[en] Surface modification of minerals using organosilanes has been studied for a variety of applications. Our current interest is (1) to investigate the structure, formation, and properties of organic modified, layered aluminosilicate minerals, and (2) to develop the methods to encapsulate hazardous metals (e.g. Cu, Ni and Pb) in organic modified minerals for environmentally safe storage. The organic modified minerals are prepared by the reactions of the mineral with a series of organosilanes (RSiCl₃, R=alkyl or phenyl groups) in organic solvents. The physical and chemical properties of the prepared hydrophobic materials, characterized by elemental analysis, thermogravimetric analysis, surface area measurement, ¹³C NMR, X-ray powder diffraction and X-ray absorption spectroscopy, will be presented

[en] Based on the fuel assembly mechanical design experience and the review results on the foreign advanced nuclear fuel and the foreign patents of the spacer grid, various kinds of spacer grid candidates are derived. In order to compare the mechanical/structural performance of the derived candidates, some mechanical/structural screening tests, such as, F-δ characteristic test and fretting wear test on the spacer grid springs, buckling/impact characteristic test on the 5x5 array partial spacer grid assemblies, and fuel rod support/vibration characteristic test, are performed. As a result of the screening test on the spacer grid candidates, a leading candidate of the spacer grids is selected

[en] Technical part Li ion battery market is explosively growing in the world. And then, the acquisition of technologies and patents for Li ion batteries is considered as one of the important issues in the world. Economical/Industrial parts Li ion batteries have been considered as the best candidate of energy storage system for large scale application such as electric vehicles as well as small devices such as cellular phones. It is expected that Li ion battery market size grows dramatically each year. Ⅲ. Scope and Contents of Project 1. Research scope The structural information of electrode materials for ion batteries is calculated using Rietveld refinement with neutron/X-ray diffraction. Their thermal stability is measured using in situ high temperature X-ray diffraction. Ⅳ. Result of Project 1. Research results Using Rietveld refinement with neutron diffraction, we calculated Li-Ni site mixing in NCM 811 which is well known as one of the best cathode materials for Li ion batteries. Maximum entropy method (MEM) showed us the possibility of fast Li diffusion in NCM 811. And, we developed a novel cathode material Na7V3(P2O7)4 with high operation potential and excellent cyclability for the first time using Rietveld refinement with neutron/X-ray diffraction and first principle calculation.

[en] Worldwide R and D trends related to core technology of LWR fuels and status of patents have been surveyed for the feasibility study. In addition, various fuel cycle schemes have been studied to establish the target performance parameters. For the development of cladding material, establishment of long-term research plan for alloy development and optimization of melting process and manufacturing technology were conducted. A work which could characterize the effect of sintering additives on the microstructure of UO₂ pellet has been experimentally undertaken, and major sintering variables and their ranges have been found in the sintering process of UO₂-Gd₂O₃ burnable absorber pellet. The analysis of state of the art technology related to flow mixing device for spacer grid and debris filtering device for bottom nozzle and the investigation of the physical phenomena related to CHF enhancement and the establishment of the data base for thermal-hydraulic performance tests has been done in this study. In addition, survey on the documents of the up-to-date PWR fuel assemblies developed by foreign vendors have been carried out to understand their R and D trends and establish the direction of R and D for these structural components. And, to set the performance target of the new fuel, to be developed, fuel burnup and economy under the extended fuel cycle length scheme were estimated. A preliminary study on the failure mechanism of CANDU fuel, key technology and advanced coating has been performed. (author). 190 refs., 31 tabs., 129 figs

[en] Newly developed PWR nuclear fuel should received massive out-of-pile tests for verifying its performances prior to in-pile reactor evaluation. KAERI constructed the test facility, called the Fuel Assembly Mechanical Characterization Tester (FAMeCT), to carry a series of static and dynamic mechanical tests to determine the structural characteristics of the nuclear fuel on a full size model basis. These test series cover vibration, impact and stiffness characteristic tests in air. To setup the test procedure and methodology, the stripped fuel bundle without fuel rods or more commonly referred to as a 'grid cage' has been tested in air, room temperature for estimating the lateral vibration characteristics using a sine swept testing. Due to the highly nonlinear behavior of the structure, these characteristics were to be determined over a certain range of the excitation amplitude and frequency. The test grid cage is initially pre-loaded at the begin of life time (BOL) hot condition by the deflection of the upper core plate simulator. Different preloading condition (360 lbs release from the BOL condition) is also applied for an evaluation of the preload effect. The test results will also be used to verify future finite element models and as base data for further experimental and theoretical analysis

