Isotope Exchange Reaction over Improved Ceramic Tritium Breeder with Catalytic Function

In most current designs of D-T fusion reactor blankets employing ceramic breeder materials, the use of a helium sweep gas containing 0.1 % of hydrogen is contemplated to extract tritium efficiently via isotopic exchange reactions. However, the isotope exchange reaction proceeds fast only at the more elevated temperatures, so that the rate of isotope exchange reactions is considerably low at lower temperatures. Taking into consideration that there is a broad temperature distribution within a blanket module, it is anticipated that the tritium bred in regions of lower temperatures will be poorly recovered. For this reason, there is still a need to develop techniques that contribute to the acceleration of the recovery of bred tritium at lower temperatures. In our previous works, the effect of catalytic active metal additives, such as Pt and Pd, on the heterogeneous isotope exchange reactions at the breeder-sweep gas interface was examined. The results indicate that the exchange reactions were considerably enhanced with the help of catalytic metals. In this work, the authors first examined the effect of the amounts of deposited catalytic active metal additives, such as Pt and Pd, on the heterogeneous isotope exchange reactions at the breeder-sweep gas interface. The results of this works indicate that the exchange reaction on the surface of Li₄SiO₄ is enhanced even if the amount of deposited Pd is as low as 0.015 %. It was also found that the deposition of 0.15 wt% of Pt enhances the exchange reaction rate. The authors also examined the effect of non-noble metal additive, such as Ni, on the heterogeneous isotope exchange reactions at the breeder-sweep gas interface. The results indicate that the exchange reactions were considerably enhanced with the help of Ni. Thus, it was found that Ni is also effective for the enhancement of the exchange reaction rate.