Search Results
Abstract
Recovered salt can be reused in the electrorefining process and the final removed salt from uranium (U) deposits can be fed into a following U casting process to prepare ingot. Therefore, salt distillation process is very important to increase the throughput of the salt separation system due to the high U content of spent nuclear fuel and high salt fraction of U dendrites. Yields on salt recovered by a batch type vacuum distiller transfer device were processed for obtaining pure eutectic salt and U. In this study, the influence of the various temperature slopes of each zones on salt evaporation and recovery rate are discussed. From the experimental results, the optimal temperature of each zones appear at the Top Zone and Zone 1 is 850 °C, Zone 2 is 650 °C and Zone 3 is 600 °C, respectively. In these conditions, the complete evaporation of pure salt in 1.4 h occurred and the amount of recovered salt was about 99 wt%. The adhered salt in U deposits was separated by a temperature slope zone of salt distillation equipment. From the experimental results using U deposits, the amount of salt evaporation was achieved more than 99 wt% and the salt evaporation rate was about 1.16 g/min. Also, the mount of recovered salt was about 99.5 wt%.
Abstract
The oxidizing reaction of some rare-earth chlorides (Pr/CeCl3) in an eutectic (LiCl-KCl) salt was studied by O2 injection. In this study, oxychlorides (REOCl) or oxides (REO2) were formed as reaction products. The results conformed to the thermodynamic equilibrium data calculated by HSC-Chemistry 5.1 software. The conversion ratio of the rare-earth chlorides to insoluble precipitates was over 0.999, after injecting O2 for 7 hours at 650 °C for the eutectic salt temperature.
Abstract
It is important to increase a throughput of the salt removal process from uranium deposits which is generated on the solid cathode of electro-refiner in pyroprocess. In this study, it was proposed to increase the throughput of the salt removal process by the separation of the liquid salt prior to the distillation of the LiCl–KCl eutectic salt from the uranium deposits. The feasibility of liquid salt separation was examined by salt separation experiments on a stainless steel sieve. It was found that the amount of salt to be distilled could be reduced by the liquid salt separation prior to the salt distillation. The residual salt remained in the deposits after the liquid salt separation was successfully removed further by the vacuum distillation. It was concluded that the combination of a liquid salt separation and a vacuum distillation is an effective route for the achievement of a high throughput performance in the salt separation process.
Abstract
Distillation and condensation characteristics of LiCl-KCl eutectic salts containing rare earth precipitates were investigated and a conversion of the rare earth oxychlorides to oxides was performed. The distillation flux was increased by about 1,000 times by reducing the pressure from 760 Torr to 0.5 Torr. The composition of the recovered salts was changed according to the condensed spot. The conversion temperature of the multicomponent oxychlorides was decreased when compared to that of a single component. It was found that the concentration of the chloride gas in the flue gas is an index to establish whether the conversion is completed or not.
Abstract
Uranium dendrites which were deposited at a solid cathode of an electrorefiner contained a certain amount of salts. These salts should be removed for the recovery of pure metal using a cathode processor. In the uranium deposits from the electrorefining process, there are actinide chlorides and rare earth chlorides in addition to uranium chloride in the LiCl–KCl eutectic salt. The evaporation behaviors of the actinides and rare earth chlorides in the salts should be investigated for the removal of salts in the deposits. Experiments on the salt evaporation of rare earth chlorides in a LiCl–KCl eutectic salt were carried out. Though the vapor pressures of the rare earth chlorides were lower than those of the LiCl and KCl, the rare earth chlorides were co-evaporized with the LiCl–KCl eutectic salt. The Hertz–Langmuir relation was applied for this evaporation, and also the evaporation rates of the salt were obtained. The co-evaporation of the rare earth chlorides and LiCl–KCl eutectic were also discussed.
Abstract
Epithermal Instrumental Neutron Activation Analysis has been used to measure the concentration of uranium in eutectic salt solutions in support of a research program in which the actinide elements are separated from rare earths and other fission products using high-temperature electo-deposition. The uranium response over three decades in concentration follows a negative power function; and high concentrations of samarium interfere with the determination of uranium but can be accurately corrected. The EINAA method was successfully used to analyze NIST SRM 278 Obsidian and NIST SRM 1566a Fly Ash.
Abstract
The distillation behaviour of cadmium at a reduced pressure was investigated to develop an actinide recovery process from a liquid cadmium cathode in a laboratory scale cadmium distiller. The apparent evaporation rate of cadmium increased with an increasing temperature whereas the rate decreased with an increasing vacuum pressure. The evaporation rate of cadmium varied within 9.7–40 g/cm2/h in the temperature range of 500–650 °C and pressure range of 0.5–10 Torr (0.0667–1.33 kPa). The theoretical values calculated by the Hertz–Langmuir relation were much higher than experimentally measured values. The deviation was compensated by an evaporation coefficient (α) obtained empirically. About 0.02–0.20 wt% of residue was left in the crucible after distillation and found to be CdO. It could be concluded that the temperature range of 500–650 °C is favourable for the cadmium distillation process if residual eutectic salt does not exist in the cadmium alloy surface.
: 618 – 621 . 23. Fauth , DJ , Frommell , EA , Hoffman , JS , Reasbeck , RP , Pennline , HW . Eutectic salt promoted lithium zirconate: novel high temperature sorbent for CO 2