[en] The final goal of this project is to obtain assessment data and evaluation technology for long-term geochemical behavior of radionuclides in multi-barriers in the near-field of repository. To achieve the goal, the geochemical behavior of radionuclides was evaluated due to changes in the groundwater and minerals, and the geochemical behavior of solute was evaluated based on KURT. The alteration of disposal containers, buffer materials, and bedrock were assessed considering evolution of disposal environment in the near-field, and the evaluation data on geochemical reaction with radionuclides were established to reduce uncertainty about the safety assessment of deep geological disposal. In the field of evaluating the spent nuclear fuel dissolution considering the disposal environment, the reaction of spent nuclear fuel matrix(UO2) and groundwater were evaluated and a congruent release source-term model was developed that could be considered for geochemical factors. In the field of evaluation of radionuclide reaction with canister corrosion products, the ability of corrosion products to sorb radionuclides is excellent in reducing environment, and in particular, highly mobile raionuclides such as iodine were captured and crystallized, resulting in retardation. In the field of evaluation of nuclide reaction with buffer, mineralogical and geochemical properties of Kyungju Bentonite were comprehensively analyzed and characteristic data on pore water of bentonite were obtained. The migration/retardation of radionuclides in bentonite due to changes in the geochemical environment were analyzed and the effects of geochemical factors on the retardation of radionuclides were also evaluated. In the field of evaluation of solute behavior based on KURT, water-rock-radionuclide reaction expeirment were conducted under high temperature/high pressure simulating disposal environments. Through this, the alteration of buffer and rock in the near-field and the migration/retardation characteristics of radionuclides were evaluated. In addition, we develop a geochemical evolution model for the prediction of geochemical behavior of radionuclides. The findings of this work are expected to be used as scientific technical data on the long-term safety of the sub-branch by predicting the geochemical behavior of radionuclide in the disposal environment

[en] Due to development of electronics, computer and information communication engineering, instrumentation and control system is developing to innovative improvement. High integrated system technologies of computer, communication and control are applied to Modern I and C system. But conservative I and C system related to nuclear power plant is currently introducing the new technique. Industrial analog equipment have already been replaced with digital equipment but some analog equipment is recently changing to digital equipment in a nuclear power plant. It is very important for nuclear power plant digital I and C system to act to designed functions and performance under the environment during a life cycle. In spite of merit of digital equipment, it is necessary for digital I and C system to be confirmed to operate functionally under the electromagnetic environment and to obtain electromagnetic environment qualification. To overcome electromagnetic interference, designers should consider the electromagnetic compatibility about digital I and C system and test the digital I and C system according to Regulatory Guide 1.180 or EPRI-TR-102323. Regulatory Guide 1.180 endorsed IEEE-STD-518, 665, 1050 covering EMC design and test procedure and applied limit according to MIL-STD-461C/D. To design nuclear power plant digital I and C system conform to EMI regulatory guide, when device, board, rack and cabinet of I and C system are designed and installed, designer should consider EMI counterpart technique. EMI counterpart technique based on IEEE-STD-518, 665, 1050 is specified about grounding, shielding, filtering, cabling and bonding

[en] Some fundamental problems associated with implementing the ICRP 60 to the radiation protection practices were discussed. The concept of effective dose are plausible one, but difficulties are involved in the determination of the dosimetric quantity in practice. Obstructions are expected in the uses of the dose conversion factors for internal exposure mainly due to the complexity. Subjective nature influences an attempt to evaluate the monetary coefficient of dose for quantitative optimization, which causes discrepancies in the resulting monetary coefficients. Particularly, the amount of money spent by the operators of nuclear power plants appeared to be far above the theoretical alpha values in most cases. (author)

[en] Structural, dielectric and piezoelectric properties of (1-x)(Na_1/2Bi_1/2)TiO₃-xPb(Mg_1/3Nb_2/3)O₃ (NBT-xPMN) solid solution have been investigated. An addition of PMN into NBT transformed the structure of sintered samples from rhombohedral to pseudocubic phase where x is larger than 0.1. In calcined powders, however, the intermediate structure were observed between rhombohedral and cubic phases near x=0.1. The formation of solid solution between NBT and PMN modified the dielectric and piezoelectric properties of NBT to be suitable for high temperature dielectric and piezoelectric material. With increasing the content of PMN, the temperature-stability of ε_r(T) increased and the high temperature dielectric loss decreased. In addition, the piezoelectric property of NBT-xPMN was enhanced, for the decrease of coercive field and conductivity promoted the domain reversal under the high electric field of the poling process

[en] In this report, we investigated kinematic motion coupling problems where the length or tension of a cable is changed due to another link's motions and we also analyzed the conventional joint decoupling configurations for cable-driven manipulators. To maintain the cable length constant regardless of the rotation of the arm, we present a structural decoupling mechanism for a cable-driven manipulator. In case of an elbow joint design, we used a novel joint decoupling mechanism where a moving pulley which actively compensates for a motion interference. For a wrist joint design, we optimized the geometrical parameters of the cable-pulley configurations. As for a shoulder joint, we adopted motion decoupled structures where an upper arm a roll and forearm pitch motion are performed in a differential driving manner. Designed motion decoupled cable driven mechanism prevents an unintended malfunction of the manipulator, and it also increases the durability of the power transmission elements of the manipulator

