Movement of active components in the shutdown dose rate analysis of the ITER neutral beam injectors

• Published in: Fusion engineering and design 2015-10, Vol.98-99, p.2130-2133
• Main Authors: Eade, Tim, Lilley, Steven, Ghani, Zamir, Delmas, Etienne
• Format: Article
• Language: English
• Subjects: Design engineering; Dosage; Injectors; ITER; Maintenance; Mathematical models; MCNP; MCR2S; Neutral beam; Neutral beams; Nuclear analysis; Remote handling; Shutdown dose rate; Shutdowns
• ISSN: 0920-3796; 1873-7196
• DOI: 10.1016/j.fusengdes.2014.12.022

•Shutdown dose rates during maintenance scenarios are an important consideration for ITER and DEMO.•The MCR2S shutdown dose rate tool has been modified to allow maintenance scenarios to be modelled in a single shutdown dose rate calculation.•The new MCR2S feature was used on three maintenance scenarios in the ITER neutral beam cell.•The importance of modelling maintenance scenarios in a physically correct way was demonstrated. The requirement for maintenance in areas with relatively high shutdown dose rate fields is a key issue to address in the design and engineering of ITER, next generation devices and future commercial fusion reactors. In order to estimate the shutdown dose rate during maintenance and intervention scenarios CCFE's Mesh Coupled implementation of the Rigorous 2 Step method (MCR2S) has been modified to allow components to be moved from on-load locations to new locations for the purpose of shutdown dose rate calculations. Scenarios, such as opening of doors, removal of shielding and other processes, can be modelled in a more physically accurate manner. The new MCR2S capability has been applied to three intervention scenarios within the ITER neutral beam cell. Here, calculations show that by moving these components a significant increase in the dose rate in certain locations of the neutral beam cell can be expected and need to be taken into account when designing the neutral beam cell remote handling equipment and maintenance procedures.