The production of no carrier added arsenic radioisotopes in nuclear reactors (original) (raw)
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Separation of no-carrier-added arsenic-77 from neutron irradiated germanium
Radiochimica Acta, 2000
Germanium metal target / Neutron irradiation / No carrier added arsenic-77 / HZO column Summary. Arsenic-77 (T 1/2 = 1.6 d) was produced by irradiating natural germanium in Pakistan Research Reactor-1. The nuclear reaction 76 Ge(n, γ ) produces 77 Ge, which decays by emission of β − particles into 77 As. The neutron irradiated target was dissolved in aqua regia, excess of acid was removed by evaporation and finally the solution in basic media was passed through hydrous zirconium oxide (HZO) column. The Ge was quantitatively retained on HZO, while 77 As was present in the effluent. More than 90% 77 As was recovered. The chemical impurity of Ge in 77 As was < 0.01 µg/mL.
A new method for radiochemical separation of arsenic from irradiated germanium oxide
Applied Radiation and Isotopes, 2005
Radioarsenic labelled radiopharmaceuticals could be a valuable asset to Positron Emission Tomography (PET). In particular, the long half-lives of 72 As (T 1/2 ¼ 26 h) and 74 As (T 1/2 ¼ 17.8 d) allow to investigate slow physiological or metabolical processes, like the enrichment and distribution of antibodies in tumor tissue. This work describes the direct production of no-carrier-added (nca) arsenic isotopes *As, with * ¼ 71, 72, 73, 74 or 77, the reaction to [*As]AsI 3 and its radiochemical separation from the irradiated solid germanium oxide via polystyrene-based solid-phase extraction. The germanium oxide target, irradiated at a cyclotron or a nuclear reactor, is dissolved in concentrated HF and Ge is separated almost quantitatively (99.97%) as [GeF 6 ] 2À . [*As]AsI 3 is formed by addition of potassium iodide. The radiochemical separation yield for arsenic is 490%. [*As]AsI 3 is a versatile radioarsenic labelling synthon. r
The studies performed in the frame of a project destined for the search of new (t,n) and (p,n) reactions of interest in nuclear reactors are described. Experimental evidences of the observations of the reactions: 46 Ti(t,n) 48 V, 48 Ti(p,n) 48 V, 52 Cr(t,n) 54 Mn, 56 Fe(p,n) 56 Co, 72 Ge(t,n) 74 As and 74 Ge(p,n) 74 As, are presented. Additional data on some secondary reactions, already characterised for the production of 7 Be, 56 Co, 58 Co, 65 Zn and 88 Y, were also obtained. The significance of these data is discussed.
Preparation of thin arsenic and radioarsenic targets for neutron capture studies
Journal of Radioanalytical and Nuclear Chemistry, 2009
A simple method for the electrodeposition of elemental arsenic (As) on a metal backing from aqueous solutions has been developed. The method was successfully applied to stable As ( 75 As). Thin (2.5 mg cm -2 ) coherent, smooth layers of the metalloid on Ti foils (2.5 lm thickness) were obtained. Electrodeposits served as targets for 75 As(n,c) 76 As neutron capture experiments at Los Alamos Neutron Science Center (LANSCE). Respective 73 As(n,c) 74 As experiments are planned for the near future, and 73 As targets will be prepared in a similar fashion utilizing the new electrodeposition method. The preparation of an 73 As (half-life 80.3 days) plating bath solution from proton irradiated germanium has been demonstrated. Germanium target irradiation was performed at the Los Alamos Isotope Production Facility (IPF).
Applied Radiation and Isotopes, 2012
As generation Particle fluence modeling 74,73 As neutron capture target a b s t r a c t Germanium metal targets encapsulated in Nb shells were irradiated in a proton beam. Proton and secondary neutron beam fluences as well as radionuclide activity formation were modeled using MCNPX in combination with CINDER90. Targets were chemically processed using distillation and anion exchange. Good agreement between the measured radiochemical yields and MCNPX/CINDER90 estimates was observed. A target of pentavalent 73,74 As radioarsenic for neutron activation studies was prepared.
Applied Radiation and Isotopes, 2007
A method for the separation of no-carrier-added (nca) arsenic radionuclides from bulk amounts of irradiated germanium oxide (GeO 2 ) target was developed in view of their potentialities in different biological and nuclear medicine applications. The b À emitting 77 As radionuclide, produced by the decay of 77 Ge through the nat Ge(n,g) 77 Ge nuclear reaction, was used for standardization of the radiochemical separation procedure. The radiochemical separation was performed by precipitation followed by solvent extraction. About 99% post-irradiation recovery of the GeO 2 target material, in a form suitable for reuse in future irradiation, was achieved. The developed method was suitable for the production of nca arsenic radionuclides either as trivalent or pentavalent arsenic in various vehicles which provided flexibility of formulations of different kinds of compound. The overall radiochemical yield for the complete separation of 77 As was 90%. The separated nca 77 As was of high radionuclidic purity and did not contain detectable amounts of the target material. This method can be adopted for the radiochemical separation of other different arsenic radionuclides produced from GeO 2 through cyclotron as well as reactor irradiation. r
Chromatographic separation of germanium and arsenic for the production of high purity 77As
Journal of Chromatography A, 2016
A simple column chromatographic method was developed to isolate 77 As (94 ± 6% (EtOH/HCl); 74 ± 11 (MeOH)) from germanium for potential use in radioimmunotherapy. The separation of arsenic from germanium was based on their relative affinities for different chromatographic materials in aqueous and organic environments. Using an organic or mixed mobile phase, germanium was selectively retained on a silica gel column as germanate, while arsenic was eluted from the column as arsenate. Subsequently, enriched 76 Ge (98 ± 2) was recovered for reuse by elution with aqueous solution (neutral to basic). Greater than 98% radiolabeling yield of a 77 Astrithiol was observed from methanol separated [ 77 As]arsenate [17].
Producing radioisotopes in power reactors
Journal of Radioanalytical and Nuclear Chemistry, 2012
The demand of radioisotopes is rising due to wide-ranging applications in industry, agriculture, medicine and in research. Two sources of artificial radioisotopes are accelerators and reactors. The reactor offers large volume for irradiation, simultaneous irradiation of different samples and economy of production, whereas accelerators are generally used to produce those isotopes which can not be produced by reactor. Radioisotope production started on a significant scale in several countries with the commissioning of research reactors starting from the late 1950s. The period from 1950 to 1970 saw construction of a large number of research reactors with multiple facilities. After 1980, because of the decommissioning of many old ones, the number of operating reactors has been steadily decreasing. The research reactors used for radioisotope production could be broadly classified into swimming pool type and tank type reactors. CANDU power reactors currently produce many millions of curies per year of 60 Co for MDS Nordion's use in industry and commerce. Studies related to production of other isotopes in power reactors have also been performed. Indeed, while a very few reactors have come online in the past decade, many more have been retired or may retire in coming years. After failure of MAPLE project, there has been unwillingness to built new reactors. Activism and politics has made it so difficult to build new reactors that we are left to use only the reactors we inherited from a nuclear era. Many design considerations and requirements for the production of isotopes in power reactors must be assessed, such as; operator and public safety, minimum impact on station efficiency and reactor operations, shielding requirements during reactor operation with target adjusters and removal of the target adjusters from core, transportation within the station, and finally the processing and shipment off-site. Use of power reactors for isotope production is reviewed.