"Investigation of pressure loss coefficient of hot duct break scenario in ALLEGRO reactor using the CATHARE thermohydraulic code"

Abstract

"Preliminary thermohydraulical calculations carried out for the ALLEGRO 75 MW CEA 2009 design (Mayer and Bentivoglio 2014) pointed out that the peak cladding temperature exceeded the required temperature limit in case of hot duct break scenario, when the aggravation event of the stop of the second blower was taken into account. The value of the pressure loss coefficient used in the hot duct break modeling plays pivotal role in the corresponding peak cladding temperature (PCT). In this study we investigate how this pressure loss value influences the peak cladding temperature in ALLEGRO reactor. We selected the French CATHARE thermohydraulical code as a simulation tool to describe the hot duct break transient and to determine the PCT values. We carried out several transient calculations by varying the pressure loss coefficient and the results confirmed its importance. It was found that if the pressure loss value is less than 1.4 the PCT limit exceeds the criterion of 850 oC."