Structure Design Of ITER MPD Rotary Joint

The penetrating neutrons with high-energy produced in the nuclear fusion experiments can cause varying degrees of damage to components and materials inside of the reactor.Therefore,it is necessary to perform irregular maintenance on those components.However,the maintenance work needs to be carried out in an extreme physical environment.For example,residual electromagnetic radiation and energy radiation may still exist inside of the reactor even wher it is shutdown.Then it will be a necessary means to maintain the internal components through remote handling to achieve a high efficient operation of the reactor.In the ITER remote handling system,the MPD system is an important subsystem that can perform a variety of maintenance tasks.In addition to taking on large loads,the multi-joint mechanical arm,which is the core component of the MPD system,has also to consider the limitations from the reactor structure,so it will be a difficult work to achieve the design requirements.Therefore,by determining the key joint of the mechanical arm and exploring the possibility of its successful design,it is of great significance to the design and function realization of the entire MPD system.Based on the conceptual design of the MPD system,this article extracted the major design requirements.According to the maxim force on each joint and to compare the design space of every joint,the fourth joint was selected as the key joint to be designed.To satisfy the design requirements,the overall design of the drive chain and product selection of the main drive components were completed.Through the analysis of the performance requirements of the drive chain,the design requirements for the main reducer were clarified and the design and performance check of the main reducer was completed.In order to achieve the load capacity of the main support structure,the support structure in the conceptual design was improved,and a support scheme with better overall performance was obtained.Finally,through the comparison of the three-dimensional models of the two transmission chains,the transmission scheme of RV as the intermediate reducer was selected and the main structural design of the fourth joint was completed.