Research On Key Components Of Tokamak In-vessel Inspection Manipulator

Tokamak is a type of magnetic confinement device to produce controlled fusion power,and the interior is toroidal vacuum vessel.By the powerful neural beam injection heating and microwave heating method,the plasma inside the vessel can reach the temperature needed for fusion reaction.Meanwhile,it is a must to set up an electric circuit through the external winding,which generates a huge toroidal magnetic field inside vessel to control the plasma in center of the vessel for reaction.However,the first wall tiles inside the vessel may get damaged because of the impact of high energy plasma during fusion reaction,therefore a periodical examination of first wall is necessary to ensure safety.Because the condition inside Tokamak vessel is very rigorous such as high temperature and high radiation level,the manipulator used to execute investigation or maintenance tasks may easily get damaged,such as the motor coil burnt out due to high temperature,and the failure of some electronics because of the high radiation effect and so on.Hence it is required to research the protection method for the key components when designing the manipulator.On one hand,aiming at the high radiation condition,the design of a single-axis motion module that can tolerate high level of radiation is proposed after an enormous amount of studies.This module consists of control system,visual system,communication devices and other parts,for which the radiation protection methods are respectively considered.The knowledge and experience will be valuable for a future design of a high-radiation tolerant manipulator.On the other hand,faced with the high temperature,hardened components are adopted for the large arm of manipulator while a water cooling method is proposed to protect the small arm,which has the advantages such as economy and security over the extensively researched gas cooling system.Temperature measuring points are arranged to monitor the real-time temperature inside manipulator vessel.With the external pump,flow valve etc.,they construct a closed-loop control system with temperature feedback.An experiment is conducted to demonstrate that the overall manipulator can operate for two hours at high temperature(100°C).Moreover,ANSYS simulation indicates that the cooling system can also work for higher temperature environment.Finally,the global energetic system perspective provides optimization plan for a future design of cooling system.