[en] The objective of the irradiation test of DUPIC fuel at HANARO is to obtain the data of in-core behavior and evaluate the nuclear, thermal and mechanical performance of DUPIC fuel. The irradiation of DUPIC fuel will start at April 25, 2000 for about 2 months, and the burnup of 2,000 MWD/MTU will be attained for this period. The pre-irradiation examinations for DUPIC fuel, such as visual inspection, dimension measurement, He leak test and microstructure observation, was carried out. The post-irradiation examination items for the irradiated DUPIC fuel are planned to be the NDA test, visual inspection and dimension measurement, as well as the analyses for the fission gas release, the microstructure of pellets and the distribution and shape of imbedded nuclides. The DUPIC mini-elements were fabricated in the DFDF (IMEF M6 cell) using the G23-G2 rod. For the HANARO core calculation, the initial composition of DUPIC fuel was estimated using ORIGEN-2 code based on the burnup history of the G23-G2 rod. The design features of DUPIC pellets, the mini-element and the irradiation capsule, were supplemented considering the characteristics of DUPIC fuel and the results from the irradiation test of the simulated DUPIC fuel performed in 1999. The nuclear, thermohydraulic and mechanical characteristics of DUPIC fuel under the normal operation condition were evaluated for the safety analysis on the HANARO. Using these results, potential accidents initiated by DUPIC fuel were estimated, and Safety analyses on the locked rotor and RIA accidents were carried out in order to assess the integrity of DUPIC fuel under the accident condition initiated by the HANARO. Based on the results of these safety analyses, the supplemental countermeasures for securing the sufficient thermal margins were set up, as well. At the last, similar overseas and domestic cases were introduced

[en] Space grid in LWR fuel assembly is a key structural component to support fuel rods and to enhance heat transfer from fuel rod to the coolant. Therefore, the original spacer grid has been developed. In addition, new phenomena in fuel behavior occurs at the high burnup, so that models to analyze those new phenomena were developed. Results of this project can be summarized as follows. - Seven different spacer grid candidates have been invented and submitted for domestic and US patents. Spacer grid test specimen(3x3 array and 5x5 array) were fabricated for each candidate and the mechanical tests were performed. - Basic technologies in the mechanical and thermal hydraulic behavior in the spacer grid development are studied and relevant test facilities were established - Fuel performance analysis models and programs were developed for the high burnup pellet and cladding, and fuel performance data base were compiled - Procedures of fuel characterization and in-/out of-pile tests were prepared - Conceptual design of fuel rod for integral PWR was carried out. (author)

[en] The objectives of the project is to establish the performance evaluation system for the experimental verification of DUPIC fuel. The scope and content for successful accomplishment of the phase 1 objectives is established as follows : irradiation test of DUPIC fuel at HANARO using a noninstrument capsule, study on the characteristics of DUPIC pellets, development of the analysis technology on the thermal behaviour of DUPIC fuel, basic design of a instrument capsule. The R and D results of the phase 1 are summarized as follows : - Performance analysis technology development of DUPIC fuel by model development for DUPIC fuel, review on the extendability of code(FEMAXI-IV, FRAPCON-3, ELESTRESS). - Study on physical properties of DUPIC fuel by design and fabrication of the equipment for measuring the thermal property. - HANARO irradiation test of simulated DUPIC fuel by the noninstrument capsule development. - PIE and result analysis

[en] Project of the Atomic Energy Technology Record is the project that summarizes and records whole process, from the background to the performance, of each category in all fields of nuclear science technology which have been researched and developed at KAERI. This project includes development of Data And Documents Advanced Management System(DADAMS) to collect, organize and preserve various records occurred in each research and development process. In addition, it means the whole records related to nuclear science technology for the past, present and future. This report summarizes research contents and results of 'Project of Atomic Energy Technology Record'. Section 2 summarizes the theoretical background, the current status of records management in KAERI and the overview of this project. And Section 3 to 6 summarize contents and results performed in this project. Section 3 is about archiving of core atomic energy technology, Section 4 summarizes about the operation of DADAMS, Section 5 summarizes about collecting, organizing and digitalizing of research records and Section 6 summarizes about the construction of Atomic Energy Larchiveum.

[en] A shape optimal design method is adopted for a spacer grid strap. It is made of punched sheet metal process, functioning as springs and dimples supporting fuel rods. For stress analysis of the assembled fuel rod support, a typical cell out of the repeated pattern in the assembly is modeled using 4-node shell elements. A commercial code, ABAQUS, is used for detailed stress analysis. For the optimization, design variables are taken from geometric parameters representing the shape of the bent leaf spring part. Objective function is considered in relation to mechanical functions. Maximum von- Mises stress is also considered