Tritex, a forced convection loop with Pb-17Li

Preliminary Failure Modes and Effects Analysis of the US DCLL Test Blanket Module

“…The staff noted some issues with valves leaking past their seats-the oxides and corrosion products apparently built up on the valve seats and prevented complete valve closure. One major power outage at the laboratory, due to fault in their electrical distribution equipment, allowed the Pb-17Li to freeze in the entire loop (Feuerstein 1999). This total freeze required careful reheating to not overstress the piping.…”

“…At high temperatures, in the 500°C range, the Pb-17Li was found to be very fluid (i.e., low viscosity); it would easily flow out of small cracks or leaks (Feuerstein 1988). Between 1988 and1996, TRITEX ran for 13,000 hours (Feuerstein 1999). The small loop, small number of components, and low operating time are insufficient to give good component failure rate data statistics, but the operating experiences are indicative of the types of events, equipment failure modes, and problems that could occur with a Pb-17Li flow loop.…”

“…Some Pb-17Li got to the bellows and had to be cleaned out. The staff were stated to have been amazed that the electromagnetic (EM) pump electrical components, which had to be used to heat the alloy as well as move alloy, survived for the operating life of the flow loop, 13,000 hr (Feuerstein 1999). The EM pump magnets could reach 400°C in normal operation.…”

“…Even though the drain was performed at 477°C, the film remained (Feuerstein 1999). This behavior is not uncommon with other liquid metals besides Pb-17Li.…”

“…The TRITEX drain tank was insulated and was continually heated to 350°C to avoid thermal shock problems if the alloy had to be dumped to the drain tank on short notice (Feuerstein 1999). This should be a consideration for DCLL TBM designers.…”