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To monitor radioactivity and its emissions in retired nuclear facilities, this study established an analytical method for 63 Ni and 55 Fe in mixed soil samples from a decommissioning reactor. After ashing at 400 °C for 4 hours, the sample was dissolved in a mixture of concentrated hydrochloric acid, nitric acid, and hydrofluoric acid, and then heated to dryness and dissolved in 9 mol/L hydrochloric acid. Subsequently, 63Ni and 63Fe were separated and purified using sodium hydroxide precipitation, anon exchange chromatography, and nickel specific rein extraction, and then measured by the liquid scintillation method. The results showed that the final stable recovery rates of Ni and Fe were 98.8% and 95.8%, respectively. The minimum detection limit and minimum detectable activity for 63Ni and 55Fe were 208 (counting) and 0.041 Bq,208 (counting) and 0.144 Bq, respectively. The actual activity concentrations of 63Ni and 55Fe in the samples were 76.9 Bq/g and 30.4 Bq/g, respectively. The recovery simulation experiment was conducted using standard soil substances, achieving a recovery of over 95%. Experiments were conducted on the separation of Ni and Fe from various elements using alkali precipitation and anon exchange chromatography, respectively. Among them, the sodium hydroxide precipitation method effectively coprecipitated Ni and Fe, and removed most of Re,Sr, and all Cs at pH value between 8.7 and 11.1. The decontamination factors for Co,Fe, and Zn in the nickel fraction of anion exchange chromatography were all above 660, wide the decontamination factors for Co,Eu,Mn,Ni, Sr,Zn, and Zr in the iron fraction were all above 2 000. This work also investigated the purification effects of DMG precipitation method and nickel specific resin method on Ni, respectively. The recovery of Ni by DMG precipitation method was 87.14%, and the recovery of Ni by nickel resin method was close to 100% when the nickel interference element ratio was above 10:1. Moreover, the purification effect of interference elements such as Ba, Eu, Fe, Mn, and Sr was the best. Therefore, before using nickel resin, other methods such as alkali precipitation and ion exchange resin should be used for preliminary separation. This method is simple to operate and has a high recovery, which can meet the needs of monitoring 63Ni and 55Fe in retired nuclear facilities. [ABSTRACT FROM AUTHOR]

Radioactive wastes, such as concrete and soil, generated during the decommissioning of nuclear facilities contain radionuclides with varying levels of activity. Beta-emitting radionuclides can be identified after thoroughly decomposition and separation from the sample matrix. Among these radionuclides, Fe–55 and Ni–63 play vital roles in the management of radioactive waste from nuclear facilities owing to their pronounced incidence and high mobility in the environment. This study documents the results of the extraction efficiencies of Fe and Ni with a rapid pretreatment method within 2 h by wet digestion methods using hydrochloric acid and nitric acid (3:1, v/v). The average Fe and Ni extraction efficiencies for certified reference materials in soil and sediment matrix were evaluated to be 84–94% and 90–96% with analytical precision within 5%, respectively. [ABSTRACT FROM AUTHOR]

The measurement of 55Fe and 63Ni is of great significance for the monitoring of liquid effluents from nuclear power plant. In this paper, a combined analysis method of 55Fe and 63Ni in liquid effluent sample is established. 55Fe and 63Ni are enriched by precipitation of iron hydroxide and nickel hydroxide and separated by TRU resin and nickel resin, then measured by low-level liquid scintillation spectrometer. Also the relevant measurement conditions are analyzed and studied. When the amount of sample is 1.0 L and the measurement time is 60 min, the detection lower limit of this method is 0.06 Bq/L for 55Fe and 0.02 Bq/L for 63Ni, which meets the analysis requirements of 55Fe and 63Ni in liquid effluents of nuclear power plant.

