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[en] A method for the simultaneous determination of 226Ra and 210Pb in groundwater and soil samples by liquid scintillation counting was developed. Radium and lead were separated together from the samples as Ba(Ra)·PbSO4 co-precipitate, which was centrifuged and dissolved with 0.1 M EDTA solution (pH 9.0). Radium was separated as Ba(Ra)SO4 co-precipitate by adding ammonium sulfate and adjusting the pH of the solution to 4.2. Lead remaining in the solution was separated as PbSO4 precipitate by adding 9 M sulfuric acid. These Ba(Ra)SO4 and PbSO4 precipitates were purified with EDTA solution and used for measurement. To save time and to make counting samples simpler, direct counting of Ba(Ra)SO4 and PbSO4 precipitates instead of the phosphoric acid fusion method was attempted. Ba(Ra)SO4 and PbSO4 precipitates were suspended in the scintillation gel, and measured. Two liquid scintillation cocktails, Instagel[r] XF and UltimaGoldtm AB were used to prepare the counting samples. A mixture of water (40%), Instagel[r] XF (40%) and UltimaGoldtm AB (20%) formed a stable gel. Activities of 226Ra and 210Pb were calculated from the alpha spectrum of Ba(Ra)SO4 and beta spectrum of PbSO4, respectively. The long-term stability of the suspension gel was good. The analytical results of 226Ra and 210Pb in spiked groundwater samples were in good agreement with the known concentrations of 226Ra and 210Pb. The analytical values of 226Ra and 210Pb in the soil reference samples were within 11.5 and 1.6% of the relative error from the reference values, respectively
[en] The Korean Regulation of the Act provides a procedure for testing the performance of dosimetry system for the purpose of monitoring personnel exposure to ionizing radiation. This regulation is based on the ANSI N13.11-1993 standards (Personnel Dosimetry Performance — Criteria for Testing) and enforced since 1995 in Korea. Through undergoing periodic review of the ANSI Standard by ANSI policy, several modification of ANSI N 13.11-1993 was issued by ANSI N13.11-2001 and 2009 with considering that the standard should be applied the real radiation working fields. The important changes of ANSI N13.11-2009 compared to the 1993 version can be shown in the other literature. In this paper, for the new performance test, the Test Categories were revised, and the test procedures necessary for the performance test such as the type of radiation, type of mixed radiation field, dosimeter irradiation methods and the number of irradiations dosimeters in each test category were determined. Revised test categories for the personal dosimetry performance test are established to reflect the on-site conditions where the radiation workers are exposed and to conform the international standards. The characterizations of the new system are as followings. I) Easy to maintain traceability the Irradiation system by using ISO radiations 2) Reflecting the dose response according to the incident angle of photon by the movement of the radiation workers to the test item 3) Strengthened evaluation of low-energy beta particles, reflecting low-energy beta that arc being used for medical use 4) Addition of non-moderated Cf-252 source to improve the performance evaluation of high-energy neutrons from accelerators, etc.
[en] 1. Establishment of retrospective dosimetry technology for radiation accident dosimetry 1) Development of retrospective dosimetry technology using personal electronic devices (smart phones) 2) Development of retrospective accident dosimetry technique using building materials 3) Designing and assembling of OSL spectrum measurement equipment and development of required software for OSL/TL analysis 2. Interpretation of new models for intake of radionuclides and it’s application to internal dosimetry system 1) Analysis and application of HATM 2) Analysis of OIR and establishment of application system 3) Calculation of retention functions for each radionuclide using OIR 3. Establishment of radiological performance testing scheme of radiation detection systems used for radiation protection, radiological emergency and security 1) Production of the reference X-ray fields (ISO LK qualities) and gamma ray field for test and calibration of personal electronic dosimeters and workplace monitors. 2) Establishment of field performance testing systems used for radiation protection.
