Primary-to-secondary leak monitoring using information obtained from measurement of reference radionuclides in NPP water

Detection of heat-exchange equipment failures in the primary circuit is one of the problems to be solved by radiochemical monitoring during operation of nuclear power installations. A series of experimental and numerical studies were performed in a low-power installation with a water-cooled water-moderated reactor where sequential failure of heat exchangers in two reactor water cleanup and cooling units occurred and progressed. The mechanism of transport of radionuclide impurities from the primary to secondary circuits was determined, and data for different radionuclides were obtained to compare how valuable each radionuclide was as information source for leak detection and monitoring.     

Radiochemical Determination of Plutonium in Natural Water

A procedure was developed for radiochemical determination of plutonium in natural waters of various salinity; it includes concentration of plutonium on iron hydroxide with addition of ²⁴²Pu tracer and radiochemical analysis of the resulting concentrate with -spectrometric measurement of plutonium isotopes.     

Plasmochemical Utilization of Spent Radioactive Organic Fluids

A procedure was proposed for decomposing liquid radioactive organic wastes in low-temperature plasma to form solid inorganic products. Thermolysis of two types of extraction systems with heavy fluorinated diluents, proposed for application in radiochemical industry, was studied. The solid and gaseous thermolysis products were completely analyzed. No fluorine-containing organic compounds were detected in the exhaust gases. To prevent formation of corrosive products, a metal cation was added forming insoluble compounds with the decomposition products. A convenient procedure for simultaneous feeding of organic compound and calcium salt in a methanol solution was proposed.     

Study of the conditions for ibuprofen labeling with 125I to prepare an inflammation imaging agent

A procedure was developed for radioiodination of ibuprofen with ¹²⁵I via an electrophilic substitution reaction. With the aim to optimize the labeling conditions and obtain a high radiochemical yield of ¹²⁵I-ibuprofen (¹²⁵I-Ibup), the effect exerted on the process by the reaction conditions (ibuprofen concentration, pH, reaction time, temperature, oxidizing agent) was studied. With 3.7 MBq of Na¹²⁵I, 100 μg of ibuprofen as substrate and 100 μg of iodogen as oxidizing agent, with the reaction performed in ethanol at 60°C for 10 min, the maximum radiochemical yield of ¹²⁵I-Ibup (78%) was obtained. The labeled compound was separated and purified to remove inactive ibuprofen by HPLC. The biological distribution in normal and inflamed mice shows that radioiodinated ibuprofen is suitable for imaging of inflammation only induced with turpentine oil.     

Radiochemical monitoring of water and air media in nuclear power industry

General approaches to organization of radiochemical monitoring in nuclear power industry and the existing methods and technical means for performing it are discussed. Principles of rapid radiochemical analysis are presented, and its advantages over other methods of radiochemical analysis are substantiated. Schemes of instruments for radiochemical monitoring, based on principles of rapid radiochemical analysis, are described. The results of their testing at operating nuclear power plants are reported.     

Microwave-assisted sample treatment in a fully automated flow-based instrument: oxidation of reduced technetium species in the analysis of total technetium-99 in caustic aged nuclear waste samples

An automated flow-based instrument for microwave-assisted treatment of liquid samples has been developed and characterized. The instrument utilizes a flow-through reaction vessel design that facilitates the addition of multiple reagents during sample treatment and removal of the gaseous reaction products and enables quantitative removal of liquids from the reaction vessel for carryover-free operations. Matrix modification and speciation control chemistries that are required for the radiochemical determination of total (99)Tc in caustic aged nuclear waste samples have been investigated. A rapid and quantitative oxidation procedure using peroxydisulfate in acidic solution was developed to convert reduced technetium species to pertechnetate in samples with high content of reducing organics. The effectiveness of the automated sample treatment procedures has been validated in the radiochemical analysis of total (99)Tc in caustic aged nuclear waste matrixes from the Hanford site.     

