Dynamic outgassing of deuterium, helium and nitrogen from plasma-facing materials under DEMO relevant conditions
Dynamic outgassing of deuterium, helium and nitrogen from plasma-facing materials under DEMO relevant conditions
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DOI：
10.1088/0029-5515/57/1/016020
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发表时间：
2016
期刊：
影响因子：
3.3
通讯作者：
S. Möller;D. Matveev;Y. Martynova;B. Unterberg;M. Rasinski;T. Wegener;A. Kreter;C. Linsmeier
中科院分区：
文献类型：
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作者：
S. Möller;D. Matveev;Y. Martynova;B. Unterberg;M. Rasinski;T. Wegener;A. Kreter;C. Linsmeier
在约束等离子体磁聚变装置中，用于聚变反应的大量氢同位素可以通过注入储存在面向等离子体的材料中。在托卡马克中，这些残留氢的解吸遵循tα定律，α =-0.7。对于脉冲聚变反应堆，这种除气可以限定脉冲间等待时间。这项工作提出了新的实验数据的动态放气在ITER级钨暴露在PSI-2的条件下，纯和混合D2等离子体。在高达900 K的样品温度下，施加1022 D+ m−2 s的峰值离子通量长达6 h。在68 V偏压下将纯D2和混合D2 + He、D2 + N2和D2 + He + N2等离子体施加到样品。在293 K和580 K下，用真空四极杆质谱仪观察了D2、He、N的脱气过程，时间范围为40 s ~ 200 000 s。在293 K时，放气衰减遵循单次幂定律，指数α = −0.7 ~ −1.1，但在580 K时，发现从α = −0.25下降到−2.35。对于DEMO，可以预期抽气时间约为1-5 h。除气在所有情况下都由D2主导。
In confined plasma magnetic fusion devices significant amounts of the hydrogen isotopes used for the fusion reaction can be stored in the plasma-facing materials by implantation. The desorption of this retained hydrogen was seen to follow a tα law with α ≈ −0.7 in tokamaks. For a pulsed fusion reactor this outgassing can define the inter-pulse waiting time. This work presents new experimental data on the dynamic outgassing in ITER grade tungsten exposed under the well-defined conditions of PSI-2 to pure and mixed D2 plasmas. A peak ion flux of 1022 D+ m−2 s is applied for up to 6 h at sample temperatures of up to 900 K. Pure D2 and mixed D2 + He, D2 + N2 and D2 + He + N2 plasmas are applied to the sample at 68 V bias. The D2, He, N outgassing at 293 K and 580 k are observed via in-vacuo quadrupole mass spectrometry covering the range of 40 s–200 000 s after exposure. The outgassing decay follows a single power law with exponents α = −0.7 to −1.1 at 293 K, but at 580 K a drop from α = −0.25 to −2.35 is found. For DEMO a pump-down time to 0.5 mPa in the order of 1–5 h can be expected. The outgassing is in all cases dominated by D2.