Tritium distribution analysis of Be limiter tiles from JET-ITER like wall campaigns using imaging plate technique and β-ray induced X-ray spectrometry

• Published in: Fusion engineering and design 2020-11, Vol.160, p.111959, Article 111959
• Main Authors: Lee, S.E., Hatano, Y., Hara, M., Masuzaki, S., Tokitani, M., Oyaizu, M., Kurotaki, H., Hamaguchi, D., Nakamura, H., Asakura, N., Oya, Y., Likonen, J., Widdowson, A., Jachmich, S., Helariutta, K., Rubel, M.
• Format: Article
• Language: English
• Subjects: Analytical techniques; Beryllium; Deposition; Deposition profiles; Deuterium; Distribution analysis; Impurities; Ion beam analysis; Ion beams; ITER-like wall; Joint European Torus; Magnetoplasma; Maximum concentrations; Nuclear power plants; Plasma facing surfaces; Poloidal limiters; Positrons; Radiography; Retention mechanism; Scientific imaging; Spectrometry; Tiles; Tokamak devices; Tritium; Tritium analysis; X ray spectrometry; X rays; X-ray spectroscopy
• ISSN: 0920-3796; 1873-7196; 1873-7196
• DOI: 10.1016/j.fusengdes.2020.111959

•Tritium distributions in Be limiter tiles from the JET with ITER-like wall were analyzed.•The largest tritium retention was observed at the center of outer poloidal limiter.•The inner wall guard limiter and upper dump plate showed smaller tritium retention than outer poloidal limiter.•Distributions of tritium found at castellation grooves were similar to those of metallic impurities and deuterium. Tritium (T) distribution on the plasma-facing surfaces (PFSs) and inside castellation of Be limiter tiles from the JET tokamak with the ITER-like wall (ILW) was analyzed using imaging plate (IP) technique and β-ray induced X-ray spectrometry (BIXS). Regarding to PFSs, the outer poloidal limiter (OPL) showed significantly higher T concentrations than the inner wall guard limiter (IWGL) and upper dump plate (DP). The concentration of T on OPL was high at the central part. However, deuterium (D) and metallic impurities showed maximum concentration at the edges. This difference in distributions indicated different deposition and retention mechanisms between T and D. In contrast, deposition profiles of T concentrations on the castellated surfaces extended up to ∼ 5 mm into the gap, i.e. were similar to those of D and metallic impurities found by ion beam analysis.