کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
8041368 | 1518687 | 2014 | 5 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Thermal behavior of deuterium implanted into nuclear graphite studied by NRA
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی مواد
سطوح، پوششها و فیلمها
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چکیده انگلیسی
This paper focuses on the thermal behavior of deuterium, simulating tritium, implanted into virgin nuclear graphite of French gas-cooled reactors, which are being decommissioned. Deuterium ions D+ were implanted into graphite (around 3 at.% at the projected range Rp) at two different depths (around 670 nm and 2.8 μm) and annealed up to about 300 h in a temperature range from 200 °C to 1200 °C under vacuum or argon flow. Before and after heat treatments, D distribution profiles in the samples were followed using the nuclear reaction D(3He,p)4He, with a millimetric beam at the 4 MV Van de Graaff accelerator of IPNL (Institut de Physique Nucléaire de Lyon, France). The results show that the deuterium release becomes significant at temperatures higher than 600 °C and is almost totally completed at 1200 °C. The comparison of the results, obtained for both implantation depths, points out the role of the porosity with respect to deuterium permeation. The release follows two stages: a rapid step where it occurs within a few hours, followed by a much slower step during which the release of deuterium saturates. The initial stage is characterized by an activation energy of 1.3 eV and might correspond to detrapping of D located at crystallite edges and its diffusion at the crystallite surfaces. We assume that the second stage kinetics corresponds to a very slow diffusion of D located inside the crystallites and chemisorbed to carbon atoms through sp2 or sp3 bonds.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms - Volume 332, 1 August 2014, Pages 90-94
Journal: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms - Volume 332, 1 August 2014, Pages 90-94
نویسندگان
M. Le Guillou, N. Toulhoat, Y. Pipon, N. Moncoffre, N. Bérerd, A. Perrat-Mabilon, R. Rapegno,