In this study, a method for selective separation of 63Ni and 55Fe with simultaneous wash-out of 60Co was developed. Purification of 63Ni and 55Fe was carried out using a chelating ion-exchange resin Chelex 100. The elaborated procedure was applied for aqueous and stainless steel matrices. Average recoveries were around 80% for both isotopes, confirmed by ICP-MS and LSC measurements. 60Co, interfering with the isotopes spectra in the same energy range, was washed-out from the system prior to 63Ni and 55Fe separation. The most important advantages over existing methods are short separation time (c.a. 8 h), application of a single chromatographic column and overall simplicity. [ABSTRACT FROM AUTHOR]

We present the validation of a radiochemical procedure for the determination of 55Fe and 63Ni in water and steel samples from nuclear decommissioning activities. The in-house validation was an essential requirement of the accreditation to ISO/IEC 17025. A combination of co-precipitation, anion chromatography and extraction chromatography steps was used for separating and purifying both radionuclides. The activities were measured by liquid scintillation counting. Due to the lack of reference materials, the method was validated by analysing simulated samples and by the standard addition technique. The parameters precision/accuracy, repeatability/linearity, selectivity/specificity, decision threshold, detection limit and uncertainty of the method were evaluated. [ABSTRACT FROM AUTHOR]

In the field of nuclear waste management is the determination of difficult to measure isotopes important for the isotopic nuclide inventory in disposal material. Accelerator mass spectrometry propose a new precise and reliable way for the quantification of the radioactive material by the means of direct atom counting. For the radiological characterization of radioactive material, the reference nuclides 60Co or 152Eu are normally used, because they are relatively easy to measure by gamma ray spectroscopy. The disadvantages are the relatively short half-lives and in the case of reactor concrete they are produced at trace elements. In addition, the technique of projectile X-ray AMS (PXAMS) offers the opportunity to measure medium mass isotopes like 63Ni and 90Sr, by the measurement of characteristic X-rays. We investigated the X-ray production yields for different target materials in a projectile ion energy range of 0.35 MeV/u to 1.80 MeV/u for the determination of attainable sensitivities. [ABSTRACT FROM AUTHOR]

BackgroundThe energy deposition behavior of β particles in transducer material is an important issue in the simulation of a betavoltaic battery, which is usually performed by Monte Carlo software Casino and MCNP (Monte Carlo N Particle Transport Code). However, it is difficult to simulate the continuous energy spectrum of β particles by Casino software. The commercial software MCNP is subject to many restrictions on its copyright, it is very necessary to study the energy deposition of β particles in transducer materials based on the universal open-source Monte Carlo program Geant4 (GEometry ANd Tracking, version 4).PurposeThis study aims to develop a model based on Geant4 to study the energy deposition of β particles in betavoltaic battery transducer materials.MethodsBased on the framework of Geant4 software, a general simulation model of energy deposition behavior was developed. The continuous β spectrum, the self-absorption of radioactive source, and the backscattering of β particles on the source-transducer interface were taken into account completely in this model for the Monte-Carlo simulation study, and the computation results were compared with that of Casino software.ResultsSimulation comparison results show that this simulation model can accurately simulate the energy deposition behavior of β particles in the transducer materials of betavoltaic battery.ConclusionsSimulation model proposed in this study can be used to study the energy deposition of β particles in the transducer materials with advantages of convenient application, open software and easy extension to other source-transducer combinations.

A method for sequential determination of 55Fe and 63Ni in leaching solution of cement solidification using liquid scintillation counting (LSC) was developed. In this method, 55Fe and 63Ni were first precipitated in the form of hydroxide and subsequently purified by anion exchange chromatography and dimethylglyoxime precipitation. After the purification, 55Fe and 63Ni were determined by LSC. The performance of the method was examined, and minimum detectable activity concentration was determined to be 0.82 Bq L−1 for 55Fe and 0.42 Bq L−1 for 63Ni in leaching solution samples with a counting time of 1 h. High decontamination factors for 55Fe and 63Ni were also obtained. [ABSTRACT FROM AUTHOR]

