Wüest M. 51 Wykes M. 82 Yamaguchi M. 17 Ybarra G. 129 Yubero F ...

JUNE 28 WEDNESDAY MORNING
WS-18-WeM-INV.11 QA EFFORTS IN MANUFACTURING LARGE CRYOPUMP
SYSTEMS FOR NUCLEAR FUSION APPLICATION. Hans S. Jensen and Chr. Day. Institute
for Technical Physics, Forschungszentrum Karlsruhe, 76021 Karlsruhe, Germany.
Forschungszentrum Karlsruhe (FZK) is contributing to the ITER (Latin: The way) project, the next
generation fusion machine. ITER is the experimental step between today’s studies of plasma physics
and tomorrow's electricity-producing fusion power plants. It is an international project involving
many Associations from all over the world. The philosophy of the ITER construction, which is
planned to be ready in ten years from now, is based on in-kind contributions. This means that each
Association is actively taking responsibility for the components it provides to ITER: responsibility in
cost, time, compliance to the Technical Specification, and quality. Within the general Quality Assurance
framework which is set by the ITER Legal Entity, there is quite some flexibility left for the individual
Association as to how fulfil quality aspects for the specific component; this approach is
typical for a big R&D project, such as ITER, involving many prototypical components. Forschungszentrum
Karlsruhe is expected to become the leading Association for provision of the large
tailor-made cryopumping systems for ITER.
This talk exemplifies the FZK experiences of manufacturing and the related quality assurance management
for a recently accomplished R&D project, namely for a cryosorption pumping system used
in a test facility of a neutral beam injector that will be used to heat the plasma of a nuclear fusion reactor
with a beam of deuterium or hydrogen molecules. The huge gas throughput into the vessel of
the test facility results in challenging needs on the cryopumping system, comprising two identical
tailor-made pumps. To establish a mean pressure of several 10 -5 mbar in the test vessel a pumping
speed of about 350 m 3 /s per pump is needed. This was realized with charcoal coated cryopanels
which effectively pump hydrogen. For the cooling of the cryopanels, liquid helium at saturation
pressure is used and therefore a two-phase forced flow in the cryopump system must be controlled.
FZK received the responsibility to design, build, install and test the hardware for this task. The FZK
specified requirements, detailed in 11 individual technical specifications which each included strict
QA requirements. The manufacturing of the components were placed with a large number of industrial
companies within Europe. The central contract for the assembly of the cryopumps was placed
with an industrial company with experience in manufacture of advanced scientific components. This
Main Assembly Contractor (MAC) manufactured the cryopumps using FZK design and drawings,
but MAC also received a number of special components as FZK free issue items, where FZK was responsible
for the testing and quality control before, during and after the manufacture.
This presentation begins with a short outline of the cryopumping system design. It then identifies the
FZK activities during some of the manufacturing processes, in particular the Third Party premanufacturing
approval, construction approval, inspection of approved materials, checking welders´
qualifications, signing quality plans, witnessing the pressure testing, witnessing the vacuum leak testing,
etc. The vacuum integrity of the different circuits is of paramount importance and vacuum leak
testing has been included as holding points in the Quality Plan. All components have been tested to