Estimation of low level waste by a regulatory clearance in JT-60U fusion device

Sukegawa, Atsuhiko; Oikawa, Akira; Miya, Naoyuki; Fujita, Takaaki

The low level waste of JT-60U fusion device has been estimated by a regulatory clearance. The JT-60U consists of the heating devices such as neutral beam injectors and radio frequency systems, the main devices including the vacuum vessel and the coils, and the diagnostic devices in the torus hall. Those structure materials of the JT-60U device include copper, stainless steels, carbon steel, high manganese steel, inconel 625, ferritic steel, and lead. The gross weight of the device is about 6,400 tons. Radiation transport calculations are performed using 1D code ANISN. In the activation calculations, ACT-4 was employed. The stainless steels of about 50 tons are used for the base of the first wall on the vacuum vessel in JT-60U. For the low level waste management, the evaluation for the steels with the activated nuclides is important. IAEA RS-G-1.7 is applied to the clearance level for the structures of the activated materials. The activated level of the material with Co takes about 45 years until less than the clearance level.