Ion mobility spectrometry instrumentation today is widespread in the area of transport security and counterterrorism. This method of detection of explosive substances is highly appreciated for the existence of portable detectors capable of detecting concentrations of 10−13–10−14 g/cm3 at atmospheric pressure using traditional ionization methods including corona discharge and beta radiation. However, low vapor pressure of some explosives imposes requirements on limit of detection (LOD) down to 10–15‒10−16 g/cm3. In this paper we compare a radioactive 63Ni ionization source with a laser ionization source and reveal the parameters of laser ionization of a group of explosives, namely trinitrotoluene (TNT), cyclotrimethylene-trinitramine (RDX), cyclotetramethylene-tetranitramine (HMX) and pentaerythritol tetranitrate (PETN), which can reduce the limit of detection of portable devices. A laser ionization source can provide a higher signal to noise ratio than radioactive 63Ni at optimal intensity of laser radiation for PETN and HMX of 3 × 107 W/cm2 and 2.5 × 107 W/cm2, respectively. Limits of detection were estimated: 3 × 10−15 g/cm3 for RDX, 8 × 10−15 g/cm3 for PETN and less than 3 × 10−15 g/cm3 for HMX. These results are promising to further improve the capabilities of detectors of low volatility explosives without sacrificing portability, light weight and reasonable cost of the laser source.

A simple method for the simultaneous detection of stable and long-lived Mn, Ni, Co and Cu isotopes has been created by coupling an ion chromatographic system (IC) to an ICP-MS. The analytical procedure was tested with two chromatographic columns: a strong cation exchange and an anionic/cationic mixed bed. It was found that the best separation of the metals is typically obtained when mobile phase contains 0.05 mol/L of tartaric acid. Ammonia solution was used for adjustment of the eluent’s pH and this avoided contamination of the ICP-MS with eluent metals. The developed method was demonstrated in researching the samples of corrosion deposits from a pipeline of a nuclear power plant. The established 59Ni scaling factor to 60Co being 3.8 × 10−2 and it’s correlated to the literary data. [ABSTRACT FROM AUTHOR]

Activity Standards of 63Ni was used to benchmark our triple-to-double coincidence ratio (TDCR) primary standardization instrument Hidex 300SL TDCR device under different chemical and colour quench conditions. The results were compared with a secondary standardization instrument Tricarb 2910TR that employs transformed spectral index of external standard to assess the quench level of samples. Excellent agreement was observed (within 3 %) for a wide range of standard activity and quench conditions. The method was subsequently used for validating chemical separation procedure for estimation of 63Ni in neutron activated standard nickel and steel samples. Further the method was applied for estimation of 63Ni from decommissioning waste of a research reactor, APSARA. [ABSTRACT FROM AUTHOR]

Abstract: Fast neutron activation data for 63Ni in copper samples exposed to the Hiroshima atomic bomb are important in evaluating neutron doses to the survivors. Up to until now, accelerator mass spectrometry and liquid scintillation counting methods have been applied in 63Ni measurements and data were accumulated within 1500m from the hypocenter. The slope of the activation curve versus distance shows reasonable agreement with the calculation result, however, data near the hypocenter are scarce. In the present work, two copper samples obtained from the Atomic bomb dome (155m from the hypocenter) and the Bank of Japan building (392m) were utilized in 63Ni beta-ray measurement with a Si surface barrier detector. Additionally, microscopic observation of the metal surfaces was performed for the first time. Only upper limit of 63Ni production was obtained for copper sample of the Atomic bomb dome. The result of the 63Ni measurement for Bank of Japan building show reasonable agreement with the AMS measurement and to fast neutron activation calculations based on the Dosimetry System 2002 (DS02) neutrons. [Copyright &y& Elsevier]

