Design of the monorail crane system for remote handling of the ITER neutral beam cell

This paper describes the preliminary design result of the Monorail Crane System (MCS), which is a subsystem of the ITER Neutral Beam Remote Handling System. Since the concept design of the MCS, the design is elaborated further detail considering new maintenance requirements, updated interfaces with the components to be maintained, and the latest configurations in the NB cell. The main design updates are described as follows. First, the railway is changed from the one monorail with two side reaction rails to a dual rail system, which has better load distribution within the crane trolley and the building mountings. Second, additional railway and a switching mechanism are added between the HNB#1 and #2 to access to the VVPSS components, which are newly added in the NB cell. Third, the mounting of the transversal beams supporting the dual rails onto the embedded plates are updated and further elaborated. Forth, the crane trolley is designed to have independent redundant kinematic chains so that it is recoverable from a single point failure. Fifth, series of braking systems such as a service brake, an auxiliary brake, and an emergency brake are integrated in each kinematic chain to cope with normal and accidental loads. Sixth, seismic uncoupling devices are integrated to protect the mechanical components of the crane itself and the building structure. Lastly, detailed cabling design is implemented from the control cubicle to the locations where the subcomponents are located.