The VINON-LOCA test facility: exploring the LOCA phenomenology through an out-of-pile thermal sequence on irradiated pressurized fuel rod

Since the out-of-pile semi-integral tests performed at Studsvik in 2011 for NRC [1] and Halden Loss-Of-Coolant Accident (LOCA) test series IFA-650 [2], a major safety interest has raised Fuel Fragmentation, Relocation Dispersal (FFRD) during LOCA sequence. In addition to characteristics of fuel ejected from rod after clad failure, behaviour before failure is still be investigated, especially its fragmentation possible relocation within ballooning phase. Furthermore, chronology sequencing these phenomena particular interest. For this purpose, VINON-LOCA program, lying framework trilateral agreement between EDF, Framatome CEA, aimed performing Out-Of-Pile heating on irradiated repressurized rods, reproducing typical Loss Of Coolant thermal The experimental set-up located so-called VERDON lab LECA-STAR hot cell complex. This was dedicated VERDON-ISTP program [3]. thus largely instrumented addressing not only FFRD topics, but also Fission Gas Release (FGR), combining both online measurement (gamma stations, gamma camera, acoustic sensor, pressure, temperatures, flow meters, microGC…), preand post-test characterization scanning, tomography, metrology, fragments weighing sieving, gas analyses…). An extensive substantial qualification campaign been validate furnace design regarding desired conditions, qualify instrumentation. Following some preliminary modelling calculations, it included an out-of-cell twin mockup dummy inactive rods cell. allowed achieving successfully first end 2019 UO2 rodlet. A second experiment planned with increased instrumentation capabilities, notably 2D camera motion detection.