Studies of Be migration in the JET tokamak using AMS with Be-10 marker
2016 (English)Conference paper (Refereed)Text
The JET tokamak is operated with beryllium limiter tiles in the main chamber and tungsten coated carbon fiber composite tiles and solid W tiles in the divertor. One important issue is how wall materials are migrating during plasma operation. To study beryllium redistribution in the main chamber and in the divertor, a Be-10 enriched limiter tile was installed prior to plasma operations in 2011-2012. Methods to take surface samples have been developed, an abrasive method for bulk Be tiles in the main chamber, which permits reuse of the tiles, and leaching with hot HCl to remove all Be deposited at W coated surfaces in the divertor. Quantitative analysis of the total amount of Be in cm(2) sized samples was made with inductively coupled plasma atomic emission spectroscopy (ICP-AES). The Be-10/Be-9 ratio in the samples was measured with accelerator mass spectrometry (AMS). The experimental setup and methods are described in detail, including sample preparation, measures to eliminate contributions in AMS from the B-10 isobar, possible activation due to plasma generated neutrons and effects of diffusive isotope mixing. For the first time marker concentrations are measured in the divertor deposits. They are in the range 0.4-1.2% of the source concentration, with moderate poloidal variation.
Place, publisher, year, edition, pages
2016. Vol. 371, 370-375 p.
Nuclear fusion, ITER-like Wall, Materials migration, Beryllium, Accelerator mass spectrometry (AMS)
Accelerator Physics and Instrumentation
IdentifiersURN: urn:nbn:se:uu:diva-295580DOI: 10.1016/j.nimb.2015.12.007ISI: 000373412000074OAI: oai:DiVA.org:uu-295580DiVA: diva2:941149
22nd International Conference on Ion Beam Analysis (IBA), JUN 14-19, 2015, Opatija, CROATIA