Present status of SPIDER upgrades

n the quest to reach ITER target parameters for the additional heating systems, a Neutral Beam Test Facility (NBTF) was set up at Consorzio RFX (Italy), including two experiments. MITICA is the full-scale Heating Neutral Beam (HNB) prototype, expected to enter into operation in 2025, while SPIDER, inaugurated in 2018, is aimed at testing and optimizing in advance the ion source. The first SPIDER experimental campaign was concluded at the end of 2021, and a major shutdown is ongoing to implement refurbishments and modifications, in order to restart operation towards the target parameters. The beam source was disassembled for a thorough inspection, which led to additional necessity or opportunity for improvement, beyond the already identified refurbishment, repairs or enhancements foreseen within the lessons learned after the results obtained and the events occurred during operation. A double-digit number of projects led to about 30 procurements for refurbishment of existing parts or manufacturing of new replacing ones. Further to that, two projects of outstanding relevance are driving the shutdown cost and schedule. The pumping system shall be enhanced in order to keep the pressure in the vessel low enough to avoid RF electric field induced discharges on the rear side of the source, still keeping the pressure inside at the prescribed values. Non-Evaporable Getter (NEG) pumps will be installed on a new dedicated vessel module on the source side of SPIDER experiment. RF generators substitution was decided after demonstrating the limitations caused by the original oscillators: intrinsic frequency instabilities on resonant loads and presence of high voltage inside the generator prevented the system to work efficiently and safely at the required conditions. Solid state amplifiers have been chosen for the replacement, as they have already been tested positively at IPP. This contribution presents the status of these main upgrades.