• Tunnel and Underground Space
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• v.19 no.1
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• pp.11-18
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• 2009

Use of nuclear energy inevitably brings the problem of radioactive waste disposal. Repositories for disposing radioactive waste use underground space that is unconnected with the outside and the diagonal system, which allows the waste to be deposited. Ventilation if necessary because high-level radioactive waste generates heat. In this study, the air velocity through diagonal branches with regulators of different sizes and in different locations, was measured. The air velocity is determined by the size of the first and last regulators, regardless of the size of other regulators. In the diagonal system. Consequently, once the desired total airflow rate has been achieved by installing the appropriate first and last regulators, the other regulators fan be evenly installed to maintain the minimum air velocity needed.

• Journal of Radiation Protection and Research
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• v.21 no.3
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• pp.155-166
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• 1996

All nuclear facilities and components should receive an initial ALARA review before the installation and thereafter whenever modifications are planned. A major objective in design aspects of ALARA is to identify areas where specific engineering input can reduce personnel exposure. The basic factors which should be considered in the ALARA design review process include curd control, shielding and isolation of radiation sources accessibility maintainability and reliability, and contamination control. Because many diverse aspects must be considered in the ALARA design reviews, a proper ALARA checklist should be used to aid the designer in preventing any of the ALARA review considerations from being slipped away. In order to develop the practical ALARA checklist, check items for basic ALARA factors have been prepared, and what should be considered in reviewing each item has been discussed here. Based on the proposed factors and items, an ALARA checklist was developed.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.5 no.4
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• pp.297-308
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• 2007

The granulation equipment of concentrated wastes is manufactured for the polymer solidification of concentrated wastes. It uses liquid sodium silicate as a granulating agent for the granulating of dried powder containing boric acid. The granulating agent is sprayed in the form of droplet and mean size of dried granules is $2{\sim}4mm$. The new technology which has been used for the polymer solidification of spent resin in U.S. and certified by Nuclear Regulatory Commission (NRC) is successfully applied to concentrated wastes. This uses in-situ solidification process within drum without mechanical mixing. Maximum loading of waste can be achieved without increasing of waste volume. Polymer waste forms were evaluated with several test such as fire test, compressive strength test, leaching test, immersion test, irradiation test, and thermal cycling test according to standard test procedures.

• Nuclear Engineering and Technology
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• v.12 no.1
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• pp.1-8
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• 1980

The grafting studies were concentrated on working out the methodology for radiation of flame retardants to polyester/cotton (65/35) blend fabric. The Fyrol 76 was used as a flame retardant in develping methodology for localizing flame retardants on the surface of the blend fabric. By judicious control of the swelling conditions, time_of contact with the monomer, and dose rate, locating the graft in the fiber became possible. The yield of the graft polymerization was depended upon the total dose and the preswelling conditions. Oxygen Index was used to evaluate the effect of the location of Fyrol 76 and other flame retardants within the surface upon the flame retardance efficiencies. To get a better flame retardance efficiency by :the localized grafting of Fyrol 76 to polyester/cotton blend fabric, a technique of one step processing at room temperature was developed substituting the ordinary two-step processing at high temperature.

• Journal of Radiation Protection and Research
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• v.11 no.1
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• pp.70-76
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• 1986

In order to establish the national standards of neutron measurements, a manganese sulphate ($MnSO_4$) bath system was developed under the IAEA technical support. This bath system was made up of a spherical s.s. 316 L bath, of 3.5 mm thick and of 125 cm internal diagmeter, filled with a manganese sulphate solution, a solution circulating system, and a $^5Mn\;{\gamma}-ray$ monitoring system. The solution pumped from the bath was introduced into a Marinelli beaker-type monitor vessel which was equipped with two seperate detectors, $3.8cm{\phi}{\times}3.8cm$ NaI(T1) crystals. The performance of the system were tested using the neutron sources, $^{241}Am-Be\;and\;^{252}Cf$, mounted at the center of the bath. From the decay curve analysis of $^{56}Mn$ activity, neutron emission rate of $^{252}Cf$ by the comparative method was obtained to be $3.71{\times}10^7\;n/s\;per\;50{mu}g$ as of November 15, 1985.

