Characteristics on tritium release during plasma operation on JT-60U

Oikawa, Akira; Nakamura, Hirofumi; Kaminaga, Atsushi; Masaki, Kei; Yamazaki, Takeshi*; Tanabe, Tetsuo*

During DD plasma discharges, tritium produced by the discharges are accumulated on in-vessel components including a carbon based first wall. A few week of detritiation campaign with no-deuterium plasma discharges take place before the scheduled maintenance work on JT-60U. It is recently found that a longer pulse and higher power electron cyclotron resonance heating(ECRH) with deuterium on JT-60U also provides effectively detritiation of the plasma facing components, simultaneously improving confinement and supressing neutron yield. This approach could help control tritium inventory under plasma discharges on fusion devices. The enhanced radiation power is expected to cause the particle recycling and resultantly enhanced detritiation. The higher plasma current with higher electron density with the longer pulse of ECR power injection enhances the detritiation capability.