Search

In the Advanced Fusion Neutron Source (A-FNS), an accelerator-driven fusion-relevant neutron source that is planned for development in Japan, a few grams (3.5 g at full power operation) of tritium will be generated every year, mainly in the lithium target system. Since the generated tritium would migrate out of the lithium target system, it is necessary to estimate the tritium migration into and out of the lithium target system for the design of detritiation systems for the A-FNS. Therefore, a preliminary estimation is performed in the present study. As a result, it is found that almost all of the generated tritium in the lithium target system would be trapped in the impurity removal system, while less than 0.5% would migrate out. It is also indicated that the amount of tritium that would migrate out of the lithium target system would be able to be processed with the existing techniques so far. [ABSTRACT FROM AUTHOR]

Hydrogen isotope retention and chemical state for the tiles exposed to plasma in the JET–ITER-like wall (ILW) during two campaigns in 2011–2012 (first campaign, ILW-1) and 2015–2016 (third campaign, ILW-3) were studied and compared by means of X-ray photoelectron spectroscopy and thermal desorption spectroscopy. In both campaigns the upper part of the inner divertor tiles was the deposition-dominated area, while erosion was observed on the outer divertor tiles. Therefore, higher deuterium retention was found on the inner divertor tiles. The major D desorption peak for the inner divertor tiles from ILW-3 was located at the temperature range of 470°C to 520°C, which was higher than measured after ILW-1: 370°C to 430°C. The XPS analyses showed the formation of a BeO layer on the ILW-3 inner divertor tiles, while after ILW-1 the layers also contained a significant amount of carbon. Deuterium retention was reduced toward the outer divertor tiles. The differences could be related to the difference in the power level in the two campaigns. [ABSTRACT FROM AUTHOR]