Pub Date : 2024-02-19DOI: 10.1134/s1066362223060024
M. I. Volgin, S. A. Kulyukhin, Yu. M. Nevolin
Abstract
Oxidation of UO2 and UN by atmospheric oxygen and nitrogen hemioxide, which is a hard-to-localize greenhouse gas, was investigated by thermal analysis. For oxidation, mixtures of N2O–N2 and O2–N2 were used with a 20% volume fraction of the oxidizing agent. For UO2 and UN, the phase composition of the final oxidation product in air and in N2O is the same―U3O8. In both cases, N2O behaves as a milder oxidizing agent compared to atmospheric oxygen. Oxidation of UO2 and UN in an N2O flow starts at a temperature 180 and 70°C higher than in air, respectively. The oxidation of UN in an N2O flow proceeds in three stages. At the first stage, the reaction products are UO2 and U2N3; UO2 is the product of the second stage; and at the third stage U3O8 is produced. No pronounced staging is observed in the UO2 oxidation process. The possibility of utilizing nitrogen hemioxide when it is used in the course of voloxidation (oxidation) of spent nuclear fuel is shown.
{"title":"Comparative Analysis of UN and UO2 Oxidation in Air and Nitrogen Hemioxide","authors":"M. I. Volgin, S. A. Kulyukhin, Yu. M. Nevolin","doi":"10.1134/s1066362223060024","DOIUrl":"https://doi.org/10.1134/s1066362223060024","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Oxidation of UO<sub>2</sub> and UN by atmospheric oxygen and nitrogen hemioxide, which is a hard-to-localize greenhouse gas, was investigated by thermal analysis. For oxidation, mixtures of N<sub>2</sub>O–N<sub>2</sub> and O<sub>2</sub>–N<sub>2</sub> were used with a 20% volume fraction of the oxidizing agent. For UO<sub>2</sub> and UN, the phase composition of the final oxidation product in air and in N<sub>2</sub>O is the same―U<sub>3</sub>O<sub>8</sub>. In both cases, N<sub>2</sub>O behaves as a milder oxidizing agent compared to atmospheric oxygen. Oxidation of UO<sub>2</sub> and UN in an N<sub>2</sub>O flow starts at a temperature 180 and 70°C higher than in air, respectively. The oxidation of UN in an N<sub>2</sub>O flow proceeds in three stages. At the first stage, the reaction products are UO<sub>2</sub> and U<sub>2</sub>N<sub>3</sub>; UO<sub>2</sub> is the product of the second stage; and at the third stage U<sub>3</sub>O<sub>8</sub> is produced. No pronounced staging is observed in the UO<sub>2</sub> oxidation process. The possibility of utilizing nitrogen hemioxide when it is used in the course of voloxidation (oxidation) of spent nuclear fuel is shown.</p>","PeriodicalId":747,"journal":{"name":"Radiochemistry","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2024-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139903060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-19DOI: 10.1134/s1066362223060073
A. A. Ioshin, I. V. Volkov, E. V. Polyakov
Abstract
The sorption behavior of traces Sr(II) toward β-Ca3(PO4)2 (TCP) depending on the concentration of the cation, pH, and concentrations of humic acids (HA) in the solution was studied. Thermodynamic analysis of the solubility of TCP (1) was performed taking into account the formation of Ca(OH)2 (CH, 2), Ca(H2PO4)2 (MCPA, 3), CaHPO4·2H2O (DCPD, 4), Ca5(PO4)3OH (hydroxyapatite, OHAp, 5), and Ca2P2O7 (DCPP, 6). It was shown that, depending on the pH of the solution, the main equilibrium phases with the solution are phases 4 and 5. X-ray diffraction analysis, Raman spectroscopy, and 31P NMR data of the phase (1) samples after contact with a solution of 0.01 M NaNO3 for about 10 days showed the presence of only the phase 1. The solubility of 1 regarding the concentration of Ca2+, PO43– ions and the stoichiometric ratio (Ca/P) in solutions, depending on pH, correspond to the presence of surface phases 4 or 5. The model of surface complexation in the Henry region adequately describes the mechanism of Sr(II) sorption by the surface phase 5 on TCP particles in the form of the SrHPO40 complex. The formation of the HA complex of Sr(II) in solution does not affect distribution coefficient Kd(Sr) in the range of HA concentrations of 0–150 mg/L due to the competitive effect of hydrogen phosphate ions on strontium complexes.
