• Journal of Radiation Protection and Research
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• v.23 no.2
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• pp.65-74
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• 1998

One of the important things in low level radioactivity measurement is determination of the optimized counting time. Counting strategy has to be established, in order to count the radioactivity of the sample by condition of optimized measurement. There were three kinds of counting strategies in this report ; about fixed time, about fixed count, to compared sample, background, and reference level. The best of them was satisfied rendition to give about condition of instrument and process, as an example, efficiency of detector, counter capacity, maximum and average background count rate of counter, reference level and limit of derision and detection, etc. Therefore, we can decide the optimized counting time in the screening and monitoring. And we can save the time for courting the sample of course the data of count will be counted by optimized accuracy finally, in rountine measurement of radioactivity these strategies will be used available.

• 대한방사선방어학회:학술대회논문집
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• 2009.04a
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• pp.108-109
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• 2009

• Journal of Radiation Protection and Research
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• v.24 no.3
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• pp.171-184
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• 1999

In this paper, using statistical theory the basic concepts and the formulars of lower limit of detection were deasribed. Assuming that risks of 5% are acceptable (95% confidence level), lower limits of detection were calculated on the measuring apparatus for alpha, beta and gamma nuclides. Also, on the basis concepts of lower limit of detection, the MDA values were calculated for the radionuclides detected easily in the environment. These results make it possible to evaluate confidence limits on the radioanalytical results in the environmental sample.

• Journal of Radiation Protection and Research
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• v.26 no.4
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• pp.393-398
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• 2001

The non-combustible RI wastes disposed of in hospital every year emit ${\gamma}$-ray or ${\beta}$-ray but their activities are very low to the extent of background. Development of more simple methods is needed because the conventional detection methods are so ineffective and complex. In this study, to solve this problem, detection method using efficiency curve for ${\gamma}$-ray emitting radioactive wastes measurement is proposed and experimental detection efficiency equation is also determined through HPGe's standard specimen measurement. For ${\beta}$-emitting radioisotopes detection, new measurement method using detection efficiency estimated by Monte Carlo simulation and SBD measurements is also proposed. According to the results of this paper, the unknown activity of low-level radioactive wastes without LSC requiring the preparation of standard sample and measurement for standard source detection efficiency could be determined efficiently and simply about ${\pm}17%$ in errors by using the theoretical detection efficiency and the SBD measurement result.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.06a
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• pp.284-289
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• 2005

According to the nuclear safety regulation policy including the administration of radionuclides in low level radwastes, the evaporator bottoms were mixed with cement to form a stable solidification for identifying the recovery possibility of the C-14. The chemical oxidation method was applied for the extraction of C-14 from the cement waste form. The emitting beta ray of the C-14 extracted from the radwastes was measured with the liquid scintillation counter and calculated by using the quenching correction curves. Only the beta emitting radioactive nuclides of the C-14 in the radwastes was showed the radioactivities with the range of $2.7E+00\;{\sim}\;3.07E+02$ Bq/g.

• Journal of Radiation Protection and Research
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• v.26 no.2
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• pp.51-58
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• 2001

In the low level radioactivity measurement, such as environmental radioactivity, there were used commonly cylindrical and Marinelli type beakers by means of measurement container. If there are differences in the matrix density or sample height between standard source and sample, it must be determined full energy peak efficiency considering self absorption effect. In this paper, we compared measured efficiency with calculated full energy peak efficiencies in the HPGe detector using the Monte Carlo method. For cylindrical container, we calculated the variation of the efficiency with sample height. Also, we calculated the variation of the detection efficiency with apparent density in the cylindrical and Marinelli container. It was seen that it need to be corrected for self absorption in the energy range of below 1000keV. Also, in order to verify the validity of calculation, we compared the calculated value with reference value using NIST SRM 4353 reference soil.

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

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.9 no.3
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• pp.141-148
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• 2011

It is clarified in the radioactive waste transfer regulation that the concentration of radioactive waste for the major radio nuclide has to be examined when radioactive waste is guided to the radioactive waste stores. In case of the low level radioactive waste sample, the analytical results of radioactive waste concentration frequently show a value lower than minimum detectable activity (MDA). Since the MDA value basically depends on the amount of a sample, background value, measurement time, counting efficiency, and etc, it would be necessary to increase a sample amount with a intention of minimizing MDA. In order to measure a concentration of $^{129}I$ in low and medium level radioactive waste, $^{129}I$ was collected by using a distillation technique after leaching the simulated radioactive waste sample with a non-volatile acid. The recovery of $^{129}I$ measured was compared with that measured with column elution technique which is a conventional method using an anion-exchange resin. The recovery of inactive iodide by using the distillation method and column elution were found as $86.5{\pm}0.9%$ and $87.3{\pm}2.7%$, respectively. The recovery and MDA value calculated for distillation technique when 100 g of extracted solution of $^{129}I$ was taken, were found to be $84.6{\pm}1.6%$ and $1.2{\times}10^{-4}Bq/g$, respectively. Consequently, the proposed technique with simplified process lowered the MDA value more than 10 times compared to the column elution technique that has a disadvantage of limited sampling amount.