Analysis of long-lived isotopes by liquid scintillation spectrometry

Neutron production cross sections are reported for reactions leading to long-lived isotopes in fusion reactor materials. Pure elements and separated isotopes were irradiated with 14.6–14.8 MeV neutron fluences up to 10¹⁸ n/cm². Undesired activities were chemically separated and the long-lived activities were measured using both liquid scintillation and x-ray spectrometry. Results are presented for the reactions⁵⁶Fe(n,2n)⁵⁵Fe(2.73 y),⁶⁴Ni(n,2n)⁶³Ni(100 y),⁶³Cu(n,p)⁶³Ni, and⁶⁰Ni(n,2n)⁵⁹Ni(76,000 y).Work supported by the U.S. Department of Energy.     

Isolation and quantification of Fe and Ni in reactor effluents using extraction chromatography and liquid scintillation analysis

A novel extraction chromatographic resin based on diisobutyl ketone has been developed for the isolation of ⁵⁵Fe. This material has been used in conjunction with a dimethylglyoxime-based resin for the sequential separation of ⁵⁵Fe and ⁶³Ni and isolation of these radionuclides from associated contaminants. The preparation and characterisation of these resins is described along with an assessment of their performance for the isolation of ⁵⁵Fe and ⁶³Ni from a mixture of nuclear activation products. In addition, a refined approach for the measurement of these nuclides by liquid scintillation counting is discussed. The findings of these studies have been combined to develop a robust procedure for the analysis of ⁵⁵Fe and ⁶³Ni in reactor effluents which is now the preferred method for a number of UK analytical laboratories.     

TDCR measurements of 3H, 63Ni and 55Fe using Hidex 300SL LSC device

The commercial Hidex LSC system has been used to measure triple to double coincidence ratio (TDCR), experimental counting efficiency (CE) and the absolute activity for radioactive standards of pure beta emitters viz. ³H, ⁶³Ni and ⁵⁵Fe, an electron capture nuclide. Colour and chemical quench measurements of ⁶³Ni and ⁵⁵Fe have been done. An excellent match between TDCR and CE has been obtained for beta emitters, while very large deviations have been observed for ⁵⁵Fe. The deviation between TDCR and experimental efficiency has been found to be nearly uniform. Based on this, an empirical correction factor for TDCR which gives the correct efficiency has been evaluated, to enable efficient application of this commercial instrument for ⁵⁵Fe estimation. These TDCR correction factors were further validated by applying for ⁵⁵Fe activity measurements in ASTM standard steel samples irradiated to a fixed neutron flux in research reactor CIRUS. Finally, ⁵⁵Fe activity in steel sample from APSARA reactor decommissioning waste was successfully estimated using this modified TDCR.     

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.     

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.     

New method for simultaneous determination of55Fe and59Fe in blood samples

A new simple method for the simultaneous determination of⁵⁹Fe and⁵⁵Fe concentration in 5 ml samples of blood is described and carefully evaluated. Before the measurement of the activity of the radionuclides, organic matter was eliminated by HNO₃?HClO₄ wet ashing. Iron was electroplated onto a copper plate. The accuracy of results was studied by assessing samples, which contained known amounts of radioactivity and determining the counts per nanocurie in each case. The accuracy of the results of⁵⁹Fe and⁵⁵Fe determinations was found to be about 5%.     

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%.     

A compilation of cross-sections for the reaction (n, 2n) with 14 MeV neutrons for some important fusion reactor structural materials

A compilation of the cross section (n, 2n) for⁴⁶Ti,^{50, 52, 54}Cr,⁵⁵Mn,^54,56Fe,⁵⁹Co,^58,59Ni,⁹³Nb,^92,100Mo with 14 MeV neutrons is presented in the form of a table containing the results of nearly 190 different measurements, mainly obtained by activation analysis. Brief assessment of the experimental methods and the data status are given.     

A compilation of cross-sections for charged particle production by 14 MeV neutrons for Fe,Co and Ni isotopes

A compilation of the (n, p), (n, n′p), (n, α, (n, n′α) and (n,³He) cross-sections for⁵⁴Fe,⁵⁶Fe,⁵⁷Fe−⁵⁸Fe,⁵⁹Co,⁵⁸Ni,⁶⁰Ni,⁶¹Ni,⁶²Ni and-⁶⁴Ni by 14 MeV neutrons is presented in the from of a table containing the results of some 180 different measurements, mainly obtained by activation analysis. Brief assessments of the experimental methods and the data status are given.     

Formation cross section of iron-60 with reactor neutrons in59Fe(n, γ)60Fe reaction

Ingrowth of⁶⁰Co radioactivity in an iron sample irradiated in a nuclear reactor has been measured for determination of formation cross section of⁶⁰Fe in the⁵⁹Fe(n, )⁶⁰Fe reaction with reactor neutrons. After 5 years cooling, the irradiated iron was purified from⁶⁰Co and other radioactive nuclides by an anion exchange separation method and isopropyl ether extraction in hydrochloric acid. The amount of⁶⁰Co ingrowth was measured by -spectrometry using a Ge-detector coupled to a multichannel pulse height analyzer 4 years after the purification of iron. Neutron flux of the irradiation position was calculated from the amount of⁵⁵Fe produced. The observed value of 12.5±2.8 barn is slightly greater than reported value for burnup cross section of⁵⁹Fe(n, x)X, where x refers , , d, p and 2n, and X is any nuclide produced by the above reactions.     

