Scoping studies on ITER tungsten first wall and borated water in Vacuum Vessel

The 2023 ITER rebaselining includes the replacement of beryllium (Be) First Wall (FW) with tungsten (W). Furthermore, at the March 2023 Technical Coordination Meeting (TCM) the investigation of borated water in Vacuum Vessel (VV) – Primary Heat Transfer Systems (VV-PHTS) has been requested. In this context, scoping studies were made by using ITER C-Model, to assess the impact of these design changes on nuclear heating of different Plant Breakdown Systems (PBS). The pre-and post-processing of the calculations has been carried out using F4Enix, a new open-source Python package for Monte Carlo simulations input and output files parsing developed at Fusion for Energy (F4E). This paper wants to show and provide physical explanation of the results of the scoping studies, with particular attention to radiation shielding of superconducting magnets. The analysis evidenced that a thickness of at least 3 mm of W is needed to reach the shielding performance of 10 mm of Be, and that borated water provides relevant nuclear heating reduction mainly in the Toroidal Field Coils (TFCs), but its usability is limited by different technical reasons.