• Journal of Conservation Science
• /
• v.16 s.16
• /
• pp.5-14
• /
• 2004

Luminescence dating is based upon the premise that several commonly occurring minerals (e.g. quartz and feldspar) can be used as natural dosimeters, recording the amount of radiation to which they have been exposed. We report results of optical dating on quartz samples separated from archaeological remains (burnt soils and potteries), which were excavated at Myungam-Ri, Asan, and Chungnam province and at Sayang-Ri, Chinchun, Chungbuk province, considered as the cultural site of the early Bronze Age. The resultant dates were in good agreement with the ages derived by archaeological assessment. It is concluded that the optical dating introduced in here should contribute significantly to future archaeological dating work.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.51 no.3
• /
• pp.10-21
• /
• 2014

In Fukushima accident, when the severe accident such as a natural disaster happens, it is impossible to monitor the plant status due to a extreme environment and station blackout and most I&C systems break downs. Finally, these cause the loss of emergency cooling function and thus results in a hydrogen explosion and radiation leak. In this paper, the emergency response system is introduced that monitors and controls properly when the sever accidents like Fukushima accident happen, And the performance requirements of a wireless communication system used in the emergency respons system is described and the performance of emergency communication system is analyzed using the markov model.

• Journal of the Korean Society of Radiology
• /
• v.8 no.7
• /
• pp.443-447
• /
• 2014

$^{134}Cs$ radioactive concentration among soil samples is difficult to classify due to the background impact on crust originated natural radioactive nuclide, and overlapping and interfering between peaks. The ways to identify true peaks in gamma-ray spectroscopy are as follows to reduce statistical fluctuation by smoothing based on the fact that the shapes of peak are mostly Gaussian, to inspect the levels of width and height of peaks, to add functions on low-energy trailing phenomena, or 4) to check the peaks after modifying Gaussian function itself. Therefore, it is considered that information and knowledge for spectrum analysis are necessary.

• Journal of Radiation Protection and Research
• /
• v.23 no.4
• /
• pp.237-242
• /
• 1998

The goal of this work was to optimize the liquid scintillation counting techniques for the determination of C-14 in environmental samples such as biological and air samples. Carbon-14 activities in most environmental samples were measured with direct $CO_2$ absorption method. The highest figure of merit was found through the variation of Carbosorb $E^{TM}$ and Permatluor $V^{TM}$ ratio, in the measurement windows. The best condition was 1:1 volume ratio. Average 2.35 g of $CO_2$ was reproducibly absorbed in the 20 ml mixture within 40 min. The counting efficiency determined by repeated analysis of NIST oxalic acid standard and the background count rate were measured to be $58.8{\pm}1.4%$ and $1.88{\pm}0.06\;cpm$, respectively in case of saturated solution. The correction curves of counting efficiency for partially saturated solutions and for saturated solutions with quenching were prepared, respectively. The overall uncertainty of the sample specific activity for near background levels was estimated to be about 7 % for 4 hours counting at 95 % confidence level. The long-term stability of samples has been checked for all the counting techniques over a two week periods, and no apparent change in counting efficiency and background level was found at that time.

• Journal of Radiation Protection and Research
• /
• v.34 no.4
• /
• pp.190-194
• /
• 2009

Gamma spectral results for macroalgae samples taken from the environment of Ulchin nuclear power plants in Korea (east coast), showed 766 keV peaks, which were identified as $^{95}Nb$ by several research institutes. After the enhancement of liquid radioactive waste disposal facility at Ulchin NPP site, the $^{95}Nb$ amount in the liquid radioactive waste outflow has drastically reduced, but the expected reduction in $^{95}Nb$ specific activity from environmental samples did not actually show up on gamma spectroscopy. Detailed re-investigation revealed that along with 766 keV peak, other peaks (63, 92 and 1001 keV) from $^{234}Th-^{234}mPa$ decay series were also detected on spectroscopy, and that the measured half lives of the four peaks were very close to known half life of $^{234}Th-^{234}mPa$ decay series, which is 24.1 day. The measured gamma yield ratios of 766 keV peak to 1001 peak were very close to known ratio 0.35 for $^{234}mPa$. It is concluded that 766 keV peaks on gamma spectroscopy of Ulchin NPP environmental samples were mainly from $^{234}mPa$, which is one of naturally occurring radionuclides.

• Journal of Radiation Protection and Research
• /
• v.19 no.2
• /
• pp.121-132
• /
• 1994

This study concerns about the measurement and the investigation of environmental radiation characteristics which the components and the distribution of exposure rates by terrestrial y-rays in Taegu area. $4^{'}{\phi}{\times}4^{'}$ NaI(T1) scintillation detector with a multichannel analyzer was used in the measurement of y-rays as a part of in-situ spectrometry at twenty eight different locations in this area. The conversion into the exposure rate from the measured ${\gamma}-ray$ spectrum has been carried out leading to a net exposure rate and component ones by $^{40}K,\;^{238}U$ series and $^{232}Th$ series products which are known by the major parts in the terrestrial ${\gamma}-rays$ generally. As a result, the average exposure rate by the terrestrial ${\gamma}-rays$ in Taegu area is $9.4{\mu}R/h$ and the distribution of individual exposure rates shows more or less differences between these locations even after the consideration of diurnal and yearly variations which are always involved in these measurements. The component parts of exposure rates are distributed $^{40}K\;2.9{\sim}4.6{\mu}R/h,\;^{238}U$ series $1.2{\sim}3,\;1{\mu}R/h,\;^{232}Th$ series $2.5{\sim}5.0{\mu}R/h$ over the measured locations.

