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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Nuclear Engineering and Technology
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Journal DOI :
Korean Nuclear Society
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Volume & Issues
Volume 40, Issue 7 - Dec 2008
Volume 40, Issue 6 - Oct 2008
Volume 40, Issue 5 - Aug 2008
Volume 40, Issue 4 - Jun 2008
Volume 40, Issue 3 - Apr 2008
Volume 40, Issue 2 - Mar 2008
Volume 40, Issue 1 - Feb 2008
Selecting the target year
THE IMPORTANCE OF PATIENT-SPECIFIC DOSE CALCULATIONS IN NUCLEAR MEDICINE
Stabin, Michael G. ;
Nuclear Engineering and Technology, volume 40, issue 7, 2008, Pages 527~532
DOI : 10.5516/NET.2008.40.7.527
As therapeutic uses of radionuclides in nuclear medicine increases, the use of patient-specific methods for calculation of radiation dose becomes more important. In this manuscript basic methods and resources for internal dose calculations are outlined, with a focus on how current changes and advances are making more accurate and detailed, patient-individualized dose calculations possible. Most current resources make use of standardized models of the human body representing median individuals, but the use of image-based and more realistic models will soon take their place, and will permit adjustments to represent individual patients and tailor therapy planning uniquely for each subject.
A SOLUTION TO THE PROBLEM WITH ABSORBED DOSE
Braby, Leslie A. ;
Nuclear Engineering and Technology, volume 40, issue 7, 2008, Pages 533~538
DOI : 10.5516/NET.2008.40.7.533
In some situations, for example at very low doses, in microbeam irradiation experiments, or around high energy heavy ion tracks, use of the absorbed dose to describe the energy transferred to the irradiated target can be misleading. Since absorbed dose is the expected value of energy per mass it takes into account all of the targets which do not have any energy deposition. In many situations that results in numerical values, in Joules per kg, which are much less than the energy deposited in targets that have been crossed by a charged particle track. This can lead to confusion about the biochemical processes that lead to the consequences of irradiation. There are a few alternative approaches to describing radiation that avoid this potential confusion. Examples of specific situations that can lead to confusion are given. It is concluded that using the particle radiance spectrum and the exposure time, instead of absorbed dose, to describe these irradiations minimizes the potential for confusion about the actual nature of the energy deposition.
PREVENTION OF CIGARETTE SMOKE INDUCED LUNG CANCER BY LOW LET IONIZING RADIATION
Sanders, Charles L. ;
Nuclear Engineering and Technology, volume 40, issue 7, 2008, Pages 539~550
DOI : 10.5516/NET.2008.40.7.539
Lung cancer is the most prevalent global cancer,
of which is caused by cigarette smoking. The LNT hypothesis has been inappropriately applied to estimate lung cancer risk due to ionizing radiation. A threshold of
for lung cancer has been observed in never smokers. Lung cancer risk among nuclear workers, radiologists and diagnostically exposed patients was typically reduced by
following exposure to <100 mSv low LET radiation. The consistency and magnitude of reduced lung cancer in nuclear workers and occurrence of reduced lung cancer in exposed non-worker populations could not be explained by the HWE. Ecologic studies of indoor radon showed highly significant reductions in lung cancer risk. A similar reduction in lung cancer was seen in a recent well designed case-control study of indoor radon, indicating that exposure to radon at the EPA action level is associated with a decrease of
in lung cancer. A cumulative whole-body dose of
gamma rays is associated with a marked decrease in smoking-induced lung cancer in plutonium workers. Low dose, low LET radiation appears to increase apoptosis mediated removal of
-particle and cigarette smoke transformed pulmonary cells before they can develop into lung cancer.
BETTER UNDERSTANDING OF THE BIOLOGICAL EFFECTS OF RADIATION BY MICROSCOPIC APPROACHES
Kim, Eun-Hee ;
Nuclear Engineering and Technology, volume 40, issue 7, 2008, Pages 551~560
DOI : 10.5516/NET.2008.40.7.551
Radiation has stochastic aspects in its generation, its choice of interaction mode during traveling in media, and its impact on living bodies. In certain circumstances, like in high dose environments resulting from low-LET radiation, the variance in its impact on a target volume is negligible. On the contrary, in low dose environments, especially when they are attributed to high-LET radiation, the impact on the target carries with it a large variance. This variation is more significant for smaller target volumes. Microdosimetric techniques, which have been developed to estimate the distribution of radiation energy deposited to cellular and subcellular-sized targets, contrast with macrodosimetric techniques which count only the average value. Since cells and DNA compounds are the critical targets in human bodies, microdosimetry, or dose estimation by microscopic approach, helps one better analyze the biological effects of radiation on the human body. By utilizing microbeam systems designed for individual cell irradiation, scientists have discovered that human cells exhibit radiosensitive reactions without being hit themselves (bystander effect). During the past 10 or more years, a new therapeutic protocol using discontinuous multiple micro-slit beams has been investigated for its clinical application. It has been suggested that the beneficial bystander effect is the essence of this protocol.
