Preliminary Assessment of the Operational Performance of the Pb-16Li Heat Extraction System

A dual-coolant heat extraction system has been designed, developed, and operated for extraction of the heat load from molten Pb-16Li in a thermo-fluid lead lithium magnetohydrodynamic experiment. The system uses the heat transfer oil Therminol 55 as a primary coolant that extracts heat from lead lithium in a Pb-16Li/thermic fluid (TF) heat exchanger (HX). The extracted heat load is further rejected to cooling water by a TF/water HX, in which demineralized water extracts the heat load from the hot heat transfer oil. In this system, the heat transfer oil is circulated in the loop at a nominal flow rate of ~35 liters per minute (lpm) and in the temperature range of 250°C to 270°C, while the water loop is operated at a nominal flow rate of ~30 lpm at room temperature. In the present study, the performance of the heat extraction system is tested to extract a heat load of ~24 kW continuously for the duration of ~100 h. During the experiment, the overall heat transfer coefficient, heat duty, and effectiveness of the HXs are validated with theoretical estimations. The present study discusses design and operation details of the system, along with the performance characteristics of the major components of the system.