Quantification of Transferring and Adhering for Pd, Mo, Te, Sb, Ru, Re, Cs and I During the Evaporation Under Vacuum and at Atmospheric Pressure

2003 ◽  
Author(s):  
K. Ito ◽  
T. Takata ◽  
M. Kamiya
Keyword(s):  
Nitric Acid ◽  
Nuclear Waste ◽  
Sodium Nitrate ◽  
Atmospheric Pressure ◽  
Liquid Waste ◽  
Waste Recycling ◽  
Nuclear Fuel Reprocessing ◽  
Recycling Of Wastes ◽  
Fuel Reprocessing ◽  
Nitrate Solutions

In order to modify current nuclear fuel reprocessing plants on the basis of a more sophisticated, economical, and safer nuclear waste recycling system, the production of low-level radioactive wastes must be reduced and the recycling of wastes must become more efficient. To simulate liquid waste recycling operations, evaporators under vacuum and at atmospheric pressure were used to determine adhering and transferring rates for Pd, Mo, Te, Sb, Ru, Re, Cs and I in the nitric acid and sodium nitrate solutions. In the evaporation from the HNO3 and NaNO3 solutions containing precipitate PdI2, the percentage values for materials adhering on the inside of lid at vacuum pressure were 0.01 ∼ 0.1%/m2, however at atmospheric pressure the values were 0.001 ∼ 0.01%/m2. Adhering percentage values on the condenser were 0.0001 ∼ 0.001%/m2 for the vacuum and atmospheric pressure systems. The transferred percentages into the distillate for Pd, Mo, Te, Sb, Ru, Re, and Cs were 0.0001 ∼ 0.001% in the HNO3 and NaNO3 solutions for the vacuum and atmospheric pressure systems, and those of I were about 10% for HNO3 system at atmospheric pressure, 2∼7% for HNO3 system under vacuum, 0.01∼0.1% for NaNO3 system under vacuum. Reducing rates for the treated solution were one third of feeding solutions in the evaporation under vacuum and at atmospheric pressure.

Studies on hydrolysis and radiolysis of N,N,N′,N′-tetraoctyl-3-oxapentane-1,5-diamide

2002 ◽  
Vol 90 (3) ◽  
Author(s):  
Y. Sugo ◽  
Y. Sasaki ◽  
S. Tachimori
Keyword(s):  
Gamma Irradiation ◽  
Room Temperature ◽  
Degradation Products ◽  
Liquid Waste ◽  
Amide Bond ◽  
Radioactive Liquid Waste ◽  
Ether Bond ◽  
Nuclear Fuel Reprocessing ◽  
High Level ◽  
Fuel Reprocessing

SummaryHydrolytic and radiolytic stabilities of a promising extractant, N,N,N′,N′-tetraoctyl-3-oxapentane-1,5-diamide (TODGA), for actinides in high-level radioactive liquid waste from nuclear fuel reprocessing were investigated in air at room temperature. Hydrolysis by nitric acid was not observed, whereas radiolysis by gamma irradiation was notably observed. The radiolysis study showed that an amide-bond, an ether-bond, and a bond adjacent to the ether-bond tended to be broken by gamma irradiation, and dioctylamine and various N,N-dioctylmonoamides were identified as the main degradation products by GC/MS and NMR analyses. The

Interference of Zr(IV) during the extraction of trivalent Nd(III) from the aqueous waste generated from metallic fuel reprocessing

2020 ◽  
Vol 108 (7) ◽  
pp. 543-554
Author(s):  
T. Prathibha ◽  
K. Rama Swami ◽  
S. Sriram ◽  
K. A. Venkatesan
Keyword(s):  
Nitric Acid ◽  
Mechanical Stability ◽  
Nitric Acid Concentration ◽  
Liquid Waste ◽  
Aggregate Size ◽  
Metallic Fuel ◽  
High Level Liquid Waste ◽  
Spectral Techniques ◽  
Extraction Behavior ◽  
Fuel Reprocessing

AbstractA metallic alloy of uranium–zirconium and uranium–plutonium–zirconium has been proposed as a fuel for fast reactors, owing to the possibility of achieving high breeding ratio in a short span of time. About 6–10 wt.% of zirconium has been added to these actinide fuels to increase the melting temperature and thermal-mechanical stability. Aqueous reprocessing of the spent metallic fuel generates the high-level liquid waste (HLLW) that contains about 60 % of the total zirconium from the fuel. In view of this, the extraction behavior of a trivalent representative ion, Nd(III) in the presence of Zr(IV) was studied from nitric acid medium using the candidate ligands proposed for trivalent actinide separation from HLLW, such as N,N,N′N′-tetraoctyldiglycolamide (TODGA), and N,N-di-octyl-2-hydroxyacetamide (DOHyA). The extraction was studied as a function of nitric acid concentration, zirconium and neodymium concentration and Nd(III) to Zr(IV) ratio. The findings of dynamic light scattering (DLS) and ATR-FTIR spectral techniques were used for understanding the complex chemistry of Zr(IV) extraction under different conditions. Poor extraction of nitric acid, smaller aggregate size, no third phase formation during the extraction of Zr(IV) and Nd(III) and other unique solvent properties favor the DOHyA molecule in n-dodecane as a solvent for partitioning of trivalent actinides from HLLW generated from metallic fuel reprocessing.

