As the acceptance criteria for low-intermediate-level radioactive waste cave disposal facilities of Korea Radioactive Waste Agency (KORAD) were revised, the requirements for characterization of whether radioactive waste contains hazardous substances have been strengthened. In addition, As the recent the Nuclear Safety and Security Commission Notice (Regulations on Delivery of Low- Medium-Level Radioactive Waste) scheduled to be revised, the management targets and standards for hazardous substances are scheduled to be specified and detailed. Accordingly, the Korea Atomic Energy Research Institute (KAERI) needs to prepare management methods and procedures for hazardous substances. In particular, in order to characterize the chemical requirements (explosiveness, ignitability, flammability, corrosiveness, and toxicity) contained in radioactive waste, it must be proven through documents or data that each item does not contain hazardous substances, and quality assurance for the overall process must be provided. In order to identify the characteristics of radioactive waste that will continue to be generated in the future, KAERI needs to introduce a management system for hazardous substances in radioactive waste and establish a quality assurance system. Currently, KAERI is thoroughly managing chelates (EDTA, NTA, etc.), but the detailed management procedures for hazardous substances related to chemical requirements in radioactive waste in the radiation management area specified above are insufficient. The KAERI’s Laboratory Safety Information Network has a total periodic regulatory review system in place for the purchase, movement, and disposal of chemical substances for each facility. However, there is no documents or data to prove that the hazardous substances held in the facility are not included in the radioactive waste, and there are no procedures for managing hazardous substances. Therefore, it is necessary to establish procedures for the management of hazardous substances, and we plan to prepare management procedures for hazardous substances so that chemical substances can be managed according to the procedures at each facility during preliminary inspection before receiving radioactive waste. The procedure provides definitions of terms and types of management targets for each characteristic of the chemical requirements specified above (explosiveness, ignition, flammability, corrosiveness, and toxicity). In addition, procedure also contains treatment methods of radioactive waste generated by using hazardous substances and management methods of in/out, quantity, history of that substances, etc. As the law is revised in the future, management will be carried out according to the relevant procedures. In this study, we aim to present the hazardous substance management procedures being established to determine whether radioactive waste contains hazardous substances in accordance with the revised the notice and strengthened acceptance criteria. Through this, we hope to contribute to improving reliability so that radioactive waste could be disposed of thoroughly and safely.
Hazardous waste is also becoming more important as opportunities for industrial waste recycling are extended. Some hazardous industrial wastes that contain many inorganic materials and heavy metals can be reused as resources: Heavy metal recovery, heat energy, etc. To facilitate the waste-to-energy system, waste generation characteristics should be defined and managed by analyzing hazardous material content. This study examines the inorganic materials (Pb, Cu, As, Hg, Cd, Cr6+, CN, Ni, Zn, F, and Ba) of industrial wastes and the generation process (case of the Korean Standard Industrial Classification) using Absolutely Hazardous (AH) Waste Lists (LoW and EU). In particular, manufacture classification was a main waste generation process (82% for “AH”). Moreover, these 10 components (Pb, Cu, As, Hg, Cd, Cr6+, CN, Ni, Zn, and F, but not Ba) are compared with the regulatory limits on heavy metals in soil: Hg and As must be under the limit of the 3 Level (0.3 ~ 7.3 mg/kg).
In South Korea, the “Waste Control Act” regulates the use and purpose of recycling waste and specifies recycling methods and specific standards. However, these processes requires a long time and large budget, because they need to be reviewed based on data specific to the type of waste involved. The use and purpose of recycling can be considered by its functional and environmental aspects. The functional aspect of recycling may vary widely, depending on product characteristics In contrast, environmental standards will have more points in common. Recycling standards that consider the environmental impact and characteristics of waste are not prepared specifically. Therefore, when a large amount of waste is recycled, or recycling standards are applied to a new type of waste, the methodology for review of its environmental characteristics can be controversial. This study is meant to recognize the necessity of recycling standards and to prepare environmental standards and new recycling purposes for waste related to recycling three types of gypsum waste (phospho, titan, desulfurization). Several companies were selected for this study. In the gypsum waste-generating company, gypsum waste samples were collected and analyzed for pH, heavy metal content, water content, hazardous substance content, etc. In addition, we attempted to obtain the company's opinions on waste recycling. We determined the hazardous materials found in these three types of gypsum waste, raised awareness of waste, and confirmed that industry waste can be efficiently recycled for new uses under the improved.
