First mirror test in JET for ITER: Complete overview after three ILW campaigns

The First Mirror Test for ITER has been carried out in JET with mirrors exposed during: (i) the third ILW campaign (ILW-3, 2015-2016, 23.33 h plasma) and (ii) all three campaigns, i.e. ILW-1 to ILW-3: 2011-2016, 63,52 h in total. All mirrors from main chamber wall show no significant changes of the total reflectivity from the initial value and the diffuse reflectivity does not exceed 3% in the spectral range above 500 nm. The modified layer on surface has very small amount of impurities such as D, Be, C, N, O and Ni. All mirrors from the divertor (inner, outer, base under the bulk W tile) lost reflectivity by 20-80% due to the beryllium-rich deposition also containing D, C, N, O, Ni and W. In the inner divertor N reaches 5 x 10(17) cm(-2), W is up to 4.3 x 10(17) cm(-2), while the content of Ni is the greatest in the outer divertor: 3.8 x 10(17) cm(-2). Oxygen-18 used as the tracer in experiments at the end of ILW-3 has been detected at the level of 1.1 x 10(16) cm(-2). The thickness of deposited layer is in the range of 90 nm to 900 nm. The layer growth rate in the base (2.7 pm s(-1)) and inner divertor is proportional to the exposure time when a single campaign and all three are compared. In a few cases, on mirrors located at the cassette mouth, flaking of deposits and erosion occurred

First mirror test in JET for ITER: Complete overview after three ILW campaigns

The First Mirror Test for ITER has been carried out in JET with mirrors exposed during (1) the third IIW campaign (11.W-3, 2015-2016, 23.33 h plasma) and (ii) all three campaigns, Le LW1 to ILW-3: 20112016 63,52 h in total. All mirrors from main chamber wall show no significant changes of the total reflectivity from the initial value and the diffuse reflectivity does not exceed 3% in the spectral range above 500 nm. The modified Layer on surface has very small amount of impurities such as D, B, C N O and Ni. All mirrors from the divertor (inner, outer, base under the bulk ile) lost reflectivity by 20-80% due to the beryllium-rich deposition also containing D, CN, O, Ni and W. In the inner divertor N reaches 5 x 107 cm2 W is up to 4.3 x 10 cm while the content of Ni is the greatest in the outer divertor 3.8 x 10 cm Oxygen-18 used as the tracer in experiments at the end of ILW-3 has been detected at the level of 1.1 x 10 cm . The thickness of deposited Layer is in the range or 90 nm to 900 nm. The layer growth rate in the base (2.7 pms !) and inner divertor is proportional to the exposure time when a single campaign and all three are compared. In a few cases, on mirrots located at the cassette mouth, flaking of deposits and crosion occurred.EURATOM 63305

Gas Analyses of First complete JET Cryopump Regeneration with ITER-Like Wall

Analytical results of a complete JET cryopump regeneration, including the nitrogen panel, following the first ITER-Like Wall campaign are presented along with the in-situ analyses of residual gas. H/D mixtures and impurities such as nitrogen and neon were injected during plasma operation in the vessel to study radiation cooling in the scrape-off-layer and divertor region. The global gas inventory over the campaign is incomplete, suggesting residual volatile impurities are remaining on the cryogenic panel. This paper presents results on a) residual deuterium on the panel which is related to the campaign very low, b) impurities like nitrogen which sticks on the panel and c) the ammonia production which can be observed in the RGA spectrum.Comment: 7 pages, 3 figures. This is an author-created, un-copyedited version of an article accepted for publication in Physica Scripta. IOP Publishing Ltd and IAEA are not responsible for any errors or omissions in this version of the manuscript or any version derived from i