• Design & Manufacturing
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• 제7권1호
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• pp.7-10
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• 2013

Pencil-core dies are relatively new technology in Korea. It is not that no one had tried to make them but had failed due to lack of technologies. However, Posco TMC Co., Ltd, one of the leading die makers in the world, is capable of sophisticated dies including pencil-core dies. Spark plugs made by pencil-core dies have energy efficiency close to 100 percent, which compares to 46 percent of conventional spark plugs. Even though they are now mostly installed in LPG automobiles, more and more diesel and gasoline vehicles are adopting them. This study focuses on how to improve core shape precision using controling design and parts machining methods for pencil-core dies and productivity.

• Nuclear Engineering and Technology
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• 제56권3호
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• pp.922-932
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• 2024

This paper presents the design features and preliminary design analysis results of the Wielenga Innovation Static Salt Reactor (WISSR). The WISSR incorporates features that make it both flexible and inherently safe. It is based on innovative technology that controls a nuclear reactor by moving molten salt fuel into or out of the core. The reactor is a low-pressure, fast spectrum transuranic (TRU) burner reactor. Inherent shutdown is achieved by a large negative reactivity feedback of the liquid fuel and by the expansion of fuel out of the core. The core is made of concentric, thin annular fuel chambers containing molten fuel salt. A molten salt coolant passes between the concentric fuel chambers to cool the core. The core has both fixed and variable volume fuel chambers. Pressure, applied by helium gas to fuel reservoirs below the core, pushes fuel out of a reservoir and up into a set of variable volume chambers. A control system monitors the density and temperature of the fuel throughout the core. Using NaCl-(TRU,U)Cl₃ fuel and NaCl-KCl-MgCl₂ coolant, a road-transportable compact WISSR core design was developed at a power level of 1250 MWt. Preliminary neutronics and thermal-hydraulics analyses demonstrate the technical feasibility of WISSR.

• Nuclear Engineering and Technology
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• 제53권11호
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• pp.3528-3542
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• 2021

A detailed geometrical model of a Krško reactor core was developed using a Monte Carlo neutron transport code MCNP. The main goal of developing an MCNP core model is for it to be used in future research focused on ex-core calculations. A script called McCord was developed to generate MCNP input for an arbitrary fuel cycle configuration from the diffusion based core design package CORD-2, taking advantage of already available material and temperature data obtained in the nuclear core design process. The core model was used to calculate 3D power density profile inside the core. The applicability of the calculated power density distributions was tested by comparison to the CORD-2 calculations, which is regularly used for the nuclear core design calculation verification of the Krško core. For the hot zero power and hot full power states differences between MCNP and CORD-2 in the radial power density profile were <3%. When studying axial power density profiles the differences in axial offset were less than 2.3% for hot full power condition. To further confirm the applicability of the developed model, the measurements with in-core neutron detectors were compared to the calculations, where differences of 5% were observed.

• Nuclear Engineering and Technology
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• 제46권3호
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• pp.291-298
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• 2014

This paper concerns estimating uncertainties of the core neutronics design parameters of power reactors by direct sampling method (DSM) calculations based on the two-step McCARD/MASTER design system in which McCARD is used to generate the fuel assembly (FA) homogenized few group constants (FGCs) while MASTER is used to conduct the core neutronics design computation. It presents an extended application of the uncertainty propagation analysis method originally designed for uncertainty quantification of the FA FGCs as a way to produce the covariances between the FGCs of any pair of FAs comprising the core, or the covariance matrix of the FA FGCs required for random sampling of the FA FGCs input sets into direct sampling core calculations by MASTER. For illustrative purposes, the uncertainties of core design parameters such as the effective multiplication factor ($k_{eff}$), normalized FA power densities, power peaking factors, etc. for the beginning of life (BOL) core of Yonggwang nuclear unit 4 (YGN4) at the hot zero power and all rods out are estimated by the McCARD/MASTER-based DSM computations. The results are compared with those from the uncertainty propagation analysis method based on the McCARD-predicted sensitivity coefficients of nuclear design parameters and the cross section covariance data.

• Architectural research
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• 제8권1호
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• pp.25-36
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• 2006

Campus core is an essential element in a university's physical environment for symbolic importance of high educational philosophy as well as hierarchical significance of campus structure. Yet, as modern expansion develops into and out of campus core, a challenging design and planning problem for a growing university is how to integrate a new development into the existing core structure and how to expand the fast-growing development beyond the core while maintaining a symbiotic harmony between the campus core and the modern expansion. Such challenge addresses four design frameworks for symbiotic development of the campus core and the modern expansion: (1) building grouping with territorial proximity; (2) building design rules for form and texture; (3) open space network with pedestrian walkway; (4) use-programming for on-campus student community. This study aims to explore these issues with in-depth case study of the Princeton University campus in Princeton, New Jersey in the United States. The study concludes that the Princeton campus is a result from successful synthesis of all the complex design elements, especially in relationship between the old and the new; and adds further that the development of a modern university campus requires a comprehensive plan that takes into account the older buildings when conceiving the new in symbiotic relationship along with open space network as well as functional program distribution.

