Advanced ASDEX Upgrade pellet guiding system design

Area of Science:

• Nuclear Fusion Engineering
• Plasma Physics
• Materials Science

Background:

• Cryogenic pellet injection is crucial for fueling future fusion power plants.
• High-field side injection in tokamaks is essential for optimal fueling performance.
• The ASDEX Upgrade tokamak utilizes cryogenic hydrogen pellet injection at speeds up to 1000 m/s.

Purpose of the Study:

• To design and implement an improved pellet guiding tube for the ASDEX Upgrade tokamak.
• To enhance cryogenic pellet injection performance by optimizing the guiding tube geometry.
• To provide insights for future fusion device pellet guiding tube designs.

Main Methods:

• A novel geometry concept inspired by civil engineering (e.g., railroad track design) was applied.
• The new design incorporates clothoid shape sections for continuous track curvature.
• The guiding tube features a 270° looping turn with a 17 m path length and rectangular cross-section.

Main Results:

• The new design ensures continuous curvature, unlike the previous elliptical sections with discontinuous curvature.
• The improved geometry facilitates smoother pellet transitions within the guiding tube.
• The advanced design is expected to enhance the pellet launching system performance on ASDEX Upgrade.

Conclusions:

• Continuous curvature in pellet guiding tubes is vital for improved performance in fusion devices.
• Clothoid curves offer a superior design approach for pellet guiding tubes compared to discontinuous elliptical sections.
• This research contributes valuable knowledge for the development of advanced fueling systems in future fusion power plants.