Preparation of <Superscript>26</Superscript>Al, <Superscript>59</Superscript>Ni, <Superscript>44</Superscript>Ti, <Superscript>53</Superscript>Mn and <Superscript>60</Superscript>Fe from a proton irradiated copper beam dump

The station for pions cancer therapy was operated at PSI from 1980 to 1992. After a cooling time of 12 years it’s made of copper beam dump was cut and samples were taken for analytical purposes. The sampling collected about 500 g of high active copper chips that can be used for separation of exotic radionuclides. The analyses by gamma spectrometry, LSC and AMS showed main nuclides present to be ⁶⁰Co, ⁵⁴Mn, ²²Na, ⁶⁵Zn, ²⁶Al, ⁵³Mn, ⁵⁹Ni, ⁶³Ni, ⁵⁵Fe and ⁶⁰Fe and ⁴⁴Ti with a daughter nuclide ⁴⁴Sc. In the frame of ERAWAST project a procedure combining selective precipitation and ion exchange for the separation of the rare radionuclides from the copper beam dump was developed. The proposed separation procedure is easy for remote controlled implementation in a hot cell. The ion exchange separation of Ni, Al, Mg, Ti and Fe was complete and high decontamination factors for copper and cobalt were achieved. Based on the developed procedure a remotely controlled system for separation of exotic radionuclides from the copper chips was set up. The full scale system was installed in a hot cell where high activity levels can be handled. In order to evaluate the reliability and functionality of the system extensive tests have been done. During the test period 13.86 g in total of the proton irradiated copper beam dump were processed for separation of ²⁶Al, ⁵⁹Ni, ⁵³Mn, ⁴⁴Ti and ⁶⁰Fe. The results showed that the system was operational and the radionuclide separation was selective with high chemical yield. The procedure manages as well the generated liquid wastes containing high level of ⁶⁰Co activity.     

Influence of biological activity on <Superscript>65</Superscript>Zn and <Superscript>109</Superscript>Cd removal from tidal water by chronically-polluted mangrove sediments

The biological activity influence on the mangrove sediment capacity to remove ⁶⁵Zn and ¹⁰⁹Cd from tidal water was evaluated in a site chronically polluted. Benthic Activity Indexes (BAI), corresponding to relative estimates of biological impact on radiotracer accumulation, were higher for ¹⁰⁹Cd (~?38%) than for ⁶⁵Zn (~?10%) in the top centimetre of sediment. However, BAI exceeded 96% for deeper sediment layers. This apparent decrease in radiotracer diffusion into deep sediments through biological activity inhibition is stronger than reported for much less polluted mangrove nearby, suggesting that benthic organisms tolerant of chronic metal pollution may affect metal sorption mechanisms.     

Radiochemical separation and quality assessment for the <Superscript>68</Superscript>Zn target based <Superscript>64</Superscript>Cu radioisotope production

The radiochemical separation of the different radionuclides (⁶⁴Cu, ⁶⁷Cu, ⁶⁷Ga, ⁶⁶Ga, ⁵⁶Ni, ⁵⁷Ni, ⁵⁵Co, ⁵⁶Co, ⁵⁷Co, ⁶⁵Zn, ¹⁹⁶Au) induced in the Ni supported Cu substrate — ⁶⁸Zn target system, which was bombarded with the 29.0 MeV proton beam, was performed by ion-exchange chromatography using successive isocratic and/or concentration gradient elution techniques. The overlapped gamma-ray spectrum analysis method was developed to assess the ⁶⁷Ga and ⁶⁷Cu content in the ⁶⁴Cu product and even in the post-⁶⁷Ga production ⁶⁸Zn target solution without the support of radiochemical separation. This method was used for the assessment of ⁶⁴⁺⁶⁷Cu radioisotope separation from ⁶⁷Ga, the quality control of ⁶⁴Cu product and the determination of the ⁶⁸Zn (p,2p)⁶⁷Cu reaction yield. The improvement in the targetry and the optimization of proton beam energy for the ⁶⁸Zn target based ⁶⁴Cu and ⁶⁷Ga production were proposed based on the stopping power and range of the incident proton and on the excitation functions, reaction yields and different radionuclides induced in the target system.     

