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The detection of hydrogen isotopes is not only the premise of ensuring safety of hydrogen energy, but also has very important application value and scientific significance in the field of fusion energy. Therefore, it is imperative to develop efficient and reliable hydrogen isotope sensors. Herein, a thermal-assisted resistive sensor is constructed based on the hydrogen isotope effect of PdCr alloy thin film for sensitive detection of hydrogen isotopes in helium atmosphere. The permeation of hydrogen isotopes in palladium lattice is facilitated through thermal effect to improve the dynamic response capability of sensor. The research results show that the response time of sensor to hydrogen and deuterium is reduced from 192 s to 113 s–17 s and 10 s respectively. However, the sensitivity deteriorated by about 40% at 110 °C compared with room temperature. Meanwhile, the PdCr alloy thin film resistive sensor represents a remarkable linear response in a range of 0.1%–4% hydrogen and deuterium, with correlation coefficients of 0.9971 and 0.9998 respectively. And the response difference of hydrogen and deuterium may be utilized to discriminate hydrogen isotopes. Furthermore, the sensor exhibits prominent selectivity, extraordinary working stability and a wide range of 100ppm-100%. Therefore, this work presents a feasible approach to design high-performance resistive hydrogen isotope sensors for the development of hydrogen energy and fusion energy. Schematic illustrations of the PdCr alloy thin film resistive sensor (a), dynamic sensitivity curve to H 2 /He and D 2 /He (b) and the influence of thermal effect on hydrogen isotope permeation process (c). [Display omitted] • A thermal-assisted resistive sensor based on the PdCr alloy thin film is constructed. • The sensor exhibits rapid response/recovery performances and reversible characteristics. • The response difference of hydrogen and deuterium may be utilized to discriminate hydrogen isotopes. • This work presents a feasible approach to design high-performance hydrogen isotope sensors. [ABSTRACT FROM AUTHOR]

Biphasic Li 2 TiO 3 –Li 4 SiO 4 ceramics have been proposed as advanced tritium breeder for solid-type breeding blankets of fusion reactors. However, the mechanism of tritium release from biphasic Li 2 TiO 3 –Li 4 SiO 4 ceramics remains to be elucidated. In this study, an integrated numerical model for tritium release from biphasic Li 2 TiO 3 –Li 4 SiO 4 ceramics was constructed for the first time. In the proposed model, besides the mass transfer steps for tritium release from single-phase ceramics (e.g. Li 2 TiO 3 and Li 4 SiO 4), a mass transfer step between the interfacial layers of Li 2 TiO 3 and Li 4 SiO 4 was also included to take into account the effect of two-phase interface in Li 2 TiO 3 –Li 4 SiO 4 ceramics. By using this model, numerical simulations of tritium release from Li 2 TiO 3 –Li 4 SiO 4 ceramics with different phase ratio and grain size were performed. The simulation results showed that the mass transfer of tritium atoms between the interfacial layers of Li 2 TiO 3 and Li 4 SiO 4 can effectively enhance tritium release from Li 4 SiO 4 in biphasic Li 2 TiO 3 –Li 4 SiO 4 ceramics. Furthermore, increasing phase ratio of Li 2 TiO 3 and decreasing grain size of Li 2 TiO 3 were both beneficial to tritium release from biphasic Li 2 TiO 3 –Li 4 SiO 4 ceramics at lower temperature. The modeling work consolidated the presumption that the two-phase interface could play an important role in the tritium release process of biphasic Li 2 TiO 3 –Li 4 SiO 4 ceramics. [ABSTRACT FROM AUTHOR]