• Applied Chemistry for Engineering
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• v.28 no.2
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• pp.133-140
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• 2017

Increasing concerns on radioactive wastes have drawn much attention on the development of remediation technologies. Massive amounts of radioactive wastes generated from hospital and nuclear power plants were exposed to our environment. Although physicochemical removal methods were developed, an eco-friendly remediation method has not yet been demonstrated. Recently, an extremophilic bacterium has received much attention due to their extraordinary characteristics. Among them, Deinococcus radiodurans (D. radiodurans) strain was regarded as the best host organism for the removal of radioactive heavy metals and radionuclides, because of their superb characteristics like tolerance against the high level of radioactivity. In this article, we briefly introduced the extraordinary nature of D. radiodurans and also discussed the potential use of D. radiodurans strain for the removal of radioactive wastes.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.2 no.1
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• pp.41-51
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• 2004

The cost-effective reduction of occupational radiation dose (ORD) at a nuclear power plant could not be achieved without going through an extensive analysis of accumulated ORD data of existing plants. Through the data analysis, it is required to identify what are the jobs of repetitive high ORD at the nuclear power plant. In this study, Percentile Rank Sum Method (PRSM) is proposed to identify repetitive high ORD jobs, which is based on non-parametric statistical theory. As a case study, the method is applied to ORD data of maintenance and repair jobs at Kori units 3 and 4 that are pressurized water reactors with 950 MWe capacity and have been operated since 1986 and 1987, respectively in Korea. The results was verified and validated, and PRSM has been demonstrated to be an efficient method of analyzing the data.

• Korean Journal of Environmental Agriculture
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• v.26 no.2
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• pp.186-191
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• 2007

The objective of this research was to assess the reliability of data and to improve nuclear analytical techniques concerning the Domestic Radioactivity Intercomparison program for environmental radioactivity monitoring of Jeju from 1998 to 2006. Gross beta for filter papers and water samples was determined, and gamma nuclides for natural and artificial nuclides in soil and water samples were analyzed. The gross beta activity of all samples except for the water samples of 1998 and 1999 showed a good agreement within the confidence intervals. In gamma nuclides, $^{40}K$ and $^{137}Cs$ of soil samples and most nuclides in the water samples, with the exception of several nuclides, were evaluated to be reliable. Based on these results, it is considered that a reliable method for the analysis and monitoring of environmental radioactivity were established, which may play an important role in case of emergency radiation accident.

• Nuclear Engineering and Technology
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• v.4 no.1
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• pp.23-30
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• 1972

A study on the preparation of wood-plastic combinations by gamma-ray induced polymerization is carried out. In monomer impregnation, the rates and amounts are determined for various woods. The polymerization rates of various monomers and monomer mixtures impregnated mainly domestic woods are studied varying the total gamma-dose and gamma-dose rates. The obtained data indicate that; 1) in impregnation of monomer, populus deltoides is the fastest in rate, and the most impregnated in amount 2) the general trends of polymerization of monomers ill woods is in the order of vinyl acetate--methyl metacrylate--styrene, ranging from 3 to 15 Mard of total does in rate of 4$\times$10$^4$rad/hr., thus vinyl acetate or methyl metacrylate is suitable monomer in view of polymerization rate, 3) the successful woods in combination with monomer are pinus rigida and pinus densiflora in view of polymerization rate, 4) the monomers in woods are more easily polymerized under the conditions of moderately lower does rate, 2.1$\times$10$^4$rad/hr.

• Nuclear Engineering and Technology
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• v.5 no.3
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• pp.202-213
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• 1973

In a continuation of the 1st series of these studies, a separation of the components in organic phases obtained from Szilard Chalmer reactions of aromatic chloro derivatives was attempted to clarify the conditions of isolating the main component. Though it was unable to isolate all constituents of organic phases, the main component was well isolated by means of a simple distillation or a thin layer chromatography. It was identified that the main component was a recombined product of the recoiled $^{38}$ Cl atom with the original sample. In cases of solid samples the main component amounted about 80-60% of the radio activity of the organic phase, whereas the main component from liquid samples gave less than 70% of the radio activity of the organic phase. A prolonged irradiation could increase the yield of a main component, but it was, in case of a radiation senintive compound, decreased as the irradiation is extended. The number of aide produets separated from an organic phase of a liquid sample was greater than that of a solid sample, and hence the main component of a solid sample was isolated easier. The overall fields of the labelled main products of 22 kinds of compounds were listed and a procedure of the separation of the main component by a thin layer chromatograply was proposed and evaluated. The feasibility of the present procedure for labelling purpose was also reviewed with respects to the chemical structure of a compound.