The role of fission gas re-solution during post-irradiation heat treatment

Greenwood, G. W.; Boltax, A.

doi:10.1016/0022-3115(62)90104-6

Cited by 85 publications

(13 citation statements)

References 3 publications

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“…This can be understood, when assuming a gas pressure in the bubbles that scales with the inverse bubble radius and is in thermodynamic equilibrium with the solute phase [14,15]. The fact that we observe the contrary behaviour here with respect to the surface temperature may be attributed to a number of reasons: In our cases, there is no simple annealing of a He population in W. Instead, there is a discontinuous flux of H and He particles impinging during the annealing time.…”

Section: H/ 6 He Loadingmentioning

confidence: 62%

Investigation of European tungsten materials exposed to high heat flux H/He neutral beams

Greuner

Maier

Balden

et al. 2013

Journal of Nuclear Materials

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Tungsten is being considered as a potential plasma-facing material for future fusion devices, primarily due to its low erosion rate and high heat resistance. The intrinsic problem of this material, the brittleness even at elevated temperatures, requires the development and assessment of new tungsten materials.In the frame of the European material development programme for future fusion power plants W containing 5 wt.% Ta as well as uniaxially forged ultra-high purity W and powder injection moulded W were assessed in a neutral beam high heat flux test facility at IPP Garching.The investigation of the morphology modification of tungsten, occurring during heat loading using H and He particles, which simulates the expected divertor operation conditions, is indispensable in order to develop reliable plasma-facing materials. The effects seen, erosion, gas retention and cavity formation, depend on both the loading conditions and the operating temperature.This contribution presents a comparative study of the surface morphology changes of different W materials under hydrogen and helium beam loading to surface temperatures between 1500°C (1773 K) and 2000°C (2273 K), using actively cooled mock-ups. Loading is performed with pure H and mixed 94% H/ 6% He beams (φ=4 × 10 21 m -2 s -1 ), resulting in 10 MW m -² thermal load. Pulse durations of 30 s are applied to achieve fluences up to 3×10 25 m -2 under stationary temperature conditions.

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Section: H/ 6 He Loadingmentioning

confidence: 62%

Investigation of European tungsten materials exposed to high heat flux H/He neutral beams

Greuner

Maier

Balden

et al. 2013

Journal of Nuclear Materials

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“…After the exhaustive analysis, we tried to match the experimental observations to either of the two theoretical model proposed to explain the evolution of He bubbles after post-irradiation annealing: Ostwald ripening [23,24,25,26] and the theory of migration and coalescence (MC) [22].…”

Section: Discussionmentioning

confidence: 99%

“…So, this research is a starting point to understand the growth of the complex defects during the annealing treatment at high temperatures of irradiated steels, which may eliminate the pre-nucleation structure and transforms it into a bubble nucleus (or embryo). The subsequent growth of this embryo or of this already formed bubble will be carried out by means of the mechanisms mentioned above if the necessary conditions of time, temperature, and concentration are met: migration and coalescence [22] or Ostwald ripening [23,24,25,26].…”

Section: Introductionmentioning

confidence: 99%

Nanoindentation and TEM to Study the Cavity Fate after Post-Irradiation Annealing of He Implanted EUROFER97 and EU-ODS EUROFER

et al. 2018

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The effect of post-helium irradiation annealing on bubbles and nanoindentation hardness of two reduced activation ferritic martensitic steels for nuclear fusion applications (EUROFER97 and EU-ODS EUROFER) has been studied. Helium-irradiated EUROFER97 and EU-ODS EUROFER were annealed at 450 °C for 100 h in an argon atmosphere. The samples were tested by nanoindentation and studied by transmission electron microscopy extracting some focused ion beam lamellae containing the whole implanted zone (≈50 µm). A substantial increment in nanoindentation hardness was measured in the area with higher helium content, which was larger in the case of EUROFER97 than in EU-ODS EUROFER. In terms of microstructure defects, while EU-ODS EUROFER showed larger helium bubbles, EUROFER97 experienced the formation of a great population density of them, which means that the mechanism that condition the evolution of cavities for these two materials are different and completely dependent on the microstructure.

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“…Since the solubility of helium in metals is negligible, coarsening via Ostwald ripening [17,18] processes are not likely to be of importance. Bubble growth is also known to occur from grain boundary migration [19] or from recrystallization.…”

Section: Discussion Weld Response Hazmentioning

confidence: 99%

Helium-Induced Degradation in the Weldability of an Austenitic Stainless Steel

Lin

Goods

Grossbeck

et al. 1990

Effects of Radiation on Materials: 14th International Symposium (Volume I)

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ABSTRACT:Autogenous gas tungsten arc welding was performed onHe-doped type 316 stainless steel. Helium was uniformly implanted in the material using the "tritium trick" to levels of 27 and 105 appm. Severe intergranular cracking occurred in both fusion and heat-affected zones. Microstructural observations of the fusion zone indicated that the pore size, degree of porosity, and tendency to form cracks increased with increasing helium concentration. Scanning electron microscopy showed that cracking in He-doped materials was due to the precipitation of helium bubbles on grain boundaries and dendrite interfaces.Results of the present study demonstrate that the use of conventional welding techniques to repair materials degraded by exposure to radiation may be difficult if the irradiation results in the generation of even rather small amounts of helium.

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The role of fission gas re-solution during post-irradiation heat treatment

Cited by 85 publications

References 3 publications

Investigation of European tungsten materials exposed to high heat flux H/He neutral beams

Investigation of European tungsten materials exposed to high heat flux H/He neutral beams

Nanoindentation and TEM to Study the Cavity Fate after Post-Irradiation Annealing of He Implanted EUROFER97 and EU-ODS EUROFER

Helium-Induced Degradation in the Weldability of an Austenitic Stainless Steel

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