{"title":"Sorption of Sr(II) Ions with Tricalcium Phosphate in the Presence of Humic Acids","authors":"A. A. Ioshin, I. V. Volkov, E. V. Polyakov","doi":"10.1134/s1066362223060073","DOIUrl":"https://doi.org/10.1134/s1066362223060073","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The sorption behavior of traces Sr(II) toward β-Ca<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub> (TCP) depending on the concentration of the cation, pH, and concentrations of humic acids (HA) in the solution was studied. Thermodynamic analysis of the solubility of TCP (<b>1</b>) was performed taking into account the formation of Ca(OH)<sub>2</sub> (CH, <b>2</b>), Ca(H<sub>2</sub>PO<sub>4</sub>)<sub>2</sub> (MCPA, <b>3</b>), CaHPO<sub>4</sub>·2H<sub>2</sub>O (DCPD, <b>4</b>), Ca<sub>5</sub>(PO<sub>4</sub>)<sub>3</sub>OH (hydroxyapatite, OHAp, <b>5</b>), and Ca<sub>2</sub>P<sub>2</sub>O<sub>7</sub> (DCPP, <b>6</b>). It was shown that, depending on the pH of the solution, the main equilibrium phases with the solution are phases <b>4</b> and <b>5</b>. X-ray diffraction analysis, Raman spectroscopy, and <sup>31</sup>P NMR data of the phase (<b>1</b>) samples after contact with a solution of 0.01 M NaNO<sub>3</sub> for about 10 days showed the presence of only the phase <b>1</b>. The solubility of <b>1</b> regarding the concentration of Ca<sup>2+</sup>, PO<sub>4</sub><sup>3–</sup> ions and the stoichiometric ratio (Ca/P) in solutions, depending on pH, correspond to the presence of surface phases <b>4</b> or <b>5</b>. The model of surface complexation in the Henry region adequately describes the mechanism of Sr(II) sorption by the surface phase <b>5</b> on TCP particles in the form of the SrHPO<sub>4</sub><sup>0</sup> complex. The formation of the HA complex of Sr(II) in solution does not affect distribution coefficient <i>K</i><sub>d</sub>(Sr) in the range of HA concentrations of 0–150 mg/L due to the competitive effect of hydrogen phosphate ions on strontium complexes.</p>","PeriodicalId":747,"journal":{"name":"Radiochemistry","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2024-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139903200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-19DOI: 10.1134/s1066362223060061
A. S. Obedkov, I. A. Bolshakova, E. V. Belova, G. V. Kostikova, O. A. Raitman, S. I. Stepanov
Abstract
The radiation thermal stability of extraction mixtures based on methyltrioctylammonium (MTOA) carbonate was studied. The volumes and maximum rate of release of gaseous products at atmospheric and elevated pressures were determined. No exothermic processes were shown to occur in the studied mixtures under experimental conditions. Irradiation up to a dose of 1 MGy has little effect on the density, viscosity, and surface tension of mixtures, but significantly reduces the phase separation rate. The distribution coefficients of Am(III) in the system of 50% MTOA carbonate in toluene are practically independent of the absorbed dose; however, irradiation can significantly affect the composition of the extractable americium complexes. The results of the study of extraction systems showed their high radiation thermal stability.
