Abstract
Reliable mitigation is necessary to eliminate the detrimental effects of a disruption event in large high-current tokamaks such as ITER. To avoid serious damage to plasma-facing components during the thermal quench phase of a disruption, material is injected to radiate the plasma energy over the inner surface of the machine. The most promising method of material injection is a process known as shattered pellet injection (SPI). SPI utilizes cryogenic cooling to desublimate gas into the barrel of a pipe gun to form a solid pellet. High-pressure gas or a mechanical punch is used to dislodge the pellet and accelerate it into a bent tube to intentionally fracture it. Pellets made of a mixture of deuterium and neon are likely candidates for thermal mitigation. The survivability of these pellets throughout their flight path, before striking the shatter tube, is essential for reliable SPI operation. Experiments were conducted to determine intact speed limits for various mixtures. This paper outlines the details of brittle fracture theory and compares a theory-based model to experimental results from various mixtures of deuterium and neon pellets.
Original language | English |
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Pages (from-to) | 831-835 |
Number of pages | 5 |
Journal | Fusion Science and Technology |
Volume | 76 |
Issue number | 7 |
DOIs | |
State | Published - Oct 2 2020 |
Funding
This work was supported by Oak Ridge National Laboratory managed by UT-Battelle, LLC for the U.S. Department of Energy under Contract No. DEAC05-00OR22725.
Keywords
- Cryogenic pellet
- brittle fracture mechanics
- disruption mitigation
- mixed gas pellet
- shattered pellet injection