Helium mobility in advanced nuclear ceramics

Agarwal, Shradha; Trocellier, P.; Serruys, Y.; Vaubaillon, S.; Miro, S.

doi:10.1016/j.nimb.2013.09.039

Cited by 22 publications

(8 citation statements)

References 130 publications

(169 reference statements)

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“…The fitted activation energy Q is 0.78 eV, which is in reasonable agreement with the experimental value of 0.77 6 0.08 eV. 10 Obviously, due to the contribution of the change in zero-point vibrational energy ᭝F zp vib at low temperatures, this result is slightly larger than the potential energy barrier of 0.77 eV. The calculated prefactor D 0 (ZrC) is 5.13 Â 10 À11 m 2 s À1 .…”

Section: Diffusion Coefficientsupporting

confidence: 84%

“…34 and 35)], which would enhance the probability of helium trapping, the diffusion coefficient will be reduced to some extent. This prediction is confirmed by Agarwal et al 10 who observed the helium blister close to the surface of ZrC compared to TiC and TiN at 1500 C, which suggests the presence of helium clusters or bubbles. Besides, Yadava 36 clearly validated the existence of over pressurized helium bubbles.…”

Section: Diffusion Coefficientsupporting

confidence: 72%

“…Previously, helium migration in ZrC has only been investigated by a non-destructive 3 He depth profiling using the resonant 3 He(d, p 0 ) 4 He nuclear reaction. 10 On the other hand, the diffusion coefficient of helium in ZrC matrix is still lacking in the literature, which can be used to quantify the released helium fraction according to the duration of the storage period. To our knowledge, it has been attracted much attention in other reactor materials like UO 2 and PuO 2 , [11][12][13] SiC, 14-16 nuclear glass, 17 and britholite.…”

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confidence: 99%

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The temperature-dependent diffusion coefficient of helium in zirconium carbide studied with first-principles calculations

Yang

Zhang

2015

Journal of Applied Physics

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The temperature-dependent diffusion coefficient of interstitial helium in zirconium carbide (ZrC) matrix is calculated based on the transition state theory. The microscopic parameters in the activation energy and prefactor are obtained from first-principles total energy and phonon frequency calculations including the all atoms. The obtained activation energy is 0.78 eV, consistent with experimental value. Besides, we evaluated the influence of C and Zr vacancies as the perturbation on helium diffusion, and found the C vacancy seems to confine the mobility of helium and the Zr vacancy promotes helium diffusion in some extent. These results provide a good reference to understand the behavior of helium in ZrC matrix. V C 2015 AIP Publishing LLC.

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Section: Diffusion Coefficientsupporting

confidence: 84%

Section: Diffusion Coefficientsupporting

confidence: 72%

mentioning

confidence: 99%

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The temperature-dependent diffusion coefficient of helium in zirconium carbide studied with first-principles calculations

Yang

Zhang

2015

Journal of Applied Physics

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“…Due to the existence of vacancies or dislocations in the real crystal, the diffusion coefficients will be reduced to a great degree, as investigated in ZrC matrix. 34,35 The formation of helium bubbles would also enhance the probability of helum trapping. To this end, we have made a relevant test to elaborate the effects of the clustering behavior of two helium atoms which can be regarded as the first step to form the helium bubbles.…”

Section: Diffusion Coefficientsmentioning

confidence: 99%

First-principles study of migration and diffusion mechanisms of helium in α-Be

Yang

et al. 2016

AIP Advances

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The behavior of interstitial helium in α-Be has been studied with first-principles method. It is found that the most favored position for helium is the basal octahedral (BO) site, closely followed by the basal tetrahedral (BT) site, in agreement with previous predictions. The interaction energy between the helium and the neighborhood Be atoms and the deformation energy of α-Be matrix are calculated. The feasible minimum-energy pathways (MEP) of interstitial helium atoms in α-Be matrix and the corresponding atomic structures of the saddle points associated with the each MEP are investigated. The temperature-dependent diffusion coefficients have also been predicted. It is confirmed that the interstitial helium diffuses two-dimensionally at low temperatures; however, it can diffuse three-dimensionally at higher temperatures. Besides, the microscopic parameters in the pre-factor and activation energy of the diffusion coefficients are obtained. Both diffusion coefficients are higher than the available experiment data, which may attribute to the fact that under real condition the diffusion is not free, i.e. the actual α-Be matric has various defects and impurities which heavily affect the diffusion of helium. Therefore, our theoretical prediction is the upper bound for helium diffusion in α-Be matrix.

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“…From these curves, the extracted kinetic parameters of helium release show that TiN exhibits a very strong helium retention up to 1600°C (less than 20% loss). 41 The 3 He(d, p) NRA characterization has been then transposed to TiC and ZrC compounds. 42 …”

Section: Off-line Characterization By Ibamentioning

confidence: 99%