Protected Loss of Flow Accident Simulation in Circe-Hero Facility: Experimental Test and System Code Assessment

Post-test simulation of a PLOFA transient test in the CIRCE-HERO facility

“…The geometrical scheme was revamped for simulation of the new test section, including a relative coarse nodalization of the steam generator, consisting of a single equivalent double wall bayonet tube with a weight of seven (Narcisi et al, 2017b). The comparison between blind calculations and experimental data showed some discrepancies, attributable to an overestimation of the power removed by the SG (Lorusso et al, 2019b). The differences could be in large part explained by the not uniform feedwater distribution through the seven DWBTs.…”

“…These considerations suggested to improve the thermal-hydraulic model, including a detailed nodalization of the secondary loop. Furthermore, the model used for blind simulations predicted reverse flow condition through the hot leg of the primary system in the first minutes after the transition event, that is not acquired by the instrumentation (Lorusso et al, 2019b). The analysis performed during the post-test phase highlighted the relationship between reverse flow and pressure drops through the primary system: the whole pressure drops were well predicted by the code, as confirmed by the steady state LBE mass flow rate, but the distribution of the pressure losses through the flow path seemed to be wrong.…”

“…In the following plots, experimental data are compared with two calculations: case 1 (#1) assumes a total FW mass flow rate equal to 0.078 kg/s (reference value provided in Lorusso et al, 2019a) and case 2 (#2) adopts the value of 0.047 kg/s. The blind simulation highlighted an overestimation of the power remove by the SG (Lorusso et al, 2019b). In case 2, the feedwater mass flow rate has been calibrated in order to obtain the correct thermal power removed by the secondary system.…”

Experimental Investigation on CIRCE-HERO for the EU DEMO PbLi/Water Heat Exchanger Development

“…This test section, designed at ENEA Brasimone R.C. and implemented in the main vessel of the lead-bismuth eutectic (LBE)-cooled pool-type facility CIRCE (CIRColazione Eutettico) [16], deals with the investigation of the thermalhydraulic features of prototypical systems and components, providing at the same time an experimental database suitable for thermal-hydraulic validation of numerical tools (i.e., system codes and Computational Fluid Dynamic codes). The HERO SGBT unit was connected to a dedicated secondary loop that provides the feedwater at high temperature and pressure (up to 18 MPa).…”

“…Both the primary and secondary systems are instrumented for monitoring and operating the facility, as well as to acquire experimental data. On the primary system, 119 TCs are distributed along the pool to capture mixing and stratification phenomena [16]. Each component of the TS is equipped with thermocouples located at the inlet and outlet sections (e.g., fitting volume, riser, separator) for their thermal-hydraulic characterization.…”