Water large leaks into liquid Pb–17Li: first experimental results on LIFUS 5 facility

Since several years ENEA is involved in experimental activities concerning the interaction between molten lithium lead alloy, in eutectic composition, and pressurised water in conditions relevant for DEMO fusion reactor, in order to predict the behaviour of a WCLL blanket module in case of an in blanket LOCA. In this ambit LIFUS 5 apparatus was designed and constructed to carry out the experimental campaign on water large leaks into liquid Pb–17Li, with the final aim to provide data for the validation of the mathematical modelling of the related phenomena. After two tests performed to qualify all mechanical components and the data acquisition system, LIFUS 5 was operated at the ENEA C.R. Brasimone for tests nos. 3 and 4. Water was injected into the reaction tank at a pressure of 155 bar with two different values of sub-cooling. The initial liquid metal temperature was fixed to 330 °C. The first pressure peak due to the water vaporization and jet expansion was clearly recognized together with the subsequent pressure increase due to further water injection and hydrogen generation. In the performed experiments the maximum pressure peak, as detected in both reaction and expansion vessels, never overcame the value of the injected water. Moreover, in these two tests a significant temperature increase in the reaction vessel occurred, strictly connected to the amount of injected water.