[en] The objective of this study is to help the general public and local residents to better understand and trust nuclear safety regulation. In order to obtain public confidence in nuclear safety regulation, the emotion and demand of public should be first understood and the change in an attitude to meet the present circumstances actively is requisite. Hence it is intended that a genuine communication shall be newly arranged and accomplished on the basis of mutual understanding. To achieve this, a series of public opinion poll have performed periodically and symposium for the public acceptance is held in order to frame a policy based on the understanding of nuclear safety and regulation of the general public and local residents. Besides nuclear safety indicators including safety sentiment indicators are being developed as a means to understand the safety of operating nuclear power plants from the viewpoint of the general public, a plan for the harmonious communication of nuclear safety information is established, and handbooks of nuclear terminologies and report-writing are under development in part. Finally plans for convergence of the public opinions and a wide public involvement in nuclear safety regulation are formulated and their applicability as organization and administration program is now under consideration

[en] Two exposed K-type microthermocouples (Hot Wire-type and Conical Tip-type) were fabricated. Dynamic response time was measured by Laser technique and an algorithm was developed to determine local phase temperatures. Signals from a single electrical conductivity probe were compared to those of mocrothermocouples simultaneously. Geometric conditions such as wire diameter, features of sensing part effected dynamic characteristics of thermocouples seriously. The Conical Tip-type microthermocouple was proved to be more available than the former

[en] Multidimensional thermal-hydraulic code calculations are necessary to predict complex thermal-hydraulic phenomena within the downcomer during LBLOCA calculation. The main objective of present study is to evaluate the TRACE code capability with DVI related Upper Plenum Test Facility Data, which is on the developing by US-NRC. Another objective is to develop the APR-1400 plant standard input deck preparing the LBLOCA calculation using TRACE code. TRACE input decks for UPTF Test 6,7,21 was developed and TRACE code was evaluated with theses input decks. The result of comparison on lower plenum penetration rate with data showed that TRACE code predict reasonable lower plenum penetration rate. On the calculation of Test 21(Run 272) and Test 5(Run 062), high subcooled water is injected, TRACE code overprediced the bypass rate. Analysis showed that the condensation model in TRACE code overpredict the condensation of steam within upper downcomer region. It is identified that the condensation model in TRACE code needs improvement. TRACE code input deck for APR-1400 was developed and preliminary LBLOCA case was calculated. The result was very sensitive to its input deck change in terms of peak cladding temperature. it showed that the quality assurance during input deck development is crucial especially in the best estimate thermal-hydraulic calculation

[en] Nuclear safety concern, which may accompany such external environmental factors as privatization and restructuring of the electric power industry, is emerging as an international issue. In order to cope with the concern about nuclear safety, it is important to feedback valuable experiences of advanced countries which ever restructured their electric power industries earlier and further to reflect the current safety issues, which are raised internationally, fully into the nuclear safety regulatory system. This paper is to review the safety issues that might take place in the process of increasing competition in the nuclear power industry, and further to present a basic direction and effective measures for ensuring nuclear safety in response thereto from the viewpoint of safety regulation. It includes a political direction for regulatory body's efforts to rationalize and enforce efficiently its regulation. It proposes to ensure that regulatory specialty and regulatory cost are stably secured. Also, this paper proposes for maintaining a sound nuclear safety regulatory system to monitor thoroughly the safety management activities of the industry, which might be neglected as a result of focusing on reduction of the cost for producing electric power

[en] The surface electronic structure of 1500 ?A thick Fe3O4(100) films has been investigated by spinresolved photoemission spectroscopy with vacuum ultra-violet (VUV) synchrotron radiation. The films, epitaxially grown on MgO(100) substrates using plasma assisted molecular beam deposition, are briefly exposed to air during transfer to the photoemission chamber. It is shown that clean surfaces of Fe3O4 films after exposure to air can be recovered through mild annealing in an oxygen atmosphere. The presence of the characteristic Verwey transition, as detected in the valence band photoemission spectra, provides evidence for the excellent electronic quality at the surface of these films. The top of the valence band is found to be negatively spin-polarized, with a value of ∼ ?50%; this result strongly points towards the localized nature of the 3d states in this system

