• Title/Summary/Keyword: nuclear safeguards

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Investigations on the Pu-to-244Cm ratio method for Pu accountancy in pyroprocessing

  • Sunil S. Chirayath;Heukjin Boo;Seung Min Woo
    • Nuclear Engineering and Technology
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    • v.55 no.10
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    • pp.3525-3534
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    • 2023

  • Non-uniformity of Pu and Cm composition in used nuclear fuel was analyzed to determine its effect on Pu accountancy in pyroprocessing, while employing the Pu-to-244Cm ratio method. Burnup simulation of a typical pressurized water reactor fuel assembly, required for the analysis, was carried out using MCNP code. Used fuel nuclide composition, as a function of nine axial and two radial meshes, were evaluated. The axial variation of neutron flux and self-shielding effects were found to affect the uniformity of Pu and Cm compositions and in turn the Pu-to-244Cm ratio. However, the results of the study showed that these non-uniformities do not affect the use of Pu-to-244Cm ratio method for Pu accountancy, if the measurement samples are drawn from the voloxidized powder at the feed step of pyroprocessing. 'Material Unaccounted For' and its uncertainty estimates are also presented for a pyrprocessing facility to verify safeguards monitoring requirements of the IAEA.

  • https://doi.org/10.1016/j.net.2023.06.010 인용 PDF

Lab scale electrochemical codeposition experiments for comparison to computational predictions

  • Lafreniere, Philip;Zhang, Chao;Simpson, Michael;Blandford, Edward D.
    • Nuclear Engineering and Technology
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    • v.52 no.9
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    • pp.2025-2033
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    • 2020

  • Signature-based safeguards (SBS) is being developed to assist tradition nuclear material accountancy methods in tracking material in pyroprocessing facilities. SBS involves identifying off-normal scenarios that would result in improper movement of material in a pyroprocessing facilities and determining associated sensor response signatures. SBS investigations are undertaken in the computational space utilizing an electrochemical transport code known as enhanced REFIN with anodic dissolution (ERAD) to calculate the affect of off-normal conditions in the electrorefiner (ER) on material movement. Work is undertaken to experimentally validate the predictions and assumptions made by ERAD for off-normal occurrences. These experiments were undertaken on a benchtop scale and involved operating an electrochemical cell at 10 separate current densities for constant current operations to deposit U and Gd at a W cathode. These experiments were then modeled using ERAD to compare calculated predictions versus analytical experimental results it was found. It was discovered both the experimental and calculated results reflect a trend of increased codeposition of U and Gd with increasing current density. ERAD was thus demonstrated to be useful for predicting trends from anomalous operation but will require further optimization to be utilized as a quantitative design tool.

  • https://doi.org/10.1016/j.net.2020.02.005 인용 PDF KSCI