Deuterium Stream Management Leaving the LPCE Column in a CECE Process for Heavy Water Detritiation

In heavy water detritiation using the combined electrolysis and catalytic exchange (CECE) process, deuterium leaving the electrolyzer is fed to the bottom of the liquid-phase catalytic exchange column (LPCE) in which tritium exchanges between the tritiated deuterium gas (moving upward in the LPCE column) and D₂O liquid (moving downward in the LPCE column). Once the deuterium gas leaves the LPCE column, typically a trickle bed recombiner (TBR) is used to convert the incoming deuterium gas into the heavy water.

In this study a different approach is presented in which instead of using a TBR, an additional LPCE column is used. In the additional LPCE column, deuterium gas is scrubbed with demineralized light water. This process alternative has many advantages over using a TBR. First, the oxidation of isotopic hydrogen is highly exothermic and requires a separate water-cooling circuit to maintain the temperature within the TBR. Second, a TBR requires a relatively complex internal design to ensure proper distribution of the gas, otherwise catalyst burnup may occur. Using a LPCE column instead of a TBR eliminates these complications. This paper presents a high-level layout of the process plant in which a LPCE column is used instead of a TBR. Column modeling and results are also presented.