The separation and purification of hydrogen play an essential role in the field of new energy. In addition, it has great significance and economic value in recovering hydrogen isotope gas from plasma ash discharge gas faced by nuclear fusion reactors. Here, we studied the rapid separation of hydrogen and helium by electrochemical hydrogen pump (EHP), a new hydrogen separation and purification method. In the experiment of the hydrogen-helium separation, the recovery rate of hydrogen can reach 97.4%, and the proportion of hydrogen can reach 99.99%. Furthermore, the effects of catalyst layer structure, membrane materials and working conditions for its performance were analyzed. This experiment found that proton conduction in the catalyst layer and proton exchange membrane became the speed-control step of the process. Moreover, efficient catalyst layer design and membrane materials with high proton conductivity are beneficial to improve EHP's performance further. This study could guide further enhancing the hydrogen-helium separation rate in EHP. It aims to promote the development of hydrogen separation and purification of EHP, making it an efficient method of hydrogen-helium separation instead of palladium membrane. • The basic performance of EHP in hydrogen-helium separation were evaluated. • Proton migration is a speed-controlled step of the EHP process. • EHP is superior to palladium membrane in hydrogen treatment rate and cost. [ABSTRACT FROM AUTHOR]

Large amounts of tritiated water (HTO) will be produced during the operation of nuclear power plants and fusion devices, which is harmful to the environment and human due to its radioactivity and toxicity. So, the tritium concentration of tritiated water must be reduced to a very low value before discharge. Hydrogen-water isotope exchange reaction (H 2 + HTO→H 2 O + HT) based on palladium membrane reactor has been proposed to process tritiated water. However, a comprehensive study about the influence of operation parameters on the membrane reactor performance is insufficient, which is not conducive to the design of reactor in practical application. Moreover, the commonly used Pt/Al 2 O 3 or Ni/SiO 2 catalysts are not active for tritiated water dissociation, so the catalytic activity of these catalysts is not high. In order to process tritiated water more effectively, a two-stage membrane reactor has been designed and established in this work, and Pt/TiO 2 catalyst with rich oxygen vacancies is used to catalyze the hydrogen-water isotope exchange reaction for the first time. The membrane reactor performance shows an approximate linear relationship with a new combined parameter S 0.5 P 1.5 R / F 2 (S is membrane area, F is water flow rate, P is vapor partial pressure, R is swamping ratio), which can be used predict the membrane performance. The isotope exchange reaction activity of Pt/TiO 2 is better than that of Pt/Al 2 O 3 due to its good ability for water dissociation and the hydrogen spillover effect. At last, a tritiated water processing experiment by using two-stage membrane reactor with Pt/TiO 2 catalyst with rich oxygen vacancies has been carried out. The tritium decontamination factor reaches 40588, which is the highest experimental value so far. The results indicate that the two-stage Pd membrane reactor based on hydrogen-water isotope exchange reaction is an efficient technology for tritiated water processing. • A two-stage membrane reactor has been designed and established to process tritiated water. • The reactor performance shows an approximate linear relationship with a new combined parameter. • The catalytic activity of Pt/TiO 2 with rich oxygen vacancies is better than that of Pt/Al 2 O 3. • Tritium concentration of tritiated water can decrease by 4 orders of magnitude by using our reactor. [ABSTRACT FROM AUTHOR]

Li 2 TiO 3 ceramic pebbles with uniform structure, high density and good mechanical property were successfully fabricated by wet process. The Li 2 TiO 3 pebbles sintered at 1000 °C for 4 h had satisfactory density (91% T.D.) and crush load (a.v. 27.1 N). The apparent activation energy of Li 2 TiO 3 grain growth was 201 ± 7 kJ/mol. Accelerated densification was observed in a reducing atmosphere, this might be attributed to the oxygen vacancies generated by the reduction of Ti4+ to Ti3+ in 0.1%H 2 +He atmosphere, which facilitate the diffusion of ions through the lattice. The grain growth was controlled by lattice diffusion under reducing atmosphere, and the apparent activation energy was 168 ± 6 kJ/mol. The mechanical results show that the crush load of Li 2 TiO 3 pebbles decreased with the increase of temperature, and the average crush load at 500 °C was 13.9 N. In addition, the thermal cycling and long-time annealing experiments suggested that Li 2 TiO 3 pebbles have good structural and performance stability. The Li 2 TiO 3 ceramics prepared by wet process were satisfactory tritium breeder materials with ideal application potential. [ABSTRACT FROM AUTHOR]