The chemical stability of simulated waste forms Zr_（1–x）Nd_xSiO_（4–x/2） was investigated using the static leach test（MCC-1） with lixiviants of three pH values（pH=4, 6.7 and 10） at three temperature points（4...The chemical stability of simulated waste forms Zr_（1–x）Nd_xSiO_（4–x/2） was investigated using the static leach test（MCC-1） with lixiviants of three pH values（pH=4, 6.7 and 10） at three temperature points（40, 90 and 150 oC） for periods ranging from 1 to 42 d, and the influence of temperature, pH, as well as their combined effects were explored in detail. The results showed that all the normalized release rate of Nd firstly decreased with leaching time and closed to equilibrium after 14 d. As the temperature increased, the normalized release rate of Nd also increased, but it was no more than 3×10^（–5） g/（m^2·d）. And, the normalized release rate of Nd reached the highest values（~5×10^（–5） g/（m^2·d）） when pH=4, whilst the normalized release rate of Nd remained the lowest value（~1×10^（–5） g/（m^2·d）） near neutral environment（pH=6.7）.展开更多
Zircon was employed to immobilize simulated tetravalentactinide nuclide（Ce^4＋）. Zr_（1–x）Ce_xSiO_4（0≤x≤0.10） ceramics were synthesized and their chemical durabilities were investigated systematically. The eff...Zircon was employed to immobilize simulated tetravalentactinide nuclide（Ce^4＋）. Zr_（1–x）Ce_xSiO_4（0≤x≤0.10） ceramics were synthesized and their chemical durabilities were investigated systematically. The effects of p H and temperature on the chemical durability of the as-prepared compounds were investigated using the MCC-1 static leaching test, and their coupling effects were also explored. It was found that the normalized release rates of Ce in deionized water and alkaline solutions（pH=10） were smaller than those in acid solutions（p H=4）. At a certain p H value, the normalized release rate of Ce（LR Ce） increased with the temperature in the initial period. However, the leaching progress almost reached a balance after 14 days, and both of the p H and the temperature had slight impact on the leaching of Ce element. Moreover, the LR_（Ce） were below 10^（–5）g/m^2/d after 42 days, which was lower than those of other nuclear waste forms in all discussed leachates.展开更多
基金Project supported by the National Natural Science Foundation of China(41302028,41302029,21507105)Thousand Youth Talents Plan(Y42H831301)+3 种基金Key Project of Sichuan Education Department(14ZA0099,15ZB0116)Foundation of Laboratory of National Defense Key Discipline for Nuclear Waste and Environmental Safety,Southwest University of Science and Technology(15yyhk10)the Doctor Foundation in Southwest University of Science and Technology(10zx7126)Hebei Science and Technology Support Program(15211121)
文摘The chemical stability of simulated waste forms Zr_（1–x）Nd_xSiO_（4–x/2） was investigated using the static leach test（MCC-1） with lixiviants of three pH values（pH=4, 6.7 and 10） at three temperature points（40, 90 and 150 oC） for periods ranging from 1 to 42 d, and the influence of temperature, pH, as well as their combined effects were explored in detail. The results showed that all the normalized release rate of Nd firstly decreased with leaching time and closed to equilibrium after 14 d. As the temperature increased, the normalized release rate of Nd also increased, but it was no more than 3×10^（–5） g/（m^2·d）. And, the normalized release rate of Nd reached the highest values（~5×10^（–5） g/（m^2·d）） when pH=4, whilst the normalized release rate of Nd remained the lowest value（~1×10^（–5） g/（m^2·d）） near neutral environment（pH=6.7）.
基金Project supported by the National Natural Science Foundation of China(21507105,41302029)Thousand Youth Talents Plan(Y42H831301)+3 种基金Key Project of Sichuan Education Department(15ZB0116)Foundation of Laboratory of National Defense Key Discipline for Nuclear Waste and Environmental Safety,Southwest University of Science and Technology(15yyhk10)the Doctor Foundation in Southwest University of Science and Technology(10zx7126)Sichuan’s Training Program of Innovation and Entrepreneurship for Undergraduate(201610619039)
文摘Zircon was employed to immobilize simulated tetravalentactinide nuclide（Ce^4＋）. Zr_（1–x）Ce_xSiO_4（0≤x≤0.10） ceramics were synthesized and their chemical durabilities were investigated systematically. The effects of p H and temperature on the chemical durability of the as-prepared compounds were investigated using the MCC-1 static leaching test, and their coupling effects were also explored. It was found that the normalized release rates of Ce in deionized water and alkaline solutions（pH=10） were smaller than those in acid solutions（p H=4）. At a certain p H value, the normalized release rate of Ce（LR Ce） increased with the temperature in the initial period. However, the leaching progress almost reached a balance after 14 days, and both of the p H and the temperature had slight impact on the leaching of Ce element. Moreover, the LR_（Ce） were below 10^（–5）g/m^2/d after 42 days, which was lower than those of other nuclear waste forms in all discussed leachates.
