“…Laju pendinginan rendah yang digunakan menyebabkan pembentukan fasa δ-hidrida dalam matriks α-Zr [16]. Fasa hidrida dalam bentuk platelet dengan panjang ~40 m mulai teramati cukup banyak pada sampel uji yang dihidrogenasi pada temperatur sekitar 500 °C seperti yang ditunjukkan pada Gambar 3.…”

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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“…The fuel cladding encases radioactive uranium fuel pellets undergoing fission, and its outside surface is exposed to pressurized coolant water or heavy water, which takes away the generated heat for power generation . Zircaloy‐4 fuel cladding tubes undergo waterside corrosion during service and hydrogen produced due to the corrosion diffuses into it

\begin{matrix} lefttrue \\ Zr + 2 {normalH}_{2} O \to {ZrO}_{2} + 4 H \\ 4 H + 2 Zr \to 2 {ZrH}_{2} \end{matrix}

…”

Section: Introductionmentioning

confidence: 99%

“…1,2 Zircaloy-4 fuel cladding tubes undergo waterside corrosion during service and hydrogen produced due to the corrosion diffuses into it. 3 Zr þ 2H 2 The hydrogen in solid solution form in the Zircaloy-4 matrix is highly mobile at nuclear reactor operating conditions. It migrates down both the concentration and the temperature gradients while migrates up a stress gradient.…”

Section: Introductionmentioning

confidence: 99%

Effects of δ-hydride precipitated at a crack tip on crack instability in Zircaloy-4

et al. 2017

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Summary A fraction of hydrogen produced due to the waterside corrosion of Zircaloy‐4 nuclear fuel cladding diffuses into it. Diffused hydrogen migrates up a stress gradient in the Zircaloy‐4 and accrues in the regions of higher stress like a crack tip. When the concentration of hydrogen exceeds terminal solid solubility, it precipitates as brittle hydride phases. Hydride precipitated at the tip of a crack may induce crack instability, causing failure of the cladding. To understand the effects of hydride precipitated at the tip of a crack on crack instability in Zircaloy‐4, a numerical investigation is performed on single‐edge notched tension specimen by using the extended finite element method. The mechanical properties of the Zircaloy‐4 cladding and hydride precipitated in it—used in this numerical analysis—are evaluated by using nanoindentation technique. The crack length is taken between 0.05 and 0.2 mm, while the length of the hydride is varied in the range of 0.1 to 0.2 mm. The influence of hydride dimensions, number of hydrides, orientation of hydrides, and distance of hydride from the crack tip on crack instability is evaluated. The stability of the crack is assessed in stress intensity factor and J‐integral for each case. Results reveal that stress distribution around the crack tip is significantly altered by the precipitation of hydride. The circumferential hydride is less detrimental compared with the radial hydride. As the distance of hydride from the crack tip increases, there is a decline in the stress intensity factors and J‐integrals, implicating that there may exist a critical distance beyond which hydride precipitation has negligible effect on crack instability.

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Hydrogen in Zircaloy: Mechanism and its impacts

Cited by 98 publications

References 98 publications

Hydrogen degradation of pre-oxidized zirconium alloys

Hydrogen degradation of pre-oxidized zirconium alloys

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

Effects of δ-hydride precipitated at a crack tip on crack instability in Zircaloy-4

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