Remote maintenance scenario of the caesium ovens and beam source of the ITER heating neutral beam

Abstract

Maintenance of the Heating Neutral Beam (HNB) injectors that are located in the ITER Neutral Beam (NB) cell needs Remote Handling (RH) operations because the NB cell is a radiation controlled area. This paper describes the remote maintenance sequences of the caesium ovens and the Beam Source (BS) of the ITER HNB by using the Neutral Beam Remote Handling System (NBRHS). Caesium oven maintenance is a regular maintenance that needs to be performed every Long-Term Maintenance (LTM) period as caesium is a consumable to produce caesium vapor to enhance negative ion production. The BS maintenance is a corrective maintenance to do if it fails during the lifetime of ITER. Maintenance of the caesium ovens and the BS involves many RH operations that require collaboration of the NBRHS subsystems and RH tools. Moreover, the maintenance operation needs to be done without spreading contamination from the HNB vessel to the NB cell. The developed maintenance scenario relies on the current NB cell environment and the existing interfaces in the plant system.