• Nuclear Engineering and Technology
• /
• v.4 no.4
• /
• pp.322-326
• /
• 1972

The retention of $^{51}$ Cr was studied as chromate after dissolution of irradiated ammonium chromate with reactor exposure time and various storage time at room temperature. The annealing process of ammonium chromate depending on various storage time at room temperature follows first-order kinetics from zero time value to the pseudo-equilibrium value. The retention is increased with reactor irradiation time, also following first-order kinetics.

• Proceedings of the Korean Society of Veterinary Pathology Conference
• /
• 2004.10a
• /
• pp.19-19
• /
• 2004

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 2006.09b
• /
• pp.1239-1240
• /
• 2006

Effects of $Ag_2O$ doping on the electromagnetic properties in the BiSrCaCuO superconductors. The electromagnetic properties of $Ag_2O$ doped and undoped BiSrCaCuO superconductor were evaluated to investigate the contribution of the pinning centers to the magnetic effect. It was confirmed experimentally that a large amount of magnetic flux was trapped in the $Ag_2O$ doped sample than that in the undoped one, indicating that the pinning centers of magnetic flux are related closely to the occurrence of the magnetic effect. It is considered that the area where normal conduction takes place increases by adding $Ag_2O$ and the magnetic flux penetrating through the sample increases. The results suggested that Ag acts to increase pinning centers of magnetic flux, contributing to the occurrence of the electromagnetic properties.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2009.05a
• /
• pp.243-247
• /
• 2009

A Radioactive constraint of the nuclear fuel assembly irradiated by neutron during normal operation cycle of the nuclear power plant is typically on the order of about 3 kGy/h. In order to inspect nuclear fuel assembly using a VT (vision technology) system, the light such as halogen lamp is used. As the halogen lamp has lower color temperature than the sun light, the objects under halogen lamp illumination are seemed to be tinted with red. In this paper, high brightness LED is considered to be used as the light source of VT system. The high brightness LED, which is a key light source of the VT system, have been gamma irradiated at the dose rate of 4 kGy/h during two hours up to a total dose of 8 kGy. The radiation induced color-center in the LED housing cap made of plastics materials is observed.

• Nuclear Engineering and Technology
• /
• v.45 no.3
• /
• pp.277-294
• /
• 2013

In the early 1980s, attention focused on the possibility that pressurized thermal shock (PTS) events could challenge the integrity of a nuclear reactor pressure vessel (RPV) because operational experience suggested that overcooling events, while not common, did occur, and because the results of in-reactor materials surveillance programs showed that RPV steels and welds, particularly those having high copper content, experience a loss of toughness with time due to neutron irradiation embrittlement. These recognitions motivated analysis of PTS and the development of toughness limits for safe operation. It is now widely recognized that state of knowledge and data limitations from this time necessitated conservative treatment of several key parameters and models used in the probabilistic calculations that provided the technical of the PTS Rule, 10 CFR 50.61. To remove the unnecessary burden imposed by these conservatisms, and to improve the NRC's efficiency in processing exemption and license exemption requests, the NRC undertook the PTS re-evaluation project. This paper provides a synopsis of the results of that project, and the resulting Alternate PTS rule, 10 CFR 50.61a.

• Nuclear Engineering and Technology
• /
• v.55 no.4
• /
• pp.1210-1217
• /
• 2023

The assessment of radiation fields in the lithium loop pipes and dump tank during the operation were performed for International Fusion Materials Irradiation Facility - DEMO-Oriented NEutron Source (IFMIF-DONES) in order to obtain the radiation dose-rate maps in the component surroundings. Variance reduction techniques such as weight window mesh (produced with the ADVANTG code) were applied to bring the statistical uncertainty down to a reasonable level. The biological dose was given in the study, and potential shielding optimization is suggested and more thoroughly evaluated. The MCNP Monte Carlo was used to simulate a gamma particle transport for radiation shielding purposes for the current Li Systems' design. In addition, the shielding efficiency was identified for the Impurity Control System components and the dump tank. The analysis reported in this paper takes into account the radiation decay source from and activated corrosion products (ACPs), which is created by d-Li interaction. As a consequence, the radiation (resulting from ACPs and Be-7) shielding calculations have been carried out for safety considerations.

