Automation and interlock system design for Pb-Li liquid-metal purification experimental facility

Abstract

In nuclear fusion domain, eutectic lead-lithium (Pb-Li) is of critical importance as a tritium breeder, neutron multiplier as well as a high-temperature coolant for nuclear power plants. To achieve intended plant efficiency through operation of such high-temperature fluid systems, it is necessary to control composition characteristics of operating fluid. In contrast, at elevated temperatures and higher velocities lying within operational region of interest, Pb-Li plays role of an active corrodent for structural materials, exhibiting selective leaching towards certain elements like Ni, Cr, Mn etc. Such elemental impurities alongwith oxides tend to precipitate in cooler sections of the system, thereby restricting flow of coolant resulting in overall performance degradation. To maintain the purity of Pb-Li, online removal of impurities is essential. In this view, an online Pb-Li purification facility is under fabrication at Institute for Plasma Research (IPR). Performance evaluation of this facility will be assessed over long duration operations at relevant process conditions. To operate the facility with minimum human-intervention and downtime, a PXI-express platform based data-acquisition and control system is designed using LabVIEW environment for continuous monitoring and control of process parameters. Investment protection for critical loop components is addressed using software based interlock modules. Present paper discusses developed data-acquisition system, definitions for control and interlocks logics, alarm management, remote operation of loop components and salient integrated features for a user-convenient long-duration automated operation of the facility. Detailed design and validated performances for cover gas pressure control system and timer-based latched configuration liquid-metal drain interlock are presented.