The ITER divertor Thomson scattering system: engineering and advanced hardware solutions

Abstract

A divertor Thomson scattering (TS) system being developed for ITER has incorporated proven solutions from currently available TS systems. On the other hand any ITER diagnostic has to operate in a hostile environment and very restricted access geometry. Therefore the operation in an environment of intensive stray light, plasma background radiation, the necessity meet the requirement using only a 20 mm gap between divertor cassettes for plasma diagnosis as well as to measure plasma temperatures as low as 1 eV severely constrain the divertor TS diagnostic design. The challenging solutions of this novel diagnostic system which has to ensure its steady performance and also the operability and maintenance are the focus of this report. One of the most demanding parts of the in-vessel diagnostic equipment development is the design assessment using different engineering analyses. The task definition and first results of thermal, e/m and seismic analyses are provided. The process of further improving of the design involves identification of

Physical aspects of divertor Thomson scattering implementation on ITER

“…The in-vessel collection optics have been designed simultaneously with neutron shielding to meet the following criteria normalized to 500 MW of fusion power: in-vessel optics temperature 250 C; residual radioactivity 12 days after reactor shutdown 100 µSv h −1 allowing manned service/maintenance activities in the port cell (to the right of closure plate in figure 2); contribution from the divertor to equatorial port cell 10 µSv h −1 ; energy release 2 × 10 −3 W cm −3 in the toroidal field coil and PF coil jacket walls neighbouring the divertor port. The efficiency of the neutron shield design was presented in [6].…”

“…The triple grating polychromator was described in [6] has a high degree of discrimination against stray light at the laser wavelength and was designed to measure very narrow TS spectra corresponding to T e from 0.3 eV to several hundred eV. For the upper part of the TS probing chord with T e from ∼5 eV to several 1000 eV (possible during transient events), a filter polychromator with separation of TS and LIF signals has been developed to allow the diagnostics to be combined.…”

Thomson scattering diagnostic systems in ITER

“…The suggested solution is to use triple-grating polychromator for measurements of the lower part of the chord [22]. Figure 24 illustrates the comparison of the spectral channels distribution for the grating spectrometer against the filter polychromator.…”

Tangential Thomson Scattering System for Tokamak T-15

“…Параметры лазера Nd:YAG, который будет использоваться в системе [6,7] Первое испытание этого лазера будет проводиться в составе диагностики томсоновского рассеяния на установке Т-10.…”