Tritium Control and Capture in Salt-Cooled Fission and Fusion Reactors: Status, Challenges, and Path Forward

Figures & data

TABLE I FHR Coolant Options*

Coolant	Tmelt (°C)	Tboil (°C)	ρ (kg/m^3)	ρCp (kJ/m^3 · °C)
66.7 ^7LiF-33.3 BeF2	459	1430	1940	4670
59.5 NaF-40.5 ZrF4	500	1290	3140	3670
26 ^7LiF-37 NaF-37 ZrF4	436		2790	3500
51 ^7LiF-49 ZrF4	509		3090	3750
Water (7.5 MPa)	0	290	732	4040

* Compositions in units of mole percent. Salt properties at 700°C and 1 atm. Water data shown at 290°C and 7.5 MPa for comparison.

Fig. 1. Alternative FHR fuel designs.

Fig. 2. Molten Salt Reactor Experiment.

Fig. 3. Impact of higher-field superconductors on the size of magnetic fusion system.

Fig. 4. ARC concept with salt blanket (blue) and demountable superconducting REBCO magnets.

Fig. 5. Nuclear air-Brayton combined cycle.

TABLE II Salt Characteristics of Different Systems

Property	FHR	MSR	Fusion
Salt	Fluoride	Fluoride or chloride (fast spectrum only)	Fluoride (FLiBe)
Impurities	Corrosion impurities and possible fission product impurities	High concentrations of fission products and actinides	Corrosion impurities
Use lithium salts	Optional	Depends upon goals	Required
Tritium production	Small (^7Li in coolant)	Small (^7Li in coolant)	Large (^6Li in coolant)
Tritium value	Waste	Waste	Fuel
Carbon in system	Yes	Depends upon option	No
Redox control	Ce^+2/Ce^+3, other	U^+3/U^+4	Ce^+2/Ce^+3, Be, other

Fig. 6. TRIDENT.

TABLE III TRIDENT Output for FHR with Tritium Carbon Absorber Bed

Temperatures^Table Footnotea
Coolant freezing	459°C (FLiBe)
Operating core outlet	700°C
ATWS	<800°C
Coolant boiling	1400°C (FliBe)
Pressures (Primary Loop)
PT2 unmitigated	3.3 to 20 Pa
PT2 with graphite capture	0.03 to 0.08 Pa (peak release 7.5 Ci/GWd)
PTF unmitigated	0.03 to 0.075 Pa
PTF with graphite capture	0.0027 to 0.0045 Pa (peak release 7.5 Ci/GWd)

a TRIDENT simulation.

Fig. 7. Platinum on carbon and transmission electron microscopy of platinum nanoparticles. (Courtesy of Tanaka: http://pro.tanaka.co.jp/en/products/group_f/f_5.html.)

Fig. 8 Tritium carbon absorber bed.

Fig. 9. Preliminary hydrogen adsorption experiments on nuclear graphite ISO-88, Maxsorb MSC-30, and CalgonCarbon CAL-TR 12x40 at 700°C.

Fig. 10. Additive manufacturing enables optimized structures for tritium and noble metal removal from liquid salts. Printed in Type 316L stainless steel on an SLM 280 machine using a 400-W laser. (Courtesy of SLM Solutions NA Inc.)

Fig. 11. Gas-liquid separator design.

Fig. 12. French sparging experiments: water loop and FLiNaK salt loop.

Fig. 13. Comparison of bubbles (a) streaming vertically in quiescent liquid and (b) being agitated within an acoustic field (the approximate acoustic field and size of the bubbles are 6 W/cm² and 400 μm, respectively).