The measurement of neutron-induced radionuclides from Chinese nuclear weapons tests

The concentrations of neutron-induced radionuclides have been measured in ground level air during the period between 1976 and 1981 at Nagoya (35° N, 137° E), Japan. Six Chinese atmospheric nuclear weapons tests were conducted by the government of China at Lop Nor (40° N, 90° E) during the period 1976–1981. The Chinese nuclear tests of November 17, 1976 (the 21st test) and October 16, 1980 (the 26th test), high-yield devices, produced⁵⁴Mn,⁵⁵Fe and⁸⁸Y whose production reactions are⁵⁴Fe(n, p),⁵⁶Fe(n, 2n) and⁸⁹Y(n, 2n), respectively. The tests of September 26, 1976 (the 19th test), September 17, 1977 (the 22nd test) and March 15, 1978 (the 23rd test), low-yield devices, produced⁵⁴Mn,⁵⁷Co and⁵⁸Co whose production reactions are⁵⁴Fe(n, p),⁵⁸Ni(n, pn) and⁵⁸Ni(n, p) respectively. No neutron activation product from the 24th test (December 14, 1978) was observed.     

Determination of alpha,beta, X-ray and gamma emitting radionuclides in reactor components and fuel assemblies from NPP V1 Jaslovske Bohunice

The radionuclides in reactor and fuel construction parts of the V1 Jaslovske Bohunice nuclear power plant (NPP V1) were identified and their activity was measured. Samples from reactor and fuel assemblies such as control rod connection rod, shielding/absorber parts of fuel rod, neutron in-core measurement channels, pressure vessel basic construction material and internal cladding, core barrel and protective tube unit were analyzed. Activity concentrations of ⁶⁰Co, ⁵⁵Fe, ^63,59Ni, ⁹⁰Sr, ⁹⁹Tc, ⁹³Mo, ⁹⁴Nb, transuranic elements were determined. Analytical and sampling methods are briefly described for the measured radionuclides. The presented results were used for characterization of the waste during the decommissioning of NPP V1 nuclear reactors.     

Determination of the 54Fe(n, 2n)53gFe and 54Fe(n, 2n)53mFe cross sections averaged over a 235U fission neutron spectrum

The reaction cross sections averaged over a ²³⁵U fission neutron spectrum have been measured for the ⁵⁴Fe(n, 2n)^53gFe and ⁵⁴Fe(n, 2n)^53mFe threshold reactions. The values found are, respectively: (1.14±0.13) mb, and (0.52±0.16) mb. The measured cross sections are referred to the (111±3) mb standard cross section of the ⁵⁸Ni(n, p)^58m+gCo reaction. The (81.7±2.2) mb standard cross section value for the ⁵⁴Fe(n, p)⁵⁴Mn reaction, was also used as a monitor to check the results obtained with the Ni standard, leading to an excellent agreement.     

Neutron energy spectrum determination and flux measurement using MAXED, GRAVEL, and MCNP for RACE experiments

Stainless steel flux wires were used to determine the neutron energy spectra and total flux during the Reactor Accelerator Coupling Experiments (RACE) at The University of Texas at Austin. A LINAC electron accelerator produced 20 MeV electrons at a power of 1.6 kW, which struck a tungsten-copper target to produce bremsstrahlung radiation and photoneutrons. The neutrons produced in the target were multiplied by the subcritical core of a Triga reactor. The purpose of the RACE experiments is to develop a sub-critical accelerator driven system that would be capable of transmuting actinides from spent fuel. Flux measurements were made with 1.58 mm diameter stainless steel wires placed throughout the core between the fuel rods and cadmium covered and uncovered gold and indium foils above the target. The MAXED and GRAVEL computer codes were used to perform the spectrum unfolding. The composition of the stainless steel wires was determined using neutron activation analysis with comparators prior to the flux measurement. The reactions measured in the stainless steel to determine the flux were ⁵⁰Cr(n,γ)⁵¹Cr, ⁵⁸Ni(n,p)⁵⁸Co, ⁵⁴Fe(n,p)⁵⁴Mn, and ⁵⁸Fe(n,γ)⁵⁹Fe. Flux measurements agreed well with an MCNP simulation of the experiment.     

