학술논문
熔盐减压蒸馏过程中关键金属氟化物的冷凝行为研究 / Study on the condensation behavior of the key metal fluorides in molten salts during low-pressure distillation
Document Type
Academic Journal
Author
霍雨婷; 罗艳; 项海飞; 窦强; 马杰; 翁鸿蒙; 李晴暖; HUO Yuting; LUO Yan; XIANG Haifei; DOU Qiang; MA Jie; WENG Hongmeng; LI Qingnuan
Source
核技术 / Nuclear Techniques. 47(1):49-55
Subject
Language
Chinese
ISSN
0253-3219
Abstract
在钍基熔盐堆(Thorium Molten Salt Reactor Nuclear Energy System,TMSR)中,233Pa是232Th-233U转换链中重要的中间核素,前期研究的结果表明减压蒸馏技术可以有效实现载体盐FLiBeZr和233PaF5的分离.然而,在蒸发过程中,部分金属氟化物与233PaF5一同被蒸发,但蒸发出来的氟化物可能会在不同的温度下进行冷凝.本文对含有233PaF5和多种金属氟化物的FLiBeZr熔盐进行减压蒸馏,考察不同温度下233PaF5和关键金属氟化物的冷凝行为.结果表明,233PaF5和95Nb氟化物最佳的冷凝温度均为600～700℃;237U和95Zr氟化物最佳的冷凝温度均为400～500℃.在233PaF5的最佳冷凝温度区域,考察并比较了233PaF5与关键金属氟化物间的最佳冷凝温度下分离因子(βB)与平均分离因子(βA)的差异.实验结果表明:95NbF5的βB与βA无明显差异,但237UF4和95ZrF4的βB较βA提高了2～20倍.通过金属氟化物间βB和βA的对比,表明减压蒸馏分离不同金属氟化物不仅取决于各组分的挥发性,还取决于对冷凝温度的控制.
[Background]In thorium-based molten salt reactors(TMSRs),233Pa is an important intermediate nuclide in the conversion chain of 232Th to 233U,and 233PaF5 can be effectively separated from carrier salt by low-pressure distillation.However,some of the metal fluoride is vaporized along with 233PaF5 simultaneously,and the evaporated fluoride may condense at different temperatures.[Purpose]This study aims to investigate the condensation behavior of 233PaF5 and other key metal fluorides in the FLiBeZr molten salt during the low-pressure distillation process.[Method]The FLiBeZr molten salt containing PaF5 and various metal fluorides was low-pressure distillated to examine the condensation behavior of 233PaF5 and key metal fluorides at different temperatures.Then,the optimal temperature of key metal fluorides was evaluated and the separation characteristics between them and 233PaF5 were figured out.Finally,the separation factors of 233PaF5 and the other metal fluorides were calculated and compared with those of the entire low-pressure distillation process at the optimum condensation temperature of 233PaF5.[Results]The results show that the optimal condensation temperature for 233PaF5 and 95NbF5 is within the range of 600～700℃,whilst it is within the range of 400～500℃ for 237UF4 and 95ZrF4.The comparison results show that there is no significant difference in the separation factors of 95NbF5 and 233PaF5,but the separation factors of 233UF4 and 95ZrF4 are increased by a factor of two to 20 times.[Conclusion]It is confirmed that the separation coefficient is determined primarily by volatilization,but can be further improved by varying the condensation temperature.
[Background]In thorium-based molten salt reactors(TMSRs),233Pa is an important intermediate nuclide in the conversion chain of 232Th to 233U,and 233PaF5 can be effectively separated from carrier salt by low-pressure distillation.However,some of the metal fluoride is vaporized along with 233PaF5 simultaneously,and the evaporated fluoride may condense at different temperatures.[Purpose]This study aims to investigate the condensation behavior of 233PaF5 and other key metal fluorides in the FLiBeZr molten salt during the low-pressure distillation process.[Method]The FLiBeZr molten salt containing PaF5 and various metal fluorides was low-pressure distillated to examine the condensation behavior of 233PaF5 and key metal fluorides at different temperatures.Then,the optimal temperature of key metal fluorides was evaluated and the separation characteristics between them and 233PaF5 were figured out.Finally,the separation factors of 233PaF5 and the other metal fluorides were calculated and compared with those of the entire low-pressure distillation process at the optimum condensation temperature of 233PaF5.[Results]The results show that the optimal condensation temperature for 233PaF5 and 95NbF5 is within the range of 600～700℃,whilst it is within the range of 400～500℃ for 237UF4 and 95ZrF4.The comparison results show that there is no significant difference in the separation factors of 95NbF5 and 233PaF5,but the separation factors of 233UF4 and 95ZrF4 are increased by a factor of two to 20 times.[Conclusion]It is confirmed that the separation coefficient is determined primarily by volatilization,but can be further improved by varying the condensation temperature.