Determination of <Superscript>93</Superscript>Zr in nuclear power plant wastes

A radioanalytical method (based on separation using UTEVA columns and ICP-MS measurement) has been used for determination of ⁹³Zr in 37 nuclear power plant samples. As ⁹³Nb might affect the detection of ⁹³Zr, Monte Carlo activation model was used to calculate the expected ⁹³Zr/^natZr mass ratio, which was compared to measured ones. It was found, that a decontamination factor of 10³ is sufficient to get a measurement uncertainty of less than 10%.     

Determination of <Superscript>93</Superscript>Zr and <Superscript>237</Superscript>Np in nuclear power plant wastes

A combined radioanalytical method for determination of ⁹³Zr and ²³⁷Np (as well as other actinoids) in radioactive wastes has been developed. Analytes were co-precipitated on iron(II)-hydroxide, separated and purified on UTEVA columns, and detected by inductively coupled plasma mass spectrometry. According to Zr and Np, 65 and 75% yields were achieved, respectively.     

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.     

Quantification of <Superscript>241</Superscript>Pu in aerosols released from nuclear power plants

Two peptide ligands conjugated adenine, [9-N-(tritylmercapto acetyl diglycyl aminoethyl) adenine, Tr-MAG₂-Ade] and [9-N-(tritylmercapto acetyl triglycyl aminoethyl) adenine, Tr-MAG₃-Ade], are synthesized and labeled with ^99mTc by directly labeling method. The stability of ^99mTc-MAG₂-adenine and ^99mTc-MAG₃-adenine in vitro is measured. The uptake radios of tumor to muscle at 3h post-injection are 5.70 and 4.92, respectively. The biodistribution and scintigraphic imaging studies show that the two complexes have high localization in tumor and high contrasted tumor images can be obtained, which suggest their potential utility as tumor imaging agents. But the high radioactivity of abdomen could prevent the tumor imaging in this area.     

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.     

A novel method for the cyclotron production no-carrier-added <Superscript>93m</Superscript>Mo for nuclear medicine

Amongst the various radioisotopes of molybdenum, ^93mMo in its no-carrier added form might be a potential candidate radionuclide in the field of nuclear medicine due to its suitable half-life (T _1/2 = 6.85 h) and for its intense gamma line at 263.14 keV. Aim of the presented study is to compare the calculated cross sections for the production of ^93mMo incident proton energy up to 30 MeV, theoretical calculation of production yield and calculation of target thickness requirement. Also, deposition of ⁹³NbO₂ on Cu substrate was carried out via two special sedimentation methods for the production of ^93mMo and a simple and selective extraction of molybdenum was described.     

Automated radiochemical analysis of total <Superscript>99</Superscript>Tc in aged nuclear waste processing streams

Summary A fully automated analysis procedure and instrument for the measurement of total ⁹⁹Tc in aged nuclear waste has been developed. The overall analysis approach is based on a fully automated wet radiochemical analysis method. Microwave-assisted sample oxidation is used prior to a chemical separation step in order to oxidize all of the non-pertechnetate species to pertechnetate. Separation of the pertechnetate from interfering radioactive and stable matrix species is carried out using an anion-exchange column. The separated ⁹⁹Tc is quantified using a flow-through solid cell scintillation detector. The instrument is capable of an analysis time of <13 minute per sample with a detection limit of 2000 dpm/ml. Nuclear waste samples from the Hanford site with a high content of non-pertechnetate species were successfully analyzed using this method.     

<Superscript>239</Superscript>Np as a tracer of <Superscript>237</Superscript>Np in effluent samples and low level nuclear waste

In this paper a technique to separate and measure both isotopes (²³⁷Np and ²³⁹Np) together is presented. A combined shape pulse discrimination liquid scintillation measurement with gamma-spectrometry, permits a precise measurement after the radiochemical separation. This technique was carried out by using an Eichrom chromatographic column (TEVA) as the first step of a more complete method, applied in the Nuclear Regulatory Authority, to separate actinides in nuclear waste and liquid effluents. The MCA is 0.08 Bq/l by alpha-spectrometry and 0.22 Bq/l (2σ) by liquid scintillation counting (LSC) for 93.7% of measurement efficiency and 98.4% of chemical recovery.     