Sequential separation of <Superscript>99</Superscript>Tc, <Superscript>94</Superscript>Nb, <Superscript>55</Superscript>Fe, <Superscript>90</Superscript>Sr and <Superscript>59/63</Superscript>Ni from radioactive wastes

A sequential separation procedure has been developed for the determination of ⁹⁹Tc, ⁹⁴Nb, ⁵⁵Fe, ⁹⁰Sr and ^59/63Ni in various radioactive wastes generated from nuclear power plants. Ion exchange and extraction chromatography were adopted for individual separation of the radionuclides. Precipitation was supplementarily utilized for both purification of the individual radionuclides and preparation of the radionuclide sources for use in a radioactivity measurement. The chromatographic separation behavior of the radionuclides both from the sample matrix metals and from one another was investigated using stable metals, Re (as a surrogate of ⁹⁹Tc), Nb, Fe, Sr and Ni. The validity of the procedure for reliability and applicability was evaluated by measuring the recovery of the metal carriers added to synthetic radioactive waste solutions. The recoveries by the chromatographic separation were in the range of 84.8 to 102.2% with 2s of less than 8.6%, the recoveries by the precipitation being in the range of 84.3 to 97.3% with 2s of less than 10.9%.     

Determination of <Superscript>151</Superscript>Sm and <Superscript>147</Superscript>Pm using liquid scintillation tracer methods

The long-lived rare earth isotopes ¹⁵¹Sm (90 years, β _max = 76.3 keV) and ¹⁴⁷Pm (2.62 years, β _max = 224.6 keV) are low-yield fission products that generally require lengthy separation procedures to isolate and count by their beta emissions. We will describe novel liquid scintillation counting techniques using radioactive tracers to determine radiochemical yields from an environmental matrix. The recovery of ¹⁵¹Sm is determined from the alpha decay (2.25 MeV) of ¹⁴⁷Sm in the natural Sm carrier and is in excellent agreement with the gravimetric recovery. The ¹⁴⁷Pm recovery is determined by the use of ¹⁴⁵Pm (17.7 years, EC) tracer, custom-produced at LANL using an isotopically enriched target of ¹⁴⁴Sm. We have determined the ¹⁴⁵Pm recovery both from the 37.4 keV k_α1 X-ray, and the electron-capture emissions by LSC. A comparison of these recovery methods is presented.     

Systematic radiochemical separation for the determination of <Superscript>99</Superscript>Tc, <Superscript>90</Superscript>Sr, <Superscript>94</Superscript>Nb, <Superscript>55</Superscript>Fe and <Superscript>59,63</Superscript>Ni in low and intermediate radioactive waste samples

A simple and rapid separation procedure was systemized for the determination of ⁹⁹Tc, ⁹⁰Sr, ⁹⁴Nb, ⁵⁵Fe and ^59,63Ni in low and intermediate level radioactive wastes. The integrated procedure involves precipitation, anion exchange and extraction chromatography for the separation and purification of individual radionuclide from sample matrix elements and from other radionuclides. After separating Re (as a surrogate of ⁹⁹Tc) on an anion change resin column, Sr, Nb, Fe and Ni were sequentially separated as follows; Sr was separated as Sr (Ca-oxalate) co-precipitates from Nb, Fe and Ni followed by purification using Sr-Spec extraction chromatographic resin. Nb was separated from Fe and Ni by anion exchange chromatography. Fe was separated from Ni by anion exchange chromatography. Ni was separated as Ni-dimethylglyoxime precipitates after the removal of ^134,137Cs and ^110mAg by Cs-phosphotungstate and AgCl precipitation, respectively. Finally, the radionuclide sources were prepared by precipitation for their radioactivity measurements. The reliability of the procedure was evaluated by measuring the recovery of chemical carriers added to a synthetic radioactive waste solution.     

Synthesis of water and molecular oxygen highly enriched in <Superscript>17</Superscript>O and <Superscript>18</Superscript>O isotopes from carbon oxides

The reaction of carbon oxides and hydrogen in the presence of the Raney nickel catalyst has been used for water synthesis. A procedure has been developed for the recovery and collection of the synthesized water with minimal losses and without deteriorating the ¹⁷O or ¹⁸O isotope enrichment as compared to the initial CO₂ and CO. The recovery of oxygen with high concentrations of ¹⁷O and ¹⁸O isotopes is based on the reaction of xenon difluoride with water. The yield based on oxygen achieves 99% without reduction of isotope enrichment, which is confirmed by mass-spectral measurements of oxygen isotope concentrations in the initial reagents and final reaction products.     

