• Title/Summary/Keyword: Decommissioning Waste

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Reduction of Radioactive Waste from Remediation of Uranium-Contaminated Soil

  • Kim, Il-Gook;Kim, Seung-Soo;Kim, Gye-Nam;Han, Gyu-Seong;Choi, Jong-Won
    • Nuclear Engineering and Technology
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    • v.48 no.3
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    • pp.840-846
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    • 2016

  • Great amounts of solid radioactive waste (second waste) and waste solution are generated from the remediation of uranium-contaminated soil. To reduce these, we investigated washing with a less acidic solution and recycling the waste solution after removal of the dominant elements and uranium. Increasing the pH of the washing solution from 0.5 to 1.5 would be beneficial in terms of economics. A high content of calcium in the waste solution was precipitated by adding sulfuric acid. The second waste can be significantly reduced by using sorption and desorption techniques on ampholyte resin S-950 prior to the precipitation of uranium at pH 3.0.

  • https://doi.org/10.1016/j.net.2016.01.017 인용 PDF KSCI

A new proposal for controlled recycling of decommissioning concrete waste as part of engineered barriers of a radioactive waste repository and related comprehensive safety assessment

  • In Gyu Chang;Jae Hak Cheong
    • Nuclear Engineering and Technology
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    • v.55 no.2
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    • pp.530-545
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    • 2023

  • As an alternative to conventional management options for a lot of concrete waste from decommissioning of nuclear power plants, a set of scenarios for controlled recycling of decommissioning concrete waste as engineered barriers of a radioactive waste repository was proposed, and a comprehensive safety assessment model and framework covering both pre-and post-closure phases was newly developed. The new methodology was applied to a reference vault-type repository, and the ratios of derived concentration limits to unconditional clearance levels of eighteen radionuclides for controlled recycling were provided for three sets of dose criteria (0.01, 1, and 20 mSv/y for the pre-closure and 0.01 mSv/y for the post-closure phases). It turns out that decommissioning concrete waste whose concentration is much higher than the unconditional clearance level can be recycled even when the dose criterion 0.01 mSv/y is applied. Moreover, a case study on ABWR bio-shield shows that the fraction of recyclable concrete waste increases significantly by increasing the dose criterion for the radiation worker in the pre-closure phase or the duration of storage prior to recycling. The results of this study are expected to contribute to demonstrating the feasibility of controlled recycling of a lot of decommissioning concrete waste within nuclear sectors.

  • https://doi.org/10.1016/j.net.2022.10.028 인용 PDF

Safety Assessment for the Landfill Disposal of Decommissioning Waste Solidified by Magnesium Potassium Phosphate Cement

  • Jeong, Jongtae;Baik, Min-Hoon;Lee, Jae-Kwang;Pyo, Jae-Young;Um, Wooyong;Heo, Jong
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.20 no.1
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    • pp.13-22
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    • 2022

  • The decommissioning of a nuclear power plant generates large amounts of radioactive waste, which is of several types. Radioactive concrete powder is classified as low-level waste, which can be disposed of in a landfill. However, its safe disposal in a landfill requires that it be immobilized by solidification using cement. Herein, a safety assessment on the disposal of solidified radioactive concrete powder waste in a conceptual landfill site is performed using RESRAD. Furthermore, sensitivity analyses of certain selected input parameters are conducted to investigate their impact on exposure doses. The exposure doses are estimated, and the relative impact of each pathway on them during the disposal of this waste is assessed. The results of this study can be used to obtain information for designing a landfill site for the safe disposal of low-level radioactive waste generated from the decommissioning of a nuclear power plant.

  • https://doi.org/10.7733/jnfcwt.2022.002 인용 PDF KSCI

Logistical Simulation for On-site Concrete Waste Management in Decommissioning

  • Lee, Eui-Taek;Kessel, David S.;Kim, Chang-Lak
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.17 no.4
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    • pp.389-403
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    • 2019

  • Large amounts of concrete waste are likely to arise from the decommissioning of a Kori-1 nuclear power plant. Several studies have been conducted on decommissioning concrete waste in recent decades, however, they have been limited to contaminated concrete issues or were small pilot-scale experiments. This study constructed two industrial-scale models of on-site concrete waste management for clean as well as contaminated concrete. To evaluate the performance of both the models, simulations were conducted using the Flexsim software. The concrete particle size distribution of Kori-1 and concrete processor properties based on widely used construction equipment were used as sources of input data for the simulations. It was observed that it may take over two years to complete the on-site concrete management processes owing to the performance of existing processors. In addition, it was demonstrated that it is essential to identify bottlenecks in the system and enhance the performance of the relevant processors to avoid delays of the decommissioning schedule. Our results suggest that this novel approach can contribute to developing schedules or expediting delayed activities in the Kori-1 decommissioning project.

  • https://doi.org/10.7733/jnfcwt.2019.17.4.389 인용 PDF KSCI