Thermal and structural analysis in support of the conceptual design of the DEMO helium cooled pebble bed breeding blanket intermediate heat transfer system

The EU DEMO fusion reactor has been conceived to deliver net electricity. Therefore, it must be equipped with a Balance of Plant (BoP) system aimed at removing fusion-generated heat power and transforming it into electrical power. Different BoP architectures are currently under investigation within the EUROfusion consortium, in order to meet needs and constraints of the in-vessel systems, with particular regard to the different blanket concepts.
In this regard, the BoP system involving helium cooled in-vessel components has been considered in this work, meaning that the design of the DEMO reactor endowed with the Helium Cooled Pebble Bed breeding blanket (HCPB BB) has been taken into account. Specifically, the Indirect Coupling Design (ICD) HCPB BoP variant has been assessed in this work, as it is the reference configuration selected for the Conceptual Design Phase of DEMO. It foresees an Intermediate Heat Transfer system (IHTS), aimed at decoupling the BB- Primary Heat Transfer System (PHTS) from the power conversion system. Therefore, in the present work thermal and structural numerical analysis in support of the design of the DEMO HCPB IHTS are presented. ... mehrIn particular, the pipe stress analysis of the whole IHTS is first presented, highlighting pros and cons of the current piping layout and proposing potential design improvements. Then, a detailed 3D thermal and structural assessment of the IHTS main Heat Exchanger is reported, in order to show its soundness against the prescribed thermal and structural design criteria.
The models, the assumptions, the considered loading scenarios as well as the obtained results are reported and critically discussed, highlighting their impact on the advancements of the DEMO HCPB BoP system design towards the conceptual stage.