Engineering challenges of power/particle exhaust for fusion power reactors

The divertor is the key component for power exhaust in modern magnetic confinement fusion devices. Historically, the engineering efforts were focused on high-heat-flux (HHF) technologies to cope with the severe thermal loads and surface erosion caused by intensive particle bombardment. Even today, HHF technology remains one of the most critical challenges. Consequently, the technology for HHF target has been often regarded as the synonym of divertor technology per se. When it comes to the divertor of a power plant scale reactor, the design and technology options are subject to various restrictive high level requirements and technical constraints derived from essentially different loading and boundary conditions, which pose a profound impact on design and technology options for the entire divertor system. In the framework of EUROfusion, the ‘Divertor’ project (WPDIV) has been addressing these issues for over a decade with its comprehensive design and R&D activities taking the European demonstration reactor (EU-DEMO) as reference. In this contribution, starting with the unique challenges and outstanding design issues raised specifically for the divertor of a tokamak-type fusion power plant, I’ll present potential power exhaust scenarios, the current status of design study based on the European approach, the latest R&D progress for the entire divertor system, and estimated pumping performance. Finally, the implications for future R&D endeavors are discussed.