{"title":"Influence of Irradiation on the Stability of Extraction Mixtures Based on Methyltri-n-Octylammonium Carbonate","authors":"A. S. Obedkov, I. A. Bolshakova, E. V. Belova, G. V. Kostikova, O. A. Raitman, S. I. Stepanov","doi":"10.1134/s1066362223060061","DOIUrl":"https://doi.org/10.1134/s1066362223060061","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The radiation thermal stability of extraction mixtures based on methyltrioctylammonium (MTOA) carbonate was studied. The volumes and maximum rate of release of gaseous products at atmospheric and elevated pressures were determined. No exothermic processes were shown to occur in the studied mixtures under experimental conditions. Irradiation up to a dose of 1 MGy has little effect on the density, viscosity, and surface tension of mixtures, but significantly reduces the phase separation rate. The distribution coefficients of Am(III) in the system of 50% MTOA carbonate in toluene are practically independent of the absorbed dose; however, irradiation can significantly affect the composition of the extractable americium complexes. The results of the study of extraction systems showed their high radiation thermal stability.</p>","PeriodicalId":747,"journal":{"name":"Radiochemistry","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2024-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139903202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-11DOI: 10.1134/s1066362223050053
V. O. Kaptakov, V. V. Milyutin
Abstract
The paper presents the results of testing the purification of real liquid radioactive waste from radionuclides, bottom residues of the Kola and Beloyarsk nuclear power plants (NPP), as well as low-level wastewater from the radiochemical building of the Institute of Physical Chemistry and Electrochemistry RAS (IPCE RAS) using the method of nanofiltration (NF) using a polymer membrane manufactured by the Russian company “RM Nanotech.” It has been shown that in the case of single-stage NF purification of bottoms of the Kola NPP, the coefficient of purification from 60Co is 2.8, while no purification from 137Cs practically occurs. When cleaning the bottom residues of the Beloyarsk NPP from 60Co using a five-stage scheme, a coefficient of purification from 60Co equal to 388 was obtained. The combination of nanofiltration purification and selective sorption of cesium on the ferrocyanide sorbent Temoksid-35 makes it possible to obtain a dry salt residue that is not related to radioactive waste. When using the method of nanofiltration for the treatment of low-level wastewater of the Institute of Physical Chemistry and Electrochemistry of the Russian Academy of Sciences, the degree of purification was, %: 137Сs ~ 75; 90Sr ~ 91; 241Am ~ 99.5; 152Eu ~ 91; 239Pu ~ 99.5.
{"title":"Nanofiltration Purification of Liquid Radioactive Waste","authors":"V. O. Kaptakov, V. V. Milyutin","doi":"10.1134/s1066362223050053","DOIUrl":"https://doi.org/10.1134/s1066362223050053","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The paper presents the results of testing the purification of real liquid radioactive waste from radionuclides, bottom residues of the Kola and Beloyarsk nuclear power plants (NPP), as well as low-level wastewater from the radiochemical building of the Institute of Physical Chemistry and Electrochemistry RAS (IPCE RAS) using the method of nanofiltration (NF) using a polymer membrane manufactured by the Russian company “RM Nanotech.” It has been shown that in the case of single-stage NF purification of bottoms of the Kola NPP, the coefficient of purification from <sup>60</sup>Co is 2.8, while no purification from <sup>137</sup>Cs practically occurs. When cleaning the bottom residues of the Beloyarsk NPP from <sup>60</sup>Co using a five-stage scheme, a coefficient of purification from <sup>60</sup>Co equal to 388 was obtained. The combination of nanofiltration purification and selective sorption of cesium on the ferrocyanide sorbent Temoksid-35 makes it possible to obtain a dry salt residue that is not related to radioactive waste. When using the method of nanofiltration for the treatment of low-level wastewater of the Institute of Physical Chemistry and Electrochemistry of the Russian Academy of Sciences, the degree of purification was, %: <sup>137</sup>Сs ~ 75; <sup>90</sup>Sr ~ 91; <sup>241</sup>Am ~ 99.5; <sup>152</sup>Eu ~ 91; <sup>239</sup>Pu ~ 99.5.</p>","PeriodicalId":747,"journal":{"name":"Radiochemistry","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138569744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-11DOI: 10.1134/s106636222305003x
