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@ARTICLE{Weckmann:868240,
author = {Weckmann, A. and Petersson, P. and Rubel, M. and Ström, P.
and Kurki-Suonio, T. and Särkimäki, K. and Kirschner, A.
and Kreter, A. and Brezinsek, S. and Romazanov, J. and
Wienhold, P. and Pospieszczyk, A. and Hakola, A. and Airila,
M.},
title = {{R}eview on global migration, fuel retention and modelling
after {TEXTOR} decommission},
journal = {Nuclear materials and energy},
volume = {17},
issn = {2352-1791},
address = {Amsterdam [u.a.]},
publisher = {Elsevier},
reportid = {FZJ-2019-06800},
pages = {83 - 112},
year = {2018},
abstract = {Before decommissioning of the TEXTOR tokamak in 2013, the
machine was conditioned with a comprehensive migration
experiment where MoF6 and 15N2 were injected on the very
last operation day. Thereafter, all plasma-facing components
(PFCs) were available for extensive studies of both local
and global migration of impurities – Mo, W, Inconel alloy
constituents, 15 N, F – and fuel retention studies.
Measurements were performed on 140 limiter tiles out of 864
throughout the whole machine to map global transport. One
fifth of the introduced molybdenum could be found. Wherever
possible, the findings are compared to results obtained
previously in other machines. This review incorporates both
published and unpublished results from this TEXTOR study and
combines findings with analytical methods as well as
modelling results from two codes, ERO and ASCOT. The main
findings are:• Both local and global molybdenum transport
can be explained by toroidal plasma flow and drift. The
suggested transport scheme for molybdenum holds also for
other analysed species, namely tungsten from previous
experiments and medium-Z metals (Cr-Cu) introduced on
various occasions.• Analytical interpretation of several
deposition profile features is possible with basic
geometrical and plasma physics considerations. These are
deposition profiles on the collector probe, the lower part
of the inner bumper limiter, the poloidal cross-section of
the inner bumper limiter, and the poloidal limiter.• Any
deposition pattern found in this TEXTOR study, including
fuel retention, has neither poloidal nor toroidal symmetry,
which is often assumed when determining deposition profiles
on global scale.• Fuel retention is highly inhomogeneous
due to local variation of plasma parameters – by auxiliary
heating systems and impurity injection – and PFC
temperature.• Local modelling with ERO yields good
qualitative agreement but too high local deposition
efficiency.• Global modelling with ASCOT shows that the
radial electric field and source form have a high impact on
global deposition patterns, while toroidal flow has little
influence. Some of the experimental findings could be
reproduced. Still, qualitative differences between simulated
and experimental global deposition patterns remain.The
review closes with lessons learnt during this extensive
TEXTOR study which might be helpful for future scientific
exploitation of other tokamaks to be decommissioned.},
cin = {IEK-4},
ddc = {624},
cid = {I:(DE-Juel1)IEK-4-20101013},
pnm = {113 - Methods and Concepts for Material Development
(POF3-113)},
pid = {G:(DE-HGF)POF3-113},
typ = {PUB:(DE-HGF)16},
UT = {WOS:000454165000013},
doi = {10.1016/j.nme.2018.09.003},
url = {https://juser.fz-juelich.de/record/868240},
}