IPP Annual Report 2007 - Max-Planck-Institut für Plasmaphysik ...

3D Analysis of Impurity Transport and Radiation for ITER Limiter
Start-up Configurations
Three-dimensional modelling of ITER SOL transport during
the start-up limiter phase with the EMC3-EIRENE code has
been extended to include the limiter-released Be production,
transport and radiation. The distributions of the single Be
charge-state densities and line radiation have been simulated
for two plasma densities =0.2 n G , 0.5 n G and three plasma
configurations, I p =2.5, 4.5, 6.5 MA. All Be charge states
exhibit a strong poloidal density modulation due to the small
poloidal extension of the limiters.
Diagnostics
ITER Procurement Package 21
In January 2007 a consortium of the Euratom Fusion
Associations (IPP, HAS, FZK, CEA and CIEMAT) under
the leadership of IPP began work on the task of providing a
project plan for the full development of ITER Procurement
Package 21 (PP21). PP21 consists mainly of the bolometer
diagnostic and the pressure-gauge diagnostic, but also of all
diagnostic hardware associated with lower port 16, including
that of other “client” diagnostics.
The project plan contains a definition of the scope of PP21,
of the work breakdown structure (WBS), the WBS dictionary,
an implementation schedule and management plans for
risk, procurement, communication, costs and quality. The
project plan developed by IPP concentrates on the needs of
the bolometer diagnostic and the port engineering activities.
Aspects of the project plan concerning the pressure gauge
diagnostic are the responsibility of CIEMAT.
HAS contributes with the performance analysis of the system
and the finite element analysis of the thermal behaviour of
bolometer mini-cameras. FZK has made its experience in the
nuclear analysis of the ITER environment available for the
analysis of nuclear heat loads on models of mini-cameras.
CEA contributed with its experience on various bolometer
detector concepts and on irradiation tests. In addition to providing
the project leader, IPP provided the lead engineer and
contributed with research activities on the metal-resistor
bolometer detector and to the integration of the diagnostic
into the ITER CODAC system. In order to develop the project
plan and to provide urgently needed data for the integration
of the diagnostic in ITER, a number of R&D and engineering
tasks had to be carried out in parallel to developing the project
plan. The ongoing research activities on the reference metalresistor
bolometer detector were continued and a prototype
with a 4 μm Pt absorber was successfully tested in ASDEX
Upgrade. Irradiation tests are in preparation as are the contracts
with a new cooperation partner for the development of
thin-foil detectors with 12 μm absorbers.
In April a proposal for the LOS distribution was submitted
to ITER. This was further refined in order to account for the
ITER Cooperation Project
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changes following the ITER design review. Based on this distribution,
an initial performance analysis of the diagnostic was
made. A preliminary ITER bolometer mini-camera and collimator
were designed and adapted to all locations in the divertor
cassettes (an example for divertor cassette 45 is given in
figure 3) and to some in the VV, thus giving the basic definitions
of the interfaces for the integration of the bolometer diagnostic.
Figure 3: Distribution of mini-cameras as foreseen for the locations in
divertor cassette 45
The mini-camera/collimator model was analysed for its thermal
behaviour in the divertor and behind the inner heat shield
under conditions expected for the ITER standard scenario 2.
The results showed that the mini-cameras should be able to
cope with the demanding boundary conditions if sufficient
thermal contact to actively cooled structures can be provided.
In-Vessel Neutral Pressure Measurement
The ASDEX Pressure Gauge (APG) is, at present, the main
candidate for in-vessel neutral pressure measurement in
ITER. The response of conventional APGs is found to saturate
at around 15 Pa, below the ITER requirement of 20 Pa.
With small modifications to the gauge geometry and potential
settings, however, it is possible to obtain monotonic output
with sufficient slope up to the maximum achievable pressure
of 30 Pa at 6 T. The improved pressure range is achieved at
the expense of a lower sensitivity and a somewhat stronger
dependence on the magnetic field.
Test of a Compact Soft X-Ray Spectrometer
A prototype of a compact SXR spectrometer for ITER has
been designed at the Kurchatov Institute in Moscow and is
presently being tested in ASDEX Upgrade. At present, one
spectrometer channel is equipped with a crystal made of
high purity quartz and a deeply depleted back illuminated
CCD camera chip for radiation hardness. The spectrometer
is set to monitor the resonance line of He-like argon. Due to the
large diffraction angle used (≈70°), a high resolving power