• Journal of the Korean Chemical Society
• /
• v.37 no.11
• /
• pp.961-966
• /
• 1993

The determination of noble metals such as Ir, Au and Ag in the ancient coins has been studied. For the measurement of the activity of $^{192}Ir,\;^{198}Au\;and\;^{110m}Ag$, radiochemical separations including solvent extraction and ion-exchange chromatography were applied to reduce the interference of high energy ${\gamma}$-ray emitted from various radionuclides with long half-life. As a results, $10^{-11}$ g/g level of Ir could be detected and it was found that the three kinds of the detection limits, i.e., critical, detection, quantitative limit, calculated by the method proposed by Currie, were enhanced. Prior to the re-irradiation with neutron, inactive carrier was added in order to determine the recovery yield of Ir in the radiochemical separation. The average recovery yields of Ir, Au and Ag in the 5 coins were 65.3%, 98.5%, 99.5%, respectively.

• Analytical Science and Technology
• /
• v.16 no.5
• /
• pp.418-425
• /
• 2003

Inorganic elemental content of bottom ash generated from municipal solid waste incinerator was determined by neutron activation analysis. Bottom ash samples were collected monthly from incinerator located in city D, strained out by the 5 mm sieve, dried by oven and pulverized by agate mortar. The samples were irradiated at NAA #1 irradiation hole in HANARO research reactor of Korea Atomic Energy Research Institute and the irradiated samples were measured by HPGe-gamma-ray spectrometer. From the activity of measured nuclides, 33 elements including As, Cr, Cu, Fe, Mn, Sb and Zn were determined applying activity creation formula and nuclear data. The quality control was conducted by simultaneous analysis with NIST standard reference materials.

• Analytical Science and Technology
• /
• v.17 no.1
• /
• pp.8-15
• /
• 2004

The detection efficiencies of the several solid track detectors were investigated for the determination of boron content in aqueous solution by using the alpha muti-Radioisotope(RI) source. Polycarbonate (Lexan and CR-39) and cellulose nitrate (CN-85 and LR-115) were selected as materials for alpha track detection of boron. Alpha muti-RI source, uranium metal particles and boron standard solution were used for alpha emission. In this study, four solid track detectors(CN-85, LR-115, Lexan and CR-39) were characterized under various etching conditions as well as neutron irradiation conditions. As a result, the CN-85 was turned out to be best to provide good efficiency among the four detectors. The selected solid track detector was utilized for the determination of trace amount of boron in aqueous sample and its results were discussed in the text.

• Korean Journal of Materials Research
• /
• v.8 no.11
• /
• pp.1020-1025
• /
• 1998

Irradiation-induced changes in mechanical properties and magnetic parameters were measured and compared to explore possible correlations for Mn-Mo-Ni low alloy steel surveillance specimens which were irradiated to a neutron fluence of $2.3\times10^{19}n/cm^2$(E>1.0MeV) in a typical pressurized water reactor environment at about $288^{\circ}C$. For mechanical property parameters, microvickers hardness, tensile and Charpy impact test were performed and Barkhausen noise amplitude, coercivity, remanence, maximum induction were measured for magnetic parameters. respectively. Results of mechanical property measurements showed an increase in yield and tensile strength, microvickers hardness. 41J indexed $RT_{NDT}$ and a decrease in upper shelf energy irrespective of base and weld metals. However, in the case of tensile properties, the changes in weld metal were negligible compared to the base metal. In the case of magnetic measurements, it is found that magnetic remanence, BN amplitude. BN energy have dropped significantly but coercivity(H,) has increased rapidly after irradiation. In this study. the measurements conducted on surveillance specimens of Mn-Mo-Ni low alloy steel showed that there were strong correlations between mechanical properties and magnetic properties.