Radiolabeling and biological evaluation of losartan as a possible cardiac imaging agent

A procedure was developed for preparing high radiochemical purity ^99m Tc-Losartan in a yield of about 90%. The optimal reaction conditions are as follows: 100 μg of Losartan, 50 μg of SnCl₂·2H₂O, 150 μL of phosphate buffer (pH 7), room temperature (25 ± 1°C), reaction time 5 min. Under these conditions, the radiochemical yield up of ^99m Tc-Losartan reaches 98%. The radiochemical yield and purity of the labeled product were determined by electrophoresis and paper chromatography. Biodistribution studies were carried out in normal Albino Swiss mice at different time intervals after administration of ^99m Tc-Losartan. The labeled compound cleared from the systematic circulation within 3 h after administration, and the majority of organs showed significant decrease in the uptake of ^99m Tc-Losartan. The heart uptake of ^99m Tc-Losartan was sufficiently high for using this agent as myocardial imaging agent.     

Radioiodination and biological evaluation of salbutamol as a β2-adrenoceptor agonist

A procedure for preparing high-radiochemical-purity ¹²⁵I-salbutamol was developed in order to characterize the binding properties of ??₂-adrenoceptors. Direct radioiodination of salbutamol was carried out using Chloramine T as an oxidizing agent. The optimized conditions for salbutamol labeling with ¹²⁵I are as follows: 100 ??g of salbutamol, 50 ??g of Chloramine T, 150 ??l of phosphate buffer (pH 7), room temperature (25 ± 1°C), 5 min. The radiochemical yield of up to 98% was attained. The radiochemical yield and purity of the labeled product were evaluated by electrophoresis and HPLC. Biodistribution studies were carried out in normal Albino Swiss mice at different time intervals after administration of ¹²⁵I-salbutamol. The results indicate that the labeled compound cleared from the systematic circulation within 3 h after administration and majority of organs showed significant decrease in the ¹²⁵I-salbutamol uptake. The heart and lung uptake was high. ¹²⁵I-Salbutamol can be used as ??-receptor imaging agent.     

Optimization of Automated Synthesis of 2-[18F]Fluoro-2-deoxy-D-glucose Involving Base Hydrolysis

Synthesis of 2-[¹⁸F]fluoro-2-deoxy-D-glucose ([¹⁸F]FDG) involving base hydrolysis was optimized. Fluorine-18 was isolated from irradiated water to more than 90% by sorption of [^{1 8}F]fluoride on QMA anion-exchange resin, which was followed by elution with a 96 : 4 (by volume) acetonitrile-water mixture containing Kryptofix 2.2.2 and potassium carbonate (molar ratio 2 : 1). This composition is the best for preparing the complex [K/K2.2.2]^{+ 18}F^- used in nucleophilic fluorinations. No additional azeotropic drying is required. Base hydrolysis under optimized conditions (40-45°C), followed by neutralization with HCl, removal of traces of the solvent, and purification of the final product on a combined SCX/Alumina N column, yielded [^{1 8}F]FDG of high radiochemical (>99%) and chemical purity with minimal product loss. With an RB-86 robotic system (Anatech, Sweden), the synthesis time was 38 min. The procedure is used in the Institute of Human Brain, Russian Academy of Sciences for routine synthesis of FDG; the radiochemical yield of the product by the end of synthesis (EOS) is reproducibly high: 63±3% (n = 40).     

Electrophilic iododestannylation of <Emphasis Type="Italic">N</Emphasis>-(4-(2-azanorborn-2-yl)butyl)-4-trimethylstannylbenzamide as a route to a novel radioiodinated compound for malignant melanoma

N-(4-(2-Azanorborn-2-yl)butyl)-4-[¹²⁵I]iodobenzamide was prepared by the reaction of its trimethylstannyl precursor with Na¹²⁵I in the presence of various oxidizing agents such as lactoperoxidase, Chloramine T, and Iodogen. The effect of reaction parameters such as temperature, reaction time, oxidizing agent concentration, pH, and substrate concentration was examined. The stability of the labeled product was evaluated. Chromatographic analysis of the reaction mixture by TLC using ethanol: ethyl acetate (1: 1) and by HPLC using methanol: water (55: 45) as eluent showed that the optimum radiochemical yield of the final product is 94% and the radiochemical purity is 99%. Also HPLC chromatographic analysis showed that the content of undesired by-products, especially of chlorinated products, in case of Chloramine T was higher than that in case of other oxidizing agents. With the lactoperoxidase method, the amount of undesired by-products was minimal and, therefore, the radiochemical purity was high.     

