An overview of tritium retention in dust particles from the JET-ILW divertor. (28th January 2022)

• Record Type: Journal Article
• Authors: Otsuka, T; Masuzaki, S; Ashikawa, N; Torikai, Y; Hatano, Y; Tokitani, M; Oya, Y; Asakura, N; Hayashi, T; Tanigawa, H; Iwai, Y; Widdowson, A; Rubel, M
• Other Names: collab.
• Is Part Of: Physica scripta. Volume 97:Number 2(2022)
• Publication Date: 2022-01-28
• Subjects: JET -- ITER-Like Wall -- divertor -- dust -- tritium -- imaging plate; Physics -- Periodicals; 530.05
• DOI: 10.1088/1402-4896/ac445b
• Languages: English
• ISSNs: 0031-8949

Abstract

Abstract: Tritium (T) retention characteristics in dust collected from the divertor in JET with ITER-like wall (JET-ILW) after the third campaign in 2015–2016 (ILW-3) have been examined in individual dust particles by combining radiography (tritium imaging plate technique) and electron probe micro-analysis. The results are summarized and compared with the data obtained after the first campaign in 2011–2012 (ILW-1). The dominant component in ILW-1 dust was carbon (C) originating from tungsten-coated carbon fibre composite (CFC) tiles in JET-ILW divertor and/or legacy of C dust after the JET operation with carbon wall. Around 85% of the total tritium retention in ILW-1 dust was attributed to the C dust. The retention in tungsten (W) and beryllium (Be) dominated particles was 100 times smaller than the highest T retention in carbon-based particles. After ILW-3 the main component contributing to the T retention was W. The number of small W particles with T increased, in comparison to ILW-1, most probably by the exfoliation and fragmentation of W coatings on CFC tiles though T retention in individual W particles was smaller than in C particles. The detection of only very few Be-dominated dust particles found after ILW-1 and ILW-3 could imply stable Be deposits on the divertor tiles.