Validating the best welding techniques to deliver ITER Test Blanket Modules
TIG welding robot performing preliminary welding procedures on a full size mock-up of the Test Blanket Modules box.
There are many interests vested in
ITER. Broadly speaking, the majority of people count on it to find out how
fusion power could contribute to tomorrow’s energy mix. Others, however, are
prepared to go one step further, and use the biggest fusion device as a
stepping stone, in order to extend their know-how and transfer it to the
machine that will follow. Engineers
working in the field of Test Blanket Modules (TBMs) belong in the latter category
and are seeing beyond the near future. Here is why: to achieve a fusion reaction
we need deuterium and tritium— two hydrogen isotopes that in the case of ITER will
be supplied. In future, scientists would need to find a way to breed tritium in
the machine. The role of TBMs is to explore this possibility to make the fusion
power plants of the future self-sufficient.
Europe has developed two types of
TBMs that will be located at the 16th equatorial port of ITER. Each
of them will consist mainly of steel box containing the tritium breeder,
neutron multiplier materials as well as a series of heat extraction plates. During
the last two years, technicians had to manufacture mock-ups of these boxes in
various sizes, in order to identify the best welding techniques that will be applied
at the time of production. F4E together with a large group of partners
consisting of Atmostat, CEA Saclay/Grenoble, Alsyom, Commercy, Airbus, Bodycote
and CETIM have successfully developed a preliminary welding procedure on a full
size mock-up of the TBM box measuring 1.7 x 0.5 x 0.7 m.
Positioning the arm of
the TIG welding robot inside the limited space of the full size Test Blanket
Modules box mock-up.
The challenging task was carried
out using a Tungsten Inert Gas (TIG) welding robot to carry out the welding operations
in the tight and limited space of the box. In order to cope with any
distortions resulting from the operation, and keep the surface of the box intact
without damaging any of its internal channels, special clamping tools were
designed and used during tests.
The exploration of welding
procedures is expected to come to an end during the next two years in order to
draw some technical conclusions. After welding procedures conclude the cycle of
qualification, in line with the regulatory requirements, then the real
manufacturing phase will begin. In future trials the box will be made of
EUROFER97, the candidate steel that Europe is considering to use for TBMs,
which responds well to neutron activation with a good resistance to neutron
Samples of EUROFER97
material produced by Saarschmiede GmbH Freiformschmiede on behalf of F4E
The production of EUROFER97, contracted
to Saarschmiede GmbH Freiformschmiede, has been completed. A total of
approximately 27 T have been manufactured in the form of special plates and
bars of various thicknesses from 1.2 to 45 mm.
Representatives of Saarschmiede GmbH Freiformschmiede (L-R) A. Neumann, V. Wagner and N. Lang next to EUROFER97 boxes