[en] Polycrystalline samples of (Ru_0.8Nb_0.2)Sr₂(Gd_1.5-xNd_xCe_0.5)Cu₂O_z have been synthesized by a solid-state reaction route. The X-ray diffraction data revealed that the Nd solubility limit can be placed between x=0.5 and x=0.75. The superconducting transition temperature decreased with increasing Nd content, confirming that Nd entered the lattice. Room-temperature thermoelectric power measurements showed that all the samples are in the underdoped state and the partial substitution of Nd for Gd resulted in a decrease in the carrier density on the superconducting layers.

[en] The comparative analysis of fuel cycle cost for 16 equilibrium cores was performed to evaluate the fuel cycle cost depending on the combination of four different types of burnable absorbers (BAs) and feed assemblies for 18 month cycle operation of Westinghouse type 3-loop plant using 17*17 Vantage 5H fuel. The BAs considered are IFBA, Gadolinia, Erbia, and WABA and four cases of number of feed assemblies are 56, 60, 64, and 68. The optimal and practical combination of BA and number of feed assemblies is proposed. The optimum equilibrium core loading patterns for 16 cases were generated by using self-generating method and core design characteristics and the fuel cycle cost were evaluated for each loading pattern. The cycle lengths for all the cases were fixed as 480 EPFD to exclude effect of capital cost. Uranium ore cost, conversion cost, enrichment cost, fabrication cost, and back-end cycle cost were considered to evaluate fuel cycle cost. When considering the front-end cycle cost only, with the assumption of 8% discount rate, the 60 feed assemblies with using WABA case shows best result from the economic viewpoint. But the cost differences among the cases of using WABA, IFBA, and Gadolinia were negligible. And it was founded that the major factor for fuel cycle cost is BA price. In view of the core design characteristics, IFBA and Erbia were found to be more flexible than WABA and Gadolinia

[en] Polycrystalline samples of R_0.8Ca_0.2)Ba₂Cu₃O_7-z (R = Lu and Y) were synthesized by a solid-state reaction route, and the phase stabilities were examined by heating at temperatures between 800 degree C and 900 degree C in various atmospheres. A comparative analyses of the x-ray diffraction data of the (Lu_0.8Ca_0.2)Ba₂Cu₃O_7-z and (Y_0.8Ca_0.2)Ba₂Cu₃O_7-z compounds showed that the 123 phase of both compounds is stable under heating in air and O₂ of 1 atm. However, contrary to the (Y_0.8Ca_0.2)Ba₂Cu₃O_7-z compound, the Lu_0.8Ca_0.2)Ba₂Cu₃O_z compound was found to become unstable when heated in the low oxygen partial pressure below about 8 %O₂ in N₂ , Considering the instability of parent LuBa₂Cu₃O₂ compound, this result suggests that the phase stability of Lu-based 123 compounds is sensitive to both the composition and the oxygen partial pressure.

[en] To assure that the operation of the nuclear ventilation system is effective and economic, the reasonable design of system is essential. As the nuclear ventilation system has to meet the particular conditions; to keep the rooms at an below atmospheric pressure at all times and, furthermore, to maintain frequent air circulation in the rooms, the system needs the big rotating machinery. Consequently, the construction cost and the operational cost of the ventilation system is very high. For maximum function with the minimum cost, areas are to be divided into several zones depending on the level of radioactivity and the once-through air flow in the shortest route should be adopted. The pressure difference between the zones and the number of air circulations per unit time in the rooms must be reasonable, thus, the venting air volume should be of minimum. (author). 19 refs., 7 tabs., 21 figs

[en] We investigated the effect of Nb substitution for Ru on the structural and magnetic properties of (Ru_1-xNb_x)Sr₂(Sm_1.4Ce_0.6)Cu₂O_z Samples. X-ray diffraction measurements indicated that nearly single-phase samples are formed in the range from x = 0 to 1.0. The superconducting transition temperature determined from the inflection in the field-cooled magnetic susceptibility decreased only slightly from T_c = 25 K for x = 0 to T_c = 22 K for x = 1.0, in consistent with the change in room temperature thermopower of the samples. However, the Nb substitution for Ru above x 0.25 significantly suppressed the weak ferromagnetic component of the field-cooled magnetic susceptibility. It was also found that the Nb substitution for Ru results in an enhanced diamagnetic susceptibility with Nb content above x = 0.5 in both zero field-cooled and field-cooled magnetization measurements, in contrast to the behavior of the samples with x≤0.5 in which the diamagnetic susceptibility decreases as the Nb content increases.

