[en] The safety of the thermo-mechanical performance of the fuel element (UO₂) and absorber element (UO₂-Gd₂O₃) for the KSN-1000 has been evaluated. The evaluation as based on the calculation results of fuel operating temperature and cladding stress-strain. The calculation have been carried out at constant operating condition at nominal power and over power permitted from BOL to EOL in the core. The calculation results have shown that maximum pellet temperature is 2119.7^oC or about 84% of the allowable, the maximum cladding primary membrane stress is 63.5 Mpa or about 40% of the allowable stress, the maximum cladding strain range is 0.51% or about 51% of the allowable strain range, the maximum zirconium oxide thickness is 52.09 mum or about 82% of the allowable thickness, the maximum hydrogen uptake of the cladding is 354.91-ppm or about 59% of the allowable and the maximum internal gas pressure is 13.2 Mpa or about 85% of the allowable internal pressure. Based on these results it can be concluded that fuel element and the absorber element for the KSN-1000 have met the safety criteria with quite adequate margin for normal steady-state operation. (author)

[en] The comparative study on fuel cost of the NPPs proposed by Vendors in the Feasibility Study of the first NPPs in Indonesia has been performed. The fuel cost is calculated based on the levelized cost -constant money method for single fuel batch at equilibrium core condition. The sensitivity study has also been performed in order to check the effects of the dominant economic parameters on fuel cost changing. For open cycle as well as closed cycle the study results generally show that: (a) the fuel cost of the Heavy Water Reactor proposed by AECL (PHWR and CANDU3) is 6 -43% lower compared with that of the Light Water Reactor proposed by MHl/WH, NPI, WH and GE; (b) among the Light Water Reactors, SBWR and ABWR-1000 proposed by GE have a fuel cost of 15 -300/0 higher than that of PWR proposed by MHl/WH, NPI and WH; (c) PWR proposed by NPI (Siemens and Framatome) has a fuel cost of 6 -9% lower than that of PWR proposed by MHl/WH and WH; (d) for the Light Water Reactor, the fuel cost for the closed cycle is 4 -6% higher compared with that of the open cycle; and (e) fuel cost of the Light Water Reactor is more sensitive to discount rate change compared with that of the Heavy Water Reactor

[en] The study of the effect of operation cycle length on fuel cost of a light water reactor -PWR type 600 M We class has been performed. The study includes calculation of the front end material required, i.e. uranium reloading, enriched uranium, SWU and natural uranium, and levelized fuel cost as a function of cycle length and fuel bum up. The results of study show that, for the range of bum up considered, i.e. from 30 to 60 Mwd/kg U, the extension of cycle length from 12 to 18 months increases fuel cost in the range of 5 -8% and the extension of cycle length from 12 to 24 months increases fuel cost in the range of 10 -16 %. The increase of these fuel cost is mainly due to the decrease in SWU utilization in the range of 8- 14% for the extension of cycle length from 12 to 18 months and 15 -25% for the extension of cycle length from 12 to 24 months, and to the decrease in the natural uranium utilization in the range of 6- 10% for the extension of cycle length from 12 to 18 months and 11 -18% for the extension of cycle length from 12 to 24 months. However, if it is correlated with required cost for power replacement during annual outage, the extension of cycle length from 12 to 18 or 24 months will give an advantage in the average of 8% from the total fuel cost of 12 months cycle

[en] A thermomechanical model for the prediction of fission-product-induced swelling in aluminum dispersion fuels has been applied to predict the fission -product-induced swelling behavior of U₃ Si₂ dispersion fuel. The calculations were done for U₃ Si₂ 3,5 g/cm³, 20% enriched, 4,5% porosity fuel plate at four fuel irradiations temperatures, i.e., 373 K, 573 K and 673 K, respectively. The interested phenomena were focused on the solid and gas fission products and irradiation temperature effects on fuel swelling behavior. The results were shown interested phenomena. Generally, they have very similar swelling behavior initially, the swelling increases slowly, with a relatively small swelling gradient, then rapidly increase at certain fission density. Nevertheless, it might be assumed that the fuel swells stable under irradiation, especially for 373 K irradiation temperature (was able to reach 98% fuel burnup). Moreover, it has been found that until certain fission product was relatively stable and small at four irradiation temperatures, while swelling due to gas fission product was running fast and large. The swelling becomes faster and larger with increasing in irradiation temperature, Fuel recrystallization was observed at different fission density for different irradiation temperature. (author)

[en] Plenum design of the BWR fuel element-GE-P8x8R have been evaluated. The evaluation is based on the plenum capability to accommodate the fission gas Xe and Kr released from UO₂ fuel matrices; and as acceptance criteria is increasing internal pressure of the fuel element at the end of life should be not greater than pressure of the reactor core coolant system. This evaluation includes the effect of the fuel discharge burnup and the linear power to the generated internal pressure of the fuel elements. For the fuel elements operated at design conditions, I.e. the maximum fuel discharge burnup is 40 MWd/kg U and the maximum linear power is 440 W/cm, the generated internal pressure is about 5.971 Mpa or about 82.5% from the coolant system pressure (7.24 Mpa). Based on this condition, with the maximum linear power of 440 W/cm then the maximum fuel discharge burnup can be extended up to 50 MWd/kg U without changing their plenum design

[en] A computer program for steady state thermohydraulic evaluation of the straight plate fuel element for MTR has been made. The evaluation includes axial temperature distributions along the plate (I.e. coolant, surface cladding and fuel center temperature), surface cladding temperature, and heat flux for onset of nucleate boiling (ONB), pressure drops and flow rate through the coolant channel, the condition for flow instability and the critical velocity as an upper margin at which the fuel plate will not be collapse, and heat flux for the departure from nucleate boiling (DNB). The program was made based on equations recommended in the IAEA - TECDOC No. 233. A preliminary verification of the program for the RSG-GAS fuel elements showed appropriate results

