Thermal-Hydraulic Design Issues and Analysis for the ITER Divertor

Koski, J.A.; Watson, R.D.; Goranson, P.; Hassanein, A.; Salmonson, J.C.

doi:10.13182/fst91-a29591

Cited by 14 publications

(6 citation statements)

References 3 publications

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“…The effects of the twisted tape on maintaining the highly subcooled nature of the flow can be seen in Figures 10a and 10b which show liquid subcooling. The mixing capability of the tape is far more visible with the solver predicting that the bulk of the flow remains almost 100K below the saturation temperature, a value which is expected from the design analysis as presented by Koski and Watson [21].…”

Section: Resultsmentioning

confidence: 75%

“…Subcooled flow boiling or forced convection boiling is used for its ability to deliver high rates of heat transfer in compact spaces and with limited wall superheat [18][19][20]. In ITER, however, highly subcooled boiling is utilised, where the fluid core is expected to remain 100°C below saturation temperature [21]. As the coolant is brought to saturation temperature, bubbles, typically less than a millimetre in diameter, form along the channel walls.…”

Section: Introductionmentioning

confidence: 99%

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Numerical Modeling of Subcooled Flow Boiling and Heat Transfer Enhancement: Validation and Applicability to Fusion Reactor Target Design

Young

Karimi

MacKenzie

2020

Journal of Energy Resources Technology

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Boiling flows are an extremely efficient mechanism for the transfer of ultrahigh heat fluxes and used in numerous industrial applications. In this paper, the accuracy of computational fluid dynamics in predicting the temperature distributions and heat transfer performance is examined within a nuclear fusion reactor divertor. The aim is to establish the role of computational fluid dynamics (CFD) within the design of complicated high heat flux components using a semi-mechanistic approach to flow boiling that is independent of geometry and flow conditions. An Eulerian–Eulerian two-fluid method is developed and a conjugate heat transfer model is validated against the existing experimental data where available. Overall, a satisfactory accuracy is achieved in the prediction of several important quantities. Temperature distribution throughout the divertor is found to be highly accurate and aligns with the physical testing across two expected operating regimes. Additionally, the system heat transfer coefficients and coolant temperatures are close to the assumptions already established within the literature. Heat transfer enhancement is a critical component of the divertor design, and a twisted-tape insert appears to be necessary for the system to withstand ultrahigh heat fluxes encountered within the fusion reactor. The results show that the inclusion of a twisted tape improved the heat transfer coefficient of the system by almost 45% allowing the divertor to withstand the required heat fluxes of 10 MW/m2 and 20 MW/m2.

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Section: Resultsmentioning

confidence: 75%

Section: Introductionmentioning

confidence: 99%

Numerical Modeling of Subcooled Flow Boiling and Heat Transfer Enhancement: Validation and Applicability to Fusion Reactor Target Design

Young

Karimi

MacKenzie

2020

Journal of Energy Resources Technology

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“…As the wall temperature reaches the CHF temperature (the wall temperature at a heat flux = CHF ) the model calculates the heat transfer coefficient using Marshall-98 correlation [9] as it demonstrated agreement with data from fusion-relevant experiments…”

Section: Transition Film Boilingmentioning

confidence: 85%

Transient thermal hydraulic modeling and analysis of ITER divertor plate system

El-Morshedy

Hassanein

2009

Fusion Engineering and Design

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“…for the technology phase, as described in references [3] and [14]. For this particular double null Table 3.1 summarizes the main operating requirements for the system.…”

Section: Divertor Plate Design and Normal Operation Conditionsmentioning

confidence: 99%

“…Though, improved characterization of the disruption conditions, and enlarged scope of failure mode consideration should be pursued to gain confidence in the conclusions. [44] 3-2 ITER divertor module [14] .... Coolant channel configuration for technology phase divertor [3] 3-4 Divertor plate and typical surface heat flux distribution [5] ....…”

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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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Thermal-Hydraulic Design Issues and Analysis for the ITER Divertor

Cited by 14 publications

References 3 publications

Numerical Modeling of Subcooled Flow Boiling and Heat Transfer Enhancement: Validation and Applicability to Fusion Reactor Target Design

Numerical Modeling of Subcooled Flow Boiling and Heat Transfer Enhancement: Validation and Applicability to Fusion Reactor Target Design

Transient thermal hydraulic modeling and analysis of ITER divertor plate system

Probabilistic Analysis of Divertor Plate Lifetime in Tokamak Reactors

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