Direct containment heating integral effects tests in geometries of European nuclear power plants

Ex-vessel fuel-coolant interaction experiment in the DISCO facility in the LACOMECO project

“…Only then it decreases slowly. Such behavior was not observed in the previous DISCO tests addressing DCH issues in a dry reactor cavity [1][2][3]. In experiments with dry cavity, the containment pressure decreased in all tests continuously after reaching the first Figure 7.…”

“…The DISCO facility is composed of several parts simulating the containment, the reactor coolant system (RCS), the RPV, the pit and subcompartment (which is an annular room around the pit). The linear scale of the facility for the first DCH tests with the European pressurized reactor (EPR) geometry was 1:18 [1,3]. In the present experiment, the arrangement is close to a French 900 MWe reactor but it does not reproduce precisely a given reactor.…”

“…In experiments with dry cavity, the containment pressure decreased in all tests continuously after reaching the first Figure 7. Long-term temperature in the containment with dry cavity (DISCO-H01, [1,3]). peak due to the cooling of the heated gas (Figure 5, from the test DISCO-H01, described in [1] and in more detail in [3]).…”

“…Long-term temperature in the containment with dry cavity (DISCO-H01, [1,3]). peak due to the cooling of the heated gas (Figure 5, from the test DISCO-H01, described in [1] and in more detail in [3]). With a wet cavity, the vaporization of the water leads to a further pressure increase at a lower temperature level compared to the higher gas temperatures in dry cavities and containments.…”

“…These processes, referred to as direct containment heating (DCH), may endanger the integrity of the containment. This phenomenon was extensively studied at Karlsruhe Institute of Technology (KIT) with the dispersion of corium (DISCO) facility [1], which was used to simulate at a small scale the melt ejection out of a weakly pressurized reactor vessel into a dry reactor pit [1][2][3][4].…”