In order to remove the radiotoxic nuclides, Cs+ and I–, from low-level liquid wastes, the adsorption characteristics have been studied using a mixed adsorbent of chabazite zeolite and activated carbon. The equilibrium data of each nuclide were well correlated with the DA equation in the wide range of equilibrium concentrations. The SEM-EDAX analysis provided precise understanding of the adsorption mechanism of each nuclide. A surface diffusion model was applied to estimate the intraparticle mass transfer and provided prediction results acceptable for practical implementation in the liquid waste treatment.
In the boron neutron capture therapy, an accurate determination of the boron content in a biological sample is very important.
The boron content was investigated with a standard solution of boron which was administered intraperitoneally with a dose
of 750 mg/kg body weight into mice induced cancer cells and tumors. The boron content for two types of a sample was compared
to the boronophenylalanine for the tumor and the ethylamine derivatives for the induced cancer cell, which were also investigated
for their accumulation rate in each organ such as blood, spleen, liver, kidney and brain. An analytical quality control was
carried out by using certified reference materials such as Peach Leaves, Apple Leaves and Spinach Leaves. The relative error
of the measured values was in good agreement within 2% to the certified values.
The Korea Atomic Energy Research Institute (KAERI) completed the High-flux Advanced Neutron Application Reactor (HANARO) in 1995 and the radioisotope production facilities(RIPF) in 1997. Many devices and handling tools were developed and applied for the production of radioisotopes. Emphasis on RI production plan was placed on the development of new radiopharmaceuticals, the development of new radiation sources for industrial use and the steady production of selected radioisotopes. The selected items are 166Ho-based pharmaceuticals, fission 99Mo/99mTc generators, and products of 131I and 192Ir and 60Co sources for industrial use. Now KAERI regularly produces radioisotopes (131I, 99mTc, 166Ho, 192Ir, 60Co etc.) and labeled compounds including 99mTc cold kits. Newly developed therapeutic agents are a 166Ho-chitosan complex for liver cancer treatment, a 166Ho patch for skin cancer treatment and devices such as the stent and balloon for the prevention against restenosis of the coronary artery. Feasibility studies on the installation of a 99mTc generator loading facility and on 60Co production for food irradiation were finished. The 192Ir sealed source assembly for NDT has been supplied to domestic users since May 2001. The fission moly process, separation process of non-sealed sources (125I, 33P, 89Sr, 153Sm, 188Re) and fabrication process of sealed sources (169Yb, 75Se) are also under development. For the quality assurance of our final products, we obtained ISO certification in 2000. We are carrying out a feasibility study on a new research reactor for the stable supply of radioisotopes in Korea.
It is important to increase a throughput of the salt removal process from uranium deposits which is generated on the solid
cathode of electro-refiner in pyroprocess. In this study, it was proposed to increase the throughput of the salt removal process
by the separation of the liquid salt prior to the distillation of the LiCl–KCl eutectic salt from the uranium deposits. The
feasibility of liquid salt separation was examined by salt separation experiments on a stainless steel sieve. It was found
that the amount of salt to be distilled could be reduced by the liquid salt separation prior to the salt distillation. The
residual salt remained in the deposits after the liquid salt separation was successfully removed further by the vacuum distillation.
It was concluded that the combination of a liquid salt separation and a vacuum distillation is an effective route for the
achievement of a high throughput performance in the salt separation process.
In order to reduce the toxicity of both raw wastewater and effluent from a rubber products factory, γ-ray treatment was applied
at different dose levels. The γ-ray treatment did not completely removed the toxicity, suggesting that there were major toxicants
other than destroyable organic compounds. Toxicity identification evaluation (TIE phase 1) was conducted to characterize major
toxicants using Daphnia magna. The suspected toxicants in both raw wastewater and effluent were mostly filterable materials and EDTA chelatable metals
and, to some degree, non-polar organic compounds. Anion-exchange removable compounds, most likely organics, were found only
in raw wastewater. Metal analyses showed that zinc and copper concentrations were above levels causing toxicity to D. magna. After 20 kGy γ-ray treatment of raw wastewater, filtrations both at pH 3 and at the initial pH (pH 3.6) showed dramatic
change (9 to 77% and 29 to 85%, respectively) in toxicity reduction, suggesting the formation of toxic filterable materials
which are stable even at acidic conditions. Unlike raw wastewater, there was no significant change in TIE results after γ-ray
treatment at 20 kGy for rubber effluent.
Correction equations of the coincidence-summing effect for efficiencies of HpGe detector based on the decay scheme were developed
by considering the summing up to triple coincidence. The correction equations which do not dependent on the kind of the Ge
detector are very useful for efficiency calibrations of a Ge detector in the energy region from 60 to 400 keV by using75Se radionuclide even with very short source-to-detector distances.
In order to develop an 125I seed for brachytherapy of prostate cancer, a carrier body consisting of Al2O3 and silver powder was developed. To optimize the adsorption conditions of 125I on the rods, various experiments were performed. The adsorption capacity was more than 95% after 4 hours at a volume of
50 μl containing about 5 mCi of 125I. Dosimetric properties were measured for the radial and longitudinal directions. Variations were below 11% in the longitudinal
distribution and 5% in the radial distribution. This method is effective for the preparation of 125I seeds to be used in brachytherapy treatment.
Neutron capture cross sections on 63Cu and 186W were measured by fast neutron activation method at neutron energies from 1 to 2 MeV. Monoenergetic fast neutrons were produced
by 3H(p,n)3He reaction. Neutron energy spread by target thickness, which was assumed to be the main factor of neutron energy spread,
was estimated to be 1.5% at neutron energy of 2.077 MeV. Neutron capture cross sections on 63Cu and 186W were calculated by reference comparison method on those of 197Au(n,γ). Not only statistical errors of gamma-counts from samples but also systematic errors in the counting efficiency for
HP Ge detector and the uncertainty of areal density of samples were considered in calculating neutron capture cross section.
Estimated neutron capture cross sections on 63Cu and 186W were also compared with ENDF-6 data.
Instrumental neutron activation analysis has been applied to semiconductor grade silicon to study the concentration levels of impurity elements, the contamination during the single crystal growing process, and the vertical and radial distributions of impurities, along with the decontamination effect in the analysis. Twenty elements of Au, Br, As, W, Cr, Co, Na, Eu, La, Se, Zn, U, Th, Hf, Fe, Sb, Ag, Ce, Tb and Ta have been analyzed in p- and n-type wafers, single crystals and a polycrystal by a single comparator method using two comparators of gold and cobalt. Considerable surface contamination has been found and could be removed by etching the surface with nitric and hydrofluoric acid before and after irradiation. The impurity concentration has been found to be generally increased in the process of single crystal growth. The vertical and radial distributions of impurities have revealed that some impurity elements were more concentrated in the top region of a single crystal rod than in the middle region, and that Br, Cr, La, Eu and Sb were enriched in the central region and As, U and Fe in the outer region.