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Supercritical water oxidation of tributyl phosphate
Published in Binoy K. Saikia, Advances in Applied Chemistry and Industrial Catalysis, 2022
Shenghan Sun, Shuzhong Wang, Yanhui Li, Tiantian Xu, Jianna Li, Fan Zhang, Chao He
Tributyl phosphate (TBP) is usually used as an extractant during spent fuel reprocessing (El-Dessouky et al. 2001). In the process of extraction and re-extraction, TBP will be exposed to radiation and chemical action, as well as light and heat. Affected by these, TBP will be destroyed, and chemical reactions such as degradation and polymerization will occur, with the extraction performance decreasing. The performance of the extractant deteriorates severely after being used repeatedly, and a small number of radioactive elements will be retained, which makes TBP a kind of waste and harms the environment as well. TBP is not only used as an extractant in the PUREX process but also as a plasticizer and defoamer due to its excellent physical and chemical properties (Berne et al. 2004). These are the paths for TBP to enter the environment, so an environment-friendly method to degrade TBP is a must.
Role of Enzymes in the Bioremediation of Refractory Pollutants
Published in Maulin P. Shah, Removal of Refractory Pollutants from Wastewater Treatment Plants, 2021
Viresh R. Thamke, Ashvini U. Chaudhari, Kisan M. Kodam, Jyoti P. Jadhav
Alkaline phosphatases are known to hydrolyse various organic compounds in the nuclear industry. It is most active in alkaline environments and its physiological role is dephosphorylating compounds. Tributyl phosphate (TBP) is one of the best-known extractants used in the plutonium uranium extraction process (PUREX). Several bacteria belonging to the family Enterobacteriaceae have been reported to tolerate and degrade high doses of TBP aided with induced alkaline phosphatases in a bacterial system. One of the more well-studied bacterial isolates is Klebsiella pneumonia (Kulkarni et al. 2014), which can tolerate high concentration of TBP and bring about transformation to a non-toxic metabolite di-butyl phosphate with the help of induced alkaline phosphates.
The Environment Today
Published in Anco S. Blazev, Power Generation and the Environment, 2021
The PUREX process is a straightforward chemical reaction, where the spent irradiated fuel is dissolved in nitric acid, and the insoluble solids are filtered out. An organic solvent, such as tributyl phosphate (TBP) in a kerosene solution is added to extract the uranium as UO2 (NO3)2 2TBP complex. The uranium is stripped from the kerosene solution by back-extraction into nitric acid, from where it can be easily recovered.
Elimination of the Interfacial Crud in the Extraction of Simulated High-Level Liquid Waste After Denitration in the TRPO Process
Published in Solvent Extraction and Ion Exchange, 2023
Zhaofei Zhang, Wuhua Duan, Xinwei Cheng, Wenbing Li, Jing Chen, Jianchen Wang, Taoxiang Sun
Recently, the issue of spent fuel reprocessing has become an important constraint to the development of nuclear energy as the field of nuclear energy continues to expand.[1] The Plutonium Uranium Reduction EXtraction (PUREX) process using tributyl phosphate (TBP) as the extractant can efficiently recover uranium and plutonium from the spent nuclear fuel.[2–4] However, a large amount of highly radioactive and chemically toxic liquid known as high-level liquid waste (HLLW), is generated in this process. The Partitioning-Transmutation (P&T) strategy is currently one of the main research directions for the effective treatment of HLLW, which can separate the minor actinides (MA) and long-lived fission products (LLFP) from the HLLW and convert them into short-lived or stable nuclides by means of nuclear reactions in dedicated devices such as thermal neutron reactors, fast neutron reactors, and accelerator-driven system.[5] Several extraction processes have been developed for the treatment of HLLW, such as the TRUEX process in the United States,[6] the DIAMEX process in France,[7,8] the DIDPA process in Japan,[9] and the TRPO process in China.[10–12] Among them, the TRPO process developed by Tsinghua University in China over the past 40 years is considered to be one of the most promising solvent extraction processes for the treatment of HLLW.
Evaluation of the Hydrophilic Complexant N,N,N’,N’-tetraethyldiglycolamide (TEDGA) and its Methyl-substituted Analogues in the Selective Am(III) Separation
Published in Solvent Extraction and Ion Exchange, 2019
Larissa Klaß, Andreas Wilden, Fabian Kreft, Christoph Wagner, Andreas Geist, Petra J. Panak, Irena Herdzik-Koniecko, Jerzy Narbutt, Giuseppe Modolo
The well-known PUREX (plutonium uranium reduction extraction) process which uses tributyl phosphate (TBP) as extractant is employed on an industrial scale to recover uranium and plutonium from spent nuclear fuel. Americium however is not separated by the PUREX process and remains with other minor actinides (neptunium and curium) and the fission products in high level liquid waste (HLLW), which is vitrified and prepared for final disposal. Its recovery requires the development of new processes including new extractant molecules. To recover americium from HLLW, a variety of solvent extraction processes has been developed.[2–5] The majority of such processes generate a product solution containing both americium and curium, requiring a further process to achieve their separation from one another.[6] To simplify such process schemes, different processes have been developed to directly separate only americium from HLLW, such as the EXAm (extraction of americium) process and alternative processes as described below.
Differential Pressure Changes of a High Airflow–Type HEPA Filter During Solvent Fire in Reprocessing Facilities
Published in Nuclear Technology, 2022
Shinsuke Tashiro, Gunzo Uchiyama, Takuya Ohno, Yuki Amano, Ryoichiro Yoshida, Hithoshi Abe
A mixed solvent consisting of tri-butyl phosphate (TBP) and dodecane as a diluent is used to recover useful elements (U and Pu) from spent nuclear fuels. As the solvents are combustible, the fire risk must be considered. Reprocessing facilities are equipped with high-efficiency particulate air (HEPA) filters that confine particulate radioactive materials within the facility in normal and accidental operations. For the solvent fire accident, the HEPA filter will be clogged with airborne particles, such as combustion products including soot and radioactive materials. If the differential pressure ΔP of the HEPA filter exceeds its limit with excessive clogging occurring, the HEPA filter will be damaged and radioactive materials will be leaked from reprocessing facilities.