Measurement of <Superscript>36</Superscript>Cl in nuclear wastes and effluents: Validation of a radiochemical protocol with an in-house reference sample

Summary ³⁶Cl is a beta-emitter with a very low specific activity. It is produced during the irradiation of nuclear fuel, in the reactor core of power plants, from neutron capture by stable ³⁵Cl that may be present at trace level in any part of the irradiated material. Due to its long half-life (T_1/2 = 3.01 ^. 10⁵ y), ³⁶Cl may be significant in impact assessment studies of disposal sites of nuclear wastes. Considering these different elements, the National Radioactive Waste Management Agency (Andra-France) requests information on the ³⁶Cl content of the waste packages destined to be stored at Andra sites. As for other halogens, the measurement of ³⁶Cl is a difficult analytical task in view of its potential losses during the different chemical steps and also because of the lack of international certified reference material needed to validate the chemical and measurement procedures. This paper describes the methodology processed to constitute an in-house solid reference sample with a known content of stable and radioactive chlorine. The original radiochemistry developed to extract ³⁶Cl from solid samples and purify it before a liquid scintillation counting is explained. The comparison of the results given by this radiochemical protocol and other methods allow its validation. The replication of the measurements on the constituted reference materials gives a repeatability around 8% at a confidence level of 95% that is very close to the calculated combined uncertainty value.     

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%.     

Contamination problems from glass beaker inner surface in low level <Superscript>210</Superscript>Po analysis

It was found that heating of diluted nitric or hydrochloric acids in many years stored glass beakers can result in mBq quantities of ²¹⁰Po leached from beaker walls to the solution. In the case of freshly bought beakers acid leaching of ²¹⁰Po was not observed. We suppose that acid leachable ²¹⁰Po in old beakers is mainly due to implantation of radon progenies (from air) into superficial layers of glass beaker walls.     

Extraction chromatography for the separation of <Superscript>239</Superscript>Np from <Superscript>243</Superscript>Am

Summary An extraction chromatography method was developed for the separation of 239Np from ²⁴³Am in nitric acid solution. A sorbent based on aliphatic quaternary amine Aliquat-336 and hydrophobized silica gel was prepared. ²³⁹Np reduced to the oxidation state(IV) with ferrous sulfamate in 2M or 6M HNO₃ sorbs on the prepared silica gel column. After washing with 0.1M ferrous sulfamate in 2.5M HNO₃, ²³⁹Np is eluted with 0.1M HNO₃ containing 0.02M HF. The separation of ²⁴³Am from ²³⁹Np is very effective. The purity of ²³⁹Np was found to be better than 99.5%. The proposed ²³⁹Np milking procedure is suitable for the preparation of ²³⁹Np tracer that can be used for the determination of ²³⁷Np radiochemical yield.     

Production of <Superscript>88,89</Superscript>Zr by proton induced activation of <Superscript>nat</Superscript>Y and separation by SLX and LLX

^natY foil was irradiated by 20 MeV proton to produce no-carrier-added ^88,89Zr. A comparative evaluation on radioanalytical separation methods of ^88,89Zr was carried out from irradiated target matrix by both liquid–liquid (LLX) and solid–liquid (SLX) extraction methods using di-(2-ethylhexyl) phosphoric acid (HDEHP) dissolved in cyclohexane as liquid cation exchanger and Dowex 50W-X8 H⁺ form (20–50 mesh) as solid cation exchanger. Both the methods offer good separation and high yield of nca ^88,89Zr but SLX offers much higher separation factor and better yield.     

A combined method of neutron activation analysis and radiometric measurements for <Superscript>234</Superscript>U and <Superscript>238</Superscript>U determination in soil samples of low uranium concentration

A method that combines the use of non-destructive neutron activation analysis and high-resolution α spectrometry has been developed for determination of the activities of ²³⁴U and ²³⁸U in geological samples of low uranium content. The ²³⁸U content is determined by k₀-based neutron activation analysis, whereas the ²³⁴U/²³⁸U relationship is measured by α spectrometry after isolation and electrodeposition of the uranium extracted from a lixiviation with 6 M HCl. The main advantage of the method is the simplicity of the chemical operations, including the fact that the steps destined to assure similar chemical state for the tracer and the uranium species present in the sample are not necessary. The method was applied to soil samples from sites of the North Peru Coast. Uranium concentration range 3–40 mg/kg and the isotopic composition correspond to natural uranium, with about 10% uncertainty.     