Trace element analysis in CRM of plant origin by inductively coupled plasma mass spectrometry

Three CRMs of plant origin (SRM 1515 Apple Leaves, SRM 1570a Trace Elements in Spinach Leaves, and SRM 1575 Pine Needles) were used for analytical quality assurance of Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Mo, Cd, and Pb determination by ICP-MS. The samples were decomposed using microwave assisted pressurized digestion by HNO₃ and HNO₃ + H₂O₂ mixture and temperature programmed dry ashing. Concentrations of elements in samples were evaluated by external calibration. All samples, blanks, and standards were spiked to 100 μg/L concentration of In and Bi as internal standards. During the measurement, signals of ⁵²Cr, ⁵³Cr, ⁵⁴Fe, ⁵⁵Mn, ⁵⁹Co, ⁶⁰Ni, ⁶²Ni, ⁶³Cu, ⁶⁵Cu, ⁶⁶Zn, ⁹⁵Mo, ¹¹¹Cd, ¹¹²Cd, ¹¹⁵In, ²⁰⁶Pb, ²⁰⁷Pb, ²⁰⁸Pb and ²⁰⁹Bi were monitored. Results of Pb, Cd, Cu, Zn, Mo and Co determination were in good agreement with certified values. In order to obtain accurate results for As at low levels, it was necessary to mathematically correct the analytical signal. This correction effectively eliminates the influence of interfering ArCl⁺ ions. For Cr analysis it is advisable to use as powerful oxidizing conditions during sample decomposition as possible.     

Determination of55Fe/58Fe and59Fe/58Fe isotopic ratios in irradiated Na2/FeNO/CN/5/.2H2O by SSMS

A procedure for the measurement of the isotopic composition of Fe in rradiated Na₂/FeNO/CN/₅/.2H₂O samples by SSMS is described. Decomposition with K₂S₂O₇, followed by extraction of Fe was necessary to eliminate interferences in the mass spectra. A study of the remaining interferences showed that they were of organic origin from the residual MIBK used for the extraction. The order of magnitude of the⁵⁵Fe/⁵⁸Fe and⁵⁹Fe/⁵⁸Fe ratios was calculated.SSMS: spark source mass spectrometry.     

Transition metal NMR chemical shifts and polarizability effect in organometallic complexes

The literature data on substituent influence on the ⁵¹V, ⁵⁵Mn, ⁵⁷Fe, ⁵⁹Co, ⁶¹Ni, ⁹⁵Mo, ¹⁰³Rh, ¹⁸³W, ¹⁸⁷Os and ¹⁹⁵Pt NMR chemical shifts (δ) and on J (M, P; M = Mn, Fe, Mo, Rh, W, Os) coupling constants have been analyzed for 30 series of the organometallic complexes. It has been established for the first time that the δ and J values depend on the inductive, resonance and polarizability effects of substituents. The polarizability effect is caused by the partial charge on the central M atom. The contribution of this effect ranges from 3 to 86%. Copyright © 2009 John Wiley & Sons, Ltd.     

Hexamethylphosphoramide as Analytical Reagent: Simultaneous Determination of Cobalt,Iron and Nickel

Abstract

Hexamethylphosphoramide (HMPA) gives, in aqueous solutions in the presence of SCN^? ions, complexes with many metal ions, which absorb in the visible region of spectrum. The spectra have been studied in function of ligand concentration and pH for Co, Ni and Fe complexes. For the Co complex an equation was found that describes the behaviour of the absorption vs. SCN^? and HMPA concentration. Absorption follows Lambert-Beer law and can be used for analytical determinations. Analysis of solutions containing Ni and Co in various ratios of concentration has been performed and results are discussed. Co, Ni and Fe content of an alloy has been measured by this way.     

Deuteron-induced activation cross-sections on natural copper up to 24 MeV

Activation cross-sections of ^natCu(d,x)^62,65Zn,⁶⁴Cu,^60g+mCo,⁵⁹Fe reactions were measured using a stacked foil activation technique combined with HPGe gamma-ray spectrometry up to the deuteron energy of 24 MeV. Measured data were critically compared with the available literature data and theoretical data extracted from the TENDL-2012 library, and found only partial agreements among them. Cross-sections of ^natCu(d,x)⁵⁹Fe reactions are reported here for the first time in the energy region of 19–23 MeV. Measured cross-sections of the long-lived ⁶⁵Zn, ^60gCo and ⁵⁹Fe radionuclides are significant for understanding the activation behaviour of copper, an essential structural material used in accelerator and nuclear industry.     

Adsorption characteristics of radionuclides on nickel hexacyanoferrate(ii)

The composition of nickel hexacyanoferrate(II) complexes depends on the ratios of sodium hexacyanoferrate(II) and nickel nitrate solutions mixed. The adsorption behavior of nickel hexacyanoferrate(II) is described; acid treatment of Ni₂Fe(CN)₆ accelerates the adsorption rate of cesium, but does not increase the adsorption capacity. The Ni—Cs exchange ratios of Ni₂Fe(CN)₆ are discussed. In concentrated salt solutions, the distribution coefficients of ⁵⁹Fe, ⁶⁰Co, ⁶⁵Zn. ¹³⁷Cs, ⁹⁵Zr and ¹⁴⁴Ce are determined together with those of ⁸⁵Sr and ¹⁰⁶Ru. A simple determination of ¹³⁷Cs in sea water containing ⁵⁹Fe, ⁶⁰Co, ⁶⁵Zn, ⁹⁵Zr, ¹⁴⁴Ce, ⁸⁵Sr and ¹⁰⁶Ru is described.