AbstractThe magnitude of the heat flux on the surface of the divertor plate of ITER is one of the most limiting constraints on its lifetime. A technique for sweeping the separatrix across the divertor surface will be applied to reduce the mean surface heat fluxes and erosion damages due to intense fluxes over 15 MW/m2. As a first step for the evaluation of the sweeping effects, the thermal response of the divertor plate has been analyzed under the ITER relevant heat flux conditions that a peak heat flux on the divertor plate and full width at half maximum are expected to be 30 MW/m2 and 3 cm, respectively.The analytical results show that the application of sweeping is very effective for reducing the surface temperature of the divertor plate. To realize these benefits for ITER, the divertor separatrix must be swept with a frequency of higher than 3.0 Hz over a distance of ± 10 cm.Based on the analytical results, thermal response experiments with a divertor mock-up are carried out using the JAERI Electron Beam Irradiation Stand (JEBIS). The conditions for this experiment were a peak heat flux of 30 MW/m2 with a sweeping frequency of 1.0 Hz over a distance of ± 10 cm for a 30 s long cycle. Experimental results show that the divertor mock-up has successfully endured for more than 1000 major thermal cycles without an increase of the surface temperature. Therefore, it has been experimentally demonstrated that application of the sweeping technique is very effective for improvement of the power handling capability of the divertor plate. Experimental results showed a good agreement with analytical results.