Experimental investigation on HCLL-TBS In-box LOCA

Abstract The experimental facility THALLIUM was designed and installed at ENEA C.R. Brasimone to investigate the consequence of a HCLL-TBS In box LOCA, ensuring the geometrical relevance for HCLL-TBM. Within the framework of the contractual activities with Fusion for Energy, a first experimental campaign was carried out in HCLL-TBS relevant conditions. The experiments simulated a rupture in a cooling plate of the HCLL-TBM. Thereafter, a new experimental campaign was developed by installing a larger injection valve, with the aim of analyzing a worse accidental He injection. The experimental parameters that were varied during the first campaign were frozen, varying instead injection time and pressure. The pressure trend in different points of the facility and the effectiveness of the mitigation strategy are the most important outcomes of the experiments. A different behavior with respect to the first campaign was observed. In particular, the first pressure peaks are smaller as a percentage of the injection pressure and the pressure is increasing during the whole transient. The relief valve on the expansion tank drives the transient, confirming the importance of the design of this component to mitigate the effects of an In-box LOCA. The outcomes of this experimental investigation are not only supporting the design of HCLL-TBS but also provide important data in view of the conceptual design of HCLL breeding blanket for DEMO.