Stabilization and volume reduction of radioactive spent ionexchange resins

Stabilization and volume reduction of spent radioactive ion-exchangeresins(IERs) were studied.Stabilization technology includes volume reduction with wet chemical oxidation process and immobilization of the residue into cement.Under suitable conditions,the exhausted radioactive ion-exchange resins were dissolved successfully in a H2O-Fe^2 /Cu^2 catalytic oxidation system(Fenton reagent).The analytical results indicated that the radioactive nuclides loaded in the resins were concentrated in decomposed solution and solid residues.The process parameters of wet chemical oxidation and solidification were also obtained.The decomposition ratios were 100% and more than 90% for cation and amion IERs respectively.The waste volume was decerased by 40% compared with that of original spent resins.     

放射性废离子交换树脂高温裂解处理技术研究

通过热重实验以及台架试验,进行了废阴/阳离子交换树脂的高温裂解处理技术研究。结果表明,通过电磁感应加热反应器中的金属球并辅助搅拌,可以实现树脂的高温裂解。相比于氮气和水蒸气,空气是更合适的反应气氛。在空气氛围下,当树脂处理量为1 kg/h时,设定空气流量2 m³/h,反应温度600 ℃～700 ℃,添加剂选择CuSO₄·5H₂O,阴/阳离子交换树脂经本裂解工艺处理,废物残留率分别为8%和12%左右,两种树脂最终的裂解残留率可以达到3%～5%左右,可以实现较为彻底的裂解反应。阴离子和阳离子交换树脂的裂解反应有明显的区别,其中阴离子交换树脂热敏性更高,裂解需要的温度和空气流量更低,但反应更剧烈,烟气量更大。     

Analysis and design of spent fuel transport cask impact limiters

Abstract

Three Latin American countries which operate research reactors, Argentina, Brazil and Chile, have joined efforts to improve the capability in the management of spent fuel elements from the reactors operated in the region. As a step in this direction, a packaging for the transport of irradiated fuel from research reactors was designed by a tri-national team and a half scale model for materials test reactor fuel was constructed in Argentina and tested in Brazil. Three test campaigns have been carried out so far, covering both normal conditions of transportation and hypothetical accident conditions.

In this paper both the numerical modelling and mechanical tests to select adequate shock absorbers materials are presented. Results of these tasks are used to improve the cask design.     

Influence of ion exchange resin on the performance of continuous electrodeionization (CEDI) treating low-level radioactive wastewater

With the fast development of nuclear power, low-level radioactive wastewater (LLRW) treatment will meet more severe requirements. Continuous electrodeionization (CEDI) is a novel technology to treat LLRW with advantages of lower level effluent and smaller waste production. In this study, the influences of ion exchange resins (IERs) in the concentrate and dilute compartments on the performance of CEDI were investigated. The three stacks filled with anion exchange resins in the dilute compartments were more efficient for boron removal than metal ions, while the three stacks filled with cation exchange resins were more efficient for the removal of metal ions than boron. The stack filled with a type of mixed IERs was good at removing both metal ions and boron. The correlation analysis showed that no significant correlations were found between ion exchange capacities or ion exchange kinetics with the decontamination factors of metal ions. The removal ratios of boron were positively correlated with the ion exchange capacities, but were not correlated with the ion exchange kinetics. The results can guide the CEDI stack design by filling different IERs for different purposes.