Characterization of the solids formed from simulated nuclear fuel reprocessing solutions

Rao, B. Sanjeeva; Gantner, E.; Reinhardt, J.; Steinert, D.; Ache, H. J.

doi:10.1016/0022-3115(90)90324-g

Cited by 29 publications

(11 citation statements)

References 9 publications

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“…Rao et al reported that MoO 3 was precipitated in Mo‐rich environments, but in our results, MoO 3 in the precipitates was not identified by XRD spectra. Furthermore, observing the XRD spectra of ZMH in Mo‐rich environments, 20–30 deg.…”

Section: Resultsmentioning

confidence: 99%

Encrustation Prevention of Zirconium Molybdate Hydrate

et al. 2018

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In nuclear fuel reprocessing, spent nuclear fuel is dissolved by a nitric acid. It is now known that molybdenum and zirconium in fission products react to form zirconium molybdate hydrate (ZMH). ZMH adheres to the inner surface of reprocessing equipment, which affects the extraction efficiency in the subsequent extraction process. Therefore, a new prevention method of ZMH encrustation is required for stable plant operation. In this study, the encrustation amount of ZMH was investigated. Observing the deposition process, it was clarified that ZMH fine crystals were generated and agglomerated, followed by the rapid deposition. The encrustation amount of ZMH decreased as temperature or initial Mo/Zr mole ratio increased, or as the concentration of a nitric acid was reduced.

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Section: Resultsmentioning

confidence: 99%

Encrustation Prevention of Zirconium Molybdate Hydrate

et al. 2018

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“…Infrared analysis was used as a fast method for fingerprinting the synthesised compounds, following methods previously detailed in the literature [ 11 , 24 ]. Figure 5 b, presents the Fourier Transform Infrared (FTIR) spectra for the synthesised CPM, ZM-a and ZM-b.…”

Section: Resultsmentioning

confidence: 99%

“…ZM has been the focus of several studies within literature, where it has been synthesised for various applications, such as a Technetium-99m generator [ 4 , 5 , 6 , 7 ], a precursor for the formation of the negative thermal expansion material ZrMo 2 O 8 [ 8 , 9 ] and predominately for nuclear waste based studies [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ]. Clearfield et al [ 24 ] were the first to publish a synthesis route for ZM to characterise its ion exchange properties.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Physical Property Characterisation of Spheroidal and Cuboidal Nuclear Waste Simulant Dispersions

2018

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This study investigated dispersions analogous to highly active nuclear waste, formed from the reprocessing of Spent Nuclear Fuel (SNF). Non-radioactive simulants of spheroidal caesium phosphomolybdate (CPM) and cuboidal zirconium molybdate (ZM-a) were successfully synthesised; confirmed via Scanning Electron Microscopy (SEM), powder X-ray diffraction (PXRD) and Fourier transform infrared (FTIR) spectroscopy. In addition, a supplied ZM (ZM-b) with a rod-like/wheatsheaf morphology was also analysed along with titanium dioxide (TiO2). The simulants underwent thermal gravimetric analysis (TGA) and size analysis, where CPM was found to have a D50 value of 300 nm and a chemical formula of Cs3PMo12O40·13H2O, ZM-a a D50 value of 10 μm and a chemical formula of ZrMo2O7(OH)2·3H2O and ZM-b to have a D50 value of 14 μm and a chemical formula of ZrMo2O7(OH)2·4H2O. The synthesis of CPM was tracked via Ultraviolet-visible (UV-Vis) spectroscopy at both 25 °C and 50 °C, where the reaction was found to be first order with the rate constant highly temperature dependent. The morphology change from spheroidal CPM to cuboidal ZM-a was tracked via SEM, reporting to take 10 days. For the onward processing and immobilisation of these waste dispersions, centrifugal analysis was utilised to understand their settling behaviours, in both aqueous and 2 M nitric acid environments (mimicking current storage conditions). Spheroidal CPM was present in both conditions as agglomerated clusters, with relatively high settling rates. Conversely, the ZM were found to be stable in water, where their settling rate exponents were related to the morphology. In acid, the high effective electrolyte resulted in agglomeration and faster sedimentation.

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“…An HRLW sample solution containing solid precipitates, which is observed after the dissolution of spent fuel in nitric acid and contains Pu in metal oxides, 12,13 was taken in a 50-mL flask, and a known amount of Nd(III) standard solution was added to the flask. To dissolve the solid precipitates, 2.0 mL of a mixed acid of HF (0.025 M) and HNO3 (8 M) was added into the flask, and the sample was then heated at 150˚C on a hot plate to near-dryness.…”

Section: Sample Preparationmentioning

confidence: 99%