Sample cleanup by on-line chromatography for the determination of Am in sediments and soils by alpha-spectrometry

A novel sample cleanup procedure for the Am determination in environmental samples by alpha-spectrometry is described. The method is based on the use of three analytical chromatographic columns. TEVA-Spec. from Eichrom has been packed in an analytical chromatographic column to carry out the lanthanide/actinide separation. A CS5A mixed-bed column from Dionex was used to separate Am from lanthanide impurities and other actinides. A TCC-II column from Dionex was used to connect the TEVA to the CS5A and act as a preconcentrator column for the trivalent ions. The behavior of the columns was studied by coupling the chromatograph to an ICPMS detector. A chromatographic fraction has been used for sample preparation for alpha-spectrometric determination of 241Am. The analytical procedure has been validated with certified reference materials (sediment and soil) and was applied to sediment core samples from the Irish Sea and compared with the classical radiochemical separation of Am.     

Radiochemical monitoring in life tests of fuel for new reactor cores

Detection of heat-exchange equipment failures in the primary circuit is one of the problems to be solved by radiochemical monitoring during operation of nuclear power installations. A series of experimental and numerical studies were performed in a low-power installation with a water-cooled water-moderated reactor where sequential failure of heat exchangers in two reactor water cleanup and cooling units occurred and progressed. The mechanism of transport of radionuclide impurities from the primary to secondary circuits was determined, and data for different radionuclides were obtained to compare how valuable each radionuclide was as information source for leak detection and monitoring.     

Synthesis and preliminary affinity testing of 123I/125I-N-(3-iodophenyl)-2-methylpyrimidine-4,6-diamine as a novel potential lung scintigraphic agent

Radioiodinated N-(3-iodophenyl)-2-methylpyrimidine-4,6-diamine (radioiodinated IPMPD), a potential lung scintigraphic agent, was synthesized via direct electrophilic substitution. Factors affecting the radiochemical yield were studied in detail. High radiochemical yield (92.3 ± 2.3%) was reached. The compound is stable in vitro for 24 h. Radioiodinated IPMPD was biologically evaluated in normal Albino mice. The compound demonstrated high lung uptake (21.4 ± 1.7% of injected dose per gram organ at 15 min) and thus shows promise for lung perfusion scintigraphy.     

Modification of Automatic Synthesis of [<Superscript>18</Superscript>F]Fluoromisonidazole on a GE TracerLAB Fx F-N Synthesis Module

A procedure for preparing 1-(2-hydroxy-3-[¹⁸F]fluoropropyl)-2-nitroimidazole ([¹⁸F]fluoromisonidazole, [¹⁸F]FMISO) on a commercially available GE TracerLAB Fx F-N synthesis module was developed. The product obtained meets all the requirements of the European Pharmacopoeia (8th ed.) for clinical use. Its decay-corrected radiochemical yield is 59 ± 4% (n = 5).     

Radioiodination of pindolol as a β-adrenergic receptor using different oxidizing agents

A simple, fast, and efficient method was developed for preparing radioiodinated ¹²⁵I-pindolol (¹²⁵IPIN) using different oxidizing agents. ¹²⁵I-PIN was prepared by the reaction between Na¹²⁵I and pindolol using iodogen, Chloramine-T, N-bromosuccinamide, or H₂O₂ as an oxidizing agent at pH 7. The reaction proceeds well within 30 min at room temperature (20–25°C). The radiochemical yield was determined by TLC using chloroform-acetic acid-water (15: 4: 1) as developing solvent and by HPLC using reversed-phase RP18 column and acetonitrile-0.1 M ammonium bicarbonate (pH 7.5) (1: 1) as the mobile phase at a flow rate of 1 mL min^?1. The radiochemical yield with the above oxidants was found to be 85, 93, 96.5, and 97.5%, respectively, with the radiochemical purity of ¹²⁵I-PIN over 99.9%.     