V. E. Sharov, G. V. Kostikova
Abstract
The effect of HNO3 concentration on the extraction of Eu(III), Am(III), and Cm(III) with N,N,N',N'-tetrabutyldiglycolamide was studied in 5 different diluents: nitrobenzene, toluene, chloroform, 1,2-dichloroethane, and 1,1,2,2-tetrachloroethane. The distribution coefficients of these metals as a function of the nature of the diluent in the following series of compounds was established: nitrobenzene > m-trifluoromethylnitrobenzene > mixture of n-dodecane with decanol-1 (volume ratio 90 : 10) > carbon tetrachloride > 1,2-dichloroethane > benzene > 1,1,2,2-tetrachloroethane > toluene > chloroform. The conditions for the partioning Eu(III)/Am(III) and Am(III)/Cm(III) pairs were found. An explanation was proposed for the observed increase in the separation factors of the Am(III)/Cm(III) pair with increasing concentration of nitric acid in the equilibrium aqueous phase.
{"title":"Influence of the Nature of Diluent on the Extractability of N,N,N',N'-Tetrabutyldiglycolamide for Eu(III), Am(III), and Cm(III)","authors":"V. E. Sharov, G. V. Kostikova","doi":"10.1134/s106636222305003x","DOIUrl":"https://doi.org/10.1134/s106636222305003x","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The effect of HNO<sub>3</sub> concentration on the extraction of Eu(III), Am(III), and Cm(III) with <i>N</i>,<i>N</i>,<i>N</i>',<i>N</i>'-tetrabutyldiglycolamide was studied in 5 different diluents: nitrobenzene, toluene, chloroform, 1,2-dichloroethane, and 1,1,2,2-tetrachloroethane. The distribution coefficients of these metals as a function of the nature of the diluent in the following series of compounds was established: nitrobenzene > <i>m</i>-trifluoromethylnitrobenzene > mixture of <i>n</i>-dodecane with decanol-1 (volume ratio 90 : 10) > carbon tetrachloride > 1,2-dichloroethane > benzene > 1,1,2,2-tetrachloroethane > toluene > chloroform. The conditions for the partioning Eu(III)/Am(III) and Am(III)/Cm(III) pairs were found. An explanation was proposed for the observed increase in the separation factors of the Am(III)/Cm(III) pair with increasing concentration of nitric acid in the equilibrium aqueous phase.</p>","PeriodicalId":747,"journal":{"name":"Radiochemistry","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138569252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-11DOI: 10.1134/s1066362223050119
S. Yu. Artamonova, L. G. Bondareva, M. S. Melgunov, G. V. Simonova
Abstract
The radioecological situation at the site of the peaceful underground nuclear explosion “Crystal” after removal land cover and installation of the artificial cover of rock from nearby quarry above the epicenter is considered. In 2012 the ambient dose equivalent rate of gamma radiation varied from 0.04 to 0.066 µSv/h, in 2019 the content of radionuclides in soils was (Bq/kg): 90Sr 2.5–5.3, 239,240Pu 0.03–25.4, 137Cs <2.0. In 2018–2020 the activity of radionuclides in surface water was (Bq/dm3): in drains from under the artificial cover 3H 4–12, 90Sr 0.004–0.4, 239,240Pu < 10–6, in local river water 3H 4–10.2, 90Sr 0.004–0.3. At present, the impact of surface drains from the “Crystal” site on the river network is assessed as insignificant. No more than 1/3 of 3H in the local river water comes with precipitation, and the rest of 3H comes from the “Crystal” explosion zone, mainly by an underground route. At least 91–96% of 90Sr in the local river water is due to the “Crystal” explosion: part of it comes from the explosion zone by an underground route, part is washed off from the surface of landscapes.
