Fuel Retention in the Gas Box Divertor of JET

Components of the JET Mk-II Gas Box divertor have been analysed ex-situ after 18 months of operation with that divertor structure. The aim was to give an account on the distribution of the retained fuel along the poloidal cross-section of the divertor and, in particular, in the septum. Inside the gas box thick hydrogenated deposits were formed only on surfaces located in the near-plasma region from the inner divertor side whereas very little deposition was detected deep inside the gas box, i.e. on the support and divider plates.