Mock-up testing of the monorail crane system for remote maintenance of the ITER neutral beam cell

The Monorail Crane System (MCS) is a remotely operated crane working in the ITER neutral beam (NB) cell within the Tokamak building that is a radiation controlled area where human worker access is limited. The MCS is an underhung crane that moves along the railways suspended from the NB cell ceiling. It is part of the Neutral Beam Remote Handling System (NBRHS) providing lifting and transportation capabilities for components and equipment up to 40tonnes. The long travel unit of the MCS is a first-of-a-kind design which is identified as the technical risky area for which is worth to perform mock-up testing.This paper describes the mock-up design of the railway where the MCS moves, and the long travel unit of the MCS. The mock-up railway replicates the critical parts of the railway such as that having the minimum bending radius, the S-bend, and the switching rails with discontinuity and misalignments. The mock-up MCS replicates most of the key features of the final MCS together with additional sensors for analysis. The mock-ups are manufactured to verify the manufacturing process of the final MCS. Phased testing campaigns are carried out to understand the behavior of the mock-up MCS on the different railway sections under various load cases such as no load, offset load, dynamic and static test loads, and considering different communication and control system arrangements including degraded modes. The test results demonstrate that the behavior of the mock-MCS is as expected in the design. However, a few areas are identified that need to be improved, which are the vibration and noise issues during traveling on the curved rails, stopping of traveling while carrying an offset load, which results in damage on the barcode strip and the busbar clamps installed on the railways. Post-test inspection identified permanent deformation on the edge of the railway, a leak on the lubrication on the rotating wheels, and some rusting, which need to be improved in the final MCS design. From a global point of view, no critical technical issues were observed during the testing and the tested components, especially, the high load carrying components are in good condition without any mechanical damages. Therefore, the MCS design can be further developed on this basis during the final design phase, addressing the various feedbacks gathered through the testing campaigns.