[en] Korean adult male voxel phantom were constructed by processing whole-body MR images of healthy volunteer who belongs to middle group of Korean male in height and weight. Organs and tissues on tomographic images were manually segmented and indexed using a graphic digitizer. Due to limited resolution of the raw MR images, voxels of rather large size, 2mmx2mmx10mm were used. The resulting voxel phantom was named KRMAN. The air kerma-to-organ equivalent doses and effective doses conversion coefficients were evaluated for phantom in broad parallel photon fields of different energies and directions and were compared to corresponding values given in ICRP 74 which were derived with the MIRD-type phantoms. No significant deviations between MIRD and voxel phantoms were found in the effective doses. Significant differences up to around factor of 2, however, were observed in organ equivalent doses for some organs including stomach, thyroid, testes depending on the photon energy and the irradiation direction. These are caused by difference in trunk thickness between MIRD-type phantom and Korean voxel phantom, and differences of organ positions in the body

[en] Trunk voxel phantom was constructed by using whole body CT images and tumor doses were calculated by using Monte Carlo method after simulating situation of radiotheraphy treatment planning. The whole body CT images of VHP (Visual Human Project) man were acquired from National Library of Medicine of USA. 153 slices of trunk part were extracted from whole body CT images and MCNP4B, a general purpose Monte Carlo code, was used for dose calculation. Gray scale of CT images were converted into density of medium and processed into trunk voxel phantom ported to MCNP4B input deck. The conversion method was verified by comparing cross sectional images of voxel phantom with original CT images. Tumor volumes with diameter of 3 cm were defined in liver, stomach and right lung and irradiated with 5, 10 and 15 MeV gamma beam with diameter of 6 cm. The technical basis for 3D dose calculation was established through this study for localization of 3D RTP system

[en] Tumor and normal tissue doses in boron neutron capture therapy were calculated by using Korean adult female voxel phantom KRWOMAN. The phantom was constructed by processing whole-body MR images of healthy Korean female volunteer. Organs and tissues on MR images were manually segmented and indexed using a graphic digitizer. Due to limited resolution of the raw MR images, voxels of 4mm x 4mm x 8mm were used. Test tumor in the center of brain of KRWOMAN was defined, and tumor and normal tissue dose in BNCT were evaluated using general-purposed Monte Carlo code, MCNP4B. Fundamental dose calculation system in radiation therapy including BNCT was established in this study and more application to another radiation therapy will be done using the methodology

[en] Due to the arrangement of major components within the reactor vessel, the integral reactor has relatively long distance between the core support barrel and the reactor vessel when compared with the currently operating plants. So, a neutron flux leakage at the ex-vessel represents a relatively low flux level which may generate some difficulties in obtaining a wide range of neutron flux information including the source range one. This fact may have an impact upon the design and fabrication of an ex-core neutron flux detector. Therefore, it is required to study neutron flux detectors that are suitable for the installation location and characteristics of an integral reactor. The physical constraints of an integral reactor should be considered when one designs and develops the ex-core neutron flux monitoring detectors and their systems. As a possible installation location of the integral reactor ex-core neutron flux detector assembly, two candidate locations are considered, that is, one is between the core support barrel and the reactor vessel and the other is within the Internal Shielding Tank(IST). And, for these locations, some factors such as the environmental requirements and geometrical restrictions are investigated In the case of considering the inside of the IST as a ex-core neutron flux detector installation position, an electrical insulation problem and a low neutron flux measurement problem arose and when considering the inside of the reactor vessel, a detector's sensitivity variation problem, an electrical insulation problem, a detector's insertion and withdrawal problem, and a high neutron flux measurement problem were encountered. Through a survey of the detector installation of the currently operating plants and detector manufacturer's products, the proposed structure and specifications of an ex-core neutron flux detector are suggested. And, the joint ownership strategy for a proposed detector model is also depicted. At the end, by studying the ex-core neutron flux monitoring systems of the currently operating plant and the specific design problems of an integral reactor, the functional and performance requirements of integral reactor are defined, and simultaneously, a proposed system interface and cabinet structure are suggested

[en] This study describes a practical method for interpretation of bioassay results of inhaled uranium to assess the committed effective doses both for chronic and acute intake situations. Organs in the body were represented by a series of mathematical compartments for analysis of the behavior of uranium in the body according to the gastrointestinal track model, respiratory track model and biokinetic model recommended by the ICRP. An analytical solutions of the system of balance equations among the compartments were obtained using the Birchall's algorithm, and the urinary excretion function and the lung retention function of uranium were obtained. An initial or total intakes by intake modes were calculated by applying excretion and retention functions to the urinary uranium concentration and the lung burden measured with a lung counter. The dose coefficients given in ICRP 78 are used to estimate the committed effective doses from the calculated intakes