{"title":"Modern Radioecological Situation at the Site of the Peaceful Underground Nuclear Explosion “Crystal” and Radionuclides in the Surface Waters of the Adjacent Territory (Western Yakutia)","authors":"S. Yu. Artamonova, L. G. Bondareva, M. S. Melgunov, G. V. Simonova","doi":"10.1134/s1066362223050119","DOIUrl":"https://doi.org/10.1134/s1066362223050119","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The radioecological situation at the site of the peaceful underground nuclear explosion “Crystal” after removal land cover and installation of the artificial cover of rock from nearby quarry above the epicenter is considered. In 2012 the ambient dose equivalent rate of gamma radiation varied from 0.04 to 0.066 µSv/h, in 2019 the content of radionuclides in soils was (Bq/kg): <sup>90</sup>Sr 2.5–5.3, <sup>239,240</sup>Pu 0.03–25.4, <sup>137</sup>Cs <2.0. In 2018–2020 the activity of radionuclides in surface water was (Bq/dm<sup>3</sup>): in drains from under the artificial cover <sup>3</sup>H 4–12, <sup>90</sup>Sr 0.004–0.4, <sup>239,240</sup>Pu < 10<sup>–6</sup>, in local river water <sup>3</sup>H 4–10.2, <sup>90</sup>Sr 0.004–0.3. At present, the impact of surface drains from the “Crystal” site on the river network is assessed as insignificant. No more than 1/3 of <sup>3</sup>H in the local river water comes with precipitation, and the rest of <sup>3</sup>H comes from the “Crystal” explosion zone, mainly by an underground route. At least 91–96% of <sup>90</sup>Sr in the local river water is due to the “Crystal” explosion: part of it comes from the explosion zone by an underground route, part is washed off from the surface of landscapes.</p>","PeriodicalId":747,"journal":{"name":"Radiochemistry","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138569782","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-11DOI: 10.1134/s1066362223050016
V. V. Kalistratova, A. V. Smirnov, E. V. Belova
Abstract
A thermal analysis of an acetohydroxamic acid solution in 12 M HNO3 was carried out. The activation energy, specific thermal effect, time and rate of the exothermic reaction, pre-exponential factor, starting temperature and self-heating value of the sample, pressure change and specific volume of released gases were determined. Under experimental conditions this reaction was found to occur in an autocatalytic mode. Based on experimental data, a kinetic equation for the reaction was derived, which was used to create a model of the reaction under various conditions. The reliability of the modeling results was verified by differential scanning calorimetry.
摘要 对 12 M HNO3 中的乙酰羟肟酸溶液进行了热分析。测定了活化能、比热效应、放热反应的时间和速率、预指数、样品的起始温度和自热值、压力变化和释放气体的比容。在实验条件下，发现该反应以自催化方式发生。根据实验数据，推导出了该反应的动力学方程，并利用该方程建立了不同条件下的反应模型。差示扫描量热法验证了建模结果的可靠性。
{"title":"Simulation of Thermal Decomposition of Acetohydroxamic Acid Nitrate Solution upon SNF Reprocessing","authors":"V. V. Kalistratova, A. V. Smirnov, E. V. Belova","doi":"10.1134/s1066362223050016","DOIUrl":"https://doi.org/10.1134/s1066362223050016","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>A thermal analysis of an acetohydroxamic acid solution in 12 M HNO<sub>3</sub> was carried out. The activation energy, specific thermal effect, time and rate of the exothermic reaction, pre-exponential factor, starting temperature and self-heating value of the sample, pressure change and specific volume of released gases were determined. Under experimental conditions this reaction was found to occur in an autocatalytic mode. Based on experimental data, a kinetic equation for the reaction was derived, which was used to create a model of the reaction under various conditions. The reliability of the modeling results was verified by differential scanning calorimetry.</p>","PeriodicalId":747,"journal":{"name":"Radiochemistry","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138569257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-11DOI: 10.1134/s1066362223050065
M. B. Rozenkevich
Abstract
According results of a theoretical analysis of the countercurrent column operation for the liquid phase catalytic exchange (LPCE) between hydrogen and water in a mode with independent flows of hydrogen and water, it is shown that there are temperature-dependent maximum values of the molar ratio of hydrogen and water flows, at which the separation performance of the column towards isotope mixtures of protium–tritium and protium–deuterium diminishes. Options for the operation of a chemical treatment column were experimentally studied provided that water vapor condensate is returned to the column from the output steam–gas flow or without it. The experimental results are consistent with the theoretical analysis performed.
