Safety

JT-60SA requires sophisticated provision especially for radiation shielding and radioactive waste management in order to comply with the related law and regulations defined between the local governments, including Ibaraki prefecture and Naka city, and JAEA as the Implementing Agency.

The device shall have the following additional safety features beyond those already provided for JT-60U:

(1) For radiation shielding, the vacuum vessel is designed so that boric acid water is circulated between shells. This provides moderate doses below the regulation limits, though some existing openings including the clearances between the doors and the walls of the assembly hall require additional shielding.

(2) To control gaseous effluent, including activated air from the torus hall and/or the vacuum vessel, it is planned to process it with ventilation. This approach requires some modification of the existing heating, ventilation and air conditioning system of the experimental building.

(3) The liquid waste drain system that treats borated water and tritiated water also requires some modification of the drain line and an additional disposal tank for dilution.

(4) Radiation monitoring systems need to be expanded into the extended controlled areas of the plant.

(5) Additional neutron and gamma radiation detectors.

(6) The cobalt content of steels facing significant neutron doses is kept to low levels in the system specifications.