Simulation studies of divertor power exhaust with neon seeding for CFETR with GW-level fusion power

A conventional single null divertor geometry has been proposed for Chinese fusion engineering testing reactor (CFETR) with fusion powerup to gigawatt level. Modeling using the SOLPS5.0 code package shows promising results for divertor power exhaust by seeding with neon(Ne) and deuterium (D 2 ). Partial detachment for both inner and outer divertor targets can be achieved with a peak heat load lower than3MW/m 2 . The effective ion charge number, Z eff , at the core boundary is below three, which can be further reduced by increasing theupstream D 2 puffing rate. A higher D 2 puffing rate helps to increase electron density (n e ) in scrape-off layer (SOL) and the impurity screen-ing ability. Based on the SOLPS modeling results, the lifetime of tungsten (W) divertor targets has been estimated by using the DIVIMPcode, which indicates that W sputtering is mainly contributed by Ne ions at a far SOL region due to high electron and ion temperature(T e and T i ) there. Upstream D 2 puffing can reduce the W erosion rate and W impurity concentration inside the separatrix due to decreasingT e and T i at the far SOL region. The modeling results show a viable operation regime for the CFETR divertor.

中国聚变工程试验堆（CFETR）拟采用传统单零偏滤器几何结构，其聚变功率可达吉瓦级。采用SOLPS5.0代码包进行的模拟显示，通过注入氖（Ne）和氘（D₂），偏滤器功率排散可获得良好效果。内、外偏滤器靶板均可实现部分脱靶，且峰值热负荷低于3MW/m²。堆芯边界处的有效离子电荷数（Zₑff）低于3，且可通过提高上游氘注入率进一步降低。更高的氘注入率有助于提高刮削层（SOL）中的电子密度（nₑ）及杂质屏蔽能力。基于SOLPS模拟结果，利用DIVIMP代码估算了钨（W）偏滤器靶板的寿命，结果表明，远刮削层区域因电子和离子温度（Tₑ和Tᵢ）较高，钨溅射主要由该区域的氖离子引起。上游氘注入可降低远刮削层区域的电子和离子温度（Tₑ和Tᵢ），从而减少分界面内的钨侵蚀率及钨杂质浓度。模拟结果表明，CFETR偏滤器存在可行的运行模式。