Abstract: Beta-emitters 36Cl and 63Ni, and the electron capture radionuclide 55Fe were used to calibrate a secondary standardization instrument Quantulus-1220TM. An external standard technique was applied to assess the quenching level of samples. Nitromethane as an artificial quencher was used for sample preparation at different quenching levels. The dependence of the counting efficiency on the quenching level was determined. Samples of beta-emitters were re-measured with the triple-to-double coincidence ratio (TDCR) primary standardization instrument. The specific activities of beta-emitters were determined with the help of the software TDCRB-02 and compared with known values. It was found that for 36Cl and 63Ni the discrepancy was 0.9% and 2.7%, respectively, within the specified uncertainty limits. A new sample with 90Sr was prepared and measured with the TDCR device. In this case, the divergence from the expected value was 1.7%. Results suggest the suitability of the TDCR techniques for low-level counting. [Copyright &y& Elsevier]

Abstract: The implementation of 63Ni and 55Fe determination methods in an environmental laboratory implies their validation. In this process, the uncertainties related to these methods should be analysed. In this work, the expression of the uncertainty of the results obtained using separation methods followed by liquid scintillation counting is presented. This analysis includes the consideration of uncertainties coming from the different alternatives which these methods use as well as those which are specific to the individual laboratory and the competency of its operators in applying the standard ORISE (Oak Ridge Institute for Science and Education) methods. [Copyright &y& Elsevier]

Abstract: The adsorption of 63Ni from aqueous solutions using NKF-6 zeolite was investigated by a batch technique under ambient conditions. The adsorption was investigated as a function of contact time, pH, ionic strength, foreign ions, humic substances (FA/HA) and temperature. The kinetic adsorption was well described by the pseudo-second-order rate equation. The adsorption of 63Ni on NKF-6 zeolite was strongly dependent on pH and ionic strength, and the adsorption of 63Ni increased with increasing NKF-6 zeolite content. At low pH values, the presence of FA enhanced the adsorption of 63Ni on NKF-6 zeolite, but the presence of HA had no drastic effect. At high pH values, the presence of FA or HA decreased the adsorption of 63Ni on NKF-6 zeolite. The adsorption isotherms were well represented by the Langmuir model. The thermodynamic parameters (i.e., ΔH 0, ΔS 0 and ΔG 0) for the adsorption of 63Ni were determined from the temperature dependent isotherms at 293.15, 313.15 and 333.15 °K, respectively, and the results indicate that the adsorption reaction was favored at high temperature. The results suggest that the adsorption process of 63Ni on NKF-6 zeolite is spontaneous and endothermic. [ABSTRACT FROM AUTHOR]

Abstract: An accurate knowledge of the neutron capture cross sections of 62,63Ni is crucial since both isotopes take key positions which affect the whole reaction flow in the weak s process up to . No experimental value for the 63Ni cross section exists so far, and until recently the experimental values for 62Ni at stellar temperatures ranged between 12 and 37mb. This latter discrepancy could now be solved by two activations with following AMS using the GAMS setup at the Munich tandem accelerator which are also in perfect agreement with a recent time-of-flight measurement. The resulting (preliminary) Maxwellian cross section at kT =30keV was determined to be . Additionally, we have measured the 64Ni 63Ni cross section close to threshold. Photoactivations at 13.5MeV, 11.4MeV and 10.3MeV were carried out with the ELBE accelerator at Forschungszentrum Dresden-Rossendorf. A first AMS measurement of the sample activated at 13.5MeV revealed a cross section smaller by more than a factor of 2 compared to NON-SMOKER predictions. [Copyright &y& Elsevier]

The diode junction nuclear battery is a long-lived, high-energy-density, but low electrical current power source with many specialized applications. In this type of battery, nuclear radiation is directly converted to electric power. A model is described and used to design the device configuration. Details of fabrication and testing of a planar geometry battery with 63Ni radiation source are described. The electron beam induced current (EBIC) measurement technique and CASINO Monte Carlo simulation code were employed to analyze the device performance. Finally, an improved design with 3-dimensional surface microstructures that will provide improved performance is presented. [ABSTRACT FROM AUTHOR]

