[en] The structures of new spiroxazine derivatives containing a megogenic group attached to 9-position of the naphthoxazine ring was synthesized and characterized by their photo- and thermochromic properties and the intrinsic liquid crystal behavior. All of these derivatives showed the reversible photo- and thermochromism near the melting temperature and only one derivative demonstrated quasi-liquid crystalline behavior. The structural changes as increasing the sample temperature were monitored by FT-IR. The photochromic response of visible absorption at 575 and 606 nm upon 365-nm irradiation was also monitored by UV-Vis absorption spectroscopy. DSC data showed that compound 1 demonstrated a phase transition at near 65 deg. C during cooling and heating cycle followed by the iso-melting process. Furthermore, polarizing microscopic study and X-ray diffraction (XRD) measurement indicated that compound 1 demonstrated Schlieren texture and nematic liquid crystalline characteristics with one-directional isotropic alignment

[en] Measurement of the natural frequencies for the fuel assembly mock-up of HANARO reactor, which is a research reactor operating in KAERI, wa implemented. There are two types of the fuel assembly model, one is 18-element fuel bundle assembly and the other is 36-element one. They were locked inside the shell type flow tubes, respectively. The flow tube (round flow tube) corresponding to the 18-element fuel assembly mock-up has a form of cylindrical shell and the tube (hexagonal flow tube) to the 36-element fuel assembly model does hexagonal shell. The in-air fundamental natural frequency of the round flow tube was turned out to be 54 Hz and the in-water one 26 Hz. The in-air fundamental natural frequency of the hexagonal flow tube resulted as 58.5 Hz and the in-water one was reduced to 29 Hz due to added mass effect. Also the in-air fundamental natural frequency of the 18-element fuel assembly structure (fuel assembly and round flow tube) was found to be 26 Hz and the in-water one 16 Hz. Finally the in-air frequency of the 36-element fuel assembly one (fuel assembly and hexagonal flow tube) was estimated as 28 Hz, and in-water one 11 Hz. (author). 3 refs., 2 tabs., 45 figs

[en] This study is carried out by KAERI(Korea Atomic Energy Research Institute) to construct the basic facilities for development and production of medical radioisotope. For the characteristics of radiopharmaceuticals, the facilities should be complied with the radiation shield and GMP(Good Manufacturing Practice) guideline. The KAERI, which has carried out the research and development of the radiopharmaceuticals, made a design of these facilities and built them in the HANARO Center and opened the technique and facilities to the public to give a foundation for research and development of the radiopharmaceuticals. In the facilities, radiation shielding utilities and GMP instruments were set up and their operating manuals were documented. Every utilities and instruments were performed the test to confirm their efficiency and the approval for use of the facilities will be achieved from MOST(Ministry of Science and Technology). It is expected to be applied in development of therapeutic radioisotope such as Re-188 generator and Ho-166, as well as Tc-99m generator and Sr-89 chloride for medical use. And it also looks forward to the contribution to the related industry through the development of product in high demand and value

[en] Fission Mo-99 is the only parent nuclide of Tc-99m, an extremely useful tool for mdeical diagnosis, with an estimated usage of greater than 80% of nuclear medicine applicatons. HEU and LEU targets to optimize in HANARO irradiation condition suggested and designed for domestic production of fission Mo-99. The optimum process conditions are established in each unit process to meet quality requirements of fission Mo-99 products, and the results of performance test in combined process show Mo separation and purification yield of the above 97%. The concept of Tc generator production process is established, and the result of performance test show Tc production yield of 98.4% in Tc generator procuction process. The drafts is prepared for cooperation of technical cooperation and business investment with foreign country. Evaluation on economic feasibility is accompanied for fission Mo-99 and Tc-99m generator production

[en] This R and D project is planed to supply domestic demands of Mo-99 through fission route, and consequently this project will be expected to rise up utilization of HANARO and KAERI's capability for marketing extension into domestic and oversea radiopharmaceutical market. HEU and LEU target types are decided and designed for fission Mo-99 production in domestic. Experimental study of target fabrication technology was performed and developed processing equipments. And conceptual design of target loading/unloading in/from HANARO device are performed. Tracer test of Mo-99 separation and purification process was performed, test results reach to Mo-99 recovery yield above 80% and decontamination factor above 1600. Combined Mo-99 separation and purification process was decided for hot test scheduled from next year, and performance test was performed. Conceptual design for modification of existing hot cell for fission Mo-99 production facility was performed and will be used for detail design. Assumption for the comparison of LEU and HEU target in fission Mo-99 production process were suggested and compared of merits and demerits in view of fabrication technology and economy feasibility

[en] The design study for the KALIMER upper internal structure (UIS) and reactor refueling system has been described. Two distinct features are plug-in UIS and extended refueling outage. For the UIS system, the functional, structural and material requirements have been determined and the accommodation approaches to meet these functional requirements described. For the refueling system, the functional, structural, process and I and C (Instrument and Control) requirements have been established and the accommodation approaches for the functional and process requirements described. The impact on plant availability due to extension of the refueling outage has also been investigated. The accommodation approaches for UIS system show that the design concept of the system will satisfy the functional requirements with a few design issues to be resolved, such as UIS plug in/out handling system and cask design. It is also shown that the functional and process requirements of the refueling system are achievable with the design of the IVTM cask and related transfer system and the extended refueling outage has little effect (within 1%) on the plant availability if extra refueling time do not exceed 1 week. 1 refs. (Author)

