Technetium transmutation and production of artificial stable ruthenium

Peretroukhine, Vladimir F.; Radchenko, V.M.; Kozar, A. A.; Тарасов, В.А.; Toporov, Iury; Rotmanov, K. V.; Lebedeva, L.S.; Rovny, Sergey I.; Ershov, V.V.

doi:10.1016/j.crci.2004.05.002

Cited by 15 publications

(7 citation statements)

References 11 publications

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“…Therefore, the 100 Ru was likely formed by neutron capture reactions on 99 Tc as described above. Consistent with this idea, transmutation of 99 Tc via neutron capture reactions to form 100 Ru has been explored as a possible nuclear waste minimization strategy. ,,, The neutron capture cross section for 99 Tc is estimated to be 20 barns at thermal energies . The higher 100 Ru/ 101 Ru ratio in lot 1 relative to lots 2 and 3 is consistent with a longer irradiation time for the production of this sample.…”

Section: Resultsmentioning

confidence: 99%

Nuclear Sample Provenance and Age Determination Using Ruthenium Isotopes

et al. 2022

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Measurements of the ruthenium isotopic composition of nuclear samples could provide information about the method of sample production, sample irradiation history, and age. To investigate the feasibility and applicability of this idea, this study focuses on measurements of the ruthenium isotope composition of a nominally single-isotope 106Ru radioactivity standard, where the complications of environmental mixing are eliminated. The measurements of the 106Ru standards reveal unusual stable ruthenium isotopic compositions consistent with fissiogenic ruthenium. Three different lots of the material have been investigated, and the isotopic composition is found to be different for lot 1 as compared to lots 2 and 3, indicating a longer irradiation duration incurred during the production of lot 1. Through measurements of 106Ru and its 106Pd daughter, radiochronometry can be used to infer the ages of the samples. Lot 1 is older than lots 2 and 3 and was produced 4.91(5) years before the reference date of 1/1/21, approximately 2.7 years before lots 2 and 3. In an effort to better understand the sample production pathway, the isotopic measurements are compared with nuclear reactor simulations, which suggest that the material was generated by irradiation of a low-enriched uranium target material in a light water reactor. These findings have significant implications for nuclear treaty monitoring, providing an example of the power of ruthenium isotope measurements to discern details of sample origin and history.

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Section: Resultsmentioning

confidence: 99%

Nuclear Sample Provenance and Age Determination Using Ruthenium Isotopes

et al. 2022

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“…The burnup of 18% Tc is attained at the maximum intensity of neutron flux over 600 days (Bonnerot et al, 2005;Fuels…, 2005). The value of 71% has been obtained at the Research Institute of Atomic Reactors owing to a special configuration of target and a very high fluence of thermal neutrons (Peretroukhine et al, 2004).…”

Section: Prospects For 99 Tc Transmutation In Reactors and Acceleratorsmentioning

confidence: 99%

Isolation of long-lived technetium-99 in confinement matrices

2009

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Amongst fission products formed in atomic reactors, 99 Tc is the most hazardous for the environment because of its long half-life (213000 yr), high content in spent nuclear fuel (SNF) (0.8-1.0 kg per ton of SNF), low sorption ability, and high mobility under aerobic conditions. The bulk of 99 Tc (~200 t) is incorporated into SNF. In the course of SNF reprocessing, this radioisotope is released as a separate fraction or along with actinides. More than 60 t of highly concentrated 99 Tc have been accumulated to date. It is evident that isolation of 99 Tc from the environment is a matter of great urgency. The immobilization of technetium in a highly stable and poorly soluble matrix is a necessary element in settling this problem. Ceramics composed of titanates with pyrochlore, perovskite, and rutile structures are proposed as matrices able to retain technetium along with actinides. The high chemical stability of these compounds has been corroborated by experiments. The difficulties in production of such matrices are related to the fugacity of Tc and the necessity of converting it into Tc(IV). To overcome this obstacle, self-propagating high-temperature synthesis (SHS), characterized by reductive conditions and a high reaction rate, is proposed. The charge for matrix synthesis consists of reducing agents (metallic powders with a strong affinity to oxygen, e.g., Ti and Zr), oxidants (MoO 3 , Fe 2 O 3 , CuO), and additives (TiO 2 , ZrO 2 , Y 2 O 3 , CaO, etc.), which taken together with other elements form target phases. Instead of Tc, Mo, close in chemical properties, is used in matrix synthesis as a simulator. Samples of Mo-bearing matrices have been synthesized with SHS; their phase compositions and Mo distribution therein are characterized. It has been shown that up to 40 wt % Mo can be incorporated into the synthesized matrices in the form of metal or structural admixtures in titanates. The titanate-zirconate pyrochlore-based matrices are the most appropriate for the joint immobilization of actinides, REEs, and 99 Tc.

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“…The epithermal neutron flux in the neutron trap was 1.1 Â 10 14 cm À2 s À1 and changed insignificantly during irradiation. The transmutation rate achieved in the SM-3 reactor permits 50% conversion of technetium-99 into ruthenium-100 in 150 days (Peretroukhine et al, 2004).…”

Section: Introductionmentioning

confidence: 99%