Graphite surface destruction under plasma ion and oxygen gas irradiation

Begrambekov, L. B.; Buzhinsky, O. I.; Vergasov, S; Zakharov, A.M.; Otroschenko, V.G.; Telkovsky, V. G.

doi:10.1016/0022-3115(90)90158-j

Cited by 5 publications

(7 citation statements)

References 5 publications

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“…Research into the behaviour of composite carbon-carbide materials of CFC and KUP-VM type on ion irradiation were carried out in the study reported in [4]. It was found that homogeneous surface layers are produced during irradiation by helium plasma ions (E = 600 eV; i = 1 mA; T = 500 • C); thus the heterogeneous composite material is transmuted into an ordinary graphite.…”

Section: Methodsmentioning

confidence: 98%

“…The research carried out on mock-ups [4,5] in real conditions of operating tokamaks [6][7][8][9][10][11] reveals the considerable modification of the irradiated surface after exposure (figures 1(a) and (b)). The surface modification essentially depends on the load value, on its duration, on the temperature and, in particular, on the presence of oxygen molecules in the vacuum volume [4]. Homogeneous surface layers are produced on experimental samples, but separate pores appear whose size grows with increasing loading (figures 1a and b).…”

Section: Methodsmentioning

confidence: 98%

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Modification of the graphite tile surface in tokamaks

Buzhinskij

Begrambekov²,

Otroshchenko

2005

Plasma Devices and Operations

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The paper presents the results of experimental research on the surface modification of graphite protective elements from different graphite materials of MPG-8, RGT, ATJ, CFC, etc., types exposed in the T-10, T-11M, DIII-D, NSTX and Tore Supra tokamaks, as well as after plasma and ion irradiation in devices simulating wall boundary conditions in tokamaks. It is revealed that, in all cases of exposure, significant modification of the carbon-graphite materials surface occurs as a result of the plasma and ion beam. In addition, homogeneous pyrolitic layers with hexagonal planes oriented parallel to the irradiated surface are produced on the surface of protective elements. Thus, the physicomechanical characteristics of the plasma-facing surface degrade sharply. Application of a protective crystalline boron carbide coating reduces considerably the negative consequences of this phenomenon.

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Section: Methodsmentioning

confidence: 98%

Section: Methodsmentioning

confidence: 98%

Modification of the graphite tile surface in tokamaks

Buzhinskij

Begrambekov²,

Otroshchenko

2005

Plasma Devices and Operations

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“…Samples from the RGT-type graphite were tested under the conditions of the divertor plasma of the DIII-D tokamak in divertor material evaluation system (DiMES) dust experiments [7], and also under ion bombardment of the gas-discharge plasma [3,4]. During the exposure under divertor conditions, a sample was installed on the bottom of the DIII-D tokamak divertor at a major radius of 148.5 cm.…”

Section: Methodsmentioning

confidence: 99%

“…The use of fine-grained recrystallized RGT graphite modified by titanium is promising with respect to reducing the above-mentioned negative phenomena [2,3] graphites modified by titanium carbide have a number of properties, which are extremely important for construction materials of the first wall, limiters and divertor plates. Titanium carbide has a higher heat resistance than boron carbides do.…”

Section: Introductionmentioning

confidence: 99%

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Application of RGT graphite in fusion devices

Buzhinskij

Otroshchenko

West

2007

Plasma Devices and Operations

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The application of fine-grained recrystallized RGT graphite modified by titanium is considered. Thermally stabilized fine-grained RGT graphite modified by 10 at.% Ti has a density of 2.1 g cm −3 , a heat conductivity of up to 800 W m −1 K −1 , a low porosity and a small retention of hydrogen isotopes. The paper presents the results of full-scale tests on RGT graphite samples carried out in the T-10 and T-11M tokamaks in Russia, in the DIII-D tokamak in the USA, and in the MK-200 and PLADIS plasma facilities. The tested samples made from RGT graphite were found to be sufficiently stable, in particular, under irradiation for 600 ms by plasma with an electron temperature of 60 eV, an electron density of 2.5 × 10 14 cm −3 and a power of the parallel heat flux of 5 kW cm −2 , which are typical for the working modes and disruptions of plasma discharges in tokamaks.

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