Radiochemical neutron activation analysis for certification of ion-implanted phosphorus in silicon

A radiochemical neutron activation analysis procedure has been developed, critically evaluated, and shown to have the necessary sensitivity, chemical specificity, matrix independence, and precision to certify phosphorus at ion implantation levels in silicon. 32P, produced by neutron capture of 31P, is chemically separated from the sample matrix and measured using a beta proportional counter. The method is used here to certify the amount of phosphorus in SRM 2133 (Phosphorus Implant in Silicon Depth Profile Standard) as (9.58 +/- 0.16) x 10(14) atoms x cm(-2). A detailed evaluation of uncertainties is given.     

Determination of radiochemical and radionuclide purity of a <Superscript>131</Superscript>I preparation

The radiochemical purity of a ¹³¹I preparation (the iodide fraction) was determined by ascending paper chromatography using a mixture of sodium iodide, sodium iodate, and sodium carbonate as a carrier and aqueous methanol as an eluent. The chromatogram was developed with a scanning β-ray spectrometer. The radiochemical purity of ¹³¹I determined by this procedure was 99.98%. The radionuclide purity of the ¹³¹I preparation was measured on a γ-ray spectrometer with an ultrapure Ge detector. The content of radionuclide impurities estimated from their detection limits in the ¹³¹I preparation isolated from TeO₂ in 3–4 days after its irradiation in a reactor was no more than 0.03%. The ⁷⁵Se content in the preparation aged for 6–7 months (which corresponds to a decrease in the ¹³¹I activity by a factor of 10⁶–10⁷ owing to decay) corresponds to 2 × 10^?6% of the activity by the end of irradiation.     

Efficacy of Heat Disinfection With the Aksys Personal Hemodialysis System

The first objective of this study was to validate the use of water at 85°C ± 5°C to achieve high-level disinfection of a clean-in-place extracorporeal dialysis circuit. The second objective was to demonstrate that applying this hot water method to the entire fluid pathways of a newly designed dialysis instrument, including an integral reverse-osmosis membrane, routinely allowed the production of back-filtered dialysate meeting the U.S. Pharmacopeia (USP) standard for the water for injection (WFI). In a first study, six dialyzers were inoculated with P. aeruginosa, incubated, and subjected to 75°C water for 30 minutes. No organisms could be recovered from the experimental dialyzers nor from three negative controls, but they were recovered from three positive controls. In a second study, the carbon tanks in the water inlet line and the dialysate tank were both inoculated with massive amounts of dialysis water-adapted Gram-negative organisms, followed by seven dialysis treatments using bovine blood, where the fifth and sixth procedures were separated by 2 idle days and the sixth and seventh procedures were separated by 3 idle days. In addition, the bovine blood used in each treatment was highly contaminated. In every case, the back-filtered dialysate met the WFI standard. From the above results we conclude that a hot water disinfection process is efficacious in reducing even grossly exaggerated contamination in the Aksys personal hemodialysis system to the point where it can produce water and dialysate that greatly exceed the Association for the Advancement of Medical Instrumentation (AAMI) standards and priming and rinse-back solution (back-filtered dialysate) that meets the USP standard for WFI.     

火焰原子吸收分光光度法测定环境水样中钾和钠

采用火焰原子吸收分光光度法测定环境水样中钾和钠的含量,通过对不同波长条件下钾钠吸光度的比较,选择出最佳灵敏线应用于本机分析试验,过程简单,效果十分理想。方法灵敏度高、线性关系良好、结果准确稳定,检出限钾为0.005mg/L、钠为0.008mg/L。应用此方法测定2种水样中的钾和钠,相对标准偏差1.2%～1.9%,回收率95.2%～103.2%。     

Preparation of radioiodo-metoprolol and its biological evaluation as a possible cardiac imaging agent

¹²⁵I-Metoprolol was prepared by electrophilic substitution reaction in the presence of Chloramine-T (CAT) as an oxidizing agent. The reaction conditions were optimized. The radiochemical yield of ¹²⁵I-metoprolol exceeding 90% was attained in 10 min at ambient temperature (25 ± 1°C). The radiochemical yield and purity of the labeled product were evaluated by electrophoresis, thin-layer chromatography (TLC), and high-performance liquid chromatography (HPLC). Biodistribution studies of ¹²⁵I-iodometoprolol were carried out in normal Albino Swiss mice. The results indicate the possibility of using [¹²⁵I]-iodometoprolol for myocardial imaging.