Rapid isocratic HPLC investigation of radiochemical purity for <Superscript>90</Superscript>Y-DOTATATE

DOTA-conjugated peptides, such as [DOTA⁰, Tyr³]ocreotide (DOTATOC) and [DOTA⁰, Tyr³]octreotate (DOTATATE) can be labeled with radionuclides such as ⁹⁰Y, ¹⁷⁷Lu and ¹¹¹In at high specific activities. These radiolabelled somatostatin analogues are used for peptide receptor radionuclide therapy (PRRT). Currently, radio-high performance liquid chromatography (radio-HPLC) and radio-thin layer chromatography (radio-TLC) are the methods of choice for the analysis of the labeled compounds. In literature, radiochemical purity of the radiolabelled DOTATATE was investigated using gradient reversed-phase radio-HPLC. However, these studies indicate long retention time of the radiolabelled compound of 14.52 min. In our study, a new simple and rapid reversed-phase isocratic system enables the radiochemical purity of the radiolabelled DOTATATE within a few minutes.     

Development of a radiochemical separation for selenium with the aim of measuring its isotope 79 in low and intermediate nuclear wastes by ICP-MS

Selenium (Se) 79 is a beta emitter produced from ²³⁵U fission thus occurring as one of the fission products found in nuclear reactors. Due to its long half life (about 10⁵ years), ⁷⁹Se is one of the radionuclides of interest for the performance of assessment studies of waste storage or disposal. Thus, the National Radioactive Waste Management Agency (Andra, France) requests its monitoring in wastes packages before their disposal in specific sites.Measurement of ⁷⁹Se is difficult owing to its trace level concentration and its low activity in nuclear wastes. A radiochemical procedure has to be carried out in order to separate selenium from the matrix and to concentrate it before the measurement with a mass spectrometric or a nuclear technique. The beginning of the development is presented in this paper. The optimised protocol firstly developed in view of an ICP-MS measurement, includes five steps based on microwave digestion, evaporation and separations on ion exchange resins. It was tested first on synthetic solutions and was optimised in order to be applicable to a large number of sample types. The recoveries of the whole procedure were evaluated using natural ⁸²Se or the gamma emitter ⁷⁵Se as a radioactive spiker. Then, the protocol was applied to two solid samples spiked with natural selenium, a glass microfiber filter and an ion exchange resin, and two liquid samples spiked with ⁷⁵Se, a synthetic solution and an effluent. The yields obtained for both samples ranged from 70 up to 80%.     

An improved method for the preparation of [<Superscript>14</Superscript>C]thiourea of high radiochemical purity

Summary An improved method for the preparation of [¹⁴C]thiourea of high radiochemical purity is described. [¹⁴C]thiourea is prepared by the barium cyanamide route and is purified by vacuum-sublimation. The labeled product showed ammonium [¹⁴C]thiocyanate as a radiochemical impurity in the range of 2-4%. This was further purified by silica-gel column chromatography to get the product having more than 99% radiochemical purity.     

Validation of <Superscript>90</Superscript>Sr separation method using molecular recognition product AnaLig<Superscript>®</Superscript> Sr01 gel and extraction chromatography Sr<Superscript>®</Superscript> resin

Two separation techniques for strontium determination using AnaLig^® Sr01 molecular recognition technology and extraction chromatography Sr^®  resin were tested. The methods performance was investigated by analysis of NPL (High Alpha–Beta 2003) intercomparison sample. The results obtained for both procedures were compared in terms of activities and recoveries. Data analysis proved a good agreement with the reference values. The AnaLig^® Sr01 separation method for ⁹⁰Sr determination was successfully validated with the same performance as the Sr^® resin method.     

<Superscript>1</Superscript>H and <Superscript>31</Superscript>P nuclear spin-lattice relaxation in C-phosphorylated oximes

The ¹H spin-lattice relaxation times of the proton-bearing groups and the ³¹P spin-lattice relaxation times in C-phosphorylated oximes R¹C(=NOH)P(=O)R²R³ (R¹ = Ph, R² = R³ = OMe; R¹ = Ph, R² = OMe, R³ = OCH²CH²Br; R¹ = PhCH², R² = R³ = OCHMe²) and dioxime R²P(=O)C(=NOH)(CH₂)₄C(=NOH)P(=O)R² (R = OMe) in DMSO-d₆ were measured. The characteristic reorientation times of the whole molecules were estimated using the measured values of the ¹H relaxation times and the results of semiempirical PM3 quantum chemical calculations of the molecular geometries. The reorientation times were used to identify the contributions of different relaxation mechanisms to the rate of ³¹P spin-lattice relaxation. The anisotropy of the chemical shielding of ³¹P nuclei was evaluated from the difference between the ³¹P relaxation rates measured at 101.27 and 161.92 MHz.