Tritium and helium embrittlement of austenitic steels used in tritium storage and delivery system

Yang, Sojeong; Lee, Jae-Uk; Kang, Hyun−Goo; Chang, Min-Sun; Oda, Takuji

doi:10.1016/j.jnucmat.2020.152349

Cited by 7 publications

(3 citation statements)

References 54 publications

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“…Li et al reported that the effect of aging on the storage and delivery performance was negligible after one-time long-term aging (460–1720 days) . However, the conditions of this experiment are largely different from the planned operation scenario of ITER-SDS, which is a two-week storage and delivery cycle repeated 96 times in 6 years of service. , Hence, a detailed understanding of the helium behavior in UT 3 and alpha-U is necessary to ensure the long-term performance of SDS.…”

Section: Introductionmentioning

confidence: 89%

“…The stable phase of uranium is the alpha phase (space group 63) under the planned operation conditions of the ITER-SDS, which will be operated at room temperature for tritium storage and 723 K for tritium delivery . Before studying the migration properties of helium, we tested the validity of the parameters for the DFT calculations of the lattice constants, the vacancy formation energy, and the interstitial helium formation energy in alpha-U.…”

Section: Methods and Computational Detailsmentioning

confidence: 99%

“…In the tritium storage period, helium is produced in UT 3 by the beta decay of tritium with a half-life of 12.3 years. The produced helium within UT 3 is not released immediately after the decay because of its small recoil energy. , Moreover, some of the generated helium does not leave the host material by heating even above the decomposition temperature of UT 3 , and a major release of helium requires heating at 800–1000 K. , Because the tritium delivery is planned to be conducted at 723 K in ITER-SDS to avoid high-temperature damage of devices, , helium will pile up in both UT 3 and alpha-U, which would affect the storage and delivery performance of U or UT 3 . Li et al reported that the effect of aging on the storage and delivery performance was negligible after one-time long-term aging (460–1720 days) .…”

Section: Introductionmentioning

confidence: 99%

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First-Principles Calculations of the Diffusivity of Interstitial Helium in Alpha-U Considering Anisotropy, Isotope Effects, and Quantum Effects

et al. 2021

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The interstitial migration of helium in alpha-U, which is planned to be used as a tritium storage material for nuclear fusion reactors and as a metallic fuel for advanced nuclear reactors, is studied by first-principles calculations. First, all migration paths are identified using the nudged elastic band method, and the migration barrier is determined for each path considering the thermal expansion of the lattice. In addition, the jump attempt frequencies are determined by applying harmonic transition state theory coupled with vibration analysis. Subsequently, the diffusion coefficient is evaluated numerically by kinetic Monte Carlo calculations using the determined migration barriers and jump attempt frequencies for all migration paths. Diffusion in the [010]-direction is found to be the most unlikely until sufficiently high temperature, while [001]-diffusion is the most dominant diffusion direction through the whole temperature range. The isotope effect, which is important because the beta decay of tritium produces helium-3, is not large and approaches the classical limit as the temperature increases. The quantum tunneling crossover temperature is computed to be approximately 100 K for helium-3 and 86 K for helium-4, which ensures the validity of the present calculation results over a wide temperature range. The diffusion coefficients are obtained as for helium-3 and for helium-4 over a temperature range from 200 to 900 K.

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Section: Introductionmentioning

confidence: 89%

Section: Methods and Computational Detailsmentioning

confidence: 99%