Discover the test facility of the ITER Pre-Compression Rings
Members of the teams from F4E, ITER IO, CNIM and Douce Hydro in front of the Pre-Compression Rings tooling, CNIM, La Seyne-sur-Mer, France.
A set of 18 Toroidal Field (TF) coils will create a massive magnetic cage
to confine ITER’s superhot plasma. While keeping the hot gas away from the
walls of the vacuum vessel, they may experience some fatigue or deformation
resulting from the powerful magnetic fields. Nine pre-compression rings hold
the key to the survival of the TF coils. They will need to be positioned at
different levels—three on top and three below the inner “vault” formed by the
wedged noses of the TF coils. An extra set of three will be manufactured as
spare in case there is any future need to replace the lower set.
The pre-compression rings have an inner diameter of approximately 5 m,
a cross-section of nearly 300 x 300 mm and will weigh roughly 3 t each. They
are made of fiberglass composite, consisting of more than a billion minuscule
glass fibers, which will be glued together using epoxy resin. Europe is
responsible for their production.
While their fabrication is still ongoing, ITER International Organization (IO) has
taken the initiative to develop a facility where they will undergo a series of tests.
The contract has been awarded to the consortium CNIM/Douce Hydro. F4E has
developed the conceptual design of the test facility and is responsible for
A brand new 140 m2 test facility, located in La
Seyne-sur-Mer, is getting ready to receive the first pre-compression rings. The
construction works are completed and the central beam has been recently installed.
This central column will host a tooling of 36 actuators exercising a force of
1000 t each. The goal will be to test the fabrication quality of each of the
pre-compression rings by checking their resilience to the high loads they will
experience in operation. When one of them is positioned on the tool, the 36
actuators will start to operate simultaneously, maintaining a position accuracy
of 0.1 mm while releasing a total force of 36 000 t. This stress test will last
a few hours and will be supplemented by other tests to confirm that the creep
and fatigue performance is also adequate.
ITER Pre-Compression Rings (PCRs) tooling to test the
resilience of the PCRs. It consists of 36 actuators that will exercise a force
of 1000 t each. The tests will be carried out at CNIM, La Seyne-sur-Mer,
All teams, counting in total approximately 40 people, are working
round the clock to meet the tight schedule making sure that the facility is
fully operational by September. The first tests will be performed during the
last quarter of the year when the first pre-compression rings prototypes will
be delivered. Luigi Semeraro, F4E Metrology Group Leader, and Thierry Boutboul,
F4E Magnets Technical Officer, explained that “F4E and ITER IO, in
collaboration with the CNIM/Douce Hydro consortium, have made remarkable
efforts to set up this test facility and deliver it on record time.”
Philippe Lazare, Managing Director of CNIM Industrial
Systems Division, elaborated on the background and on-going progress. “CNIM,
expert in manufacturing large parts of technical composite, and Douce Hydro,
specialist in high-pressure hydraulics, have partnered to provide ITER with the
Pre-Compression Rings Test Facility. The tight schedule has been respected, the
study and the production has been delivered on time. In a few weeks, the
machine that will be installed at CNIM will measure the millimetric
deformations of the first rings subjected to exceptional mechanical
constraints.” he stated.