[en] It is important to get basic data to analysis physical properties, behavior in reactor and performance of the DUPIC fuel because physical properties of the DUPIC fuel is different from the commercial UO₂ fuel. But what directly measures physical properties et al. of DUPIC fuel being resinterred simulated spent fuel through OREOX process is very difficult in laboratory owing to its high level radiation. Then fabrication of simulated DUPIC fuel is needed to measure its properties. In this study, processes on powder treatment, OREOX, compaction and sintering to fabricate simulated DUPIC fuel using simulated spent fuel are discribed. To fabricate simulated DUPIC fuel, the powder from 3 times OREOX and 5 times attrition milling simulated spent fuel is compacted with 1.3 ton/cm². Pellets are sintered in 100% H₂ atmosphere over 10 h at 1800 deg C. Sintered densities of pellets are 10.2-10.5 g/cm³

[en] The moisture separator eliminating moisture in steam generator of nuclear power plant, can be damaged by several causes. Especially, the swirl vane which is an important part of it is vulnerable to the damage. As the moisture separator of Westinghouse 'F' model is designed not to be replaced by new one, the development of repair technology is mandatory for the sake of life extension in nuclear power plant. Through the inspection of swirl vane in Kori No.2 steam generator, we found there were various failures which were mainly caused by steam erosion. In this paper, we present the repair procedure and three different repair methods according to the degree of failure

[en] This report presents the pressure drop, vibration and endurance test results for mini-plate fuel rig which were designed fabricately by KAERI. From the pressure drop test results, it is noted that the flow rate across the capsule corresponding to the pressure drop of 200 kPa is measured to be about 9.632 kg/sec. Vibration frequency for the capsule ranges from 14 to 18.5 Hz. RMS (Root Mean Square) displacement for the fuel rig is less than 14 μm, and the maximum displacement is less than 54 μm. Based on the endurance test results, the appreciable fretting wear for the DUPIC capsule was not detected. Oxidation on the support tube is observed, also tiny trace of wear between contact points observed. (author). 4 refs., 10 tabs., 45 figs

[en] An integral reactor in comparison with loop reactor is that all of major primary components are placed in reactor vessel. It is necessary of helical bending to be manufactured once-through steam generator in the integral reactor, On the other hand dimensions variation and introduced residual stress of the part of helical bend can be serious problem. We have executed the mock-up test of Titanium tube which is being considered integral steam generator for the sake of detecting the dimension variation and residual stress of bending part. In this paper, we present the bending properties of Titanium tube and applicable possibility in integral steam generator

[en] A study on induction plasma deposition with ceramic materials, yttria-stabilized-zirconia ZrO₂-Y₂O₃ (m.p. 2640 degree C), was conducted with a view of developing a new method for nuclear fuel fabrication. Before making dense pellets of more than 96%T.D., the spraying condition was optimized through the process parameters, such as chamber pressure, plasma plate power, powder spraying distance, sheath gas composition, probe position, particle size and powders of different morphology. The results with a 5mm thick deposit on rectangular planar graphite substrates showed a 97.11% theoretical density when the sheath gas flow rate was Ar/H₂ 120/20 l/min, probe position 8cm, particle size -75 μm and spraying distance 22cm by AMDRY146 powder. The degree of influence of the main effects on density were powder morphology, particle size, sheath gas composition, plate power and spraying distance, in that order. Among the two parameter interactions, the sheath gas composition and chamber pressure affects density greatly. By using the multi-pellets mold of wheel type, the pellet density did not exceed 94%T.D., owing to the spraying angle

[en] This paper presents the analysis of DUPIC fuel rods to be irradiated at HANARO reactor, using a code of FEMAXI-IV. The centerline temperature of the pellet and gap behaviour in cladding were calculated and used for the rod design. FRAPCON-III was used to analyze the thermal conductivity of pellet, which is one of the most important parameters for the analysis of the thermal behavior at in-pile, because DUPIC fuel contains many fission products. The cladding surface heat transfer coefficient was modified for simulation. The change of the inner pressure of the fuel rod during irradiation was also examined. It is concluded that ,from the simulation results, the optimal rod diameter was 250μ for case LHR 500W/cm

[en] It is important to get basic data to analysis physical properties, behavior in reactor and performance of the DUPIC fuel because physical properties, fission gas release, grain growth and et al. of the DUPIC fuel is different from the commercial UO2 fuel. But what directly measures physical properties et al. of DUPIC fuel being resinterred simulated spent fuel through OREOX process is very difficult in laboratory owing to its high level radiation. Then fabrication of simulated DUPIC fuel is needed to measure its properties. In this study, processes on powder treatment, OREOX, compaction and sintering to fabricate simulated DUPIC fuel using simulated spent fuel are discribed. To fabricate simulated DUPIC fuel, the powder from 3 times OREOX and 5 times attrition milling simulated spent fuel is compacted with 1.3 ton/cm2. Pellets are sintered in 100% H₂ atmosphere over 10 h at 1800 .deg. C. sintered densities of pellets are 10.2∼10.4 g/cm³

[en] Plasma etching process of UO₂ by using fluorine containing gas plasma is studied as a secondary fuel removal process for DUPIC (Direct Use of PWR spent fuel Into Candu) process which is taken into consideration for potential future fuel cycle in Korea. CF₄/O₂ gas mixture is chosen for reactant gas and the etching rates of UO₂ by the gas plasma are investigated as functions of CF₄/O₂ ratio, plasma power, substrate temperature, and plasma gas pressure. It is found that the optimum CF₄/O₂ ratio is around 4:1 at all temperatures up to 400 deg C and the etching rate increases with increasing r.f. power and substrate temperature. Under 150W r.f. power the etching rate reaches 1100 monolayers/min at 400 deg C, which is equivalent to about 0.5mm/min. (author)

[en] Thermal diffusivity of simulated DUPIC fuel was measured using Laser Flash Method in the temperautre range from room temperature to 1350 deg C. Density of simulated DUPIC fuel used in the measurement of thermal difusivity was 10.16 g/cm³ (94.2% of theoretical density) at room temperature and diameter and thickness were 10 mm and 1 mm, respectively. Thermal diffusivity decreased from 0.01857 cm²/s at room temperature to 0.00523 cm²/s at 1350 deg C. Thermal diffusivity of simulated DUPIC fuel and UO₂ and simulated spent fuel. The difference of thermal diffusivity between simulated DUPIC fule and UO₂ and simulated spent fuel was high and it decreased due to temperature increase

[en] Conceptual design of DUPIC irradiation pellets with double cladding was carried out. And the preliminary study of the temperature effect on the design and manufacturing parameters of DUPIC pellets through HEATING and GENGTC was performed. The analysed results of the newly designed DUPIC pellets to be irradiated in HANARO, were, 1) thermal conductivity of fuel, linear power of fuel and axial gap affected greatly the temperature of fuel, 2) thickness of sheath, gamma heating rate and thermal transfer coefficient affected little the temperature of fuel. 3) the centerline temperature calculated by HEATING was evaluated higher than that by GENGTC such presented to be desirable for using GENGTC in the view point of safety GENGTC, 4) by transient thermal analysis, after 160 seconds, the temperature of fuel reaches its equivalent temperature. (author). 3 tabs., 16 figs