• Nuclear Engineering and Technology
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• 제31권4호
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• pp.391-400
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• 1999

A conceptual core design of the 1,300MWe KNGR (Korean Next Generation Reactor) without using soluble boron for reactivity control was developed to determine whether it is technically feasible to implement SBF (Soluble Boron Free) operation. Based on the borated KNGR core design, the fuel assembly and control rod configuration were modified for extensive use of burnable poison rods and control rods. A new fuel rod, in which Pu-238 had been substituted for a small amount of U-238 in fuel composition, was introduced to assist the reactivity control by burnable poison rods. Since Pu-238 has a considerably large thermal neutron capture cross section, the new fuel assembly showed good reactivity suppression capability throughout the entire cycle turnup, especially at BOC (Beginning of Cycle). Moreover, relatively uniform control of power distribution was possible since the new fuel assemblies were loaded throughout the core. In this study, core excess reactivity was limited to 2.0 %$\delta$$\rho$ for the minimal use of control rods. The analysis results of the SBF KNGR core showed that axial power distribution control can be achieved by using the simplest zoning scheme of the fuel assembly Furthermore, the sufficient shutdown margin and the stability against axial xenon oscillations were secured in this SBF core. It is, therefore, concluded that a SBF operation is technically feasible for a large sized LWR (Light Water Reactor).

• Nuclear Engineering and Technology
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• 제54권8호
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• pp.3085-3094
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• 2022

The design concept of a Small High-flux Multipurpose LBE(Lead Bismuth Eutectic) cooled Fast Reactor (SHMLFR) was proposed in the paper. The primary cooling system of the reactor is forced circulation, and the fuel element form is arc-plate loaded high enrichment MOX fuel. The core is cylindrical with a flux trap set in the center of the core, which can be used as an irradiation channel. According to the requirements of the core physical design, a series of physical design criteria and constraints were given, and the steady and transient parameters of the reactor were calculated and analyzed. Regarding the thermal and hydraulic phenomena of the reactor, a simplified model was used to conduct a preliminary analysis of the fuel plates at special positions, and the temperature field distribution of the fuel plate with the highest power density under different coolant flow rates was simulated. The results show that the various parameters of SHMLFR meet the requirements and design criteria of the physical design of the core and the thermal design of the reactor. This implies that the conceptual design of SHMLFR is feasible.

• 수산해양교육연구
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• 제20권2호
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• pp.184-200
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• 2008

The purpose of this paper is to develop instructional activity support model for capstone design in order for improving creative engineering education. To do this, having extracted the core idea of capstone design, and elicited core learning activity process, and grasped core supportive factors according to each core learning activity process that elicited, an improved instructional design model for capstone design was then developed through formative evaluation with respect to the draft of the instructional system development model for capstone design. As to major research methods, case analysis, requirements analysis through interview, and formative evaluation by experts were employed, and then research studies were undertaken. The formative evaluation by experts was carried out for two hours in 2007, and the experts participated in the evaluation consisted of total 6 persons: two specialists of capstone design contents, two professionals in field works, and two expert instructional designers in education engineering. Interview results had been reflected in this research when developing final instructional design model for capstone design. The core learning activity process of the final instructional design model for caption design, which developed in this research, comprises following stages: (1) Team building $\rightarrow$ (2) Integrated meeting between industry and academy $\rightarrow$ (3) Analysis of tasks $\rightarrow$ (4) Clarification of tasks $\rightarrow$(5) Seeking solutions for issues $\rightarrow$ (6) Eliciting priority of solutions $\rightarrow$ (7) Designing solutions and construction $\rightarrow$ (8) Exhibiting outcomes and presentation $\rightarrow$(9) Gaining comprehensive insights Also, in the core learning activity process, supportive factors that support implementation of each step were presented having been categorized into facilitator (teacher, and professionals in field works), learner and tool, etc.

• 한국주거학회논문집
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• 제14권2호
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• pp.63-75
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• 2003

The planning of access area, so called "core" plays an important role of planning for multifamily housing, especially multistory housing. For all possibility of various planning and design, this area has been mostly planned and designed in uniformity. And only few attempts have so far been made in studying core, on the contrary to the unit plan or plotplan. It is keenly needed to develop various skills of planning and design in this sector. The purpose of this study is to find out the usable elements of planning and design, those are correspondent to normative targets. For this end, most possible core types are classified in to three categories: circulation types in the housing block, axis types to the entrance of housing units and number of accessed housing units. And then, sizable developments for norm of core have been effectuating in view of function, relationships both with housing unit and block. Based on this classification of types and listed norm, several European examples are analyzed and evaluated by merits and demerits of their respective core types. In addition to this analysis, some adequate planning conditions, positive vs. negative types of core, and detailed planning elements are prepared with regard to the norm of core. It is noteworthy that a variety of possible core planning cases are available by means of combination of lower categories in the classified core types. It is expected that this study will render service for some helpful planning and design guide in the practice

• 한국조명전기설비학회지:조명전기설비
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• 제5권3호
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• pp.78-83
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• 1991

This study proposes a unified method to design toroidal transformer and its optimal design algorithm. This unified design method was derived from the fundamental equation of power on the basis of electromagnetic energy of a core and the definition of three parameters(K1, K2, KW) that influence the form of a core and the ratio of a core and coil. Accordingly this design method condenses the whole data for design of toroidal transformer to a standard variable which is the inner diameter of a core. The minimal cost, weight and volume values of the transformer were computed by means of the algorithm to search the optimal values of the parameters. Furthermore, through the CAD, the efficiency of this unified design method and optimal algorithm proposed in this paper was confirmed.