Radial-hydride Embrittlement of High-burnup Zircaloy-4 Fuel Cladding

Daum, Robert S.; Majumdar, S.; Liu, Yung; Billone, M.C.

doi:10.1080/18811248.2006.9711195

Cited by 88 publications

(20 citation statements)

References 12 publications

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“…It was shown in the early 1960s by Louthan and Marshall [12,13] that radial hydrides may drastically reduce the ductility of zircaloy claddings. There is also a large number of more recent data that demonstrate the ductility reduction under ring-compression, tensile and pressure tests [14][15][16][17][18][19]. The hydride effect may actually be stronger for a modest hydride content (100-200 ppm) than for a very high hydride content (1000 ppm).…”

Section: Introductionmentioning

confidence: 89%

“…In [11] only relatively few hydrides were radial even after 10 thermo-mechanical load cycles. There are, however, many examples in the literature where most hydrides are radial after load cycles [14,10,15,30,22], so the Cases 5-7 are not unrealistic.…”

Section: Multi Crack Configurationmentioning

confidence: 94%

“…The increased strength is because hydrides are stiffer than the matrix and hence this increase of the strength applies only to non-fractured hydrides. Radial hydrides, however, fracture at low loads and the strength is then also generally reduced, although much less that the total elongation [14,15].…”

Section: Introductionmentioning

confidence: 96%

“…The internal pressure at room temperature is typically 3-7 MPa [9]. When the spent fuel is transferred from wet to dry storage the temperature increases to 400°C, the hydrides dissolve and the pressure increases (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16). The hydrides are then reprecitated as partially radial hydrides as the temperature drops.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

An elasto-plastic fracture mechanics based model for assessment of hydride embrittlement in zircaloy cladding tubes

Karl-Fredrik

Jakšić

Vokál

2010

Journal of Nuclear Materials

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Section: Introductionmentioning

confidence: 89%

Section: Multi Crack Configurationmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

An elasto-plastic fracture mechanics based model for assessment of hydride embrittlement in zircaloy cladding tubes

Karl-Fredrik

Jakšić

Vokál

2010

Journal of Nuclear Materials

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“…17). Rings 5,8,and 10 were tested at 5 mm/s displacement rate and 150°C to 2-mm crosshead displacement with about a 20-s hold time prior to unloading. Ring 3 was tested at 30°C to 1.7-mm crosshead displacement and controlled unloading at 5 mm/s.…”

Section: Rct Results For High-burnup Zirlo™ From Rodlet 648dmentioning

confidence: 99%

Ductile-to-Brittle Transition Temperature for High Burnup Zircaloy-4 and ZIRLO (TM) Cladding Alloys Exposed to Simulated Drying Storage Conditions.

Billone¹,

Burtseva²,

Yan³

2013

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EXECUTIVE SUMMARYStructural analyses of high-burnup fuel storage and transport casks require cladding mechanical properties and failure limits to assess fuel behavior. Properties and limits currently used are based on as-irradiated cladding samples from fuel rods discharged from reactors and stored in pools. Such cladding has reduced ductility due to irradiation effects and the presence of circumferential hydrides. However, as-irradiated cladding is not brittle. Pre-storage dryingtransfer operations and early stage storage subject cladding to higher temperatures and much higher pressure-induced tensile stresses than experienced in-reactor or during pool storage. If these are high enough, then radial hydrides could precipitate during pre-storage operations (slow cooling) and during dry-cask storage (very slow cooling). Radial hydrides represent an additional embrittlement mechanism that can reduce cladding failure limits during storage as the cladding temperature decreases below a ductile-to-brittle transition temperature (DBTT). As such, the effects of radial hydrides must be included in structural analyses when the cladding temperature is below or marginally above the DBTT.A test procedure was developed to simulate the effects of elevated temperatures, pressures and stresses during transfer-drying operations and early storage, as well as cooling slowly under decreasing pressures and stresses during both drying and storage. Pressurized and sealed rodlets were heated to the target temperature for a prescribed hold time and slow cooled at a computercontrolled linear temperature rate. The procedure was applied to both non-irradiated/prehydrided (PH) and high-burnup Zircaloy-4 (Zry-4) and ZIRLO™ using the NRC-recommended 400°C maximum temperature limit and a 5°C/h cooling rate. Following drying-storage simulation, samples sectioned from rodlets were subjected to ring-compression tests (RCTs). The RCT was used as a ductility screening test and to simulate pinch-type loading that would occur during cask transport. RCT load-displacement results were used to determine the DBTT for each cladding alloy as a function of the drying-storage hoop stress at 400°C. A strong correlation was found between the extent of radial hydride formation across the cladding wall and the extent of wall cracking during RCT loading.Prior to testing high-burnup cladding, a large number of tests were conducted with PH Zry-4 and ZIRLO™. It was observed that PH cladding with the same hydrogen content (350 to 650 wppm) was a poor surrogate for high-burnup cladding with respect to extent of radial-hydride precipitation and ductility reduction following simulated drying-storage. This was due to the uniform pre-test distribution of hydrides and the high-ductility metal matrix characteristic of PH cladding. However, test results for PH cladding were useful in defining a metric for the extent of radial hydride precipitation and in identifying the higher susceptibility of cladding with lower hydrogen contents (<300 wppm) to radial hydride precipitation.i...

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