EXPERIMENTAL AND ANALYTICAL STUDIES ON THE INSTABILITY IN THE LZCS FOR CANDU REACTORS
Ji, Joon-Suk ; Lee, Kwang-Ho ; Yun, Bum-Su ; Cha, Jung-Hun ; Kim, Sang-Nyung ;
Nuclear Engineering and Technology, volume 40, issue 7, 2008, Pages 561~570
DOI : 10.5516/NET.2008.40.7.561
When reactivity insertion such as refueling occurs in CANDU reactors, the power and the water levels are tilted in the upper outer zone of the LZCS (Liquid Zone Control System) and fluctuate unstably for a certain period of time (1-5 days). The instability described above is observed in most CANDU reactors in service around the world, but its root cause is unidentified and no solutions to this problem have been established. Therefore, this study attempted to prove experimentally and analytically that the root cause lies in the hold-up of light water on the top of the TSP (Tube Support Plate) due to the mismatch between net volumetric flow rate of light water and helium crossing the narrowed porous TSP installed within the LZCS compartment. Our method was to perform a hydrodynamic simulation of in/outflow of light water and helium. Two solutions for the aforementioned instability of LZCS are suggested. One is to regulate the compartment for both inflowing helium gas and outflowing light water; the other is to enlarge the flow paths of helium and light water within TSP. The former may be applicable to nuclear reactors in service and the latter to those planned for construction.
FAST BDD TRUNCATION METHOD FOR EFFICIENT TOP EVENT PROBABILITY CALCULATION
Jung, Woo-Sik ; Han, Sang-Hoon ; Yang, Joon-Eon ;
Nuclear Engineering and Technology, volume 40, issue 7, 2008, Pages 571~580
DOI : 10.5516/NET.2008.40.7.571
A Binary Decision Diagram (BDD) is a graph-based data structure that calculates an exact top event probability (TEP). It has been a very difficult task to develop an efficient BDD algorithm that can solve a large problem since it is highly memory consuming. In order to solve a large reliability problem within limited computational resources, many attempts have been made, such as static and dynamic variable ordering schemes, to minimize BDD size. Additional effort was the development of a ZBDD (Zero-suppressed BDD) algorithm to calculate an approximate TEP. The present method is the first successful application of a BDD truncation. The new method is an efficient method to maintain a small BDD size by a BDD truncation during a BDD calculation. The benchmark tests demonstrate the efficiency of the developed method. The TEP rapidly converges to an exact value according to a lowered truncation limit.
A CONCEPTUAL STUDY OF PYROPROCESSING FOR RECOVERING ACTINIDES FROM SPENT OXIDE FUELS
Yoo, Jae-Hyung ; Seo, Chung-Seok ; Kim, Eung-Ho ; Lee, Han-Soo ;
Nuclear Engineering and Technology, volume 40, issue 7, 2008, Pages 581~592
DOI : 10.5516/NET.2008.40.7.581
In this study, a conceptual pyroprocess flowsheet has been devised by combining several dry-type unit processes; its applicability as an alternative fuel cycle technology was analyzed. A key point in the evaluation of its applicability to the fuel cycle was the recovery yield of fissile materials from spent fuels as well as the proliferation resistance of the process. The recovery yields of uranium and transuranic elements (TRU) were obtained from a material balance for every unit process composing the whole pyroprocess. The material balances for several elemental groups of interest such as uranium, TRU, rare earth, gaseous fission products, and heat generating elements were calculated on the basis of the knowledge base that is available from domestic and foreign experimental results or technical information presented in open literature. The calculated result of the material balance revealed that uranium and TRU could be recovered at 98.0% and 97.0%, respectively, from a typical PWR spent fuel. Furthermore, the anticipated TRU product was found to emit a non-negligible level of
-ray and a significantly higher level of neutrons compared to that of a typical plutonium product obtained from the PUREX process. The results indicate that the product from this conceptual pyroprocessing should be handled in a shielded cell and that this will contribute favorably to retaining proliferation resistance.
