• Title/Summary/Keyword: Radioactive environment

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Calcium Sulfo Aluminate (CSA) Cement from Coal Ash Utilized as Barriers for Radioactive Waste Disposal

  • Ramakrishna, Chilakala;Thriveni, Thenepalli;Whan, Ahn Ji
    • Journal of Energy Engineering
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    • v.27 no.1
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    • pp.33-39
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    • 2018
  • In this paper, we reviewed briefly about the barrier materials for the radioactive waste disposal. The primary concept of the radioactive waste disposal is safety. The goal of the radioactive waste management is to assure that the environment is not adversely affected and also public. There are a wide variety of materials are available for the radioactive waste disposal or storage. Among those coal fly ash is one of the significant materials are used as a barrier material. Here we reported, the Calcium sulfo aluminate (CSA) from coal fly ash is effectively suitable for the radioactive waste disposal. This is one of the ways of utilization of waste and manufactured the valuable materials for future indeeds.

Ion Exchange Behavior of $^{137}Cs,\;^{60}Co$ on Diphosil, a new ion exchange resin (Diphosil 이온교환수지에 의한 $^{137}Cs,\;^{60}Co$의 이온교환 거동)

  • Kim, Su-Jeong;Lee, Sang-Jin;Yang, Ho-Yeon;Shin, Sang-Woon
    • Journal of Radiation Protection and Research
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    • v.29 no.1
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    • pp.1-8
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    • 2004
  • Diphosil, a new version of the organic-inorganic composite resin developed by ANL has a structure of the chelating diphosphonic acid groups grafted to a silica support. To apply Diphosil for the treatment of liquid radioactive waste from nuclear power plants, the adsorption equilibrium and column experiments were carried out for the main radionuclides, $^{137}Cs\;and\;^{60}Co$, in the liquid radwaste stream. Through the adsorption equilibrium experiments, the removal efficiencies of $^{137}Cs\;and\;^{60}Co$, and the effects of non-radioactive ions on the removal efficiency have been measured in various conditions using radiotracers. The breakthrough curves for the tested tracers were obtained from the laboratory scale column tests using the simulated liquid radioactive waste. In addition, the removal capacity of Diphosil is compared with that of Amberlite IRN 77 resin, generally used in nuclear power plants.

Water Balance Evaluation of Final Closure Cover for Near- surface Radioactive Wastes Disposal Facility

  • Keunmoo Chang;Park, Joo-Wan;Yoon, Jeong-Hyoun;Park, Heui-Joo;Kim, Chang-Lak
    • Nuclear Engineering and Technology
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    • v.32 no.3
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    • pp.274-282
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    • 2000
  • The simulation of water balance was conducted for suggested four alternative multi-layer cover design of near-surface radioactive waste disposal facility under domestic climate condition. The analysis was also conducted for the most favorable one out of four alternative cover design under conservative scenarios. Until 100 years after closure of disposal vault, the infiltration flux for the most favorable cover design was negligible even under doubling of the ambient precipitation condition. When the degradation of asphalt and geomembrane after 100 years of closure was considered, the infiltration flux significantly increased almost to the design criteria of cover system in I' Aube disposal facility. And it was found that the hydraulic conductivity of bentonite/sand as a bottom barrier should be no greater than 1$\times$10$^{-7}$ cm/sec recommended by U.S. EPA.

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Chinese buffer material for high-level radiawaste disposal --Basic features of GMZ-l

  • WEN Zhijian
    • Proceedings of the Korean Radioactive Waste Society Conference
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    • 2005.11b
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    • pp.236-244
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    • 2005
  • Radioactive wastes arising from a wide range of human activities are in many different physical and chemical forms, contaminated with varying radioactivity. Their common feature is the potential hazard associated with their radioactivity and the need to manage them in such a way as to protect the human environment. The geological disposal is regarded as the most reasonable and effective way to safely disposal high-level radioactive wastes in the world. The conceptual model of geological disposal in China is based on a multi-barrier system that combines an isolating geological environment with an engineered barrier system. The buffer is one of the main engineered barriers for HLW repository. The buffer material is expected to maintain its low water permeability, self-sealing property, radio nuclides adsorption and retardation property, thermal conductivity, chemical buffering property, overpack supporting property, stress buffering property over a long period of time. Benotite is selected as the main content of buffer material that can satisfy above. GMZ deposit is selected as the candidate supplier for Chinese buffer material of High Level Radioactive waste repository. This paper presents geological features of GMZ deposit and basic property of GMZ Na bentonite. GMZ bentonite deposit is a super large scale deposits with high content of Montmorillonite (about $75\%$) and GMZ-l, which is Na-bentonite produced from GMZ deposit is selected as reference material for Chinese buffer material study.

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AN INTEGRATED APPROACH TO RISK-BASED POST-CLOSURE SAFETY EVALUATION OF COMPLEX RADIATION EXPOSURE SITUATIONS IN RADIOACTIVE WASTE DISPOSAL

  • Seo, Eun-Jin;Jeong, Chan-Woo;Sato, Seichi
    • Journal of Radiation Protection and Research
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    • v.35 no.1
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    • pp.6-11
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    • 2010
  • Embodying the safety of radioactive waste disposal requires the relevant safety criteria and the corresponding stylized methods to demonstrate its compliance with the criteria. This paper proposes a conceptual model of risk-based safety evaluation for integrating complex potential radiation exposure situations in radioactive waste disposal. For demonstrating compliance with a risk constraint, the approach deals with important exposure scenarios from the viewpoint of the receptor to estimate the resulting risk. For respective exposure situations, it considers the occurrence probabilities of the relevant exposure scenarios as their probability of giving rise to doses to estimate the total risk to a representative person by aggregating the respective risks. In this model, an exposure scenario is simply constructed with three components:radionuclide release, radionuclide migration and environment contamination, and interaction between the contaminated media and the receptor. A set of exposure scenarios and the representative person are established from reasonable combinations of the components, based on a balance of their occurrence probabilities and the consequences. In addition, the probability of an exposure scenario is estimated on the assumption that the initiating external factors influence release mechanisms and transport pathways, and its effect on the interaction between the environment and the receptor may be covered in terms of the representative person. This integrated approach enables a systematic risk assessment for complex exposure situations of radioactive waste disposal and facilitates the evaluation of compliance with risk constraints.