Experimental Study on the Delivery Rate and Recovery Rate of ZrCo Hydride for ITER Application

Density Functional Theory-Based Kinetic Modeling of Reactions of Hydrogen Isotopes (H2, D2, T2) and Carbonaceous Gases (CO2, CO, CH4) on the ZrCo(110) Surface

“…On the other hand, the practical poisoning effect of impurity gas on ZrCo could be more pronounced because experiments normally utilized powder samples, ,, whose molecular adsorption/desorption kinetics are much faster due to higher ratio surface area and possible surface defects. In addition, as shown from experiments , as well as our simulation results above, theadsorption rate of D 2 (T 2 ) is generally slower than H 2 , which would call for longer reaction time to reach certain D 2 (T 2 )-storage capacity for ZrCo and thus make it more likely to react with gaseous contaminants. Therefore, efforts are needed to manipulate the components of the input gas as well as reaction temperature and time and gas pressure for hydrogen adsorption/desorption of ZrCo, which would otherwise be poisoned by impurities.…”

“…Kinetic isotope effects were identified by comparing the reaction properties of hydrogen and its isotopes on the ZrCo slab. The adsorption rate of lighter H 2 is faster than D 2 and T 2 which is in line with experimental observations. , The KIEs vary with specific reaction steps as well as with the reaction temperature. While equilibrium coverage distributions and reaction mechanisms from kinetic modeling are generally the same among hydrogen isotopes, resident times for H, D, and T to be the major species on the ZrCo surface are different.…”

“…This means that the adsorption rate of the lighter H 2 or D 2 on ZrCo(110) is faster than their heavier counterparts, which is consistent with experimental observations. 34,61 For the desorption reaction, an inversed KIE was observed with the desorption rate of lighter H 2 (D 2 ) molecule lower than that of D 2 (T 2 ), and the KIE decreases with higher reaction temperatures (Figure 3). While the relatively smaller KIE-(D 2 /T 2 ) for adsorption and its less dependence on temperature could induce a low isotope effect for the D 2 /T 2 storage process, which is friendly for fuel storage and delivery for a fusion reactor, 7,62 the inversed desorption process tends to release heavier hydrogen isotopes at a higher rate.…”

Isotope engineering achieved by local coordination design in Ti-Pd co-doped ZrCo-based alloys

“…Moreover, the kinetic isotope effect during rapid storage and delivery processes can be evaluated by thermal analyses and real-time monitoring of gaseous isotopic composition [27][28][29][30][31][32] . The noticeable fluctuation of isotopic composition during desorption but negligible during absorption with various H/D ratio were observed for ZrCobased alloys at practical scales, which hinders the stable supply with desirable isotopic ratio [27][28][29][30]33 . Owing to the prominent kinetic isotope effect, the isotopic composition deviation could be up to 7.30% during temperature programmed desorption with initial H/D = 1/1 in a fullscale ZrCo bed assembly 33 .…”