Influence of temperature and hydrogen content on stress-induced radial hydride precipitation in Zircaloy-4 cladding

Desquines, Jean; Drouan, D.; Billone, M.C.; Püls, M. P.; March, Patrick A.; Fourgeaud, S.; Getrey, C.; Elbaz, V.; Philippe, Marc

doi:10.1016/j.jnucmat.2014.06.049

Cited by 40 publications

(16 citation statements)

References 26 publications

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“…During CCT testing, the hoop bending stress is heterogeneous and its maximum value is obtained at outer diameter and equatorial location. This maximum hoop stress value is determined from the normalized applied load in the elastic range according to references [14,15]:…”

Section: Mechanical Test Resultsmentioning

confidence: 99%

See 1 more Smart Citation

An attempt for a unified description of mechanical testing on Zircaloy-4 cladding subjected to simulated LOCA transient

Desquines¹,

Drouan²,

Torres³

et al. 2016

EPJ Nuclear Sci. Technol.

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Abstract. During a Loss Of Coolant Accident (LOCA), an important safety requirement is that the reflooding of the core by the emergency core cooling system should not lead to a complete rupture of the fuel rods. Several types of mechanical tests are usually performed in the industry to determine the degree of cladding embrittlement, such as ring compression tests or four-point bending of rodlets. Many other tests can be found in the open literature. However, there is presently no real intrinsic understanding of the failure conditions in these tests which would allow translation of the results from one kind of mechanical testing to another. The present study is an attempt to provide a unified description of the failure not directly depending on the tested geometry. This effort aims at providing a better understanding of the link between several existing safety criteria relying on very different mechanical testing. To achieve this objective, the failure mechanisms of pre-oxidized and pre-hydrided cladding samples are characterized by comparing the behavior of two different mechanical tests: Axial Tensile (AT) test and "C"-shaped Ring Compression Test (CCT). The failure of samples in both cases can be described by usual linear elastic fracture mechanics theory. Using interrupted mechanical tests, metallographic examinations have evidenced that a set of parallel cracks are nucleated at the inner and outer surface of the samples just before failure, crossing both the oxide layer and the oxygen rich alpha layer. The stress intensity factors for multiple crack geometry are determined for both AT and CCT samples using finite element calculations. After each mechanical test performed on high temperature steam oxidized samples, metallography is then used to individually determine the crack depth and crack spacing. Using these two important parameters and considering the applied load at fracture, the stress intensity factor at failure is derived for each tested sample. This procedure provides an assessment scheme to determine experimentally the fracture toughness of the prior-b region in the mid-wall of the oxidized samples. The obtained fracture toughness for CCT and AT samples are thus compared, confirming that the linear elastic fracture mechanics is a relevant tool to describe the strength of LOCA embrittled cladding alloys.

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Section: Mechanical Test Resultsmentioning

confidence: 99%

“…The CCT test consists in compressing the sample as illustrated in Figure 2 at a displacement rate of 1 mm/min (see Refs. [14,15] for complementary details). After mechanical testing, upper and lower parts of AT samples were reused to machine 10 mm long "C"-shaped ring compression samples.…”

Section: Testing Protocolmentioning

confidence: 99%

An attempt for a unified description of mechanical testing on Zircaloy-4 cladding subjected to simulated LOCA transient

Desquines¹,

Drouan²,

Torres³

et al. 2016

EPJ Nuclear Sci. Technol.

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“…Pada kondisi operasi normal, hal tersebut sudah diperhitungkan dalam desain keselamatan sebuah reaktor nuklir, tetapi pada kondisi transien, kehilangan aliran pendingin primer atau Loss of Cooling Accident (LOCA) misalnya, kombinasi faktor tersebut dapat menyebabkan situasi fatal bagi keselamatan reaktor nuklir. Degradasi sifat mekanik yang diikuti dengan kerusakan kelongsong bahan bakar nuklir sebagian besar disebabkan oleh temperatur tinggi yang disertai oleh serapan hidrogen seperti pada skenario terjadinya LOCA [1]. Oleh karena itu, pengaruh hidrogen terhadap degradasi sifat mekanik kelongsong Zr-4 menjadi salah satu perhatian utama dalam pengoperasian reaktor nuklir, terutama setelah peristiwa kebocoran reaktor nuklir di Fukushima-Daichi [2].…”

Section: Pendahuluanunclassified

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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“…Refs. [7,8,24,30,32,39]. When re-orientation tests are done by pressuring the tubes, the stress in the tube is generally kept constant [23,25,27].…”

Section: Hydride Re-orientation Testmentioning

confidence: 99%

“…For an overview of mechanical tests see for instance [1e3]. One of the most common tests is the ring compression test [4e6], which is easy to perform also in hot cells, but rather complicated to analyse due to the very non-homogenous deformation; the C-shaped compression test is similar but easier to analyse as it promotes a more homogeneous deformation [7,8]; the ring tensile tests [9e11], for both hoop or axial properties are also popular but less suited for irradiated material due to more complicated specimen preparation; slotted-arc test provides plain strain but specimen preparation is also rather complicated [12], internal pressure tests [13] provide bi-axial stresses, but are rather complicated to perform and require much material. Axi-symmetric deformation can also be attained by open-end pressure tests [14], in which case relative small specimens can be used but strains vary along the axial direction.…”

Section: Introductionmentioning

confidence: 99%

An evaluation of the segmented expanding cone-mandrel test to assess hydride re-orientation and ductility reduction for Zircaloy-2 cladding tubes

Karl-Fredrik

Negyesi

Száraz

et al. 2015

Journal of Nuclear Materials

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Influence of temperature and hydrogen content on stress-induced radial hydride precipitation in Zircaloy-4 cladding

Cited by 40 publications

References 26 publications

An attempt for a unified description of mechanical testing on Zircaloy-4 cladding subjected to simulated LOCA transient

An attempt for a unified description of mechanical testing on Zircaloy-4 cladding subjected to simulated LOCA transient

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

An evaluation of the segmented expanding cone-mandrel test to assess hydride re-orientation and ductility reduction for Zircaloy-2 cladding tubes

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