Synthesis of maghemite nano-particles and its application as radionuclidic adsorbant to purify <Superscript>109</Superscript>Cd radionuclide

Maghemite nano-particles were synthesized by a solid-state chemical reaction for its highly selective use as, cyclotron-produced, ¹⁰⁹Cd (462.9 days) purification method of choice. ¹⁰⁹Cd radiochemical separation starts with Ag activities precipitated with HCl 0.0015 M followed by, on a second step, ¹⁰⁹Cd separation from Cu carrier and ⁶⁵Zn (243.8 days) using Ca (NO₃)₂ 0.01 M. Experimental parameters such, pH and sorbent concentration, on ¹⁰⁹Cd extraction efficiency were investigated. Phase morphology, nanostructure and size of nano-particles were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). A 10–20 nm average grain size was derived from XRD line broadening and SEM data. Heat treatment on Fe³⁺:Fe²⁺ ratios equal to 2:1, produced powders, resulting in tetragonal (maghemite) structure at 300 °C and rhombohedra (hematite) at 600 °C. ¹⁰⁹Cd chemical and radionuclidic purity were determined by ICP-AES and HPGe detector gamma-ray spectrometry. The overall recovery and radionuclide purity were 80.0% from obtained 129.63 kBq/C MeV (70 kBq/μAh) initial activity and 91.4%, respectively.     

Zinc uptake in swine intestinal brush border membrane vesicles using a <Superscript>65</Superscript>Zn/<Superscript>69m</Superscript>Zn duel isotope experiment

Supplemental zinc as ZnO is routinely added to nursery pig diets at 15 to 20 times the nutritional requirement to alleviate physiological stress and enhance performance. The mechanism by which Zn accomplishes this function is unknown, however, high concentrations of Zn are excreted in the environment at undesirable levels. To study Zn uptake, we developed a multi-stage digestion model followed by exposure to swine intestinal brush border membrane vesicles (BBMV). We report on the feasibility of using a duel label (⁶⁵Zn and ^69mZn) to simultaneously quantify the competitive uptake of Zn from co-existing zinc supplements using our BBMV model.     

Pilot measurements of <Superscript>237</Superscript>Np in forest litter from Poland

Described are results and the procedure for a pilot study on ²³⁷Np content in forest litter samples from Poland in relation to their plutonium activity. Neptunium was determined by inductively coupled plasma mass spectrometry (ICP-MS) and Pu by alpha spectrometry. Two samples originated from a location with pure global fallout and two others from a place with about 65% of the plutonium from Chernobyl. Plutonium activities were determined twice: at Krakow and in Monaco. The two results were consistent and ^239 + 240Pu activities ranged from about 1 to about 7 Bq/kg dry weight (dw). The chemical recovery for Np was between 27 and 89%. Results for ²³⁷Np activity concentrations were between 0.099 ± 0.005 and 2.21 ± 0.076 mBq/kg dw. Observed activity ratios were lower than expected and could be explained by fractionation of Np against Pu in forest litter.     

Separation of <Superscript>142</Superscript>La from fission products by SISAK technique

A rapid separation system based on SISAK technique was established to isolate ¹⁴²La successfully from fission products. SISAK technique is often applied in the separation of nuclides with the half-life of seconds or minutes. Here it was used to separate the parent nuclide of ¹⁴²La, which the half-life is in the magnitude of several seconds. According to the separation procedure designed in the paper, the activity of ¹⁴²La acquired is more than 10⁴ Bq and the decontamination factors for most γ-emitters are higher than 10³.     

Extraction of metal ions (Fe<Superscript>3+</Superscript>, Co<Superscript>2+</Superscript>, Ni<Superscript>2+</Superscript>, Cu<Superscript>2+</Superscript> and Zn<Superscript>2+</Superscript>) using immobilized-polysiloxane iminobis(n-2-aminophenylacetamide) ligand system

A new insoluble solid functionalized ligand system bearing chelating ligand group of the general formula P-(CH₂)₃-N[CH₂CONH(C₆H₄)NH₂]₂, where P represents [Si–O] _n polysiloxane network, was prepared by the reaction of the immobilized diethyliminodiacetate polysiloxane ligand system, P-(CH₂)₃N(CH₂CO₂Et)₂ with 1,2-diaminobenzene in toluene. ¹³C CP-MAS NMR, XPS and FTIR results showed that most ethylacetate groups (–COOEt) were converted into the amide groups (–N–C=O). The new functionalized ligand system exhibits high capacity for extraction and removal of the metal ions (Fe³⁺, Co²⁺, Ni²⁺, Cu²⁺ and Zn²⁺) with efficiency of 95–97% after recovery from its primary metal complexes. This functionalized ligand system formed 1:1 metal to ligand complexes.     