Slag and coal ash were selected to evaluate the recyclability of waste generated during the heat treatment processes. A list of waste types and recyclable types of the two wastes were identified. A recycling environmental hazardous assessment was reviewed step by step. In addition, the hazardous properties of slag and coal ash were investigated, and the chemical components, leaching, and content of harmful substances in the waste were analyzed. The two selected wastes were classified as general wastes. As a result of chemical analysis with XRF, the two wastes did not produce toxic gases in contact with water and show leaching toxicity from the analysis of harmful substances. In addition, waste is often brought into contact with the soil when recycled, so the content of slag and coal ash is analyzed and compared with the 2 region standard of soil; two samples were within the standard. Therefore, the surveyed wastes can be recycled in non-matrix contact types and the recycling purpose and method permitted by the new law is excluded from the recycling environmental hazardous assessment. However, to recycle wastes for new uses, the recycling environmental hazardous assessment is required.
The management of household hazardous waste (HHW), a component of municipal solid waste (MSW) has become a major of concern partly due to their potential toxicity upon disposal. Improper management of such waste can deteriorate the environment and cause serious damage to the human health. This paper discusses the current fundamental management practices, which include the generation rate, collection systems and treatment using the survey reviews of households and interviews held with experts in the Daejeon metropolitan city. Surveys of more than 378 people in Daejeon Metropolitan City were conducted to investigate the characteristics, generation rate, social behavior and awareness regarding disposal of HHW. The target items used in this study includes used lamps, used batteries, pharmaceuticals, and household pesticide chemicals. According to the survey conducted, the generation rates of HHW varied depending upon the dwelling type, collection system, and waste type. Apartment complex residents participated actively in source separation, using the established collection system with limited items (e.g., fluorescent lamps and batteries), while single family housing residents tend to store HHW at households. There is still a need for public awareness, detailed policies and legislation requiring source segregation at households, and better collection systems for HHW. The results of this study can be used for developing better management of HHW in municipal solid waste streams to prevent potential environmental impacts and human health risks.
The pyrolysis reactions of atomic hydrogen with chloroform were studied in a 4 cm i.d, tubular flow reactor with low flow velocity (518 ㎝/sec) and a 2.6 ㎝ i.d. tubular flow reactor with high flow velocity (1227 ㎝/sec). The hydrogen atom concentration was measured by chemiluminescence titration with nitrogen dioxide, and the chloroform concentrations were determined using a gas chromatography. The chloroform conversion efficiency depended on both the chloroform flow rate and linear flow velocity, but did not depend on the flow rate of hydrogen atom.
A computer model was employed to estimate a rate constant for the initial reaction of atomic hydrogen with chloroform. The model consisted of a scheme for chloroform-hydrogen atom reaction, Runge-Kutta 4th-order method for integration of first-order differential equations describing the time dependence of the concentrations of various chemical species, and Rosenbrock method for optimization to match model and experimental results. The scheme for chloroform-hydrogen atom reaction included 22 elementary reactions. The rate constant estimated using the data obtained from the 2.6 cm i.d. reactor was to be 8.1 × 10 exp (-14) ㎤/molecule-sec and 3.8 × 10 exp (-15) ㎤/molecule-sec, and the deviations of computer model from experimental results were 9% and 12%, for the each reaction time of 0.028 sec and 0.072 sec, respectively.