[en] In this research, the CFD simulations were performed with the commercial Fluent CFD package by Ansys Inc. The results from simulations were also compared to the experiments and other simulations. The results show similar trends to the other simulations but it seems that additional mesh and time step dependency tests should be proceeded. The debris bed itself is an exact feature of two-phase flow in porous media. Therefore, in the early years, researchers had tried to figure out frictional force of two phase flow in porous media, which lead to the 1-D analytical model to evaluate dry-out heat flux(DHF) in porous debris bed. However, for the last decay, it is revealed that even very small amount of liquid inflow into debris bed from bottom or side of debris bed could extend the limitation of cooling dramatically (down comer paper). Therefore, the requirements have risen to evaluate the realistic cooling limit of debris bed with consideration of lateral water inflow. In the sense, multi-dimensional CFD simulations has been tried recently. In this research, we developed user defined function in Fluent 15.0 to simulate ex-vessel debris bed coolability. The user defined functions are verified by 1-D analytic models and they shows good agreements in terms of its dry out condition and liquid saturation profiles. Following validation processes with 2D geometry with COOLOCE-10 experiments are also conducted and the Fluent calculations show similar trends to the experiments and previous simulations in literature with MEWA code

[en] It is important to ensure the coolant ingression into the internally heat generated debris bed which is governed by pressure drop in debris bed to assure the long-term cooling of debris bed on the cavity floor. For this reason, it is necessary to understand the pressure drop mechanism in porous bed that can be characterized by physical parameters that include porosity, particle morphology, particle size distribution etc. According to previous investigations on molten fuel coolant interaction (FCI) experiment, the settled particulate debris bed after fuel-coolant interaction were stratified and it was composed of multi-sized particles with irregular shape. (Karbojian et al., 2009; Magallon, 2006). Among these characteristics of debris bed, this study focused on the effect of particle size distribution on frictional pressure drop in bed. The experiment using single-phase water was conducted to investigate the effect of spherical particle size distribution on frictional pressure drop in mixed bed. This study reports the experimental data for measured frictional pressure drops in bed according to the particle Reynolds number. It is composed of multi-sized spherical particles whose sizes are varied from 1 mm to 10 mm. Besides, the experimental data is compared to the Ergun equation with the mean particle diameters (mass, area, length, and number mean diameters). The results of this study are also compared to those of KTH published in 2011. The conclusions are summarized as follows. The calculated mean particle diameters can be changed according to chosen particle sizes and those mass fractions even though the cumulative mass fractions are almost similar trend. As results of obtaining the effective diameter in mixed using measured frictional pressure drops and the Ergun equation, it is close to the length mean diameter when the particle Reynolds number is lower than 7, however, it has the value between the length mean diameter and the area mean diameter when the particle Reynolds number is higher than 7. It is contrast to the results of KTH that the area mean diameter is more suitable at the lower particle Reynolds number and the length mean diameter is well predict frictional pressure drops after the particle Reynolds number is higher than 7

[en] To ensure the long-term cooling of corium in the reactor cavity, it is important to ensure the coolant ingression into the internally heat generated corium debris bed which is governed by pressure drop in porous media. For this reason, it is necessary to understand pressure drop mechanisms in porous bed to verify the feasibility of water penetration into particulate debris bed. According to the previous investigations on molten fuel-coolant interaction (FCI) experiments, it was found that quenched particulate debris bed was composed of irregular shape particles. Therefore, empirical or semiempirical models based on the Ergun equation (Ergun, 1952) for single-phase flow in porous media composed of single sized spherical particle were developed to consider the effect of particle shape on frictional pressure drop by means of adding a shape factor or modifying the Ergun constants etc. (Leva, 1959, Handley and Heggs, 1968, Macdonald, 1979, Foumeny et al., 1996). An experimental investigate on single-phase frictional pressure drop of water in packed bed was conducted in the transparent cylindrical test section with the inner diameter of 100 mm and the height of 700 mm to study the effect of particle shape on frictional pressure drop in porous media. This paper reports the experimental data for spherical particles with the diameter of 2 mm and 5 mm and cylindrical particles with ED of 2 mm and 5 mm. And also, the experimental data compared with the models to predict frictional pressure drop in particulate bed. The conclusions are summarized as follows. As a result of the experiment to measure frictional pressure drop in particulate bed composed of cylindrical particles the models predict the experimental data well within 22.11 % except the Handley and Heggs model when ED is applied to the models

[en] The vibration characteristics of Ulchin 3 reactor internals and the natural vibration modes of the fuel assembly have been extracted through reactor noise analysis by using the ex-core and in-core neutron signals which are close to each other. As a result, the fundamental bending mode frequency of the reactor internal structure is found to be around 8 Hz and the fundamental shell mode frequency 14.5 Hz, respectively. It is also shown that the fundamental bending mode frequency of the fuel assembly is 2.3 Hz and the 2^nd bending mode frequency 5.8 Hz, respectively. These results can be used for the supplements of the Korean standard PWR's CVAP (Comprehensive Vibration Assessment Program) data