Determination of <Superscript>237</Superscript>Np, <Superscript>93</Superscript>Zr and other long-lived radionuclides in medium and low level radioactive waste samples

The majority of long-lived radionuclides produced in the nuclear fuel cycle can be regarded as “difficult-to-measure” nuclides, hence chemical separation is needed before the nuclear measurement of them. A combined radiochemical procedure that enables the simultaneous determination of some “difficult-to-measure” nuclides in medium and low level radioactive wastes has been developed in our laboratory. Recently, this method has been extended for determination of ²³⁷Np and ⁹³Zr. ²³⁷Np and ⁹³Zr are pre-concentrated by co-precipitation on iron(II) hydroxide and zirconium oxide, separated by extraction chromatography using UTEVA, and measured by inductively coupled plasma mass spectrometry (ICP-MS). As even traces of polyatomic ions and isotopes at m/z 237 or 93 cause considerable interferences during ICP-MS detection, a purification step by extraction chromatography was needed. Analyzing real samples (evaporation concentrates of a nuclear power plant) 66–99% and 31–99% chemical yields were achieved for Np and Zr, respectively.     

A biomonitoring study: <Superscript>210</Superscript>Po and heavy metals in mussels

In various samples of Mytilus galloprovincialis, ²¹⁰Po was determined by alpha-spectrometry while Mn, Fe, Ni, Cu, Zn, Cd, Sn, Hg and Pb by energy dispersive, polarised X-ray fluorescence spectrometry (EDPXRF). The mussels of different sizes were taken from 7 sites in the central Adriatic Sea along the Marche coastal region during the four seasons of the year. ²¹⁰Po activity concentration ranged between 57 and 343 Bq·kg⁻¹ dry weight. The concentration ranges of heavy metals (μg·g⁻¹ dry weight) were as follows: Mn: 72.9–83.1; Fe: 45.1–754; Ni: 1.3–7.6; Cu: 17.9–156; Zn: 60.9–189; Cd: 0.6–1.0; Sn: 0.6–3.9; Hg always <0.5; Pb: 2.0–9.0. The data obtained depend upon the site and the period of the sampling and they are also compared with those obtained by other authors for the same organism in the Mediterranean and other Italian seas.     

<Superscript>210</Superscript>Pb and <Superscript>137</Superscript>Cs dating of sediments from Zigetang Lake,Tibetan Plateau

Zigetang Lake located in the central Tibetan Plateau was selected for the purpose of understanding of recent sedimentation rates. Based on ¹³⁷Cs dating marker, the sediment rate was 0.077 cm·yr⁻¹. The sedimentation rate was calculated to be 0.071 cm·yr⁻¹ and 0.029 g·cm⁻²·yr⁻¹ on the basis of ²¹⁰Pb CIC model. ²¹⁰Pb CRS model was also used for understanding of recent sedimentation change. The sediment accumulation rates for the CRS model ranged from 0.022 to 0.038 g·cm⁻²·yr⁻¹ with an irregular high value of 0.12 g·cm⁻²·yr⁻¹ around 1932 at Zigetang Lake core in the past eighty years.     

Modeling β-γ coincidence spectra of <Superscript>131m</Superscript>Xe, <Superscript>133</Superscript>Xe, <Superscript>133m</Superscript>Xe,and <Superscript>135</Superscript>Xe

In support of the Comprehensive Nuclear-Test-Ban Treaty (CTBT), improvements have been made to the model of the Automated Radioxenon Sampler/Analyzer (ARSA) β-γ coincidence detector for radioxenon monitoring. MCNPX is used to simulate the detector response for all the electrons and photons emitted from ^131mXe, ¹³³Xe, ^133mXe, ¹³⁵Xe, and ¹³⁷Cs signals. A MatLab code was written to incorporate the MCNPX results in the calculation of β-γ coincidence spectra. These will aid in the development of the Spectral Deconvolution Analysis Tool (SDAT)¹ and to calibrate β-γ coincidence systems. The models developed for this work include improvements over previous models in their ability to address Compton scattering in the β-cell, and the β-distribution offset in the 31 keV γ-ray region for ¹³³Xe.     

