[en] The CF value of 190.96 of was obtained from the surveillance test data of the first to the fifth for Kori-1 power plant. Using this value the RT_PTS was estimated that the screening value will reach at the 27.93 EFPY before expected EOLE (End of Licence Extension). Because this value cannot satisfied the limit of EOLE for Kori-1, the precise re-assessment of integrity of RPV is needed to extend the period of operation using the advanced fracture mechanics instead of the CVN method. The master curve method studied at KNPP and BVPS-1, whose RPVs have problem of low RT_PTS like Kori-1, was investigated. The RT_PTS of Kori-1 RPV was anticipated using the data and concepts of the master curve method used in KNPP RPV assessment. The anticipated RT_PTS at 32 EFPY is about 288 .deg. F, which is lower value than the screening temperature proposed in regulation. But, the margin to the screening temperature is not so much as expected value before investigation

[en] Most of significant defects in the pressure boundaries of nuclear power plant were disposition to be monitored periodically every inservice inspection. Due to the difficulty of the defect sizing during operation, it is necessary to develop the continuous flaw monitoring techniques. The Tip Diffraction method, specifically speaking, spot seems to be suitable for flaw monitoring. The optimum conditions of selecting the transducer were 3.5 MHz and 45-57 degree according to compatibility with the defect height. The effective calculation of the defect height was to assume the fact that the incident beam is parallel. This method would be supplemented to ASME method about the defect characterization for the surface flaw

[en] Transferrin receptors (Tf-R) were expressed on the surfaces of cancer cells. In cancer cells that are rapidly proliferating, transferrin receptors are upregulated due to the need for increasing non-hem iron to catalyze the first and rate-limiting step of DNA synthesis. Therefore transferrin (Tf) is thought to be a major ligand to find cancer cells. In this study, we investigated the targetability of Tf conjugated compounds to Tf-R expressed on cancer cells for detection and diagnosis and the usefulness of gamma probe-targeting delivery system on monitoring whether the gene complex bind to the cells specifically. For the detection and diagnosis of Tf-R positive cancer cells, Tf-chitosan conjugates were synthesized as previously described by Kircheis et al with some modifications. Succinimidyl 6-hydrazino nicotinate hydrochloride (HYNIC) was bound to Tf-chitosan conjugates. HYNlC-Tf-chitosan conjugates were labelled with 99m Tc. For tumor model, 5- to 6-week-old female BALB/c nude mice were injected subcutaneously in the left thigh with Ramos cells (human Burkitt's lymphoma). The gamma imagings were acquired after administration of Tc-99m Tf-chitosan conjugates. To compare the image acquired with HYNIC-Tf conjugate, Ga-67 study was performed. Radiolabeling yields of both Tf-chitosan conjugates was above 90% until 12hr. Uptake in the Ramos model of Tc-99m Tf-chitosan conjugate showed higher than those of Ga-67. A few minutes after injection Tc-99m Tf-chitosan conjugate localized mainly in the circulation (heart), kidneys, and tumor. At 24hr after injection, tumor to nontumor ratio of Ga-67 was approximately 4, but those of Tc-99m Tf-chitosan conjugate showed until 5 only 2 hr after injection. Using Tc-99m Tf-chitosan conjugate, transferrin binding to transferrin receptor on tumor cell could be seen in vivo

[en] Irradiation-induced changes in the magnetic parameters and mechanical properties of a reactor pressure vessel (RPV) Linde80 high copper weld were measured and compared to explore possible correlations between the measurements. The specimens employed in the present study were obtained from a RPV surveillance program. The material was tested in the unirradiated and two different post-irradiation conditions(Irr. I: 1.23 x 10¹⁹ n/cm², Irr. II: 3.94 x 101⁹ n/cm² , E>1.0 MeV, 288□). Saturation magnetization (M_s), remanence (M_r), coercivity (H_c), and Barkhausen noise amplitude (BNA) were measured for magnetic parameters, and Vickers microhardness tensile and Charpy impact tests were performed for mechanical property parameters. After irradiation, hysteresis loops appeared to turn clockwise, resulting in an increase in H_c, and BNA appeared to decrease after irradiation while all the mechanical property changes followed the same trend as previously observed for low copper weld. Again, although limited, H_c and BNA were confirmed to be viable magnetic parameters that can be used in monitoring the mechanical parameter changes due to neutron irradiation. (author)

