Characterisation of flakes generated in JET after DD and DT plasma operations

Approximately 1 g of the 150 g collected at the JET was send to the Tritium Laboratory Karlsruhe (TLK) for physico-chemical characterisation. The flakes were extensively analysed using several experimental tools, such as calorimetry, X-ray-diffraction, thermal desorption, helium pycnometry, scanning electron microscopy, etc. The specific surface area measurements according to the Brunauer-Emmett-Teller (BET) method, showed a value of about (4.7 +/- 0.3) m(2) g(-1) while their average tritium activity was estimated to be (1.17 +/- 0.1) TBq g(-1) (i.e. 3-3.3 mg of tritium per gram of flakes) and their average real density (1.69 +/- 0.02) g cm(-3). Based on these results we estimate that at the end of the remote tile exchange (RTE) at JET the 3.0 g of tritium which did not return to the AGHS after the DTE1 remained in the vessel mainly in form of flakes, i.e. approximately (950 +/- 80) g of flakes are still inside the machine. (c) 2004 Elsevier B.V. All rights reserved.