Determination of retained tritium from ILW dust particles in JET

Quantitative tritium inventory in dust particles from campaigns in the JET tokamak with the carbon wall (2007-2009) and the ITER-like wall (ILW 2011-2012) were determined by the liquid scintillation counter and the full combustion method. A feature of this full combustion method is that dust particles were covered by a tin (Sn) which reached 2100 K during combustion under oxygen flow. The specific tritium inventory for samples from JET with carbon and with metal walls was measured and found to be similar. However, the total tritium inventory in dust particles from the ILW experiment was significantly smaller in comparison to the carbon wall due to the lower amount of dust particles generated in the presence of metal walls.Peer reviewe

Infrared imaging video bolometer for the large helical device

A new type of infrared imaging bolometer, known as the infrared imaging video bolometer (IRVB) has been under development at the National Institute of Fusion Science (NIFS) over the last year. A prototype of this diagnostic has been designed and constructed at NIFS and installed on the large helical device (LHD) and successfully operated. This diagnostic utilizes a 66×90×0.001 mm gold foil mounted in a frame to detect the radiation and neutrals from the plasma which are incident on the foil through a 1 cm diameter pinhole. The resulting temperature distribution on the foil is measured using an AGEMA THV 900 LW infrared camera having 136×272 pixels with a frame rate of 15 Hz and a nominal sensitivity of 80 mK. An image of the foil and surrounding frame consisting of 120×160 pixels is resampled down to 12×16 pixels using a linear interpolation scheme. Using a numerical technique the spatial and temporal derivatives of the temperature distribution on the foil are calculated and the incident power density on the foil is determined using a calibration of the foil obtained by means of a HeNe laser. The resulting 10×14 pixel view of the plasma radiation at a 15 Hz frame rate has a noise equivalent power density of 0.5 mW/cm2. The IRVB was mounted on a LHD tangential port for the 1999 campaign. An image of the plasma radiation during a discharge using the inboard vacuum vessel wall as a limiter shows radiation localized near the limiting surface