The Radial Neutron Camera (RNC) is an ITER diagnostic system devoted to the radial measurement of the plasma neutron emissivity during ITER operation. In particular, plasma core measurements will be performed using 48 detectors located in the Ex-Port RNC subsystem and viewing the plasma through 16 lines-of-sight (LOS). Since discrepancies concerning the position of the LOS and the related optical path can occur during RNC installation and ITER operation, a Position Monitoring System (PMS) is foreseen to evaluate the misalignment and provide a correction tool for the neutrons count rate. During the design of the PMS for the RNC, optic fiber-based displacement sensors have been identified as the best solution to measure the displacements from reference positions along the radial, vertical and toroidal directions. Potential issues that could arise during the installation and operation of such sensors have been evaluated; MCNP calculations have been performed to determine the radiation level at the position of the PMS components. Finally, mechanical tests have been carried out at ENEA to evaluate the performance of the sensors: results indicate compliance with the specifications provided by the producer and the ITER RNC design requirements.