REVIEW AND COMPILATION OF DATA ON RADIONUCLIDE MIGRATION AND RETARDATION FOR THE PERFORMANCE ASSESSMENT OF A HLW REPOSITORY IN KOREA
Baik, Min-Hoon ; Lee, Seung-Yeop ; Lee, Jae-Kwang ; Kim, Seung-Soo ; Park, Chung-Kyun ; Choi, Jong-Won ;
Nuclear Engineering and Technology, volume 40, issue 7, 2008, Pages 593~606
DOI : 10.5516/NET.2008.40.7.593
In this study, data on radionuclide migration and retardation processes in the engineered and natural barriers of High-Level Radioactive Waste (HLW) repository have been reviewed and compiled for use in the performance assessment of a HLW disposal system in Korea. The status of the database on radionuclide migration and retardation that is being developed in Korea is investigated and summarized in this study. The solubilities of major actinides such as D, Th, Am, Np, and Pu both in Korean bentonite porewater and in deep Korean groundwater are calculated by using the geochemical code PHREEQC (Ver. 2.0) based on the KAERI-TDB(Korea Atomic Energy Research Institute-Thermochemical Database), which is under development. Databases for the diffusion coefficients (
values) and distribution coefficients (
values) of some radionuclides in the compacted Korean Ca-bentonite are developed based upon domestic experimental results. Databases for the rock matrix diffusion coefficients (
values) and distribution coefficients (
values) of some radionuclides for Korean granite rock and deep groundwater are also developed based upon domestic experimental results. Finally, data related to colloids such as the characteristics of natural groundwater colloids and the pseudo-colloid formation constants (
values) are provided for the consideration of colloid effects in the performance assessment.
FUZZY SUPPORT VECTOR REGRESSION MODEL FOR THE CALCULATION OF THE COLLAPSE MOMENT FOR WALL-THINNED PIPES
Yang, Heon-Young ; Na, Man-Gyun ; Kim, Jin-Weon ;
Nuclear Engineering and Technology, volume 40, issue 7, 2008, Pages 607~614
DOI : 10.5516/NET.2008.40.7.607
Since pipes with wall-thinning defects can collapse at fluid pressure that are lower than expected, the collapse moment of wall-thinned pipes should be determined accurately for the safety of nuclear power plants. Wall-thinning defects, which are mostly found in pipe bends and elbows, are mainly caused by flow-accelerated corrosion. This lowers the failure pressure, load-carrying capacity, deformation ability, and fatigue resistance of pipe bends and elbows. This paper offers a support vector regression (SVR) model further enhanced with a fuzzy algorithm for calculation of the collapse moment and for evaluating the integrity of wall-thinned piping systems. The fuzzy support vector regression (FSVR) model is applied to numerical data obtained from finite element analyses of piping systems with wall-thinning defects. In this paper, three FSVR models are developed, respectively, for three data sets divided into extrados, intrados, and crown defects corresponding to three different defect locations. It is known that FSVR models are sufficiently accurate for an integrity evaluation of piping systems from laser or ultrasonic measurements of wall-thinning defects.
TASK TYPES AND ERROR TYPES INVOLVED IN THE HUMAN-RELATED UNPLANNED REACTOR TRIP EVENTS
Kim, Jaew-Han ; Park, Jin-Kyun ;
Nuclear Engineering and Technology, volume 40, issue 7, 2008, Pages 615~624
DOI : 10.5516/NET.2008.40.7.615
In this paper, the contribution of task types and error types involved in the human-related unplanned reactor trip events that have occurred between 1986 and 2006 in Korean nuclear power plants are analysed in order to establish a strategy for reducing the human-related unplanned reactor trips. Classification systems for the task types, error modes, and cognitive functions are developed or adopted from the currently available taxonomies, and the relevant information is extracted from the event reports or judged on the basis of an event description. According to the analyses from this study, the contributions of the task types are as follows: corrective maintenance (25.7%), planned maintenance (22.8%), planned operation (19.8%), periodic preventive maintenance (14.9%), response to a transient (9.9%), and design/manufacturing/installation (6.9%). According to the analysis of the error modes, error modes such as control failure (22.2%), wrong object (18.5%), omission (14.8%), wrong action (11.1 %), and inadequate (8.3%) take up about 75% of the total unplanned trip events. The analysis of the cognitive functions involved in the events indicated that the planning function had the highest contribution (46.7%) to the human actions leading to unplanned reactor trips. This analysis concludes that in order to significantly reduce human-induced or human-related unplanned reactor trips, an aide system (in support of maintenance personnel) for evaluating possible (negative) impacts of planned actions or erroneous actions as well as an appropriate human error prediction technique, should be developed.