Evaluation of tungsten as a plasma-facing material for steady state magnetic fusion devices

Hirooka, Y.; Bourham, Mohamed; Brooks, J.N.; Causey, R.A.; Chevalier, G.; Conn, R.W.; Eddy, Walter H.; Gilligan, J.G.; Khandagle, M.; Ra, Y.

doi:10.1016/s0022-3115(06)80022-x

Cited by 45 publications

(21 citation statements)

References 21 publications

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“…Note that, in the current experiments, the W specimens were implanted at 21°to the normal; the TRIM 2000 calculations are for pure W surfaces, also tilted at 21°. The dashed line is a fit to the experimental data following the revised Bohdansky equation for sputtering [11], using a threshold energy of 44.5 eV [5]. There is considerable scatter in the experimental data, most probably due to variations in the surface impurity concentrations.…”

Section: Resultsmentioning

confidence: 99%

“…In contrast, Hirooka et al [5] estimated the effective net erosion of W at 1773 K during plasma bombardment, using spectroscopic methods calibrated by massloss measurements. In this case, the plasma was primarily hydrogen, with up to 2% oxygen.…”

Section: Introductionmentioning

confidence: 99%

“…The erosion yields measured were roughly consistent with the sum of the expected physical sputtering yields due to D þ and O þ . Hirooka et al [5] calculated the expected W loss due to the evaporation of volatile tungsten oxides, using the results of Wu's calculations [6], and found that this component should be roughly 0.6% of the observed erosion rate. As a check, Hirooka et al [5] compared the erosion yields for 400 eV ions at 773 K and at 1273 K, and found that there was no temperature effect on the erosion rate, indicating that the evaporation of volatile oxides was not a significant factor.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

W erosion due to low energy O+ and D+ impact

Macaulay-Newcombe

Haasz

Wu³

et al. 2004

Journal of Nuclear Materials

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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W erosion due to low energy O+ and D+ impact

Macaulay-Newcombe

Haasz

Wu³

et al. 2004

Journal of Nuclear Materials

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“…The plasma side transients refer to the overpower transients (OP), which for this work will be modeled as a linear increase in power. 17 Once the transients are classified, their frequency of occurrence need to be calculated. The frequencies of occurrence of Category 1 transients are taken from reference [1] for a pulsed machine.…”

Section: Identification and Classification Of The Transient Eventsmentioning

confidence: 99%

“…Reference [17] also concludes that tungsten is a possible choice when taking into considerations criteria like high thermal conductivity at high temperatures, minimal erosion due to sputtering and evaporation, minimized surface erosion due to melting, minimal tritium retention, low outgassing material. However, tungsten is not a very practical engineering material because machining and welding of it is generally difficult.…”

Section: Materials Propertiesmentioning

confidence: 99%

Probabilistic Analysis of Divertor Plate Lifetime in Tokamak Reactors

Golinescu

Kazimi

1994

Fusion Technology

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Probabilistic methods have been successfully used to analyze the risk associated with different existing nuclear power plant designs. Such tools can be also used at earlier stages in the design process. Defining a methodology for generation of the probabilistic lifetime reliability for a specific tokamak in-vessel component, the divertor, is the objective of this thesis. The divertor plates establish an interface between the plasma and the material surface of the tokamak device.The design of the divertor cooling system is a most demanding task since it endures the largest power density during operation. Even more severe consequences would appear under some transient conditions.In the present analysis, the divertor conditions for the technology phase of operation of the International Thermonuclear Experimental Reactor (ITER) as specified at the conceptual design stage are used as the reference design. The methodology developed to analyze the ITER divertor reliability consists of the following steps:1. description of normal operating conditions;2. thermal-hydraulic analysis for normal operation;3. identification and classification of transient events; 4. estimation of frequency of occurrence of transient events; 5. thermal analysis for transient event conditions; 6. defining the failure modes / failure criteria models; 7. assessment and propagation of uncertainties; 8. evaluation of the probability of avoiding failure of the divertor plate. The transient events considered in this work are grouped in two categories as follows:-transients that do not affect the divertor temperature distribution prior to shutdown, such as: auxiliary heating system disturbances, magnet system disturbances, main coolant disturbances, balance of plant disturbances, internal plasma disturbances; -transients that affect the divertor temperature distribution prior to shutdown, such as those on the coolant side: Loss of Coolant Accident (LOCA), Loss of Flow Accident (LOFA), and Loss of Heat Sink (LHS), and overpower (OP) transient on the plasma side. In applying this methodology, one failure mode is assumed to be the predominant failure mode: that of surface material loss due to sputtering, melting and evaporation. Taking no credit for redeposition of that material partially balances the fact that other failure modes are not accounted for. 2 The heat conduction computer code HEATING 7.2 is used for the steady-state and transient thermohydraulic analyses as well as for estimating the material loss during transients. The development of a reliability function requires defining a probability distribution function for the material loss during transients. A second order response surface (Response Surface Methodology) is derived for the material loss as a function of the uncertain parameters. The -uncertainties of the frequency of occurrence of transients and material loss parameters are propagated through the reliability function by a Monte Carlo simulation.Using the limited data available leads to the conclusion that there is a high prob...

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