[en] Recrystallization or subdivision of the original grains into fine-grained structure has been observed in high-burnup UO₂ fuels. Fuel with fine grains has potency to enhance fission gas release. Increasing of gas pressure inside the fuel rod due to fission gas release is one condition that the limit the attainable burnup level. This paper discusses the results of the study of the effect of recrystallization in high burnup UO₂ fuel on fission gas release. In this study the FASTGRASS computer code was used to predict the fission gas behavior in the fuel. In general, the result show that recrystallization causes a sharp increase of fission gas release, mainly in severe accident scenarios such as the RIA type transient. The in-reactor simulation of the PWR type-UO₂ fuel pellet (fission rate ≅ 2.03x10¹⁹ fissions/m³-s and burnup ≅ 70 MWD/kgU) shows that recrystallization, which happened in the peripheral region of fuel pellet at fractional radius of 0.9-1.0 and started at burnup of 45 MWD/kgU, gives an additional percentage of fission gas release up to 3-5 % for steady state and up to 20-25 % for RIA type-transient. (author)

[en] Coated fuel particles contained in graphite matrix are used in high temperature reactor. The main purpose of the coating layer is to retain fission products within the fuel particles. Therefore, the safety and the performance of reactor operation depend on the mechanical integrity of the coating layers. A calculation model for strength evaluation of coating layer to restrain internal gas pressure is presented in this paper. In the model, coating layer is assumed as thick walled-spherical pressure vessel, and ratio internal gas pressure and internal pressure caused the inner surface of pressure vessel wall begin to yield is used to evaluate the integrity of coating layer. Based on this model, strength evaluation of coating layers of fuel particle for High Temperature Test Reactor. (Japan) has been carried out and the result shows that the coating layers are able to restrain the build up of internal gas pressure. (author)

[en] In this study, sol-gel precipitation using external gelation for Sol Gel Microsphere Pelletization (SGMP) of UO₂ pellet for PHWR will be conducted. Suitable feed compositions along with the calcination and reduction steps of heat treatment have been chosen to optimize the properties of the dry gel microspheres. The composition in this work is viscosity 40–60 Cp, Uranyl nitrate 0.6–0.9 mol U/l, Tetrahydrofurfurilyalcohol (43–47)% volume, Polyvinyl alcohol 10–15 g/l. The feed will be heated before feeding into drop formation and gelation column that converts the feed solution into gels. The gels are then dried and heat treated at 85°C and 200°C respectively. After that the gels are calcined in O₂ at 500°C followed by reduction in H₂ and N₂ mixture at 600°C to obtain UO₂ microspheres with certain specific surface area and O/U ratio. The UO₂ microspheres are characterized with respect to the dimensions, sphericity, surface area, tap density, crush strength, and O/U ratio. The UO₂ microspheres then are pelletized in a hydraulic press to produce the green pellet densities about 55% T.D. The green pellets are sintered in H₂ and N₂ mixture at 1100°C for 6 hours. The sintered pellets are characterized with respect to the density and their microstructure. The results show that the microspheres have average size of 900 μm, tap density 1.90 g/cm³, specific surface area 6 m²/g, and crush strength 2.0 N/particle. The compaction of the microsphere gives the green density result 55% T.D at compaction pressure 300 MPa. and sintering of the green pellet give sintered density about < 90% T.D. The dimension (900 μm) and sphericity (1.10), tap density (1.9 g/cm³), O/U (2.37), specific surface area (6 m²/g), and crush strength (2.0 N/particle) of the microspheres give a better feed for direct compaction into green pellet. The use of the microsphere as compaction feed have important advantages in comparison with the use of powder metallurgical process techniques, where the dust generation and flowability problems necessitate supplementary precautions in view to minimize the exposure of personnel to radiation and this means more operation steps which complicate the process. (author)

[en] Defence-in-depth (DID) needs to be implemented not only in a nuclear power plant, but also in a non-reactor nuclear facility. The application of safety culture in a nuclear facility is one way of DID implementation. Safety culture aims at the performance of safe works, the prevention of deviation, and the accomplishment of quality operation. It is in accordance with the first level of DID concept which is the prevention of abnormal operation and failures that is done through conservative design and high quality in construction and operation. Experimental Fuel Element Installation (EFEI) is a nonreactor nuclear facility that belongs to BATAN (the National Nuclear Energy Agency of the Republic of Indonesia) that functions as its research and development facility on power reactor fuel production. The objective of safety culture implementation in the EFEI is to encourage workers to have a stronger sense of responsibility on safety and to contribute actively for its development. The enhancement of safety culture in the EFEI refers to the attributes of a strong safety culture listed in the IAEA Safety Standard Series No.GS-G-3.5 (The Management System for Nuclear Installations Safety Guide). The strategies performed were: a) Internalization of safety values through activities such as briefings, “coffee morning”, visual management, workshops, and training; b) Enhancement of leadership effectiveness through activities such as senior management visits, safety leadership training, and personnel qualification training; c) Integration of safety into all work processes through activities such as setting up HIRADC (hazard identification, risk assessment, and determining controls) documents, setting up WHA (workplace hazard assessment), and routine housekeeping; d) Learning about safety through activities such as occupational health and safety inspections, safety self-assessments, open reporting on safety incidents, and participation in the FINAS (fuel incident notification and analysis system); e) Enhancement of safety performance accountability through activities such as ensuring open and timely reporting to the regulatory agency, evaluation of the SPI (safety performance indicators), and defining clear roles and responsibilities for each worker. (author)