• Tuberculosis and Respiratory Diseases
• /
• v.43 no.5
• /
• pp.720-727
• /
• 1996

Objectives: $^{201}TI$ - chloride, $^{99m}Tc$ - MIBI, $^{99m}Tc$(V) - DMSA SPECT has been used in distinguishing lung cancer from benign lesion. To compare the diagnostic efficacy of SPECT with these tumor - seeking agents, we perfonned three consecutive SPECT using $^{201}TI$, $^{99m}Tc$ - MIBI, $^{99m}Tc$(V) - DMSA in same subjects with a solitary pulmonary lesion. Methods: SPECT was carried out at 10min and 3hr for $^{201}TI$ after injection of 20mCi, and 2hr for $^{99m}Tc$ - MIBI and $^{99m}Tc$(V) - DMSA after injection of 20mCi, respectively, in 37 patients with a solitary pulmonary lesion(27 lung cancer and 10 benign diseases). In patients showing visual uptake on lesion site, we obtained the lesion - to - background(target lesion/contralateral normal lung) uptake ratio from transverse slice for each radionuclide and also calculated the retention index for $^{201}TI$. Results: The diagnostic sensitivity of $^{201}TI$, $^{99m}Tc$ - MIBI and $^{99m}Tc$(V) - DMSA SPECT to lung cancer was 100%, 96% and 73%, and the specificity was 40%, 70% and 70%, respectively. The low specificities for these agents were mainly due to high positive uptake in patients with active pulmonary tuberculosis. There were no significant differences in uptake ratios and retention index between malignant and benign lesions, and among the histologic types of lung cancer. Conclusion : $^{201}TI$ and $^{99m}Tc$ - MIBI showed higher sensitivity than $^{99m}Tc$(V) - DMSA for detecting lung cancer, but was of limited usefulness in distinguishing lung cancer from benign lesion due to low specificity, especially in area with a high prevalence of active pulmonary tuberculosis.

• Journal of Radiation Protection and Research
• /
• v.26 no.2
• /
• pp.67-71
• /
• 2001

In order to shield the neutrons affecting the background of Low Level Gamma Ray Spectrometer, a neutron shielder was designed. The method used in this study for neutron shielding was the deceleration of fast neutrons by high density polyethylene(HDPE) and the absorption of those slowing-down neutrons by $B_4C$. The calculation results of neutron Interaction in HDPE using Monte Carlo simulation code MCNP4B showed that the thermal-neutron flux was maximum at 10 cm thickness of HDPE. The results also showed that 95% of the thermal neutrons were absorbed by 2 mm thickness of $B_4C$ absorber Consisted of 30 w% $B_4C$ and 70 w% polymer. The results of the Monte Carlo calculation were in good agreement with the experimental value obtained by a neutron shielding apparatus designed for this purpose.

• Journal of Radiation Protection and Research
• /
• v.34 no.4
• /
• pp.195-200
• /
• 2009

effluents to the environment. The activity of carbon-14, one of the radioactive effluents, in the environment is already high level and its effect on radiation exposure to the public and the environment is insignificant; thus, NPPs did not perform the carbon-14 monitoring in effluents in the past. By the way, effluents of noble gas and particulate radioactive materials originated from nuclear fuels has been continuously reduced due to both the advancement of manufacturing and integrity technology for nuclear fuels and the improvement of operation methods of NPPs. Futhermore, the portion of dose assessment by tritium and carbon-14 to the public has been relatively increased because the lower limit of detection for low-energy beta sources, such as tritium and carbon-14, is low due to the advancement of radiation detection technology. In this paper, the technical background for carbon-14 monitoring in nuclear facilities was investigated using United States technical reports and papers. This paper also reviews whether carbon-14 monitoring is necessary or not based on the investigated documents.

• The Journal of Engineering Geology
• /
• v.26 no.4
• /
• pp.531-549
• /
• 2016

The purpose of this study is to analyze the relationship of hydrochemistry, geology, fault with occurrence of uranium and radon-222 from the groundwater in the Yeongdong area. In this study, 49 groundwater and 4 surface water samples collected in the study area were collected on two separate occasions. The surface radioactivities were measured at 40 points to know the relationship between the occurrence of uranium in groundwater and surface geology. The chemical composition of groundwater showed three types : $Ca-HCO_3$, $Na-HCO_3$ and $Ca-HCO_3(SO_4,\;NO_3)$. Two groundwater of 49 samples exceeded the maximum contaminant levels of uranium, $30{\mu}g/L$, proposed by the Ministry of Environment of Korea and 11 groundwater of 40 samples for Rn-222 concentrations exceeded the 148 Bq/L maximum contaminant level of US EPA. Most of unsuitable groundwater are located in the geological boundary related with the biotite gneiss and the surface radioactivities of rock samples showed no relationship with groundwater geochemical constituents. The strike-slip fault, Youngdong fault, is $N45^{\circ}E$ direction and the high concentrations of uranium in upper part of fault, consisted of granite and granitic gneiss are detected but in lower part, consisted of metamorphic sedimentary rock are not detected. It suggests that the natural radioactive concentrations are related with the geologic characteristics and the migration and diffusion of natural radioactive materials are affected by the fault.