Determination of <Superscript>3</Superscript>H and <Superscript>14</Superscript>C in the Dry Active Wastes (DAW) generated from the Light Water Reactors (LWR) by a wet oxidation method

³H and ¹⁴C Measurements of the dry active waste (DAW), such as the cotton, paper, and vinyl, generated from a nuclear power plant (NPP) were conducted with wet oxidation using open vessel equipment based on simulation results. The recovery efficiency with the simulated samples was around 93% with a relative standard deviation (RSD) of 1–3%. A liquid scintillation counter (LSC) was used for counting and adjusted to a quenching correction curve. The counting value was evaluated for the minimum detectable activity (MDA), which was found to be about 4 × 10⁻¹ Bq/g for ³H and 2 × 10⁻² for ¹⁴C when approximately 5 g of the samples were measured. The measured DAW samples for the cotton, paper, and vinyl generated from NPP achieved of RSD values of 25, 25, and 60%, respectively, for ³H and 0–50% for ¹⁴C.     

Extraction chromatographic separation of iron from complex liquid samples and the determination of <Superscript>55</Superscript>Fe

Summary Iron separation is described from liquid samples with a high concentration of ions that enables simple determination of ⁵⁵Fe. One of the described methods consists of iron precipitation from a large volume seawater by sodium hydroxide and/or ammonium carbonate and separation from other elements (Ca, Sr, Cu, Mg, etc.) on a TRU column with 4M HCl or 8M HNO₃. In the other procedure iron is separated directly from a mixture of seawater samples and HCl on a TRU column. In both methods, the iron recovery is almost 100%. After separation, ⁵⁵Fe is determined by counting with a liquid scintillation counter. The binding of Fe and Zn on TEVA, U/TEVA and TRU resins from seawater solutions of HCl and HNO₃depends on the type of the resin, concentration of acid and other ions. Iron and zinc can be separated from seawater on a U/TEVA column with 2M HCl.     

Improvements on the method for determining of <Superscript>210</Superscript>Pb and <Superscript>210</Superscript>Po in lead

An improved method is proposed to determine the content of ²¹⁰Pb in lead using ²¹⁰Po measured by alpha-ray spectrometry. This improved method, which is based on radiochemical separation by DDTC–toluene extraction, employs EDTA and citrate as masking reagents for the lead ions. To selectively extract polonium from an alkaline solution, the pH dependency was examined using a liquid scintillation counting method. And pH 9 was chosen as an extraction condition. Then ²¹⁰Po was electrodeposited on a stainless steel disk, and the chemical recovery was followed by ²⁰⁹Po tracer. The effectiveness of the new method was validated by the agreement with the analytical results from five samples as determined by gamma-ray spectrometry.     

Estimation of <Superscript>90</Superscript>Sr activity in reprocessed uranium from the PUREX process

⁹⁰Sr estimation in reprocessed uranium was carried out by a series of solvent extraction and carrier precipitation techniques using strontium and lanthanum carriers. Fuming with HClO₄ was used to remove ¹⁰⁶Ru as RuO₄. Three step solvent extraction with 50% tri-n-butyl phosphate in xylene in presence of small amounts of dibutyl phosphate and thenoyl trifluoro acetone was carried out to eliminate uranium, plutonium, thorium and protactinium impurities. Lanthanum oxalate precipitation in acid medium was employed to scavenge the remaining multivalent ions. Strontium was precipitated as strontium oxalate in alkaline pH and ¹³⁷ Cs was removed by washing the precipitate with water. A strontium recovery well above 70% was obtained. Final estimation was carried out by radiometry using end window GM counter after drying the precipitate under an infra red lamp. The same procedure was extended to the estimation of ⁹⁰Sr in a diluted sample of the actual spent fuel solution. An additional lanthanum oxalate precipitation step was required to remove the entire ¹⁴⁴Ce impurity from this sample. This modified procedure was employed in the determination of ⁹⁰Sr in a number of reprocessed uranium samples and the over all precision of the method was found to be well within ±10%. An additional barium chromate precipitation step was necessary for the analysis of reprocessed uranium samples from high bumup fuels to eliminate trace amounts of short lived ²²⁴Ra produced during the decay of ²³²U and its daughters as they interfere in the estimation of ⁹⁰Sr.