[en] Stress analysis has been performed using computer program ANSYS in the pressurizer surge line in order to predict possibility of crack generation due to thermal stratification phenomena in pipes connected to reactor coolant system of Nuclear power plants. Highly vulnerable area to crack generation has been chosen by the analysis of fatigue due to thermal stress in pressurizer surge line. This kind of result can be helpful to choose the location requiring intensive care during inservice inspection of nuclear power plants.

[en] Crack detection technique by ultrasonics in structures and components made of austenitic stainless steel often loses its reliability due to the material characteristics during inservice inspection of nuclear power plants, especially in the area of detection and sizing in centrifugally cast stainless steel pipings. In order to understand and overcome this problem, computer program for tracing the ultrasonic rays within material has been developed to simulate the process of defect detection within weld. The program simulates through transmission and reflection technique in crack detection of austenitic stainless steel as well as ultrasonic beam propagation through multiple media including stainless steel cladding interface

[en] The asialoglycoprotein receptor (ASGP-R) is expressed on liver hepatocytes. Chitosan conjugates of galactose have shown to be specifically taken up by liver parenchymal cells via ASGP-R. In this study, Tc-99m hydrazino nicotinamide (HYNIC)-galactosylated chitosan (HYNIC-GC) was synthesized and evaluated as a targeted agent for the imaging of hepatocytes. GC was obtained after coupling of lactobionic acid as the galactose moiety and coupled with HYNIC. HYNIC-GC was radiolabeled with Tc-99m using stannous chloride and tricine as reducing agent and coligand respectively. Hepatic uptake property of Tc-99m HYNIC-GC was studied in female Balb/C mouse. Tc-99m HYNIC--GC and Tc-99m HYNIC-Chitosan as a control were intravenously injected into mice. Receptor binding was identified by coinjection with 50 mM and 80mM free galactose respectively. Biodistribution was determined at three different time points. The level of galactose substitution was 7.6%. Labeling efficiency was >90% both in vitro and serum up to 24 h. Tc-99m HYNIC-GC injected via tail vein of mice showed high selectivity of liver. On the other hands, Tc-99m HC without galactose group showed low uptake (Fig. 1A, 1B). Hepatic uptake of Tc-99m HYNIC-GC was dramatically blocked by 50 mM and 80 mM free galactose coinjection (Fig. 1C, 1D). The liver accumulated about 14 percent injected dose per gram (%ID/g) up to 120 min after injection. Tc-99m HYNIC-GC showed specific and rapid targeting to liver. It is a promising specific radiopharmaceutical with potential applications in the imaging of liver parenchymal cells

[en] The comparison and analysis of flaw detectability, flaw sizing methods and allowable criteria in accordance with the applicable codes, ASME and RCC-M Code, in ultrasonic examination of pressure vessel in nuclear power plants were studied. According to the codes, calibration blocks were made. The artificial flaws such as disc and band types in test specimens were machined. They were detected and evaluated with etch code requirements and measured values were compared with the actual flaws

[en] Stress analysis has been performed using computer program ANSYS in the pressurizer surge line in accordance with ASME Sec. III in order to predict possibility of fatigue failure due to thermal stratification phenomena in pipes connected to reactor coolant system of nuclear power plants. Highly vulnerable area to crack generation has been chosen by the analysis of fatigue due to thermal stress in pressurizer surge line. This kind of result can be helpful to choose the location requiring intensive care during inservice inspection of nuclear power plants

[en] The effect of ultrasonic search units on the detectability and size evaluation of planar flaws was studied for thicker ferritic material using the technique of the DAC curve and reference level. Cylindrical holes were used as calibration reflectors. The planar flaws such as disc and band types were machined. They were detected and evaluated with different search units and sizing criteria. The value evaluated was compared with the actual dimension of planar flaws