Search Results

You are looking at 1 - 10 of 22 items for

  • Author or Editor: Kil Lee x
  • Refine by Access: All Content x
Clear All Modify Search

Abstract  

A radiochemical neutron activation analysis using solvent extraction has been applied for the determination of trace impurities in high purity nickel. Because of the high activity of58Co produced by the nuclear reaction,58Ni(n,p)58Co, cobalt should be separated from the impurities. Removal of cobalt from the other trace elements in the aqueous acidic solution containing 1M thiocyanate ion (KSCN) was achieved by extraction with 1M2-benzylpyridin (BPy) in benzene. From the result of tracer experiments, cobalt was completely separated from most other elements except Fe, Mo and Zn. To determine the experimental accuracy, NIST SRM 673 nickel oxide was analyzed and the results agreed well within 10% deviation. This established radiochemical method was applied to the analysis of high purity nickel samples.

Restricted access

Abstract  

Tritium and 14C concentration in hot spring water in Korea were determined. Tritium in the most hot spring samples could not detected and concentration range was <0.5–1.31 TU. And 14C contents were ranged 1.7–78.6 pMC. From the 3H and 14C analysis, we found some hot springs are mixed with recent groundwater and hot spring water ages were estimated from 1,940 to 32,800 years. And also, 226Ra and 228Ra were determined simultaneously in hot spring water, and some other radionuclides were also analyzed. Content distribution of 222Rn was 50–3,760 pCi/L, 226Ra was <0.003–0.15 Bq/L and 228Ra was below the detection limit.

Restricted access

Abstract  

The contents of H-3 and C-14 in groundwater and surface waters around low and medium-level atomic waste repository site in Korea were determined. The concentrations of C-14 were in the range 0.186–0.287 Bq/L. The H-3 concentration of the groundwaters and surface waters were <0.06–5.75 and 1.22–4.74 Bq/L. The average H-3 contents of west, north and south direction were 1.18 ± 0.12, 1.11 ± 0.78 and 2.85 ± 2.66. H-3 and C-14 concentrations in the south direction were relatively higher than west and north direction samples. The surface waters sampled from catchment were four times higher than average H-3 concentration in precipitation. The concentrations of H-3 and C-14 within 5 km area samples were much higher than other samples.

Restricted access

Abstract  

The radon emanation coefficient (ε) from aquifer rock and the Henry’s law constant (H) of radon were determined by measuring activity concentrations using liquid scintillation counter (LSC). For the evaluation of the method, the coefficients were measured at 0, 10 and 20 °C and the temperature dependency of the coefficients was compared with others. The radon emanation coefficients from the rock particles used in this work are 0.0845, 0.1007 and 0.1308 at 0, 10 and 20 °C, respectively. The dimensionless Henry’s law constants for the groundwater used in this work are 0.994, 1.153 and 2.641 at 0, 10 and 20 °C, respectively. The results show a good agreement with those in literatures.

Restricted access

Abstract  

A method of tritium electrolytic enrichment was developed, optimized and validated. The enrichment parameters were compared with different current and total current charge variation and tritium separation factor was from 8 to 36 with a current density variation. The detection limit of tritium measurement is about 0.5 TU using 1,000 mL sample and 600 min counting time. Several samples of groundwaters were processed in our and another laboratory with good agreement of results within 15% deviation. Developed and validated method of tritium determination was applied groundwaters in Jeju Island with a liquid scintillation counter (LSC) and electrolytic enrichment method using Ni–Ni electrodes. The tritium concentrations in fifty eight groundwaters in Jeju Island were ranged <0.5 TU-3.9 TU and averaged value was 2.12 TU.

Restricted access

Abstract  

The objective of this research is to trace the sources of stream sediments in a small watershed influenced by anthropogenic and lithogenic origins identified by the spatial distributions and temporal variations of stream sediments using geochemical interpretation of the stable and radiogenic isotopes, major components, and heavy metals data and principal component analysis. To know the effects of both present and past mining, the stream sediments were sampled at the stream tributaries and sediment coring work. The spatial distributions of heavy metals clearly showed the effects of Cu and Pb–Zn mineralization zones at the site. Anthropogenic Pb was elevated at the downstream area by the stream sediments due to an active quarry. The results of principal components analysis also represent the effects of the stream sediments origins, including anthropogenic wastes and the active quarry and lithogenic sediment. Anomalous Cu, indicating the effect of past Guryong mining, was identified at the deep core sediments of 1.80–5.05 m depth. The influence of active quarry was shown in the recently deposited sediments of <1.50 m depth, which was proved by the profiles of radioactive 210Pb and stable Pb and Sr isotopes. This study suggests that the chemical studies using radiogenic and stable isotopes and heavy metals and multivariate statistical method are useful tools to discriminate the sources of stream sediments with different origins.

Restricted access

Abstract  

Instrumental neutron activation analysis (INAA), ICP/MS and XRF were applied for the characterization of relative locales of Korean old potteries, which had three different era and four regional characters. From the elemental analysis, two major elements such as Fe, Ti and some minor elements such as Cr, Sc, Zr were supposed to the main contributing factors for the regional classification. And the contents of rare earth elements, such as Eu and La were different in each pottery.

Restricted access

Abstract  

Instrumental neutron activation analysis has been applied in the determination of toxic and other trace elements in a set of three algae materials provided by the International Atomic Energy Agency, with the aim of environmental preservation through enhanced applications of nuclear analytical techniques. The quality of the analysis method has been evaluated by analyzing a number of biological standard reference materials. By adding mineral nutrients, the cultivation of algae for metals is enhanced, in particular, selected toxic heavy metals such as As, Cd, Cr, Hg, Ni and Pb. It is believed that the level of elemental concentration in algae samples are dependent on environmental conditions due to its biochemical properties. Therefore, algae materials may be useful as an indicator or controller of environmental water pollution.

Restricted access

Abstract  

The source of contaminating high purity silica during grinding process and analytical sensitivity of alpha-emitting impurities have been investigated. To improve the analytical sensitivity for alpha-emitting impurities in grinding high purity silica, a new procedure was studied by employing an irradiation facility in the hydraulic transfer system (HTS) and the nitrogen flushing system. The source of silica contamination was found to be attributed mostly to alumina balls. The detection limit of U and Th in 3N-grade silica samples by neutron activity analysis (NAA) could be improved to a sub-ng/g level. The contamination rates of Th, U, Cl, Fe and Na from the alumina balls were calculated to be 95%, 15%, 15% and 3.5%, respectively.

Restricted access

Abstract  

A simple method for the determination of the radon emanation fraction was studied using a liquid scintillation counter. The radon activity of the gaseous phase in a closed container was measured 1 day and 35 days after sealing and used to calculate the radon emanation fraction. Radon leakage from the container was investigated using a 226Ra radioactive standard solution (SRM4967, NIST) to plot a radon growth curve. The method was applied to materials that typically contain a high level of radium, such as phosphogypsum, phosphate fertilizer and a rock sample. The effect of temperature on the radon emanation fraction from the materials was investigated at 0, 10, 20, 30 and 40 °C. It was found that there is a linear correlation (R 2 = 0.746 − 0.946) between temperature and the emanation fraction. Within the temperature range, the radon emanation fractions were 0.241–0.466 for phosphogypsum, 0.225–0.351 for phosphate fertilizer and 0.154–0.351 for the rock sample.

Restricted access