NSUF 25-5525: Investigation of Gas Additives for Tritium Permeation Control in Neutron-irradiated Flibe
Mitigating tritium release from reactor systems is a technical challenge for advanced reactors employing molten Flibe as a primary coolant. Tritium release management is further complicated by the ability of tritium to permeate through structural metals in the reactor coolant boundary at the high temperatures intended for reactor operation. The fraction of tritium which is available to permeate through the reactor coolant boundary depends on the chemical form of tritium present in Flibe. Tritium chemistry can be influenced by changing the redox potential of the salt to drive tritium converting chemical reactions, or by supplying hydrogen-containing species to the system to drive isotopic exchange reactions. Since there will be roughly tens of grams of tritium per year produced by molten Flibe fission systems containing many metric tons of Flibe salt, the resulting tritium concentrations in the salt are sufficiently low enough that isotopic saturation approaches have a lower system-wide impact than redox control approaches. In this proposal, we discuss an experiment which can explore whether low-concentration cover gas additives can reduce the permeation rate of tritium produced by neutron irradiation of Flibe salt in a low-flux neutron beamline at MITR. The preliminary test matrix proposes HF, H2O, and CH4 additives at three additive concentration points each along with pure helium and helium-1%H2 for controls. A design concept and irradiation plan for this test series was informed by a similar Flibe beamline experiment completed as part of a previous NSUF-funded RTE. The results from the new proposed beamline test will be used to inform whether Kairos Power should pursue cover gas additives as a tritium management solution to evaluate as part of the Hermes low-power demonstration reactor program in Oak Ridge Tennessee.
Additional Info
| Field | Value |
|---|---|
| Awarded Institution | Massachusetts Institute of Technology |
| DOI | 10.46936/NSUF/60015718 |
| Embargo End Date | 2028-01-22 |
| Facility Tech Lead | Gordon Kohse |
| Irradiation Facilities | Massachusetts Institute of Technology Nuclear Reactor Laboratory |
| NSUF Call | FY 2025 Super RTE Call |
| PI | Lin-wen Hu |
| PIE Facilities | Massachusetts Institute of Technology Nuclear Reactor Laboratory |
| Project Member | Dr. David Carpenter, Group Leader, Reactor Experiments - Massachusetts Institute of Technology (https://orcid.org/0000-0001-8765-9913) |
| Project Member | Dr. Lin-wen Hu, Senior Research Scientist - Massachusetts Institute of Technology (https://orcid.org/0000-0003-3126-2225) |
| Project Member | Dr. Kieran Dolan, Senior Engineer - Kairos Power LLC (https://orcid.org/0000-0001-8550-1565) |
| Project Type | RTE |