Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of Radiation Protection and Research
Journal Basic Information
Journal DOI :
Korean Association for Radiation Protection
Editor in Chief :
Volume & Issues
Volume 23, Issue 4 - Dec 1998
Volume 23, Issue 3 - Sep 1998
Volume 23, Issue 2 - Jun 1998
Volume 23, Issue 1 - Mar 1998
Selecting the target year
Analysis of the Distributional Effects of Radioactive Materials on External Gamma Exposure
Han, Moon-Hee ; Kim, Eun-Han ; Suh, Kyung-Suk ; Hwang, Won-Tae ; Choi, Young-Gil ;
Journal of Radiation Protection and Research, volume 23, issue 4, 1998, Pages 211~218
The distributional effects of radioactive materials on external gamma exposure have been analyzed. An approximate method for estimating external gamma dose given from an arbitrary distribution of radioactive material has been developed. The minimum gamma exposure given from a point source is shown at 0.07 MeV if the source to receptor distance is shorter than 10 m. But if the receptor to point source distance is longer than 20 m, gamma exposure rate increases monotonously according to the average gamma energy. For the analysis of the effects of volume source, we estimated the gamma dose given from different size of hemisphere in which radioactive materials are distributed uniformly. When the radius of hemisphere is longer than 40 m, external gamma dose rate increases monotonously. The gamma dose rate given from the radioactive materials deposited on the ground shows the minimum value at 0.07 MeV in any case. The analysis shows that external gamma exposure is strongly dependent on the distribution of radioactive materials in the environment and gamma energy.
Contamination of Chinese Cabbage with
Related to Time of Foliar Application
Choi, Yong-Ho ; Lim, Kwang-Muk ; Park, Hyo-Guk ; Lee, Won-Yun ; Lee, Chang-Woo ;
Journal of Radiation Protection and Research, volume 23, issue 4, 1998, Pages 219~227
A solution containing
was applied to Chinese cabbage in a greenhouse via foliar spraying at 5 different times during its growth. Interception of the applied activity by plant showed no difference among radionuclides and increased with decreasing time interval between application and harvest. The maximum interception factor observed was 0.87. Percentages of the intercepted activity remaining in the whole leaves at harvest varied
, with application time and those for the inner leaves (without 6 outmost leaves) varied
, respectively. It was demonstrated that rain plays an important role in weathering loss of the activity. Tying the upper end of the plant prior to the last application lowered interception and remaining activity in the inner leaves by factors of
. Present results can be referred to in predicting the radionuclide concentration in Chinese cabbage and deciding counter-measures at the time of an accidental release from the nuclear installation.
Evaluation of Characteristics in the Reference Gamma Radiation Fields for testing of Personnel Dosimetry Performance
Oh, Jang-Jin ; Cho, Dae-Hyung ; Han, Seung-Jae ; Na, Seong-Ho ; Lee, Dew-Hey ; Lee, Byung-Soo ; Jun, Jae-Shik ; Chai, Ha-Seok ; Yi, Chul-Young ;
Journal of Radiation Protection and Research, volume 23, issue 4, 1998, Pages 229~236
In order to establish a testing system for personnel dosimetry performance, the radiation fields from photons, beta particles and neutrons are required, in recent, Korea Institute of Nuclear Safety(KINS) established the reference radation fields except neutrons and tested a variety of their properties. As a result of the test, the reference beams were shown to meet satisfactorily not only the standards of the International Organization for Standardization(ISO), but also the standard levels of the developed countries which are intercomparable with the international traceability. This paper describes the reference beam of gamma radiation. The self-designed and established reference radiation fields were investigated and analyzed by ISO and other international standards. The secondary photon contribution and the beam uniformity of the gamma radiation field were measured and evaluated to fulfill those requirements suggested by the ISO-4037. The measured air kerma rate for the
Co gamma fields was 0.1891
Gy/s sand 0.5844
Gy/s respectively. The uncertainty with 95 % confidence level of the measured air kerma rate was determined to be less than 2.5 % which is comparable to the international reference gamma radiation fields. It was found that the evaluated air kerma calibration factors of Exradin ionization chamber were in good agreement within 0.9 % and 0.03 % with those given by PTB and NIST, respectively. The gamma radiation fields installed at KINS can maintain traceability systems in Korea, Germany and United State.
Direct Absorption Method for the Determination of Carbon-14 in Environmental Samples
Cho, Soo-Young ; Woo, Hyung-Joo ; Chun, Sang-Ki ;
Journal of Radiation Protection and Research, volume 23, issue 4, 1998, Pages 237~242
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
absorption method. The highest figure of merit was found through the variation of Carbosorb
ratio, in the measurement windows. The best condition was 1:1 volume ratio. Average 2.35 g of
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
, 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.
A Methodology for Justification and Optimization of Countermeasures for Milk After a Nuclear Accident and Its Application
Hwang, Won-Tae ; Han, Moon-Hee ; Kim, Eun-Han ; Cho, Gyu-Seong ;
Journal of Radiation Protection and Research, volume 23, issue 4, 1998, Pages 243~249
The methodology for justification and optimization of the countermeasures related with contamination management of milk was designed based on the cost and benefit analysis. The application results were discussed for the deposition on August 15, when pasture is fully developed in Korean agricultural conditions. A dynamic food chain model DYNACON was used to estimate the time-dependent radioactivity of milk after the deposition. The considered countermeasures are (1) the ban of milk consumption (2) the substitution of clean fodder, which are effective in reducing the ingestion dose as well as simple and easy to carry out in the first year after the deposition. The total costs of the countermeasures were quantitatively estimated in terms of cost equivalent of doses and monetary costs. It is obvious that a fast reaction after the deposition is an important factor in cost effectiveness of the countermeasures. In most cases, the substitution of clean fodder was more effective countermeasure than the ban of consumption. A fast reaction after the deposition made longer justifiable/optimal duration of the countermeasure.
