Kinetic modelling of impurity transport in detached plasma for integrated divertor simulation with SONIC (SOLDOR/NEUT2D/IMPMC/EDDY)

Asakura

Tokunaga

et al. 2017

Recent progress of the physics and engineering design study for the 8 m-sized DEMO is reported. Parametric study for the divertor of the compact DEMO (a machine size ∼ 5.5 m) by using the SONIC code shows that the target heat load less than 10 MW/m 2 around the fusion power of ∼1.5 GW and the impurity radiation fraction of more than 80%. In the 8 m sized DEMO with these parameters, the partial detachment is obtained at the outer divertor, even in the low SOL density, due to the large impurity radiation in the SOL and divertor region. The SONIC simulation shows the peak of the target heat load is 7 MW/m 2 . However, the peak of the ion temperature at the target is considerably high, which causes significant erosion of the target. The divertor power handling and decrease in the ion temperature have to be proceeded by the scenario development of the divertor plasma operation as well as the core plasma design and the engineering design. In the engineering study side, the tungsten monoblock target with the water cooling and the Cu-alloy cooling tube is designed. The MCNP-5 neutronics analysis shows applicability of the Cu-alloy cooling tube for the divertor unit on the high heat flux region. Also the divertor cassette with a heat removability of peak heat load of 10 MW/m 2 is studied. The heat transport analysis shows the maximum temperature of 1021• C at the tungsten surface and 331• C at the Cu-alloy pipe, which are acceptable level for mechanical toughness and thermal fatigue.

Section: Numerical Modelmentioning

confidence: 99%

Progress of Divertor Study on DEMO Design

Asakura

Tokunaga

et al. 2017

“…In JAEA, a suite of integrated divertor codes SONIC [8,9] has been developed for the interpretation and prediction of the divertor plasma characteristics. The SONIC suite consists of the 2D plasma fluid code (SOLDOR), the neutral Monte-Carlo (MC) code (NEUT2D) and the impurity MC code (IMPMC).…”

Section: Integrated Divertor Code Sonicmentioning

confidence: 99%

“…On the other hand, disadvantages of the MC approach are large Monte-Carlo noise, large computer resource etc. Recently, these disadvantages have been overcome, and the IMPMC code has been self-consistently integrated with SOLDOR/NEUT2D [9]. In the present version of the SONIC, only one impurity species can be treated by IMPMC.…”

Section: Integrated Divertor Code Sonicmentioning

confidence: 99%

“…For the fusion power of P fus ∼ 3 GW, P ext ∼ 500 MW is expected. A power handling scenario has been investigated by using a suite of integrated divertor codes SONIC [8,9], in order to produce the detachment (the electron temperature T e less than a few eV for suppression of the target erosion) at the divertor target [10][11][12][13]. As will be discussed in section 3, SONIC simulation for the SlimCS divertor plasma with the large Ar impurity seeding shows the divertor power load is still higher than 10 MW/m 2 , although 92 % of P ext is radiated by the Ar impurity.…”

Section: Introductionmentioning

confidence: 99%

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Divertor Study on DEMO Reactor

Asakura

Shimizu

et al. 2014

Huge power handling in the SOL/divertor region is one of the crucial issues for a tokamak fusion reactor. Divertor design study of a DEMO reactor with fusion power of 3 GW and ITER size plasma has progressed using the integrated divertor code SONIC. Recently, to improve conversion of the solution for the DEMO divertor plasma simulation, SONIC code has been improved. The calculation time is significantly reduced by (i) the backflow model for the simplified impurity exhaust process and (ii) optimization on HELIOS at BA-IFERC. In the SONIC simulation, the partial detached divertor plasma was obtained by the Ar impurity seeding. Although the plasma heat load at the outer target was reduced by the partial detachment, the contribution of the impurity radiation and the surface recombination of the fuel ions to the target heat load became large. As a result, the peak of the total target heat load was estimated to be 16 MW/m 2 . In order to reduce the total heat load, control of the impurity radiation profile by kind of seeding impurity species and the divertor geometry has been studied. They can decrease the target heat load, but the peak heat load is still larger than the heat removal capability of the present divertor target concept. Further design study including change of the machine specifications is necessary.

“…Additionally, a particle code PARASOL [35] is used to develop kinetic models introduced into SOLDOR and a 3D MC plasma-wallinteraction code EDDY [36] is integrated with SONIC for the self-consistent calculation of physical/chemical sputtering, complex dissociation processes and energy/species dependent reflection. The dynamic evolution of X-point MARFE observed in JT-60U was investigated with SONIC code [37]. It was found that the hydrocarbons sputtered from the dome contribute to the enhanced radiation near the X-point.…”

Section: Coupling Between Core and Sol/divertor Integrated Modelsmentioning

confidence: 99%

Integrated Modeling of Whole Tokamak Plasma

Hayashi

Honda

et al. 2011

Development and integration of models for the whole tokamak plasma have progressed on the basis of experimental analyses and first principle simulations. Integrated models of core, edge-pedestal and scrape-offlayer (SOL)-divertor clarified complex and autonomous features of reactor relevant plasmas. The integrated core plasma model including an anomalous transport of alpha particles by Alfven eigenmodes is developed in the core transport code TOPICS-IB and indicates the degradation of fusion performance. The integrated rotation model is developed in the advanced transport code TASK/TX and clarifies the mechanism of alpha particle-driven toroidal flow. A transport model of high-Z impurities is developed and predicts large inward pinch in a plasma rotating in the direction counter to the plasma current. TOPICS-IB is extended to include the edge-pedestal model by integrating with the stability code, simple SOL-divertor and pellet models, and clarifies the mechanism of pellet triggered ELM. The integrated SOL-divertor code SONIC is further integrated with TOPICS-IB and enables to study and design operation scenarios compatible with both the high confinement in the core and the low heat load on divertor plates.