Extraction Behavior of Ln(III) Ions by T2EHDGA/n-Dodecane from Nitric Acid and Sodium Nitrate Solutions

2018 ◽  
Vol 36 (4) ◽  
pp. 331-346 ◽  
Author(s):  
Emily Campbell ◽  
Vanessa E. Holfeltz ◽  
Gabriel B. Hall ◽  
Kenneth L. Nash ◽  
Gregg J. Lumetta ◽  
...  
Keyword(s):  
Nitric Acid ◽  
Sodium Nitrate ◽  
Extraction Behavior ◽  
Nitrate Solutions

Research Progress of Red Oil Explosion Accidents in Nuclear Fuel Reprocessing Plant

2017 ◽  
Author(s):  
Chunlong Zhang ◽  
Hui He ◽  
Shangui Zhao ◽  
Fengli Song ◽  
XinHua Liu
Keyword(s):  
Nitric Acid ◽  
Nuclear Fuel ◽  
Acid Concentration ◽  
Preventive Measures ◽  
Nitric Acid Concentration ◽  
Purex Process ◽  
Nuclear Fuel Reprocessing ◽  
Explosion Accidents ◽  
Reprocessing Plant ◽  
Fuel Reprocessing

Since Westinghouse Savannah River Company (WSRC) of America first applied PUREX process in 1954, PUREX process is always the top priority in nuclear fuel reprocessing plant. And this process is based on liquid to liquid extraction with TBP as the extractant. TBP is irreplaceable in the development of PUREX process in nuclear fuel reprocessing, its advantages are well recognized. However TBP does have some disadvantages such as formation of red oil, which will appear in the system of high nitric acid concentration and heavy metal nitrate, once the red oil forms, it can lead a exothermic runaway decomposition in reasonable conditions, such as exceeding a certain temperature (typically 130°C) or high acid concentration. If gas products and energy released from the decomposition reaction could not be exported in time, it will lead to vessel overpressure and caused violent explosion accidents. By now, it has happened 6 times so-called red oil explosion accidents worldwide, resulting in different degrees of equipment and construction damage and environmental contamination. From 1953 to now, research related to red oil has never stopped. WSRC, Hanford Company, Oak Ridge National Laboratory and Los Alamos National Laboratory of America have conducted many studies, as well as some research institutions from Russia, UK, France and India. Defense Nuclear Facilities Safety Board of America issued a technical report in 2003, preventive measures for red oil explosion were established in this report, and these measures provided good practice experience and reference for other countries, and the temperature condition (⩽130°C)and nitric acid concentration (⩽10M)for preventing red oil explosion are employed in some countries which has built the reprocessing plant. Nevertheless, research conclusions and knowledge of red oil vary from country to country. Especially, Kumar and Smitha etc. conducted several experiments in adiabatic condition in recent years, and investigation on stability of TBP - nitric system was made, the results indicated that the red oil runway reaction will happen even in lower temperature and lower nitric acid concentration in contrast with the reported value, and they thought it would need a further study to assess the validity of present preventive measures, and to rebuild the safety limits for preventing red oil explosion in the operation of nuclear fuel reprocessing plants. In this paper, related research results of red oil explosion accidents were combed, and the characters of study work of different periods were summarized, and definition, formation conditions of red oil, pathway of runaway reaction, control and preventive measures for preventing red oil explosion of different countries were analyzed and compared, as well as the new viewpoints of recent literatures. And some research ideas for future investigation based on present work were also proposed.

Mechanism of dissolution of nuclear fuel in nitric acid relevant to nuclear fuel reprocessing

2017 ◽  
Vol 312 (1) ◽  
pp. 141-149 ◽  
Author(s):  
N. Desigan ◽  
Nirav P. Bhatt ◽  
N. K. Pandey ◽  
U. Kamachi Mudali ◽  
R. Natarajan ◽  
...  
Keyword(s):  
Nitric Acid ◽  
Nuclear Fuel ◽  
Nuclear Fuel Reprocessing ◽  
Fuel Reprocessing
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