Comparison of damages in tungsten and tungsten doped with lanthanum-oxide exposed to dense deuterium plasma shots

Shirokova, Veroonika; Laas, T.; Ainsaar, Ain; Priimets, J.; Ugaste, Ü.; Demina, E. V.; Пименов, В. Н.; Maslyaev, S. A.; Dubrovsky, A. V.; Грибков, В. А.; Scholz, M.; Mikli, Valdek

doi:10.1016/j.jnucmat.2012.12.027

Cited by 29 publications

(17 citation statements)

References 10 publications

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“…Plasma-material interaction studies showed that higher heat fl ux factor F leads to higher values of microroughness upon irradiated surfaces (see [1,9,10,22]). Therefore, the sample DFW 87a should have greater microroughness R a values than DFW 88a.…”

Section: Results and Analysis Of Surface Defectsmentioning

confidence: 99%

“…On the other hand, when a mesh of microcracks was developed during plasma pulses at PF-12, which were followed by irradiation of the sample in QSPA Kh-50 (with much smaller values of power fl ux density), no signifi cant change of micro-or macrocells' sizes was observed. For a comparison, when tungsten was produced by usual rolling and single forging technology, the mesh of microcracks occurred on the samples already after eight shots of plasma [9,10].…”

Section: Results and Analysis Of Surface Defectsmentioning

confidence: 99%

“…It is known that changing the distance between the anode and the sample (see Fig. 1) allows one to change plasma parameters on the sample surface [16,17] (see also [18,19] for an overview of PF-1000 and [10] for PF-12).…”

Section: Experimental Set-upmentioning

confidence: 99%

“…La 2 O 3 , Y 2 O 3 , TiO, etc.) or other elements (Ta, Ti) might improve the physical properties of the alloy [5][6][7][8][9][10]. Different investigations have shown that while improving some of the tungsten's properties, adding the components can also lead to generation of tungsten dust to plasmas.…”

Section: Introductionmentioning

confidence: 99%

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The experimental and theoretical investigations of damage development and distribution in double-forged tungsten under plasma irradiation-initiated extreme heat loads

et al. 2016

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Abstract. The infl uence of extreme heat loads, as produced by a multiple pulses of non-homogeneous fl ow of slow plasma (0.1-1 keV) and fast ions (100 keV), on double-forged tungsten (DFW) was investigated. For generation of deuterium plasma and fast deuterons, plasma-focus devices PF-12 and PF-1000 are used. Depending on devices and conditions, the power fl ux density of plasma varied in a range of 10 7 -10 10 W/cm 2 with pulse duration of 50-100 ns. Power fl ux density of fast ions was 10 10 -10 12 W/cm 2 at the pulse duration of 10-50 ns. To achieve the combined effect of different kind of plasmas, the samples were later irradiated with hydrogen plasma (10 5 W/cm 2 , 0.25 ms) by a QSPA Kh-50 plasma generator. Surface modifi cation was analysed by scanning electron microscopy (SEM) and microroughness measurements. For estimation of damages in the bulk of material, an electrical conductivity method was used. Investigations showed that irradiation of DFW with multiple plasma pulses generated a mesh of micro-and macrocracks due to high heat load. A comparison with single forged tungsten (W) and tungsten doped with 1% lanthanum-oxide (WL10) reveals the better crack-resistance of DFW. Also, sizes of cells formed between the cracks on the DFW's surface were larger than in cases of W or WL10. Measurements of electrical conductivity indicated a layer of decreased conductivity, which reached up to 500 m. It depended mainly on values of power fl ux density of fast ions, but not on the number of pulses. Thus, it may be concluded that bulk defects (weakening bonds between grains and crystals, dislocations, point-defects) were generated due to mechanical shock wave, which was generated by the fast ions fl ux. Damages and erosion of materials under different combined radiation conditions have also been discussed.

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Section: Results and Analysis Of Surface Defectsmentioning

confidence: 99%

Section: Results and Analysis Of Surface Defectsmentioning

confidence: 99%

Section: Experimental Set-upmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The experimental and theoretical investigations of damage development and distribution in double-forged tungsten under plasma irradiation-initiated extreme heat loads

et al. 2016

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“…The surface cracking is frequently observed on tungsten surfaces exposed to transient heat fl uxes causing signifi cant degradation of mechanical properties. The onset of cracking and crack propagation might be delayed by using alloys with elements such as tantalum or lanthanum-oxide [4,7] or by reinforcing the structure using fi bers [8]. Nevertheless, the issue of tungsten melting under transition heat loading for ITER relevant condition remains still an open question.…”

Section: Introductionmentioning

confidence: 99%

Heat load and deuterium plasma effects on SPS and WSP tungsten

et al. 2015

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Abstract. Tungsten is a prime choice for armor material in future nuclear fusion devices. For the realization of fusion, it is necessary to address issues related to the plasma-armor interactions. In this work, several types of tungsten material were studied, i.e. tungsten prepared by spark plasma sintering (SPS) and by water stabilized plasma spraying (WSP) technique. An intended surface porosity was created in the samples to model hydrogen/ helium bubbles. The samples were subjected to a laser heat loading and a radiation loading of deuterium plasma to simulate edge plasma conditions of a nuclear fusion device (power density of 10 8 W/cm 2 and 10 7 W/cm 2 , respectively, in the pulse intervals up to 200 ns). Thermally induced changes in the morphology and the damage to the studied surfaces are described. Possible consequences for the fusion device operation are pointed out.

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