• Resources Recycling
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• v.10 no.1
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• pp.56-65
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• 2001

Chemical decontamination techniques have been employed to reuse the high cost check valves contaminated with radioactivity and to reduce the radiation exposure during the inspection and maintenance work of safety injection system containing check valves. After chemical decontamination, an ultrasonic treatment was conducted to remove the fine solid particles retained in the crevices of check valves. The decontamination process conditions and the amount of chemical reagents were determined from the results of a pre-test, using the (list arm holder. The decontamination factors (DF), estimated from the activity in the solution, ranged from 14.5 to 18.5 corresponding to the activity removal of 93-95ft. The corrosion test data indicated that the general corrosion rate during a chemical decontamination-ultrasonic treatment process are low for type 304 S tainless steel, Inconel -600 and Stellite-6 materials $ (2.1\times10^{-2}$ $6.0\times10^{-2}$ and$ 1.7\times10^{-2}$ mil, respectively).

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.8 no.2
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• pp.91-97
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• 2010

As nuclear power plants are getting older, interests on a decontaminating process are increasingly attracting more attention. Chemical decontamination is crucial to lower the production of radioactive waste and radiation dose rate. Prior to this, oxidizers and detergents for target material should be chosen so as to decontaminate major systems and components of a nuclear power plant chemically. In order to decontaminate it properly, it is crucial to have information about the chemical composition and crystalline structure of CRUD, analyzing its samples from the target or the decontamination system with components. However, there is no program which enables the extraction of samples directly from the object or the decontamination system with components carrying genuine radioactivity. Therefore, it is limited to samples from corrosion products carrying partial radioactivity as a resource. The composition of CRUD varies considerably depending on refueling cycle because it is closely related to the constituent of basic material. After settling a target, it is crucial to analyze and obtain analytical information about CRUD as a decontamination target. In this paper, various technologies for manufacturing simulated CRUD are introduced as alternatives to unattained samples. A metal oxide or metal hydroxide was used to synthesize simulated cruds having chemical compositions and crystalline stricture similar to the actual one by 12 different methods. CRUD 4(metal oxides in the autoclave vessel) and CRUD 10(metal oxides in a crucible after hydrazing pretreatment)were chosen as the best method for Type 1 and Type 2.respectively. As these CRUD can be synthesized easily without using any specialized equipment or reagents in a short time and in large quantities, they are expected to stimulate the development of decontaminating agents and processes.

• Journal of the Korean Society of Safety
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• v.24 no.4
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• pp.47-52
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• 2009

This study has been to examine the occupational exposure levels of Fluorouracil (5-FU) in a hospital and to investigate the most effective cleaning reagent for control. Fluorouracil is one of the cytotoxic drugs which are therapeutic agents used to treat cancer. The health practitioners working in the cytotoxic work room and oncology ward areas are exposed to adverse health risks like cytogenetic and DNA damage from cytotoxic drugs exposure by frequent skin contact from contaminated surfaces. Four kinds of cleaning reagents has been examined to degrade the 5-FU. It was found that 5-FU was only degraded soon after the reaction in 0.5%(w/v) NaClO solution. Therefore, 0.5%(w/v) NaClO solution has been chosen to decompose any residues on the contamination surfaces. A substantial level of contamination was found on the surfaces of cytotoxic work room and oncology ward areas. The contamination ranges of the surfaces in cytotoxic work room and oncology ward areas were from 2.0 to $13.8{\mu}g/m^2$ and 5.39 to $11.53{\mu}g/m^2$ respectively. Consequently, regulation of the occupational exposure limit, procedure of special cleaning, and the use of personal protective equipment are recommended during the manipulation and administration of the drugs to avoid skin contamination from cytotoxic drugs like 5-FU.

• Biomedical Science Letters
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• v.16 no.3
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• pp.133-138
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• 2010

Despite of the increasing importance of environmental mycobacteria, detection and identification of mycobacteria from environmental sources including water have been fraught with technical difficulties. Although, several protocols to optiruize isolation of mycobacteria from water sources have been reported, standard method has not yet been established. In this study, usefulness of cetylpyridinium chloride (CPC), a cationic quaternary ammonium compound, for the isolation of environmental mycobacteria from diverse water samples was evaluated. For this, water samples from diverse water sources such as effluent water, lake water, and underground water were collected, treated with diverse concentrations of CPC, and plated on the solid agar plates. Subsequently individual colonies grown on the plates were sequence analyzed for identification of each colony. In brief, the results from this study showed that the growth of mycobacteria was enhanced by use of CPC as a pre-treatment reagent to water samples by inhibiting growth of other non-mycobacteria in water. In fact, the effect of CPC to decontaminate non-mycobacteria for isolation of mycobacteria was better than 1~4% of NaOH, which is a routinely used decontaminating reagent widely employed for culturing mycobactera from sputum specimens. Therefore, the results from this study seems to support that the CPC pre-treatment may be useful for isolation of mycobacteria from diverse sources including clinical specimens which are often contaminated with other bacteria.