{"title":"Analysis of Operating Modes of a Countercurrent Column for the Chemical Isotope Exchange between Hydrogen and Water with Independent Flows of Water and Hydrogen","authors":"M. B. Rozenkevich","doi":"10.1134/s1066362223050065","DOIUrl":"https://doi.org/10.1134/s1066362223050065","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>According results of a theoretical analysis of the countercurrent column operation for the liquid phase catalytic exchange (LPCE) between hydrogen and water in a mode with independent flows of hydrogen and water, it is shown that there are temperature-dependent maximum values of the molar ratio of hydrogen and water flows, at which the separation performance of the column towards isotope mixtures of protium–tritium and protium–deuterium diminishes. Options for the operation of a chemical treatment column were experimentally studied provided that water vapor condensate is returned to the column from the output steam–gas flow or without it. The experimental results are consistent with the theoretical analysis performed.</p>","PeriodicalId":747,"journal":{"name":"Radiochemistry","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138569745","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-11DOI: 10.1134/s1066362223050107
T. A. Goryachenkova, I. E. Kazinskaya, A. V. Travkina, D. P. Starodymova, A. P. Novikov
Abstract
The comparison of the speciations of 239Pu and chemical elements, including rare earth elements (REE), in the bottom sediments of the Kara Sea and the Laptev Sea is given. The speciations were investigated by three different methods of selective leaching. Data were obtained on the content of chemical elements and 239Pu in the composition of complexes with different lability: easily soluble, bound to organic matter, including groups of humic acids (HA) and fulvic acids (FA), as well as to amorphous oxides of Fe and Mn. It is shown that humic and low molecular weight organic acids and their compounds with chemical elements can influence the behavior of plutonium in the seawater–bottom sediments system in the waters of the Arctic seas. The possibility of using a number of REE as a marker for predicting the migration behavior of plutonium is evaluated.
{"title":"Speciation of Plutonium and Some Chemical Elements in the Bottom Sediments of the Laptev Sea and the Kara Sea","authors":"T. A. Goryachenkova, I. E. Kazinskaya, A. V. Travkina, D. P. Starodymova, A. P. Novikov","doi":"10.1134/s1066362223050107","DOIUrl":"https://doi.org/10.1134/s1066362223050107","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The comparison of the speciations of <sup>239</sup>Pu and chemical elements, including rare earth elements (REE), in the bottom sediments of the Kara Sea and the Laptev Sea is given. The speciations were investigated by three different methods of selective leaching. Data were obtained on the content of chemical elements and <sup>239</sup>Pu in the composition of complexes with different lability: easily soluble, bound to organic matter, including groups of humic acids (HA) and fulvic acids (FA), as well as to amorphous oxides of Fe and Mn. It is shown that humic and low molecular weight organic acids and their compounds with chemical elements can influence the behavior of plutonium in the seawater–bottom sediments system in the waters of the Arctic seas. The possibility of using a number of REE as a marker for predicting the migration behavior of plutonium is evaluated.</p>","PeriodicalId":747,"journal":{"name":"Radiochemistry","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138569247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-11DOI: 10.1134/s1066362223050090
