DESC0024743

Molten Salt Reactors (MSRs) are again seen as a promising advanced reactor technology because of the various benefits associated with them including: 1) option to refuel when in operation, 2) less waste generated than Light Water Reactors (LWRs), and 3) option to consume waste from other reactors. Some drawbacks of the technology include generation of a halide salt particulate mist in an off-gas, and some radionuclides, such as 36Cl particularly when using 35Cl (the most abundant form of Cl isotope) that have long half-lives; thus, posing the human health and environmental threats if released. Hence, MSRs use 37Cl isotope, despite the abundancy of trapping methods of halide salts mists and chlorine gas, todayĺs methods do not offer a facile and inexpensive way of recycling 37Cl isotope present in the off-gas stream as chloride mist and the chlorine gas. TDA Research in collaboration with PNNL will develop an efficient and low-cost process for the reversible capturing of chloride salt mist and chlorine gas from MSR off-gas. In Phase I, TDA will develop a process that will remove chloride salt mist and chlorine gas from a MSR flue gas. The technology will use a dual cartridge system where the first cartridge will condense the chloride salt mist, and the second cartridge equipped with a special high surface area absorbent doped with reactive metal sites that will capture the chlorine gas. Both chloride salt capture and the chlorine gas sorption will be reversible processes. Thus, the chloride salts and chloride gas will be recycled, and the cartridges will be re-used multiple times. Our specific Phase I objectives are to: 1) develop sorbents for reversible chlorine capture under prototypical off-gas conditions; 2) carry out characterization of the sorbent material; 3) design the dual cartridge system reversible trapping of chloride salt mist and chlorine gas; 4) demonstrate the reversibility and stable capacity through the multiple cycles. Applications in the energy generation sector would be improved sorbents for nuclear energy generation that use molten salt reactors (MSRs) to capture chloride salt vapors that are used as coolants and fuels, and to recycle gaseous chlorine gas (Cl2(g) rich in 37Cl) for use in high purity salts, which are expensive to procure, produce, and/or purify (e.g., 37Cl, 7Li). Commercial applications would include new sorbents for industry, such as the water purification field, where free residual chlorine is present in drinking water (as dissolved chlorine and/or other chlorinated compounds created from reaction with organics). Chlorine is a toxic tail gas (gases from industrial processes) in the chlor-alkali industry and must be trapped to avoid release into the environment.