[en] In the present study, the models and datum specified in the Appendix K to 10 CFR 50 and USNRC Regulatory Guide 1.157 are reviewed and the evaluation of the applicabilities of the models and datum are discussed. Eight categories including the fission product decay heat models for the conservative evaluation and 23 models and datum including fuel internal heat transfer are reviewed. The following results are obtained : (1) Based on the technical level at the time the USNRC ECCS rule was developed, the models and datum specified in the requirements and guide have their sound technical basis. (2) The models, correlations and datum reviewed can be used in either conservative or best-estimate ways and can be acceptable in the ECCS performance evaluation. (3) Some best-estimate models and datum such as ECCS bypass needed a further investigation for justification of the validity and applicability. (4) The evaluated models in this study can be regarded as acceptable models. However, some models needed to be updated to a new version since an advanced model and data has been developed and proposed. For the implementation of those new version, additional analysis and evaluation may be required
[en] Scope and Contents of Project. Development of rapid dose reconstruction technology for large-scale radiation accidents and terrorism. Development of quantification technology for neutron / gamma mixed fields. Research results. Development of new radiolabeling material and securing technology for dose restoration. Development of rapid reading technology for exposure to large-scale accident Development of integrated neutron / gamma mixed radiation quantification technology. Proposal for Applications. New radiation marker. Algorithm and program for converting dose of labeling substance into human exposure dose. In-situ dose restoration equipment. Establishment of research network with dose restoration laboratories (speed efficiency through emergency dose distribution). Exposure dose information on tracking vehicle / building interior / suspect portable goods of radiation terrorism. New materialisation material for neutron / gamma simultaneous measurement. Neutron / gamma simultaneous measurement algorithm and measurement system
[en] Using ultrasound techniques, the Human Monitoring Laboratory has measured chest wall thicknesses of a group of male workers at the Korea Atomic Energy Research Institute. A site-specific biometric equation has been developed for these workers, who are somewhat smaller than other workers reported in the literature. Chest wall thickness is an important modifier on lung counting efficiency. These data have been put into the perspective of the ICRP recommended dose limits for occupationally exposed workers: 100 mSv in a 5-year period with a maximum of 50 mSv in any one year. For measured chest wall thicknesses of 1.9 cm to 4.1 cm and a 30 min counting time, the achievable MDAs for natural uranium in the KAERI lung counter vary from 6.6 mg to 13.2 mg. These values are close to, or even exceed, the predicted amounts of natural uranium that will remain in the lung (absorption type M and S) after an intake equal to the Annual Limit on Intake corresponding to a committed dose of 20 mSv. This paper shows that the KAERI lung counter probably cannot detect an intake of Type S natural uranium in a worker with a chest wall thickness equal to the average value (2.7 cm) under routine counting conditions. (author)
[en] The surface electronic structures of superconducting MgB2 were investigated using the all-electron full-potential linearized augmented plane-wave method. Hexagonal (0001) surfaces with both B terminated (B-Term) and Mg terminated (Mg-Term) were considered. Due to the nearly-free-electron nature of the Mg surface layer, the vacuum screening range of Mg-Term is shorter than that of B-Term, which shows the covalent bonding nature of the B surface layer. Considerably enhanced densities of states near the Fermi level are found at the surface layers especially for B-Term, which is expected to yield an enhanced superconductivity in the surface of thin film MgB2 over that in bulk -- assuming no large changes in the electron-ion matrix elements and phonon frequency contributions. While this expectation is contrary to the weakened superconductivity observed in surface-oriented experiments, we attribute this discrepancy to extrinsic surface effects
[en] This report describes the contents and results for implementation of internal radiation monitoring programme, measurement of uranium present in lung by lung counter and assessment of committed effective dose for radiation workers of the KNFC. The aim of radiation protection was achieved by implementing this activity
[en] A system for calculating intake fractions using ICRP publication 66 respiratory tract model and recent biokinetic models was established. Intake fractions for whole body, an organ and excreta as a function of a particle size were calculated for all radionuclides given in annex A of ICRP publication 78. As compared with other researcher's results, it was shown that there were good agreements within a 0.3% error of each other
[en] The effects of AMAD, absorption type, and intake type were compared and analysed for internal dose evaluation of workers who chronically inhaled uranium. The committed effective dose(E50) based on AMAD, absorption type, and intake type were evaluated using the IMIE(Individual Monitoring of the Internal Exposure) computer code with 3 monthly lung detection datum during 5 years. As a result, it was shown that the lowest E50 at AMAD 1μm regardless of absorption type or intake type. AMAD affected the greatly results of E50, and intake type didn't really affect the result of E50. The relative error ranges of E50 evaluated with each AMAD(0.1∼10μm) for E50 evaluated by ICRP's recommendation(5 μm, Type S) were -36 ∼ 34%