A Study on the Diffusion of Gaseous Radioactive Effluents Based on the Statistical Method
Na, Man-Gyun ; Lee, Goung-Jin ;
Journal of Radiation Protection and Research, volume 23, issue 4, 1998, Pages 251~257
A diffusion model of radioactive gaseous effluents is improved to apply for domestic nuclear power plants. Up to now, XOQDOQ computer code package developed by U. S NRC has been used for the assessment of radioactive plume dispersion by normal operation of domestic nuclear power plants. XOQDOQ adopts the straight-line Gaussian plume model which was basically derived for the plane terrain. However, since there are so many mountains in Korea, the several shortcomings of XOQDOQ are improved to consider the complex terrain effects. In this work, wind direction change is considered by modifying the wind rose frequency using meteorological data of the local weather stations. In addition, an effective height correction model, a plume reduction model due to plume penetration into mountain, and a wet deposition model are adopted for more realistic assessments. The proposed methodology is implemented in Yongkwang nuclear power plants, and can be used for other domestic nuclear power plants.
The Study of Shielding Effect on Ovoids of Three Different Gynecological Applicator Sets in microSelectron-HDR System
Cho, Young-K. ; Park, Sung-Y. ; Choi, Jin-H. ; Kim, Hung-J. ; Kim, Woo-C. ; Loh, John-J.K. ; Kim, Joo-Y. ;
Journal of Radiation Protection and Research, volume 23, issue 4, 1998, Pages 259~266
There are three different types of gynecological applicator sets available in microSelectron-high dose-rate(HDR) System by Nucletron; standard applicator set(SAS), standard shielded applicator set(SSAS), and Fletcher-Williamson applicator set(FWAS). Shielding effect of a SAS without shielding material was compared with that of a SSAS with shielding material made of stainless steel(density
) at the top and bottom of each ovoid, and of a FWAS with shielding material made of tungsten alloy(density
at the top and bottom of each ovoid. The shielding effects to the rectum and bladder of these two shielded applicator sets were to be measured at reference points with an ion chamber and specially designed supporting system for applicator ovoids inside of the computerized 3-dimensional water phantom. To determine the middle point of two ovoids the measurement was performed with the reference tip of ion chamber placed at the same level and at the middle point from the two ovoids, while scanning the dose with the ion chamber on each side of ovoids. The doses to the reference points of rectum were measured at 20(Rl), 25(R2), 30(R3), 40(R4), 50(R5), and 60(R6) mm located posteriorly on the vertical line drawn from M5(the middle dwell position of ovoid), and the doses to the bladder were measured at 20(Bl), 30(B2), 40(B3), 50(B4), and 60(B5) mm located anteriorly on the vertical line drawn from M5. The same technique was employed to measure the doses on each reference point of both SSAS and FWAS. The differences of measured rectal doses at 25 mm(R2) and 30 mm(R3) between SAS and SSAS were 8.0 % and 6.0 %: 25.0% and 23.0 % between SAS and FWAS. The differences of measured bladder doses at 20 mm(Bl) and 30 mm(B2) between SAS and SSAS were 8.0 % and 3.0 %: 23.0 % and 17.0 % between SAS and FWAS. The maximum shielding effects to the rectum and bladder of SSAS were 8.0 % and 8.0 %, whereas those of FWAS were 26.0 % and 23.0 %, respectively. These results led to the conclusion that FWAS has much better shielding effect than SSAS does, and when SSAS and FWAS were used for gynecological intracavitary brachytherapy in microSelectron-HDR system, the dose to the rectum and bladder was significantly reduced to optimize the treatment outcome and to lower the complication rates in the rectum and bladder.
Air Density Correction of Ionization Chamber using
Radioactive Check Device
Park, Sung-Y. ; Kim, Woo-C. ; Shin, Dong-O. ; Ji, Young-H. ; Kwon, Soo-I. ; Lee, Kil-D. ; Cho, Young-K. ; Loh, John-J. ;
Journal of Radiation Protection and Research, volume 23, issue 4, 1998, Pages 267~271
It is required to measure air density correction factor at the time of absorbed dose calibration or measurement. In general, thermometer and barometer are widely used for air density correction. However, this can be done using the radioactive check device with better accuracy. The measurements of air density correction were performed by using the radioactive check device, Unidos electrometer, and 0.6 cc Farmer-type ion chamber of PTW under the different environmental conditions. Above experiments were repeated with thermometer and barometer. By comparing the two methods, they were within the difference of 0.2 %. The overall uncertainty for the dose found in thermometer and barometer was 1.2 - 1.6 %, depending upon either one step or two, whereas the overall uncertainty for the radioactive check device was 1.02 %. This method may reduce the possible error which could occur when thermometer and barometer are not calibrated at regular basis.