[en] In this 3 year phases, we developed and implemented educational training programs for international nuclear personnel based on our accumulated experience in the field of international nuclear education and training. Based on the demand for human resource development in developing countries, 12 new international curricula have been developed and implemented over the fast 3 years from 2018 to 2020. In particular, the Nuclear Training and Education Center(NTC) successfully completed its first project with the United Nations Development Program(UNDP) in 2020 by conducting an e-learning fellowship in the field of electronic beam accelerators. Furthermore, it was an opportunity to overcome the inherent limitations of the NTC and amplify the organization's capabilities by designing and implementing international education and training courses through exploring new training areas and applying innovative methods. As a result, a total of 309 trainees were turned out by conducting 19 training courses, through KAERI strength technology, international organization cooperation, and technology donation programs for three years from 2018 to 2020. In 2020, the number of participants was the lowest in three years as the education programs were reduced or changed due to the COVID-19 crisis. The development and improvement of course design for 17 courses have been carried out in accordance with the IAEA Systematic Approach to Teaching(SAT). During this phase, the foundation has been built for improving the quality of nuclear international curriculum by applying ISO 29990 for practical application of curriculum standard procedures

[en] The pressurizer in/outsurge transients, which was not evaluated in the stage of the design analysis, have been occurred during the reactor coolant system(RCS) heatup and cooldown operations. When the temperature difference between the RCS and the pressurizer is large, these in/outsurges can additonally produce the significant thermal fatigue transients in the pressurizer lower head and affect the structural integrity of the pressurizer. This study provides the concerns to the application of the technical specification, the evaluation method of the pressurizer structural integrity, and the operational strategies to mitigate the effects for the pressurizer in/outsurge transients. And, this study reviewed the plant procedures and purposed the operational strategies for mitigating the pressurizer in/outsurge transients

[en] For the efficient propulsion of the future nuclear system development long-term plan, it is needs to establish and implement of detailed plan. For satisfying the needs, the followings were carried out. - Analysis of domestic trends in developing the nuclear technology for the future nuclear system; - Analysis of the present condition and prospect on the future nuclear system - Collection of the opinions from the relevant internal grue. As a result, this study established the detailed plan of the sodium-cooled fast reactor, very high temperature reactor and pyroprocessing technology

[en] Korea has participated in the international collaboration programs for the development of future nuclear energy systems driven by the countries holding advanced nuclear technology and Korea and U.S. have cooperated in the INERI. This study aimed mainly at developing the plan for participation in the collaborative development of the Gen IV, searching the participation strategy for INERI and the INPRO, and the international cooperation in these programs. Contents and scope of the study for successful achievement are as follows; Investigation and analysis of international and domestic trends related to advanced nuclear technologies, Development of the plan for collaborative development of the Gen IV and conducting the international cooperation activities, Support for the activities related to I-NERI between Korea and U.S. and conducting the international cooperation, International cooperation activities for the INPRO. This study can be useful for planning the research plan and setting up of the strategy of integrating the results of the international collaboration and the domestic R and D results by combining the Gen IV and the domestic R and D in the field of future nuclear technology. Futhermore, this study can contribute to establishing the effective foundation and broadening the cooperation activities not only with the advanced countries for acquisition of the advanced technologies but also with the developing countries for the export of the domestic nuclear energy systems

[en] The purpose of this study is to establish the overall nuclear regulatory technical requirement structure, which is comparable to the International Rule and trends to the future demand. The report begins with the assessment of the status and structures of the nuclear regulatory requirements of Korea, the United States of America, Canada, Japan, Germany, France, and IAEA. Then, the domestic regulatory technical requirement structures of the non-nuclear fields are evaluated. Based on the results of evaluation, the problems and the preliminary direction to the development of the overall hierarchy of the nuclear regulatory requirements are suggested