A simple theory for maximum h inventory and release: A new transport parameter

Doyle, B.L.

doi:10.1016/0022-3115(82)90277-x

Cited by 138 publications

(50 citation statements)

References 9 publications

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“…25 Analytical solutions to the hydrogen transport equation have been developed [395,396] for evaluating the hydrogen inventory, recycle and permeation rate and recycle time, under steady-state conditions where hydrogen is being implanted at flux Φ to a depth R p and release is controlled by diffusion and surface recombination. …”

mentioning

confidence: 99%

Plasma-material interactions in current tokamaks and their implications for next step fusion reactors

et al. 2001

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The major increase in discharge duration and plasma energy in a next step DT fusion reactor will give rise to important plasma-material effects that will critically influence its operation, safety and performance. Erosion will increase to a scale of several centimetres from being barely measurable at a micron scale in today's tokamaks. Tritium co-deposited with carbon will strongly affect the operation of machines with carbon plasma facing components. Controlling plasma-wall interactions is critical to achieving high performance in present day tokamaks, and this is likely to continue to be the case in the approach to practical fusion reactors. Recognition of the important consequences of these phenomena stimulated an internationally co-ordinated effort in the field of plasma-surface interactions supporting the Engineering Design Activities of the International Thermonuclear Experimental Reactor project (ITER), and significant progress has been made in better understanding these issues. The paper reviews the underlying physical processes and the existing experimental database of plasma-material interactions both in tokamaks and laboratory simulation facilities for conditions of direct relevance to next step fusion reactors. Two main topical groups of interaction are considered: (i) erosion/redeposition from plasma sputtering and disruptions, including dust and flake generation and (ii) tritium retention and removal. The use of modelling tools to interpret the experimental results and make projections for conditions expected in future devices is explained. Outstanding technical issues and specific recommendations on potential R&D avenues for their resolution are presented.

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confidence: 99%

Plasma-material interactions in current tokamaks and their implications for next step fusion reactors

et al. 2001

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“…7,8) Under the irradiation of hydrogen ion with medium energy range (1-100 keV), the amount of produced defects is much larger than that of the implanted hydrogen atoms. Figure 1 shows the depth distribution of the displaced atoms per incident ion (dpa), for irradiations of 5, 7.5 and 10 keV H þ which were calculated by the TRIM92 code.…”

Section: Resultsmentioning

confidence: 99%

“…Since it is reported that some of hydrogen implanted in Si at room temperature can be desorbed thermally below 500 K without significant annealing effect on the defects in silicon, 7,10,11) we have made an additional experiment to see the change in the relative reflectance by hydrogen release as follows. After the H þ irradiation with the fluence of 1 Â 10 18 cm À2 , the irradiated silicon sample was gradually heated up to 423 K. After the temperature was reached at 423 K, the change of the relative reflectance was monitored at the fixed temperature at 423 K. Figure 4 shows the changes of the relative reflectance at 370, 500 and 700 nm with heating time.…”

Section: Changes In Optical Reflection Of Siliconmentioning

confidence: 99%

<i>In-Situ</i> Optical Reflection Measurement of a Si(100) Surface under Hydrogen Ion Irradiation

2004

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In-situ optical reflection measurements have been performed for a Si(100) surface under H þ irradiation to study dynamic change in the electronic structure of the silicon. The relative reflectance at 370 nm decreased almost linearly with displacement per atom (dpa) and was recovered by hydrogen release by 423 K annealing, suggesting that the change in the relative reflectance at 370 nm originates from the increase of hydrogen bonded to Si. With increasing H þ irradiation, the relative reflectance around 700 nm increased due to the formation of Si-H phase near the surface silicon. Furthermore, the broad minima of the relative reflectance shifted from 600 to 500 nm by H þ irradiation, probably correlating with amorphization or appearance of silicon micro/nano-crystal by displacement effect.

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“…Using diffusivity values for deuterium in MANET (D) [16], the typical projected ranges PR for hundred-eVs deuterons (tenths A), the values for the reported impinging fluxes F in Section 4 and the obtained results for K 2 , the value of the transport parameter W [15]: W = (D/R) (FK 2 ) --1/2 % 10 --3 is derived. All the results obtained show a global coherence in this sense and evidence the pure surface limited release of the deuterium atoms implanted in MANET.…”

Section: Discussion and Concluding Remarksmentioning

confidence: 99%

Deuterium Recycling Rate Constants Derived from Plasma Implantation/Desorption Shots in a Martensitic Steel Surface

Sedano

Esteban²,

Perujo

2001

phys. stat. sol. (a)

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The recombination (K 2 ) and dissociation rate constants (K 1 ) are essential magnitudes for the tracking of tritium at the First Wall (FW) of Fusion Reactors (FR). This paper presents our plasma implantation/recycling test, the modelling of the experiment and the results obtained for K 2 and K 1 in the case of a deuterium (D þ 3 /D þ 2 ) plasma in the martensitic steel DIN 1.4914 (MANET). Once parasitic contributions were accounted, the D 2 release from the target was seen to be surface limited. The values obtained for K 1 and K 2 show low dispersion on impinging flux and ion energies. For K 1 a roughly constant value of 7 Â 10 --6 mol Pa --1 m --2 s --1 is derived. The obtained K 2 is written as: K 2 = 2.414 exp (--1571/RT) (m 4 mol --1 s --1 ), with R = 8.314 J mol --1 K --1 . Our activation energies agree with those existing in the literature derived from permeation experiments. High reflection coefficients are derived, which are in good agreement with the classical theory of ion scattering at low energy.

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A simple theory for maximum h inventory and release: A new transport parameter

Cited by 138 publications

References 9 publications

Plasma-material interactions in current tokamaks and their implications for next step fusion reactors

Plasma-material interactions in current tokamaks and their implications for next step fusion reactors

<i>In-Situ</i> Optical Reflection Measurement of a Si(100) Surface under Hydrogen Ion Irradiation

Deuterium Recycling Rate Constants Derived from Plasma Implantation/Desorption Shots in a Martensitic Steel Surface

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