[en] The preliminary standard design of Advanced Power Reactor 1000 (APR1000), which uses a two-loop 1000 MWe pressurized water reactor (PWR), has been developed. The APR1000 incorporates a variety of ADFs (advanced design features) from the based model of the OPR1000. 24-month cycle operation and 30% core loading of MOX (Mixed Oxide, PuO₂-UO₂) are major ADFs of APR1000, and they have been analyzed to confirm their feasibility in this study. Through the analysis, it has been confirmed that the APR1000 core designs for 24-month cycle operation and 1/3 MOX fuel loading are effective to meet the requirements on core design criteria

[en] An efficient acceleration scheme is introduced for the fine-mesh finite difference method, where the coarse-mesh finite difference method is nonlinearly coupled with the high-order finite difference representation of the neutron diffusion operator. The coarse-mesh operator is iteratively corrected such that its solution is equivalent to that of the fine-mesh operator. The correction factors are updated by using the one-node-based high order solution, not the two-node solution as in the conventional nonlinear nodal methods. The efficiency and accuracy of the new method is demonstrated over a benchmark problem (IAEA-2D), relative to a production code, VENTURE. Numerical results show that the computational speed of the new algorithm is 10 ∼ 5 times faster than that of VENTURE, without compromising the accuracy of the solution. In addition to the fast convergence, the new algorithm is easy to implement and also is highly parallel

[en] There are thousands of obsolete radium sources all over the world. But these are a threat to health and environment in many developing countries because of improperly storing and insufficient regulations related to the safe conditioning of spent sources. The long half-life of radium makes it necessary to eventually dispose of the sources in deep geological repositories. However, these will not be available for many years to come, In order to avoid accidents that can arise from improper storage, it is necessary to collect the sources and condition them for safe storage until disposal can be made. IAEA's programme for safe conditioning of spent radium sources has been used to assist developing countries in their effort to condition radium sources and render them safe for storage. This report is intended to consider the general information, manpower requirements and their qualification, role of organizations, and operational requirements including materials, consumables and equipments for safe conditioning of spent radium sources in IAEA's programme

[en] The waste inventory records such as the activities and radio- nuclides contained in the waste packages are to be submitted with the radioactive wastes packages for the final disposal. The nearly around 10,000 drums of waste stocked in KAERI now should be assayed for the preparation of the waste inventory records too. For the successive execution of the waste assay, the investigation into the present waste assay techniques and equipment are to be taken first. Also the installation of the waste assay equipment through the comprehensive design, manufacturing and procurement should be proceeded timely. As the characteristics of the KAERI-stocked wastes are very different from that of the nuclear power plant and those have no regular waste streams, the application of the in-direct waste assay method using the scaling factors are not effective for the KAERI-generated wastes. Considering for the versal conveniency including the accuracy over the wide range of waste forms and the combination of assay time and sensitivity, the TGS(Tomographic Gamma Scanner) is appropriate as for the KAERI -generated radioactive waste assay equipment

[en] The battery is widely used in industrial area as a energy storage device for uninterruptible power supply, railroad service, switchgear operation, telecommunication, and emergency lighting. A most important factor to maintain the maximum energy of battery is the level of electrolyte. There are 174 numbers of opaque batteries as the energy storage device of uninterruptible power supply to supply continuous power to radiation monitoring system in radioactive waste treatment facility. The level of electrolyte must be maintained above adequate level to keep the energy capacity of batteries. Because the batteries are opaque, it is difficult to supplement distilled water in batteries. Current flows in the electrolyte because of presence of ionic materials, but current does not flow in the distilled water because of absence of ionic materials. An automatic topping up apparatus is designed by using this property, is applied for patent, and is registered as a patent in Korea and Japan. To introduce this apparatus in Korea will help maintenance work which consumes a lot of time and cost