WBS 1.3.1.4
Disruption Mitigation
www.usiter.org • www.iter.org • www.doe.gov • www.science.doe.gov
US Contribution
The US is responsible for R&D, design, and fabrication of the
disruption mitigation system (up to a capped value).
Overview
The system has two functions: 1) limiting the impacts of plasma
current disruptions to the tokamak vacuum vessel, first wall blankets
and other in-vessel components, and 2) suppressing the formation
and deleterious effects of high energy runaway electrons. The
mitigation and suppression are expected to be accomplished
by rapid shattered pellet injection (SPI) and/or rapid massive gas
injection (MGI).
Shattered pellet injection involves cryogenically freezing pellets of
the desired species (deuterium or neon) in a specially designed
“pipe gun.” The pellet is injected into the plasma with a high
pressure gas (deuterium) when a disruption is detected. The pellet
is “shattered” upon entry to better assimilate the material into the
plasma. Massive gas injection is similar in function to SPI, except
the material is injected as a gas instead of as a shattered cryogenic
pellet. In the case of MGI, the gas to be injected is held under high
pressure. At the onset of a disruption,
a fast acting valve opens and releases
the gas into the plasma. In addition to
neon and deuterium injection, helium
injection is also possible with MGI.
1 st Plasma Scope
Perform R&D and design for the full
system.
A prototype 3-barrel shattered pellet
injector with 16 mm barrels
US ITER Project Office • 1055 Commerce Park • Oak Ridge, Tennessee 37830-6483
Technical Description
Material delivery for thermal mitigation event: 8-10 kPa*m3 gas equivalent
(nominally 2 kPa*m3 per injector location)
Material delivery for runaway electron mitigation event: up to 90 kPa*m3 gas equivalent of material
Gas types: Neon (Ne), Deuterium (D), Helium (He)
Pellet types: Deuterium (D) or Neon (Ne)
Maximum total thermal load mitigation material delivery: 10 kPa*m3
Maximum runaway electron mitigation material delivery: 90 kPa*m3
Contact
David Rasmussen
US ITER Project Office Disruption Mitigation Team Leader
Oak Ridge National Laboratory
[email protected] | 865-574-1158
ORNL 2016-G01413/jpp
Total gas delivery (TLM+RES) limited to: 100 kPa*m3 for Ne, 50 kPa*m3 for D, and 40 kPa*m3 for He