Abstract: Zero discrimination level setting of liquid scintillation systems for counting of all single photoelectron pulses is required by both triple-to-double coincidence ratio (TDCR) and CIEMAT/NIST methods. However, this requirement may not be able to be met in some circumstances. The influence of rejection of a fraction of the single photoelectron peak has been studied both theoretically and experimentally on 3H, 63Ni, 14C and 90Sr/90Y for both the TDCR and CIEMAT/NIST methods. A modified formula for calculation of efficiency is given in consideration of the rejected fraction of the single photoelectron peak. [Copyright &y& Elsevier]

Abstract: An analytical method for the determination of 63Ni and 55Fe in nuclear waste samples such as graphite, heavy concrete, aluminium and lead was developed. Different decomposition methods (i.e. ashing, acid digestion and alkali fusion) were investigated for the decomposition of the samples and for the separation of Fe and Ni from the matrix. Hydroxide precipitation was used to separate 55Fe and 63Ni from the matrix elements and ion exchange chromatography was used to separate 55Fe and 63Ni from the interfering radionuclides as well as from each other. The separated 63Ni was further purified by extraction chromatography. The purified 63Ni and 55Fe was then measured by liquid scintillation counting. The chemical yields of the separation procedures for 55Fe and 63Ni are above 90% and the decontamination factors for all interfering radionuclides are more than 105. The detection limits of the analytical method for 55Fe and 63Ni are 0.018 and 0.014Bq, respectively. The methods developed were used in the analysis of 55Fe and 63Ni in heavy concrete, aluminium and lead from two concrete cores and graphite from thermal column in the Danish research reactor DR-2 and the results are presented in this paper. [Copyright &y& Elsevier]

The radionuclide 63Ni (T1/2=100.1 a) has been proposed as a fluence monitor for fast neutrons in copper samples from Hiroshima. Accelerator mass spectrometry (AMS) represents a powerful tool for the detection of this radionuclide, provided the isobaric interference of 63Cu can be sufficiently suppressed. In this paper, we report the fir)st results from a study on the 63Cu background observed in different sets of control samples, and in a 127-year-old environmental copper sample which was directly exposed to cosmic radiation for about 80 years. The 63Ni/Ni ratios measured in the blank samples range up to about 2 × 10-13 corresponding to concentrations of a few times 10463Ni atoms/g Cu. These results provide information on the overall background of the applied methodology and, thus, on the possible sensitivity of 63Ni measurements in copper samples by means of AMS. In the environmental sample, a 63Ni concentration of (1.0 ± 0.3) × 10563 Ni atoms/g Cu was observed which is not significantly different from the results obtained on commercially available copper material. A similar concentration would be expected in a copper sample located 1300 m from the hypocenter of the Hiroshima atomic bomb. [Copyright &y& Elsevier]

Ion mobility spectrometry instrumentation today is widespread in the area of transport security and counterterrorism. This method of detection of explosive substances is highly appreciated for the existence of portable detectors capable of detecting concentrations of 10−13–10−14 g/cm3 at atmospheric pressure using traditional ionization methods including corona discharge and beta radiation. However, low vapor pressure of some explosives imposes requirements on limit of detection (LOD) down to 10–15‒10−16 g/cm3. In this paper we compare a radioactive 63Ni ionization source with a laser ionization source and reveal the parameters of laser ionization of a group of explosives, namely trinitrotoluene (TNT), cyclotrimethylene-trinitramine (RDX), cyclotetramethylene-tetranitramine (HMX) and pentaerythritol tetranitrate (PETN), which can reduce the limit of detection of portable devices. A laser ionization source can provide a higher signal to noise ratio than radioactive 63Ni at optimal intensity of laser radiation for PETN and HMX of 3 × 107 W/cm2 and 2.5 × 107 W/cm2, respectively. Limits of detection were estimated: 3 × 10−15 g/cm3 for RDX, 8 × 10−15 g/cm3 for PETN and less than 3 × 10−15 g/cm3 for HMX. These results are promising to further improve the capabilities of detectors of low volatility explosives without sacrificing portability, light weight and reasonable cost of the laser source. [ABSTRACT FROM AUTHOR]