N. A. Bakunov, D. Yu. Bolshiyanov, A. O. Aksenov
Abstract
Modern contamination of lake–river systems bottom sediments with global and “Chernobyl” 137Cs is estimated. Drainage lakes of North-Western Russia were investigated. Lake Kopanskoe, located south of the Gulf of Finland, is on the “Chernobyl” 137Cs fallout plume, whereas Ladoga, Sukhodolskoe, Vuoksa, Imandra lakes are located at its periphery, in Karelia and Kola Peninsula. Following parameters are distinguished: lakes bottom 137Cs contamination density (kBq/m2), distribution of 137Cs in the profile of bottom sediments, 137Cs diffusion coefficients (D) in bottom sediments and content of the exchange chemical form of the radionuclide. 137Cs contamination of the lakes was formed due to suspended matter sedimentation with 137Cs, 137Cs sorption and diffusion in bottom sediments. With sedimentation ≥3 mm/year, the concentration of 137Cs increased from the top to the bottom of the core (lakes Vuoksa, Ekostrovskaya Imandra), reflecting the gradual process of 137Cs migration into the sediments. The opposite trend of 137Cs concentration was observed in the bottom sediments of lakes Ladoga and Sukhodolskoe with sedimentation ≤0.5 mm/year. Here 137Cs diffusion with D = (0.5–6.2) × 10–8 cm2/s caused slow radionuclide transfer in the bottom sediments. The main inventory of 137Cs was contained in the top layer 0–5 cm. In Lake Sukhodolskoye bottom sediments an absorbed 137Cs in an exchange chemical form, extracted into 1 М NH4Aс solution, amount only 14.4–20%.
{"title":"137Cs Migration and Profile in Bottom Sediments of Deep Drainage Lakes, North-Western Russia","authors":"N. A. Bakunov, D. Yu. Bolshiyanov, A. O. Aksenov","doi":"10.1134/s1066362223050090","DOIUrl":"https://doi.org/10.1134/s1066362223050090","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Modern contamination of lake–river systems bottom sediments with global and “Chernobyl” <sup>137</sup>Cs is estimated. Drainage lakes of North-Western Russia were investigated. Lake Kopanskoe, located south of the Gulf of Finland, is on the “Chernobyl” <sup>137</sup>Cs fallout plume, whereas Ladoga, Sukhodolskoe, Vuoksa, Imandra lakes are located at its periphery, in Karelia and Kola Peninsula. Following parameters are distinguished: lakes bottom <sup>137</sup>Cs contamination density (kBq/m<sup>2</sup>), distribution of <sup>137</sup>Cs in the profile of bottom sediments, <sup>137</sup>Cs diffusion coefficients (<i>D</i>) in bottom sediments and content of the exchange chemical form of the radionuclide. <sup>137</sup>Cs contamination of the lakes was formed due to suspended matter sedimentation with <sup>137</sup>Cs, <sup>137</sup>Cs sorption and diffusion in bottom sediments. With sedimentation ≥3 mm/year, the concentration of <sup>137</sup>Cs increased from the top to the bottom of the core (lakes Vuoksa, Ekostrovskaya Imandra), reflecting the gradual process of <sup>137</sup>Cs migration into the sediments. The opposite trend of <sup>137</sup>Cs concentration was observed in the bottom sediments of lakes Ladoga and Sukhodolskoe with sedimentation ≤0.5 mm/year. Here <sup>137</sup>Cs diffusion with <i>D</i> = (0.5–6.2) × 10<sup>–8</sup> cm<sup>2</sup>/s caused slow radionuclide transfer in the bottom sediments. The main inventory of <sup>137</sup>Cs was contained in the top layer 0–5 cm. In Lake Sukhodolskoye bottom sediments an absorbed <sup>137</sup>Cs in an exchange chemical form, extracted into 1 М NH<sub>4</sub>Aс solution, amount only 14.4–20%.</p>","PeriodicalId":747,"journal":{"name":"Radiochemistry","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138569260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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